Lecturio Medical Knowledge Essentials – Aortic Dissection

Authors: Ahmed Elsherif ¹ ; Michelle Wyatt ²
Peer Reviewers: Stanley Oiseth ³ ; Joseph Alpert ⁴
Affiliations: ¹ Suez Canal University; ² Medical Editor at Lecturio; ³ Chief Medical Editor at Lecturio; ⁴ Tucson University, Arizona

This article is not intended to substitute for professional medical advice and should not be relied on as health or personal advice. Always seek the guidance of your doctor or other qualified health professional with any questions you may have regarding your health or a medical condition.

Definition

An aortic dissection Aortic dissection Aortic dissection occurs due to shearing stress from pulsatile pressure causing a tear in the tunica intima of the aortic wall. This tear allows blood to flow into the media, creating a “false lumen.” Aortic dissection is most commonly caused by uncontrolled hypertension. Aortic Dissection ( AD AD The term advance directive (AD) refers to treatment preferences and/or the designation of a surrogate decision-maker in the event that a person becomes unable to make medical decisions on their own behalf. Advance directives represent the ethical principle of autonomy and may take the form of a living will, health care proxy, durable power of attorney for health care, and/or a physician’s order for life-sustaining treatment. Advance Directives) occurs due to longitudinal cleavage of the medial layer of the vessel wall, creating a false lumen False lumen Aortic Dissection in the aorta Aorta The main trunk of the systemic arteries. Mediastinum and Great Vessels: Anatomy. It is a surgical emergency Surgical Emergency Acute Abdomen as the dissection causes reduced blood flow Blood flow Blood flow refers to the movement of a certain volume of blood through the vasculature over a given unit of time (e.g., mL per minute). Vascular Resistance, Flow, and Mean Arterial Pressure to vital organs. In severe cases, the aorta Aorta The main trunk of the systemic arteries. Mediastinum and Great Vessels: Anatomy can rupture and be fatal.

Aortic dissection Aortic dissection Aortic dissection occurs due to shearing stress from pulsatile pressure causing a tear in the tunica intima of the aortic wall. This tear allows blood to flow into the media, creating a “false lumen.” Aortic dissection is most commonly caused by uncontrolled hypertension. Aortic Dissection is classified among acute aortic syndromes (AASs), a group of severe conditions affecting the thoracic and abdominal aorta Abdominal Aorta The aorta from the diaphragm to the bifurcation into the right and left common iliac arteries. Posterior Abdominal Wall: Anatomy that often present urgently and require immediate surgical evaluation. These syndromes, which include aortic dissection Aortic dissection Aortic dissection occurs due to shearing stress from pulsatile pressure causing a tear in the tunica intima of the aortic wall. This tear allows blood to flow into the media, creating a “false lumen.” Aortic dissection is most commonly caused by uncontrolled hypertension. Aortic Dissection, intramural hematoma Intramural hematoma Dissection of the Carotid and Vertebral Arteries, penetrating atherosclerotic ulcer, and traumatic AD AD The term advance directive (AD) refers to treatment preferences and/or the designation of a surrogate decision-maker in the event that a person becomes unable to make medical decisions on their own behalf. Advance directives represent the ethical principle of autonomy and may take the form of a living will, health care proxy, durable power of attorney for health care, and/or a physician’s order for life-sustaining treatment. Advance Directives, are potentially life-threatening and typically manifest with aortic discomfort. AASs are characterized by a shared spectrum of signs and symptoms, with aortic pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways being the most notable.[26]

Epidemiology

Aortic dissection Aortic dissection Aortic dissection occurs due to shearing stress from pulsatile pressure causing a tear in the tunica intima of the aortic wall. This tear allows blood to flow into the media, creating a “false lumen.” Aortic dissection is most commonly caused by uncontrolled hypertension. Aortic Dissection ( AD AD The term advance directive (AD) refers to treatment preferences and/or the designation of a surrogate decision-maker in the event that a person becomes unable to make medical decisions on their own behalf. Advance directives represent the ethical principle of autonomy and may take the form of a living will, health care proxy, durable power of attorney for health care, and/or a physician’s order for life-sustaining treatment. Advance Directives) is an infrequent occurrence, with new cases reported at 2–3.5 per 100,000 people every year. It is more common in men (65%) than women and is often associated with hypertension Hypertension Hypertension, or high blood pressure, is a common disease that manifests as elevated systemic arterial pressures. Hypertension is most often asymptomatic and is found incidentally as part of a routine physical examination or during triage for an unrelated medical encounter. Hypertension.
The age of presentation of AD AD The term advance directive (AD) refers to treatment preferences and/or the designation of a surrogate decision-maker in the event that a person becomes unable to make medical decisions on their own behalf. Advance directives represent the ethical principle of autonomy and may take the form of a living will, health care proxy, durable power of attorney for health care, and/or a physician’s order for life-sustaining treatment. Advance Directives depends on underlying risk factors. Age, male sex Sex The totality of characteristics of reproductive structure, functions, phenotype, and genotype, differentiating the male from the female organism. Gender Dysphoria, and hypertension Hypertension Hypertension, or high blood pressure, is a common disease that manifests as elevated systemic arterial pressures. Hypertension is most often asymptomatic and is found incidentally as part of a routine physical examination or during triage for an unrelated medical encounter. Hypertension confer the most significant risks in adults over 40, but genetic connective tissue Connective tissue Connective tissues originate from embryonic mesenchyme and are present throughout the body except inside the brain and spinal cord. The main function of connective tissues is to provide structural support to organs. Connective tissues consist of cells and an extracellular matrix. Connective Tissue: Histology diseases increase the risk of AD AD The term advance directive (AD) refers to treatment preferences and/or the designation of a surrogate decision-maker in the event that a person becomes unable to make medical decisions on their own behalf. Advance directives represent the ethical principle of autonomy and may take the form of a living will, health care proxy, durable power of attorney for health care, and/or a physician’s order for life-sustaining treatment. Advance Directives in younger patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship. It is more common in the African American population than whites, similar to hypertension Hypertension Hypertension, or high blood pressure, is a common disease that manifests as elevated systemic arterial pressures. Hypertension is most often asymptomatic and is found incidentally as part of a routine physical examination or during triage for an unrelated medical encounter. Hypertension, and Asians have the lowest incidence Incidence The number of new cases of a given disease during a given period in a specified population. It also is used for the rate at which new events occur in a defined population. It is differentiated from prevalence, which refers to all cases in the population at a given time. Measures of Disease Frequency. Dissections in younger individuals ages 30 – 40 are usually associated with genetic or connective tissue Connective tissue Connective tissues originate from embryonic mesenchyme and are present throughout the body except inside the brain and spinal cord. The main function of connective tissues is to provide structural support to organs. Connective tissues consist of cells and an extracellular matrix. Connective Tissue: Histology diseases such as Marfan syndrome Marfan syndrome Marfan syndrome is a genetic condition with autosomal dominant inheritance. Marfan syndrome affects the elasticity of connective tissues throughout the body, most notably in the cardiovascular, ocular, and musculoskeletal systems. Marfan Syndrome.[4,5]

Etiology

Acquired Causes — Risk Factors [6]

• Hypertension Hypertension Hypertension, or high blood pressure, is a common disease that manifests as elevated systemic arterial pressures. Hypertension is most often asymptomatic and is found incidentally as part of a routine physical examination or during triage for an unrelated medical encounter. Hypertension 
• Atherosclerosis Atherosclerosis Atherosclerosis is a common form of arterial disease in which lipid deposition forms a plaque in the blood vessel walls. Atherosclerosis is an incurable disease, for which there are clearly defined risk factors that often can be reduced through a change in lifestyle and behavior of the patient. Atherosclerosis
• Blunt chest trauma Blunt chest trauma Blunt chest trauma is a non-penetrating traumatic injury to the thoracic cavity. Thoracic traumatic injuries are classified according to the mechanism of injury as blunt or penetrating injuries. Different structures can be injured including the chest wall (ribs, sternum), lungs, heart, major blood vessels, and the esophagus. Blunt Chest Trauma (e.g., motor vehicle accidents Motor Vehicle Accidents Spinal Cord Injuries, though they are usually deceleration Deceleration A decrease in the rate of speed. Blunt Chest Trauma injuries that more commonly cause a complete aortic transection or iatrogenic Iatrogenic Any adverse condition in a patient occurring as the result of treatment by a physician, surgeon, or other health professional, especially infections acquired by a patient during the course of treatment. Anterior Cord Syndrome trauma (during catheterization or intra-aortic balloon pump Pump ACES and RUSH: Resuscitation Ultrasound Protocols counterpulsation)
• Pregnancy Pregnancy The status during which female mammals carry their developing young (embryos or fetuses) in utero before birth, beginning from fertilization to birth. Pregnancy: Diagnosis, Physiology, and Care, especially in the third trimester and in the postpartum period Postpartum period In females, the period that is shortly after giving birth (parturition). Postpartum Complications [7,8]
• Syphilis Syphilis Syphilis is a bacterial infection caused by the spirochete Treponema pallidum pallidum (T. p. pallidum), which is usually spread through sexual contact. Syphilis has 4 clinical stages: primary, secondary, latent, and tertiary. Syphilis (tertiary stage) with aortic involvement due to vasculitis Vasculitis Inflammation of any one of the blood vessels, including the arteries; veins; and rest of the vasculature system in the body. Systemic Lupus Erythematosus
• Amphetamines Amphetamines Analogs or derivatives of amphetamine. Many are sympathomimetics and central nervous system stimulators causing excitation, vasopressin, bronchodilation, and to varying degrees, anorexia, analepsis, nasal decongestion, and some smooth muscle relaxation. Stimulants and cocaine Cocaine An alkaloid ester extracted from the leaves of plants including coca. It is a local anesthetic and vasoconstrictor and is clinically used for that purpose, particularly in the eye, ear, nose, and throat. It also has powerful central nervous system effects similar to the amphetamines and is a drug of abuse. Cocaine, like amphetamines, acts by multiple mechanisms on brain catecholaminergic neurons; the mechanism of its reinforcing effects is thought to involve inhibition of dopamine uptake. Local Anesthetics use
• Cardiac surgery Cardiac surgery Cardiac surgery is the surgical management of cardiac abnormalities and of the great vessels of the thorax. In general terms, surgical intervention of the heart is performed to directly restore adequate pump function, correct inherent structural issues, and reestablish proper blood supply via the coronary circulation. Cardiac Surgery—especially aortic valve replacement Aortic valve replacement Aortic Stenosis, since aortic regurgitation Regurgitation Gastroesophageal Reflux Disease (GERD) can cause dilatation and aortic wall weakening [10]

Congenital Causes Congenital causes Malformations of organs or body parts during development in utero. Spinal Stenosis

• Genetic disease/ connective tissue Connective tissue Connective tissues originate from embryonic mesenchyme and are present throughout the body except inside the brain and spinal cord. The main function of connective tissues is to provide structural support to organs. Connective tissues consist of cells and an extracellular matrix. Connective Tissue: Histology abnormalities that affect the aorta Aorta The main trunk of the systemic arteries. Mediastinum and Great Vessels: Anatomy; affects the structure and function of connective tissue Connective tissue Connective tissues originate from embryonic mesenchyme and are present throughout the body except inside the brain and spinal cord. The main function of connective tissues is to provide structural support to organs. Connective tissues consist of cells and an extracellular matrix. Connective Tissue: Histology/ proteins Proteins Linear polypeptides that are synthesized on ribosomes and may be further modified, crosslinked, cleaved, or assembled into complex proteins with several subunits. The specific sequence of amino acids determines the shape the polypeptide will take, during protein folding, and the function of the protein. Energy Homeostasis (e.g., collagen Collagen A polypeptide substance comprising about one third of the total protein in mammalian organisms. It is the main constituent of skin; connective tissue; and the organic substance of bones (bone and bones) and teeth (tooth). Connective Tissue: Histology and elastin) in the walls of the aorta Aorta The main trunk of the systemic arteries. Mediastinum and Great Vessels: Anatomy — Marfan syndrome Marfan syndrome Marfan syndrome is a genetic condition with autosomal dominant inheritance. Marfan syndrome affects the elasticity of connective tissues throughout the body, most notably in the cardiovascular, ocular, and musculoskeletal systems. Marfan Syndrome (more likely to be proximal dissections), Ehlers-Danlos syndrome Ehlers-Danlos syndrome Ehlers-Danlos syndrome (EDS) is a heterogeneous group of inherited connective tissue disorders that are characterized by hyperextensible skin, hypermobile joints, and fragility of the skin and connective tissue. Ehlers-Danlos Syndrome [9]
• Turner syndrome Turner syndrome Turner syndrome is a genetic condition affecting women, in which 1 X chromosome is partly or completely missing. The classic result is the karyotype 45,XO with a female phenotype. Turner syndrome is associated with decreased sex hormone levels and is the most common cause of primary amenorrhea. Turner Syndrome (due to aortic root dilatation)
• Bicuspid aortic valve Aortic valve The valve between the left ventricle and the ascending aorta which prevents backflow into the left ventricle. Heart: Anatomy increases the chance of ascending aortic dissection Ascending aortic dissection Aortic Dissection.
• Coarctation of the aorta Aorta The main trunk of the systemic arteries. Mediastinum and Great Vessels: Anatomy

High-yield Facts

• 70 % or more of patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship with AD AD The term advance directive (AD) refers to treatment preferences and/or the designation of a surrogate decision-maker in the event that a person becomes unable to make medical decisions on their own behalf. Advance directives represent the ethical principle of autonomy and may take the form of a living will, health care proxy, durable power of attorney for health care, and/or a physician’s order for life-sustaining treatment. Advance Directives have hypertension Hypertension Hypertension, or high blood pressure, is a common disease that manifests as elevated systemic arterial pressures. Hypertension is most often asymptomatic and is found incidentally as part of a routine physical examination or during triage for an unrelated medical encounter. Hypertension. 
• Hypertension Hypertension Hypertension, or high blood pressure, is a common disease that manifests as elevated systemic arterial pressures. Hypertension is most often asymptomatic and is found incidentally as part of a routine physical examination or during triage for an unrelated medical encounter. Hypertension is more common in those with distal (type B) dissection compared to type A. 

Classification

There are several systems of classification for aortic dissection Aortic dissection Aortic dissection occurs due to shearing stress from pulsatile pressure causing a tear in the tunica intima of the aortic wall. This tear allows blood to flow into the media, creating a “false lumen.” Aortic dissection is most commonly caused by uncontrolled hypertension. Aortic Dissection based on anatomy or duration of onset of symptoms.

Stanford Classification Stanford classification Aortic Dissection

Mnemonic:
Stanford A = affects ascending aorta
Stanford B = begins beyond brachiocephalic vessels

The Stanford classification Stanford classification Aortic Dissection is the most commonly used in aortic dissection Aortic dissection Aortic dissection occurs due to shearing stress from pulsatile pressure causing a tear in the tunica intima of the aortic wall. This tear allows blood to flow into the media, creating a “false lumen.” Aortic dissection is most commonly caused by uncontrolled hypertension. Aortic Dissection.

Note: The 301 Classification modifies the Stanford Type B Aortic Dissection Aortic dissection Aortic dissection occurs due to shearing stress from pulsatile pressure causing a tear in the tunica intima of the aortic wall. This tear allows blood to flow into the media, creating a “false lumen.” Aortic dissection is most commonly caused by uncontrolled hypertension. Aortic Dissection classification to improve prognostication for thoracic endovascular aortic repair (TEVAR). It introduces three subtypes (B1, B2, B3) based on anatomical and clinical features, which helps in better risk stratification and management, with types B2 and B3 associated with higher risks for adverse events post-TEVAR. [28]

DeBakey system

In contrast, the DeBakey system is based on anatomy:

Pathophysiology

In patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship with AD AD The term advance directive (AD) refers to treatment preferences and/or the designation of a surrogate decision-maker in the event that a person becomes unable to make medical decisions on their own behalf. Advance directives represent the ethical principle of autonomy and may take the form of a living will, health care proxy, durable power of attorney for health care, and/or a physician’s order for life-sustaining treatment. Advance Directives, blood enters the intima from the media layers. The high pressure exerted by blood tears the media apart in a laminated plane. The plane is usually between the inner 2/3rds and the outer 1/3rd. The dissection can extend proximally or distally for variable Variable Variables represent information about something that can change. The design of the measurement scales, or of the methods for obtaining information, will determine the data gathered and the characteristics of that data. As a result, a variable can be qualitative or quantitative, and may be further classified into subgroups. Types of Variables distances and establishes a connection between the media and intima through a false lumen False lumen Aortic Dissection. [13]

Most dissections originate in the ascending aorta Ascending aorta Mediastinum and Great Vessels: Anatomy, usually within 10 cm of the aortic valve Aortic valve The valve between the left ventricle and the ascending aorta which prevents backflow into the left ventricle. Heart: Anatomy. These tears are commonly 1–5 cm long and are transverse or oblique in orientation Orientation Awareness of oneself in relation to time, place and person. Psychiatric Assessment, with rough edges.

• Antegrade dissection — spreads towards the iliac bifurcation and sometimes all the way down to the iliac and femoral arteries Arteries Arteries are tubular collections of cells that transport oxygenated blood and nutrients from the heart to the tissues of the body. The blood passes through the arteries in order of decreasing luminal diameter, starting in the largest artery (the aorta) and ending in the small arterioles. Arteries are classified into 3 types: large elastic arteries, medium muscular arteries, and small arteries and arterioles. Arteries: Histology
• Retrograde dissection — spreads towards the aortic root and heart

Sometimes, the dissection can spread through the intima, media, and adventitia causing external rupture. This results in huge internal bleeding or cardiac tamponade Tamponade Pericardial effusion, usually of rapid onset, exceeding ventricular filling pressures and causing collapse of the heart with a markedly reduced cardiac output. Pericarditis if the dissection extends through the adventitia but into the pericardial sac, forming a hemopericardium. Both scenarios are life-threatening and can rapidly lead to death.

When the blood enters the intima and tears through the media, it creates a false lumen False lumen Aortic Dissection. The true lumen True lumen Aortic Dissection is the natural physiological lumen of the vessel. In between both of these lumens is a layer of intima which is known as the intimal flap. As stated above, the false lumen False lumen Aortic Dissection may recanalize into the true lumen True lumen Aortic Dissection.

There are different types of aortic dissection Aortic dissection Aortic dissection occurs due to shearing stress from pulsatile pressure causing a tear in the tunica intima of the aortic wall. This tear allows blood to flow into the media, creating a “false lumen.” Aortic dissection is most commonly caused by uncontrolled hypertension. Aortic Dissection. The majority originate in the ascending aorta Ascending aorta Mediastinum and Great Vessels: Anatomy, about 10% in the aortic arch Aortic arch Mediastinum and Great Vessels: Anatomy, and 15% in the descending thoracic aorta Aorta The main trunk of the systemic arteries. Mediastinum and Great Vessels: Anatomy (distal to the ligamentum arteriosum Ligamentum arteriosum Prenatal and Postnatal Physiology of the Neonate).[12]

The reason an intimal tear occurs is unknown. It can occur due to intimal ischemia Ischemia A hypoperfusion of the blood through an organ or tissue caused by a pathologic constriction or obstruction of its blood vessels, or an absence of blood circulation. Ischemic Cell Damage from increased shear forces due to hypertension Hypertension Hypertension, or high blood pressure, is a common disease that manifests as elevated systemic arterial pressures. Hypertension is most often asymptomatic and is found incidentally as part of a routine physical examination or during triage for an unrelated medical encounter. Hypertension or genetic connective tissue Connective tissue Connective tissues originate from embryonic mesenchyme and are present throughout the body except inside the brain and spinal cord. The main function of connective tissues is to provide structural support to organs. Connective tissues consist of cells and an extracellular matrix. Connective Tissue: Histology diseases such as Marfan syndrome Marfan syndrome Marfan syndrome is a genetic condition with autosomal dominant inheritance. Marfan syndrome affects the elasticity of connective tissues throughout the body, most notably in the cardiovascular, ocular, and musculoskeletal systems. Marfan Syndrome. In patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship with Marfan syndrome Marfan syndrome Marfan syndrome is a genetic condition with autosomal dominant inheritance. Marfan syndrome affects the elasticity of connective tissues throughout the body, most notably in the cardiovascular, ocular, and musculoskeletal systems. Marfan Syndrome, the collagen Collagen A polypeptide substance comprising about one third of the total protein in mammalian organisms. It is the main constituent of skin; connective tissue; and the organic substance of bones (bone and bones) and teeth (tooth). Connective Tissue: Histology and elastin within the media are degenerative, unstructured, and dysfunctional—causing cystic Cystic Fibrocystic Change medial necrosis Necrosis The death of cells in an organ or tissue due to disease, injury or failure of the blood supply. Ischemic Cell Damage.

In approximately 10% of cases, there is no evidence of an intimal tear. These dissections may be caused by bleeding within the medial layer of the vessel resulting in secondary aortic dissection Aortic dissection Aortic dissection occurs due to shearing stress from pulsatile pressure causing a tear in the tunica intima of the aortic wall. This tear allows blood to flow into the media, creating a “false lumen.” Aortic dissection is most commonly caused by uncontrolled hypertension. Aortic Dissection.

Genetic Disease Implications

• Marfan syndrome Marfan syndrome Marfan syndrome is a genetic condition with autosomal dominant inheritance. Marfan syndrome affects the elasticity of connective tissues throughout the body, most notably in the cardiovascular, ocular, and musculoskeletal systems. Marfan Syndrome is a connective tissue Connective tissue Connective tissues originate from embryonic mesenchyme and are present throughout the body except inside the brain and spinal cord. The main function of connective tissues is to provide structural support to organs. Connective tissues consist of cells and an extracellular matrix. Connective Tissue: Histology disorder that involves the misfolding of fibrillin-1 Fibrillin-1 A fibrillin (fbn1) that functions as a structural support protein for microfibrils. It also regulates the maturation of osteoblasts by controlling the availability and concentration of tgf-beta and bone morphogenetic proteins. Mutations in the fbn1 gene are associated with marfan syndrome. Marfan Syndrome. This is a protein that forms elastic Elastic Connective Tissue: Histology tissue and has roles in signaling. One such role includes binding to TGF-beta; inappropriate functioning of the mutated fibrillin-1 Fibrillin-1 A fibrillin (fbn1) that functions as a structural support protein for microfibrils. It also regulates the maturation of osteoblasts by controlling the availability and concentration of tgf-beta and bone morphogenetic proteins. Mutations in the fbn1 gene are associated with marfan syndrome. Marfan Syndrome causes an accumulation of TGF-beta in various tissues, including the aorta Aorta The main trunk of the systemic arteries. Mediastinum and Great Vessels: Anatomy, resulting in weakened tissue with an abnormal structure and function. 
• Ehlers-Danlos syndrome Ehlers-Danlos syndrome Ehlers-Danlos syndrome (EDS) is a heterogeneous group of inherited connective tissue disorders that are characterized by hyperextensible skin, hypermobile joints, and fragility of the skin and connective tissue. Ehlers-Danlos Syndrome is a genetic condition characterized by insufficient production and processing of collagen Collagen A polypeptide substance comprising about one third of the total protein in mammalian organisms. It is the main constituent of skin; connective tissue; and the organic substance of bones (bone and bones) and teeth (tooth). Connective Tissue: Histology (an essential protein involved in the structure of tissues). This can lead to weakened vessel walls that can develop an aneurysm Aneurysm An aneurysm is a bulging, weakened area of a blood vessel that causes an abnormal widening of its diameter > 1.5 times the size of the native vessel. Aneurysms occur more often in arteries than in veins and are at risk of dissection and rupture, which can be life-threatening. Thoracic Aortic Aneurysms. [9]

Pathology

The most commonly identified lesion within the aortic wall is cystic Cystic Fibrocystic Change medial degeneration, manifesting as decreased smooth muscle, necrosis Necrosis The death of cells in an organ or tissue due to disease, injury or failure of the blood supply. Ischemic Cell Damage, elastic Elastic Connective Tissue: Histology tissue fragmentation Fragmentation Chronic Apophyseal Injury, and proteoglycan-rich extracellular matrix Extracellular matrix A meshwork-like substance found within the extracellular space and in association with the basement membrane of the cell surface. It promotes cellular proliferation and provides a supporting structure to which cells or cell lysates in culture dishes adhere. Hypertrophic and Keloid Scars deposition. Cystic Cystic Fibrocystic Change medial degeneration is usually related to genetic diseases like Marfan syndrome Marfan syndrome Marfan syndrome is a genetic condition with autosomal dominant inheritance. Marfan syndrome affects the elasticity of connective tissues throughout the body, most notably in the cardiovascular, ocular, and musculoskeletal systems. Marfan Syndrome. There may be further evidence of atherosclerosis Atherosclerosis Atherosclerosis is a common form of arterial disease in which lipid deposition forms a plaque in the blood vessel walls. Atherosclerosis is an incurable disease, for which there are clearly defined risk factors that often can be reduced through a change in lifestyle and behavior of the patient. Atherosclerosis and abnormal connective tissue Connective tissue Connective tissues originate from embryonic mesenchyme and are present throughout the body except inside the brain and spinal cord. The main function of connective tissues is to provide structural support to organs. Connective tissues consist of cells and an extracellular matrix. Connective Tissue: Histology structure in genetic conditions. Inflammation Inflammation Inflammation is a complex set of responses to infection and injury involving leukocytes as the principal cellular mediators in the body’s defense against pathogenic organisms. Inflammation is also seen as a response to tissue injury in the process of wound healing. The 5 cardinal signs of inflammation are pain, heat, redness, swelling, and loss of function. Inflammation is absent. Dissection can also be spontaneous and occur when no identifiable histologic lesions are present. [11]

Clinical Features

Symptoms

The diagnosis of thoracic aortic dissection Aortic dissection Aortic dissection occurs due to shearing stress from pulsatile pressure causing a tear in the tunica intima of the aortic wall. This tear allows blood to flow into the media, creating a “false lumen.” Aortic dissection is most commonly caused by uncontrolled hypertension. Aortic Dissection should be considered in all patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship with chest pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways. This pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways usually has the following characteristics: [12,14]

• Location: chest pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways depends on the site of the dissection and can mimic the pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways of myocardial infarction Myocardial infarction MI is ischemia and death of an area of myocardial tissue due to insufficient blood flow and oxygenation, usually from thrombus formation on a ruptured atherosclerotic plaque in the epicardial arteries. Clinical presentation is most commonly with chest pain, but women and patients with diabetes may have atypical symptoms. Myocardial Infarction). Chest pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways occurs due to the interruption of blood flow Blood flow Blood flow refers to the movement of a certain volume of blood through the vasculature over a given unit of time (e.g., mL per minute). Vascular Resistance, Flow, and Mean Arterial Pressure to the coronary arteries Arteries Arteries are tubular collections of cells that transport oxygenated blood and nutrients from the heart to the tissues of the body. The blood passes through the arteries in order of decreasing luminal diameter, starting in the largest artery (the aorta) and ending in the small arterioles. Arteries are classified into 3 types: large elastic arteries, medium muscular arteries, and small arteries and arterioles. Arteries: Histology, causing ischemia Ischemia A hypoperfusion of the blood through an organ or tissue caused by a pathologic constriction or obstruction of its blood vessels, or an absence of blood circulation. Ischemic Cell Damage (usually when the arch or root are affected). Pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways is usually more sudden and severe at the onset when compared to infarctions. Dissection is painless in about 10% of patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship.
• Onset: sudden
• Character: severe tearing/ripping pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways (tearing pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways between the shoulder blades is usually associated with a descending aortic dissection Descending aortic dissection Aortic Dissection).
• Radiation Radiation Emission or propagation of acoustic waves (sound), electromagnetic energy waves (such as light; radio waves; gamma rays; or x-rays), or a stream of subatomic particles (such as electrons; neutrons; protons; or alpha particles). Osteosarcoma: to the upper back. Pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways can radiate to the neck Neck The part of a human or animal body connecting the head to the rest of the body. Peritonsillar Abscess or jaw Jaw The jaw is made up of the mandible, which comprises the lower jaw, and the maxilla, which comprises the upper jaw. The mandible articulates with the temporal bone via the temporomandibular joint (TMJ). The 4 muscles of mastication produce the movements of the TMJ to ensure the efficient chewing of food. Jaw and Temporomandibular Joint: Anatomy (usually with arch dissection spreading to the branches of the aorta Aorta The main trunk of the systemic arteries. Mediastinum and Great Vessels: Anatomy).
• Severity: usually excruciating; can be mild in some cases.

Neurological symptoms are the presenting complaint in 20% of cases:

• Syncope Syncope Syncope is a short-term loss of consciousness and loss of postural stability followed by spontaneous return of consciousness to the previous neurologic baseline without the need for resuscitation. The condition is caused by transient interruption of cerebral blood flow that may be benign or related to a underlying life-threatening condition. Syncope ( hypovolemia Hypovolemia Sepsis in Children, arrhythmia, increased vagal tone)
• Altered mental status Altered Mental Status Sepsis in Children
• Stroke (CVA)— hemiparesis Hemiparesis The term hemiparesis refers to mild to moderate weakness involving one side of the body. Epidural Hemorrhage or hemiplegia with hemianesthesia
• Sensory Sensory Neurons which conduct nerve impulses to the central nervous system. Nervous System: Histology paresthesias Paresthesias Subjective cutaneous sensations (e.g., cold, warmth, tingling, pressure, etc.) that are experienced spontaneously in the absence of stimulation. Posterior Cord Syndrome and motor Motor Neurons which send impulses peripherally to activate muscles or secretory cells. Nervous System: Histology weakness can occur if peripheral nerves Peripheral Nerves The nerves outside of the brain and spinal cord, including the autonomic, cranial, and spinal nerves. Peripheral nerves contain non-neuronal cells and connective tissue as well as axons. The connective tissue layers include, from the outside to the inside, the epineurium, the perineurium, and the endoneurium. Nervous System: Histology are affected by the lack of blood supply.
• Hoarseness Hoarseness An unnaturally deep or rough quality of voice. Parapharyngeal Abscess due to compression Compression Blunt Chest Trauma of the laryngeal nerve

Additionally, other types of symptoms may occur with AD AD The term advance directive (AD) refers to treatment preferences and/or the designation of a surrogate decision-maker in the event that a person becomes unable to make medical decisions on their own behalf. Advance directives represent the ethical principle of autonomy and may take the form of a living will, health care proxy, durable power of attorney for health care, and/or a physician’s order for life-sustaining treatment. Advance Directives:

• Cardiovascular symptoms due to acute severe aortic valve Aortic valve The valve between the left ventricle and the ascending aorta which prevents backflow into the left ventricle. Heart: Anatomy compromise leading to secondary congestive left heart failure Heart Failure A heterogeneous condition in which the heart is unable to pump out sufficient blood to meet the metabolic need of the body. Heart failure can be caused by structural defects, functional abnormalities (ventricular dysfunction), or a sudden overload beyond its capacity. Chronic heart failure is more common than acute heart failure which results from sudden insult to cardiac function, such as myocardial infarction. Total Anomalous Pulmonary Venous Return (TAPVR) with orthopnea Orthopnea Pulmonary Edema and dyspnea Dyspnea Dyspnea is the subjective sensation of breathing discomfort. Dyspnea is a normal manifestation of heavy physical or psychological exertion, but also may be caused by underlying conditions (both pulmonary and extrapulmonary). Dyspnea
• Elevated blood pressure due to underlying hypertension Hypertension Hypertension, or high blood pressure, is a common disease that manifests as elevated systemic arterial pressures. Hypertension is most often asymptomatic and is found incidentally as part of a routine physical examination or during triage for an unrelated medical encounter. Hypertension or an increase in circulating catecholamines Catecholamines A general class of ortho-dihydroxyphenylalkylamines derived from tyrosine. Adrenal Hormones
• Hypotension Hypotension Hypotension is defined as low blood pressure, specifically < 90/60 mm Hg, and is most commonly a physiologic response. Hypotension may be mild, serious, or life threatening, depending on the cause. Hypotension, a poor prognostic sign, may result from cardiac tamponade Tamponade Pericardial effusion, usually of rapid onset, exceeding ventricular filling pressures and causing collapse of the heart with a markedly reduced cardiac output. Pericarditis, hypovolemia Hypovolemia Sepsis in Children, or increased vagal tone.
• Dysphagia Dysphagia Dysphagia is the subjective sensation of difficulty swallowing. Symptoms can range from a complete inability to swallow, to the sensation of solids or liquids becoming “stuck.” Dysphagia is classified as either oropharyngeal or esophageal, with esophageal dysphagia having 2 sub-types: functional and mechanical. Dysphagia due to esophageal compression Compression Blunt Chest Trauma
• Abdominal pain Abdominal Pain Acute Abdomen if the dissection extends to the abdominal aorta Abdominal Aorta The aorta from the diaphragm to the bifurcation into the right and left common iliac arteries. Posterior Abdominal Wall: Anatomy
• Flank pain Flank pain Pain emanating from below the ribs and above the ilium. Renal Cell Carcinoma m if the renal arteries Arteries Arteries are tubular collections of cells that transport oxygenated blood and nutrients from the heart to the tissues of the body. The blood passes through the arteries in order of decreasing luminal diameter, starting in the largest artery (the aorta) and ending in the small arterioles. Arteries are classified into 3 types: large elastic arteries, medium muscular arteries, and small arteries and arterioles. Arteries: Histology are involved
• Symptoms of systemic diseases in patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship with associated connective tissue Connective tissue Connective tissues originate from embryonic mesenchyme and are present throughout the body except inside the brain and spinal cord. The main function of connective tissues is to provide structural support to organs. Connective tissues consist of cells and an extracellular matrix. Connective Tissue: Histology disease or peripheral vascular disease

Signs

This list comprises the most common signs of aortic dissection Aortic dissection Aortic dissection occurs due to shearing stress from pulsatile pressure causing a tear in the tunica intima of the aortic wall. This tear allows blood to flow into the media, creating a “false lumen.” Aortic dissection is most commonly caused by uncontrolled hypertension. Aortic Dissection: [12,14]

• Blood pressure that is unequal in both arms, usually with a difference of > 20 mm Hg between left and right arms (may be normal in 20%) due to dissection obstructing the branches of the aorta Aorta The main trunk of the systemic arteries. Mediastinum and Great Vessels: Anatomy
• Aortic regurgitation Regurgitation Gastroesophageal Reflux Disease (GERD) is characterized by bounding (collapsing/water hammer) pulse, wide pulse pressure, diastolic murmur
• Signs of congestive heart failure Heart Failure A heterogeneous condition in which the heart is unable to pump out sufficient blood to meet the metabolic need of the body. Heart failure can be caused by structural defects, functional abnormalities (ventricular dysfunction), or a sudden overload beyond its capacity. Chronic heart failure is more common than acute heart failure which results from sudden insult to cardiac function, such as myocardial infarction. Total Anomalous Pulmonary Venous Return (TAPVR) secondary to acute severe aortic valve Aortic valve The valve between the left ventricle and the ascending aorta which prevents backflow into the left ventricle. Heart: Anatomy dysfunction leading to orthopnea Orthopnea Pulmonary Edema, dyspnea Dyspnea Dyspnea is the subjective sensation of breathing discomfort. Dyspnea is a normal manifestation of heavy physical or psychological exertion, but also may be caused by underlying conditions (both pulmonary and extrapulmonary). Dyspnea, elevated JVP, and bibasilar crackles
• Possible loss of consciousness
• Cardiac tamponade Tamponade Pericardial effusion, usually of rapid onset, exceeding ventricular filling pressures and causing collapse of the heart with a markedly reduced cardiac output. Pericarditis, characterized by distention of jugular veins Veins Veins are tubular collections of cells, which transport deoxygenated blood and waste from the capillary beds back to the heart. Veins are classified into 3 types: small veins/venules, medium veins, and large veins. Each type contains 3 primary layers: tunica intima, tunica media, and tunica adventitia. Veins: Histology, hypotension Hypotension Hypotension is defined as low blood pressure, specifically < 90/60 mm Hg, and is most commonly a physiologic response. Hypotension may be mild, serious, or life threatening, depending on the cause. Hypotension, pulsus paradoxus Pulsus paradoxus A drop in systolic blood pressure of > 10 mm hg during inspiration. Pericardial Effusion and Cardiac Tamponade, Kussmaul sign
• Superior vena cava Superior vena cava The venous trunk which returns blood from the head, neck, upper extremities and chest. Mediastinum and Great Vessels: Anatomy (SVC) obstruction can cause SVC syndrome in rare cases
• Signs of stroke—e.g., body leaning to one side due to hemiparesis Hemiparesis The term hemiparesis refers to mild to moderate weakness involving one side of the body. Epidural Hemorrhage
• Shock Shock Shock is a life-threatening condition associated with impaired circulation that results in tissue hypoxia. The different types of shock are based on the underlying cause: distributive (↑ cardiac output (CO), ↓ systemic vascular resistance (SVR)), cardiogenic (↓ CO, ↑ SVR), hypovolemic (↓ CO, ↑ SVR), obstructive (↓ CO), and mixed. Types of Shock; cold, clammy, pale, tachycardic, tachypneic
• Horner syndrome Horner syndrome Horner syndrome is a condition resulting from an interruption of the sympathetic innervation of the eyes. The syndrome is usually idiopathic but can be directly caused by head and neck trauma, cerebrovascular disease, or a tumor of the CNS. Horner Syndrome if there is compression Compression Blunt Chest Trauma of the cervical sympathetic chain
• Decreased sensation to touch in the extremities due to peripheral ischemia Ischemia A hypoperfusion of the blood through an organ or tissue caused by a pathologic constriction or obstruction of its blood vessels, or an absence of blood circulation. Ischemic Cell Damage
• Signs of hemothorax Hemothorax A hemothorax is a collection of blood in the pleural cavity. Hemothorax most commonly occurs due to damage to the intercostal arteries or from a lung laceration following chest trauma. Hemothorax can also occur as a complication of disease, or hemothorax may be spontaneous or iatrogenic. Hemothorax if the dissection ruptures into the pleura Pleura The pleura is a serous membrane that lines the walls of the thoracic cavity and the surface of the lungs. This structure of mesodermal origin covers both lungs, the mediastinum, the thoracic surface of the diaphragm, and the inner part of the thoracic cage. The pleura is divided into a visceral pleura and parietal pleura. Pleura: Anatomy; rapid shallow breathing, sharp pleuritic pain Pleuritic Pain Pneumothorax
• Acute arterial insufficiency in the lower or upper limbs, as indicated by weak pulses, pallor, loss of sensation, or motor Motor Neurons which send impulses peripherally to activate muscles or secretory cells. Nervous System: Histology weakness
• Signs of connective tissue Connective tissue Connective tissues originate from embryonic mesenchyme and are present throughout the body except inside the brain and spinal cord. The main function of connective tissues is to provide structural support to organs. Connective tissues consist of cells and an extracellular matrix. Connective Tissue: Histology disorders such as Marfan and Ehlers-Danlos syndromes; hypermobility, tall height, long arm Arm The arm, or “upper arm” in common usage, is the region of the upper limb that extends from the shoulder to the elbow joint and connects inferiorly to the forearm through the cubital fossa. It is divided into 2 fascial compartments (anterior and posterior). Arm: Anatomy span

Diagnosis

Diagnosis of aortic dissection Aortic dissection Aortic dissection occurs due to shearing stress from pulsatile pressure causing a tear in the tunica intima of the aortic wall. This tear allows blood to flow into the media, creating a “false lumen.” Aortic dissection is most commonly caused by uncontrolled hypertension. Aortic Dissection needs to be rapid and accurate. As previously explained, the diagnosis should be suspected from the history and physical examination.

Imaging

When there is a high clinical suspicion of aortic dissection Aortic dissection Aortic dissection occurs due to shearing stress from pulsatile pressure causing a tear in the tunica intima of the aortic wall. This tear allows blood to flow into the media, creating a “false lumen.” Aortic dissection is most commonly caused by uncontrolled hypertension. Aortic Dissection, imaging studies must be done emergently to confirm or exclude the diagnosis.[14] Each has its advantages and disadvantages, and selection Selection Lymphocyte activation by a specific antigen thus triggering clonal expansion of lymphocytes already capable of mounting an immune response to the antigen. B cells: Types and Functions depends on test availability and the patient’s presentation.

Chest X-ray X-ray Penetrating electromagnetic radiation emitted when the inner orbital electrons of an atom are excited and release radiant energy. X-ray wavelengths range from 1 pm to 10 nm. Hard x-rays are the higher energy, shorter wavelength x-rays. Soft x-rays or grenz rays are less energetic and longer in wavelength. The short wavelength end of the x-ray spectrum overlaps the gamma rays wavelength range. The distinction between gamma rays and x-rays is based on their radiation source. Pulmonary Function Tests

• Initial imaging shows mediastinal widening; pleural effusions may be visible.
• Calcium Calcium A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes. Electrolytes sign—the calcified intima is separated from the outer aortic soft tissue Soft Tissue Soft Tissue Abscess border by one cm (rare)
• Obliteration of the aortic knob

Transesophageal echocardiogram Echocardiogram Transposition of the Great Arteries ( TEE TEE Ultrasonic recording of the size, motion, and composition of the heart and surrounding tissues using a transducer placed in the esophagus. Imaging of the Heart and Great Vessels)

• Most rapid means of providing sufficient detail to proceed directly to the operating room [15]
• Recommended for hemodynamically unstable patients Hemodynamically Unstable Patients Blunt Chest Trauma but requires procedural sedation, which may have adverse effects
• Fast, minimally invasive, and can be used in unstable patients Unstable Patients Blunt Chest Trauma or those with renal insufficiency or contrast allergy Allergy An abnormal adaptive immune response that may or may not involve antigen-specific IgE Type I Hypersensitivity Reaction 
• Can determine if valves or ostia of the coronary arteries Arteries Arteries are tubular collections of cells that transport oxygenated blood and nutrients from the heart to the tissues of the body. The blood passes through the arteries in order of decreasing luminal diameter, starting in the largest artery (the aorta) and ending in the small arterioles. Arteries are classified into 3 types: large elastic arteries, medium muscular arteries, and small arteries and arterioles. Arteries: Histology are involved
• Can detect entry tear sites, false lumen False lumen Aortic Dissection flow Flow Blood flows through the heart, arteries, capillaries, and veins in a closed, continuous circuit. Flow is the movement of volume per unit of time. Flow is affected by the pressure gradient and the resistance fluid encounters between 2 points. Vascular resistance is the opposition to flow, which is caused primarily by blood friction against vessel walls. Vascular Resistance, Flow, and Mean Arterial Pressure/thrombus, and pericardial effusions
• Does not provide a complete view; MRI is recommended if available and the patient is stable enough

CT Scan

• Noninvasive, rapid, and accurate test that can give a 3D view of the aorta Aorta The main trunk of the systemic arteries. Mediastinum and Great Vessels: Anatomy—especially useful for surgical interventions [16,17]
• Most common initial choice in the emergency department (in stable patients Stable Patients Blunt Chest Trauma) 
• Diagnosis of AD AD The term advance directive (AD) refers to treatment preferences and/or the designation of a surrogate decision-maker in the event that a person becomes unable to make medical decisions on their own behalf. Advance directives represent the ethical principle of autonomy and may take the form of a living will, health care proxy, durable power of attorney for health care, and/or a physician’s order for life-sustaining treatment. Advance Directives by CT requires the identification Identification Defense Mechanisms of 2 distinct lumens; the intimal flap may or may not be seen.
• Injected iodinated contrast medium is used
• Highly sensitive and specific [16,17]

MR MR Calculated as the ratio of the total number of people who die due to all causes over a specific time period to the total number of people in the selected population. Measures of Health Status angiogram

• If immediately available and the patient is hemodynamically stable, MRI is the most useful for diagnosing and managing aortic dissection Aortic dissection Aortic dissection occurs due to shearing stress from pulsatile pressure causing a tear in the tunica intima of the aortic wall. This tear allows blood to flow into the media, creating a “false lumen.” Aortic dissection is most commonly caused by uncontrolled hypertension. Aortic Dissection.[19]
• Highly sensitive and specific
• May be done with or without contrast, depending on the situation
• Creates a 3D reconstruction to determine the location of the intimal tear (unlike CT scans) and the extent of the dissection
• Noninvasive
• Takes longer than CT scans; therefore may be less practical

Differential Diagnoses

Myocarditis Myocarditis Myocarditis is an inflammatory disease of the myocardium, which may occur alone or in association with a systemic process. There are numerous etiologies of myocarditis, but all lead to inflammation and myocyte injury, most often leading to signs and symptoms of heart failure. Myocarditis, myocardial infarction Myocardial infarction MI is ischemia and death of an area of myocardial tissue due to insufficient blood flow and oxygenation, usually from thrombus formation on a ruptured atherosclerotic plaque in the epicardial arteries. Clinical presentation is most commonly with chest pain, but women and patients with diabetes may have atypical symptoms. Myocardial Infarction, aortic aneurysmal rupture Aneurysmal rupture The tearing or bursting of the weakened wall of the aneurysmal sac, usually heralded by sudden worsening pain. The great danger of a ruptured aneurysm is the large amount of blood spilling into the surrounding tissues and cavities, causing hemorrhagic shock. Thoracic Aortic Aneurysms, and mechanical chest pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways (e.g., costochondritis) are other conditions in the differential diagnosis of aortic dissection Aortic dissection Aortic dissection occurs due to shearing stress from pulsatile pressure causing a tear in the tunica intima of the aortic wall. This tear allows blood to flow into the media, creating a “false lumen.” Aortic dissection is most commonly caused by uncontrolled hypertension. Aortic Dissection.

Treatment

Type A (DeBakey 1+2) acute ascending aortic dissection Ascending aortic dissection Aortic Dissection is treated emergently with open surgery, less often by endovascular stent-grafting if there are major comorbidities Comorbidities The presence of co-existing or additional diseases with reference to an initial diagnosis or with reference to the index condition that is the subject of study. Comorbidity may affect the ability of affected individuals to function and also their survival; it may be used as a prognostic indicator for length of hospital stay, cost factors, and outcome or survival. St. Louis Encephalitis Virus, and a hybrid approach has been used (surgical repair of the ascending aorta Ascending aorta Mediastinum and Great Vessels: Anatomy, and endovascular stent-graft for the descending aorta Descending aorta Mediastinum and Great Vessels: Anatomy). As soon as acute type A aortic dissection Aortic dissection Aortic dissection occurs due to shearing stress from pulsatile pressure causing a tear in the tunica intima of the aortic wall. This tear allows blood to flow into the media, creating a “false lumen.” Aortic dissection is most commonly caused by uncontrolled hypertension. Aortic Dissection is diagnosed, immediate cardiac surgical consultation is required. If experienced cardiac surgical services are not available, the patient should be promptly transferred for definitive care. [20,22,25]

Type B (DeBakey3) descending aortic dissection Descending aortic dissection Aortic Dissection is initially treated by beta-blockers Beta-blockers Drugs that bind to but do not activate beta-adrenergic receptors thereby blocking the actions of beta-adrenergic agonists. Adrenergic beta-antagonists are used for treatment of hypertension, cardiac arrhythmias, angina pectoris, glaucoma, migraine headaches, and anxiety. Class 2 Antiarrhythmic Drugs (Beta Blockers), vasodilators Vasodilators Drugs used to cause dilation of the blood vessels. Thromboangiitis Obliterans (Buerger Disease), or calcium Calcium A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes. Electrolytes channel blockers. Surgical or thoracic endovascular repair are indicated if there are complications (occlusion of a major branch, severe hypertension Severe hypertension A confirmed blood pressure ≥ 180 mm Hg systolic and/or ≥ 120 mm Hg diastolic. Uncontrolled Hypertension, chest pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways, propagation Propagation Propagation refers to how the electrical signal spreads to every myocyte in the heart. Cardiac Physiology of the dissection aneurysmal expansion, expanding hematoma Hematoma A collection of blood outside the blood vessels. Hematoma can be localized in an organ, space, or tissue. Intussusception, or rupture). Complicated type B dissections can be treated with thoracic endovascular aortic repair, now considered the gold standard intervention in this situation. [21]

Early Treatment 

IV beta blockers are the first-line early treatment of AD AD The term advance directive (AD) refers to treatment preferences and/or the designation of a surrogate decision-maker in the event that a person becomes unable to make medical decisions on their own behalf. Advance directives represent the ethical principle of autonomy and may take the form of a living will, health care proxy, durable power of attorney for health care, and/or a physician’s order for life-sustaining treatment. Advance Directives to decrease the heart rate Heart rate The number of times the heart ventricles contract per unit of time, usually per minute. Cardiac Physiology to a goal of 60 bpm. IV labetalol Labetalol A salicylamide derivative that is a non-cardioselective blocker of beta-adrenergic receptors and alpha-1 adrenergic receptors. Subarachnoid Hemorrhage, esmolol Esmolol Antiadrenergic Drugs, and propranolol Propranolol A widely used non-cardioselective beta-adrenergic antagonist. Propranolol has been used for myocardial infarction; arrhythmia; angina pectoris; hypertension; hyperthyroidism; migraine; pheochromocytoma; and anxiety but adverse effects instigate replacement by newer drugs. Antiadrenergic Drugs are used in this setting. The next step is to control hypertension Hypertension Hypertension, or high blood pressure, is a common disease that manifests as elevated systemic arterial pressures. Hypertension is most often asymptomatic and is found incidentally as part of a routine physical examination or during triage for an unrelated medical encounter. Hypertension if not achieved with beta blockers alone; add-on therapy with nitroprusside Nitroprusside A powerful vasodilator used in emergencies to lower blood pressure or to improve cardiac function. It is also an indicator for free sulfhydryl groups in proteins. Nitrates (for systolic BP > 120 mm Hg) or calcium Calcium A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes. Electrolytes channel blockers can be used if beta blockers are not tolerated.

Note: Initial treatment should be beta-blockers Beta-blockers Drugs that bind to but do not activate beta-adrenergic receptors thereby blocking the actions of beta-adrenergic agonists. Adrenergic beta-antagonists are used for treatment of hypertension, cardiac arrhythmias, angina pectoris, glaucoma, migraine headaches, and anxiety. Class 2 Antiarrhythmic Drugs (Beta Blockers) before vasodilators Vasodilators Drugs used to cause dilation of the blood vessels. Thromboangiitis Obliterans (Buerger Disease) to avoid reflex tachycardia Tachycardia Abnormally rapid heartbeat, usually with a heart rate above 100 beats per minute for adults. Tachycardia accompanied by disturbance in the cardiac depolarization (cardiac arrhythmia) is called tachyarrhythmia. Sepsis in Children.

Note: Beta-blockers Beta-blockers Drugs that bind to but do not activate beta-adrenergic receptors thereby blocking the actions of beta-adrenergic agonists. Adrenergic beta-antagonists are used for treatment of hypertension, cardiac arrhythmias, angina pectoris, glaucoma, migraine headaches, and anxiety. Class 2 Antiarrhythmic Drugs (Beta Blockers) decrease the heart rate Heart rate The number of times the heart ventricles contract per unit of time, usually per minute. Cardiac Physiology, reducing shearing forces Shearing forces Vascular Resistance, Flow, and Mean Arterial Pressure with the aorta Aorta The main trunk of the systemic arteries. Mediastinum and Great Vessels: Anatomy.

Surgery

Aortic dissection Aortic dissection Aortic dissection occurs due to shearing stress from pulsatile pressure causing a tear in the tunica intima of the aortic wall. This tear allows blood to flow into the media, creating a “false lumen.” Aortic dissection is most commonly caused by uncontrolled hypertension. Aortic Dissection involving the ascending aorta Ascending aorta Mediastinum and Great Vessels: Anatomy is a surgical emergency Surgical Emergency Acute Abdomen. The surgery involves excision of the intimal tear, obliteration of the proximal entry point into the false lumen False lumen Aortic Dissection, reconstitution of the aorta Aorta The main trunk of the systemic arteries. Mediastinum and Great Vessels: Anatomy with a synthetic graft Graft A piece of living tissue that is surgically transplanted Organ Transplantation, and repair or replacement of the aortic valve Aortic valve The valve between the left ventricle and the ascending aorta which prevents backflow into the left ventricle. Heart: Anatomy.

The 2022 ACC/AHA guidelines for the diagnosis and management of aortic disease provide updated recommendations to improve patient outcomes. Key changes include lowering the threshold Threshold Minimum voltage necessary to generate an action potential (an all-or-none response) Skeletal Muscle Contraction for surgical intervention in sporadic Sporadic Selective IgA Deficiency aortic root and ascending aortic aneurysms from 5.5 cm to 5.0 cm for selected patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship and even lower for those with heritable conditions. The guidelines also recommend indexing the aortic diameter to patient body surface area or height for significantly smaller or taller individuals and emphasize the role of thoracic endovascular aortic repair (TEVAR) in managing uncomplicated type B aortic dissection Aortic dissection Aortic dissection occurs due to shearing stress from pulsatile pressure causing a tear in the tunica intima of the aortic wall. This tear allows blood to flow into the media, creating a “false lumen.” Aortic dissection is most commonly caused by uncontrolled hypertension. Aortic Dissection. Furthermore, they stress the importance of genetic screening Genetic Screening Physical Examination of the Newborn and the potential benefits of valve-sparing aortic root replacement in appropriate cases.[27]

Complications

Aortic dissection Aortic dissection Aortic dissection occurs due to shearing stress from pulsatile pressure causing a tear in the tunica intima of the aortic wall. This tear allows blood to flow into the media, creating a “false lumen.” Aortic dissection is most commonly caused by uncontrolled hypertension. Aortic Dissection may cause these complications:[22]

• Hypotension Hypotension Hypotension is defined as low blood pressure, specifically < 90/60 mm Hg, and is most commonly a physiologic response. Hypotension may be mild, serious, or life threatening, depending on the cause. Hypotension, hypovolemic shock Hypovolemic Shock Types of Shock, and death due to  exsanguination (severe blood loss)
• Permanent disability Disability Determination of the degree of a physical, mental, or emotional handicap. The diagnosis is applied to legal qualification for benefits and income under disability insurance and to eligibility for social security and workman’s compensation benefits. ABCDE Assessment from stroke (CVA)
• Acute aortic regurgitation Regurgitation Gastroesophageal Reflux Disease (GERD) leading to proximal dissection spreading to the sinus of Valsalva and the aortic root
• Pulmonary edema Pulmonary edema Pulmonary edema is a condition caused by excess fluid within the lung parenchyma and alveoli as a consequence of a disease process. Based on etiology, pulmonary edema is classified as cardiogenic or noncardiogenic. Patients may present with progressive dyspnea, orthopnea, cough, or respiratory failure. Pulmonary Edema related to acute aortic valve Aortic valve The valve between the left ventricle and the ascending aorta which prevents backflow into the left ventricle. Heart: Anatomy regurgitation Regurgitation Gastroesophageal Reflux Disease (GERD)
• Pericardial tamponade Pericardial tamponade Compression of the heart by accumulated fluid (pericardial effusion) or blood (hemopericardium) in the pericardium surrounding the heart. The affected cardiac functions and cardiac output can range from minimal to total hemodynamic collapse. Penetrating Chest Injury due to blood in the pericardial sac (hemopericardium)
• Myocardial ischemia Myocardial ischemia A disorder of cardiac function caused by insufficient blood flow to the muscle tissue of the heart. The decreased blood flow may be due to narrowing of the coronary arteries (coronary artery disease), to obstruction by a thrombus (coronary thrombosis), or less commonly, to diffuse narrowing of arterioles and other small vessels within the heart. Coronary Heart Disease due to reduction in blood flow Blood flow Blood flow refers to the movement of a certain volume of blood through the vasculature over a given unit of time (e.g., mL per minute). Vascular Resistance, Flow, and Mean Arterial Pressure to the coronary arteries Arteries Arteries are tubular collections of cells that transport oxygenated blood and nutrients from the heart to the tissues of the body. The blood passes through the arteries in order of decreasing luminal diameter, starting in the largest artery (the aorta) and ending in the small arterioles. Arteries are classified into 3 types: large elastic arteries, medium muscular arteries, and small arteries and arterioles. Arteries: Histology
• Aortic insufficiency
• Myocardial infarction Myocardial infarction MI is ischemia and death of an area of myocardial tissue due to insufficient blood flow and oxygenation, usually from thrombus formation on a ruptured atherosclerotic plaque in the epicardial arteries. Clinical presentation is most commonly with chest pain, but women and patients with diabetes may have atypical symptoms. Myocardial Infarction ( MI MI MI is ischemia and death of an area of myocardial tissue due to insufficient blood flow and oxygenation, usually from thrombus formation on a ruptured atherosclerotic plaque in the epicardial arteries. Clinical presentation is most commonly with chest pain, but women and patients with diabetes may have atypical symptoms. Myocardial Infarction)
• Global ischemia Ischemia A hypoperfusion of the blood through an organ or tissue caused by a pathologic constriction or obstruction of its blood vessels, or an absence of blood circulation. Ischemic Cell Damage (e.g., mesenteric/intestinal, renal, spinal cord Spinal cord The spinal cord is the major conduction pathway connecting the brain to the body; it is part of the CNS. In cross section, the spinal cord is divided into an H-shaped area of gray matter (consisting of synapsing neuronal cell bodies) and a surrounding area of white matter (consisting of ascending and descending tracts of myelinated axons). Spinal Cord: Anatomy, other sites of visceral ischemia Ischemia A hypoperfusion of the blood through an organ or tissue caused by a pathologic constriction or obstruction of its blood vessels, or an absence of blood circulation. Ischemic Cell Damage/infarction)
• Compression Compression Blunt Chest Trauma of some anatomical parts such as the esophagus Esophagus The esophagus is a muscular tube-shaped organ of around 25 centimeters in length that connects the pharynx to the stomach. The organ extends from approximately the 6th cervical vertebra to the 11th thoracic vertebra and can be divided grossly into 3 parts: the cervical part, the thoracic part, and the abdominal part. Esophagus: Anatomy, SVC, ganglia (sympathetic chain causing Horner syndrome Horner syndrome Horner syndrome is a condition resulting from an interruption of the sympathetic innervation of the eyes. The syndrome is usually idiopathic but can be directly caused by head and neck trauma, cerebrovascular disease, or a tumor of the CNS. Horner Syndrome), airway Airway ABCDE Assessment, and left recurrent laryngeal nerve ( hoarseness Hoarseness An unnaturally deep or rough quality of voice. Parapharyngeal Abscess and vocal cord paralysis).
• Aortic aneurysm Aortic aneurysm An abnormal balloon- or sac-like dilatation in the wall of aorta. Thoracic Aortic Aneurysms

Prognosis

Acute aortic dissection Aortic dissection Aortic dissection occurs due to shearing stress from pulsatile pressure causing a tear in the tunica intima of the aortic wall. This tear allows blood to flow into the media, creating a “false lumen.” Aortic dissection is most commonly caused by uncontrolled hypertension. Aortic Dissection has a high mortality Mortality All deaths reported in a given population. Measures of Health Status rate, about 1% per hour for type A dissection if untreated, which highlights the importance of rapid diagnosis and referral for surgical repair or medical treatment if indicated. In-hospital mortality Mortality All deaths reported in a given population. Measures of Health Status, including operative deaths, was 22% in a review of 487 patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship. [20] Type A aortic dissections have a much worse prognosis Prognosis A prediction of the probable outcome of a disease based on a individual’s condition and the usual course of the disease as seen in similar situations. Non-Hodgkin Lymphomas than descending thoracic aortic dissections.

In a meta-analysis comparing thoracic endovascular repair versus medical management for acute uncomplicated type B aortic dissection Aortic dissection Aortic dissection occurs due to shearing stress from pulsatile pressure causing a tear in the tunica intima of the aortic wall. This tear allows blood to flow into the media, creating a “false lumen.” Aortic dissection is most commonly caused by uncontrolled hypertension. Aortic Dissection, no difference was seen in short-term (1 month) and mid-term (2.5 years) mortality Mortality All deaths reported in a given population. Measures of Health Status.[23] Patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship with complicated type B dissections have a higher mortality Mortality All deaths reported in a given population. Measures of Health Status rate than uncomplicated, and thoracic endovascular aortic repair is considered the gold standard intervention in this situation.[24]

Medically treated patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship must be closely followed with serial imaging ( MR MR Calculated as the ratio of the total number of people who die due to all causes over a specific time period to the total number of people in the selected population. Measures of Health Status or CT) every 6 months for the first 2 years, then annually.

Risk factors that affect the prognosis Prognosis A prediction of the probable outcome of a disease based on a individual’s condition and the usual course of the disease as seen in similar situations. Non-Hodgkin Lymphomas postoperatively:

• Increased preoperative evaluation time
• Older age
• Leakage of an aneurysm Aneurysm An aneurysm is a bulging, weakened area of a blood vessel that causes an abnormal widening of its diameter > 1.5 times the size of the native vessel. Aneurysms occur more often in arteries than in veins and are at risk of dissection and rupture, which can be life-threatening. Thoracic Aortic Aneurysms
• Cardiac tamponade Tamponade Pericardial effusion, usually of rapid onset, exceeding ventricular filling pressures and causing collapse of the heart with a markedly reduced cardiac output. Pericarditis
• Pre-existing cardiac pathology ( MI MI MI is ischemia and death of an area of myocardial tissue due to insufficient blood flow and oxygenation, usually from thrombus formation on a ruptured atherosclerotic plaque in the epicardial arteries. Clinical presentation is most commonly with chest pain, but women and patients with diabetes may have atypical symptoms. Myocardial Infarction, coronary artery Coronary Artery Truncus Arteriosus disease)
• Previous stroke
• Shock Shock Shock is a life-threatening condition associated with impaired circulation that results in tissue hypoxia. The different types of shock are based on the underlying cause: distributive (↑ cardiac output (CO), ↓ systemic vascular resistance (SVR)), cardiogenic (↓ CO, ↑ SVR), hypovolemic (↓ CO, ↑ SVR), obstructive (↓ CO), and mixed. Types of Shock
• Kidney failure (acute or chronic)

Screening

High-risk individuals with a family history Family History Adult Health Maintenance of collagen-vascular disease or AD AD The term advance directive (AD) refers to treatment preferences and/or the designation of a surrogate decision-maker in the event that a person becomes unable to make medical decisions on their own behalf. Advance directives represent the ethical principle of autonomy and may take the form of a living will, health care proxy, durable power of attorney for health care, and/or a physician’s order for life-sustaining treatment. Advance Directives should be screened with imaging, especially if they have hypertension Hypertension Hypertension, or high blood pressure, is a common disease that manifests as elevated systemic arterial pressures. Hypertension is most often asymptomatic and is found incidentally as part of a routine physical examination or during triage for an unrelated medical encounter. Hypertension.

Review Questions

1. The most common type of aortic dissection is…?
   1. …Stanford Type A.
   2. …Stanford Type B.
2. What imaging study is the most useful for diagnosing and managing aortic dissection in a hemodynamically stable patient?
   1. CT Scan
   2. X-ray X-ray Penetrating electromagnetic radiation emitted when the inner orbital electrons of an atom are excited and release radiant energy. X-ray wavelengths range from 1 pm to 10 nm. Hard x-rays are the higher energy, shorter wavelength x-rays. Soft x-rays or grenz rays are less energetic and longer in wavelength. The short wavelength end of the x-ray spectrum overlaps the gamma rays wavelength range. The distinction between gamma rays and x-rays is based on their radiation source. Pulmonary Function Tests
   3. Aortogram
   4. MRA MRA Imaging of the Heart and Great Vessels
   5. Echocardiogram Echocardiogram Transposition of the Great Arteries
3. What strand of tissue splits off in an aortic dissection but remains in the lumen?
   1. Intimal tear
   2. Intimal flap
   3. Medial slice
   4. Medial tear
   5. Adventitial flap

Answers: 1-1, 2-4, 3-2