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Aortic Stenosis

Aortic stenosis Stenosis Hypoplastic Left Heart Syndrome (HLHS) (AS), or the narrowing 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 aperture, is the most common valvular heart disease. While rheumatic heart disease Rheumatic Heart Disease Cardiac manifestation of systemic rheumatological conditions, such as rheumatic fever. Rheumatic heart disease can involve any part the heart, most often the heart valves and the endocardium. Rheumatic Fever remains the most frequent etiology worldwide, degenerative AS and congenital Congenital Chorioretinitis bicuspid valve defect are the 2 usual causes in developed countries. Aortic stenosis Stenosis Hypoplastic Left Heart Syndrome (HLHS) gradually progresses to 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), producing exertional 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, angina, and/or 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. A crescendo-decrescendo systolic murmur is audible in the right upper sternal border. Doppler Doppler Ultrasonography applying the doppler effect, with frequency-shifted ultrasound reflections produced by moving targets (usually red blood cells) in the bloodstream along the ultrasound axis in direct proportion to the velocity of movement of the targets, to determine both direction and velocity of blood flow. Ultrasound (Sonography) echocardiography Echocardiography Ultrasonic recording of the size, motion, and composition of the heart and surrounding tissues. The standard approach is transthoracic. Tricuspid Valve Atresia (TVA) is the imaging of choice, showing structural and 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 changes in the valvular area. Valve replacement is the only effective treatment for symptomatic severe AS. Indications for the procedure depend on the patient's symptoms, degree of AS severity, exercise tolerance Tolerance Pharmacokinetics and Pharmacodynamics, concurrent cardiac abnormalities, surgical risk, and life expectancy Life expectancy Based on known statistical data, the number of years which any person of a given age may reasonably expected to live. Population Pyramids.

Last updated: Oct 21, 2022

Editorial responsibility: Stanley Oiseth, Lindsay Jones, Evelin Maza

Overview

Definition

Aortic stenosis Stenosis Hypoplastic Left Heart Syndrome (HLHS) (AS) is the narrowing 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 aperture.

  • Causes varying degrees of blood 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 obstruction between the left ventricle (LV) and the aorta Aorta The main trunk of the systemic arteries. Mediastinum and Great Vessels: Anatomy
  • Consequently, produces left ventricular pressure overload
  • If left untreated, results in left ventricular dysfunction and 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)

Epidemiology

  • Most common valvular heart disease
  • Rheumatic heart disease Rheumatic Heart Disease Cardiac manifestation of systemic rheumatological conditions, such as rheumatic fever. Rheumatic heart disease can involve any part the heart, most often the heart valves and the endocardium. Rheumatic Fever: most common cause of AS worldwide
  • In developed countries, most common causes are:
    • Calcific aortic valve Aortic valve The valve between the left ventricle and the ascending aorta which prevents backflow into the left ventricle. Heart: Anatomy disease
    • Congenital Congenital Chorioretinitis bicuspid aortic valve Aortic valve The valve between the left ventricle and the ascending aorta which prevents backflow into the left ventricle. Heart: Anatomy (affects 1%2% of the population)
  • Prevalence Prevalence The total number of cases of a given disease in a specified population at a designated time. It is differentiated from incidence, which refers to the number of new cases in the population at a given time. Measures of Disease Frequency increases with age.
  • Men > women

Etiology

  • Senile calcific AS:
    • Also known as degenerative AS
    • Dystrophic calcification Dystrophic Calcification Cellular Accumulations 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
    • Most common cause in adults > 70 years in developed countries
    • Risk factors:
      • 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
      • Diabetes Diabetes Diabetes mellitus (DM) is a metabolic disease characterized by hyperglycemia and dysfunction of the regulation of glucose metabolism by insulin. Type 1 DM is diagnosed mostly in children and young adults as the result of autoimmune destruction of β cells in the pancreas and the resulting lack of insulin. Type 2 DM has a significant association with obesity and is characterized by insulin resistance. Diabetes Mellitus
      • Smoking Smoking Willful or deliberate act of inhaling and exhaling smoke from burning substances or agents held by hand. Interstitial Lung Diseases
      • End-stage kidney disease
      • Disturbances in mineral metabolism
  • Rheumatic heart disease Rheumatic Heart Disease Cardiac manifestation of systemic rheumatological conditions, such as rheumatic fever. Rheumatic heart disease can involve any part the heart, most often the heart valves and the endocardium. Rheumatic Fever:
    • Most common cause in the developing world
    • Often associated with mitral stenosis Mitral stenosis Mitral stenosis (MS) is the narrowing of the mitral valve (MV) orifice, leading to obstructed blood flow from the left atrium (LA) to the left ventricle (LV). Mitral stenosis is most commonly due to rheumatic heart disease. Mitral stenosis leads to impaired LV diastolic filling, increased LA pressure, and LA dilation. Mitral Stenosis
    • Presents in the 3rd to 5th decade of life
  • Congenital Congenital Chorioretinitis bicuspid aortic valve Aortic valve The valve between the left ventricle and the ascending aorta which prevents backflow into the left ventricle. Heart: Anatomy:
  • 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 
  • Unicuspid valve

Pathophysiology

Mechanisms of valvular damage

  • Senile calcific AS:
    • Hemodynamic stress results in progressive valve thickening and damage, which predispose to calcification.
    • Risk factors and calcification of the leaflet bodies → aortic valve Aortic valve The valve between the left ventricle and the ascending aorta which prevents backflow into the left ventricle. Heart: Anatomy stenosis Stenosis Hypoplastic Left Heart Syndrome (HLHS) and obstruction
    • Gross morphologic hallmark: calcified masses on the outflow cusp surfaces (which limit Limit A value (e.g., pressure or time) that should not be exceeded and which is specified by the operator to protect the lung Invasive Mechanical Ventilation full opening)
  • Rheumatic heart disease Rheumatic Heart Disease Cardiac manifestation of systemic rheumatological conditions, such as rheumatic fever. Rheumatic heart disease can involve any part the heart, most often the heart valves and the endocardium. Rheumatic Fever:
    • 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 of the valve causes necrosis Necrosis The death of cells in an organ or tissue due to disease, injury or failure of the blood supply. Ischemic Cell Damage and injury.
    • Postinflammatory fibrosis Fibrosis Any pathological condition where fibrous connective tissue invades any organ, usually as a consequence of inflammation or other injury. Bronchiolitis Obliterans of the valve leaflets leads to commissural fusion → calcification and stenosis Stenosis Hypoplastic Left Heart Syndrome (HLHS)
  • Bicuspid valve:
    • 2 cusps, which are often of unequal size
    • Malformed valves contribute to turbulence of blood 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, which eventually leads to calcific degeneration.

Mechanism of 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)

  • Normal aortic valve Aortic valve The valve between the left ventricle and the ascending aorta which prevents backflow into the left ventricle. Heart: Anatomy opening: cross-sectional area approximately 3–4 cm²
  • Change in gradient noted when the orifice area is < ½ of normal
  • Gradual progression of stenosis Stenosis Hypoplastic Left Heart Syndrome (HLHS) allows adaptive changes.
  • Obstruction of transvalvular blood 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 → increased left ventricular pressure to maintain cardiac output Cardiac output The volume of blood passing through the heart per unit of time. It is usually expressed as liters (volume) per minute so as not to be confused with stroke volume (volume per beat). Cardiac Mechanics (CO) → Left ventricular hypertrophy Left ventricular hypertrophy Enlargement of the left ventricle of the heart. This increase in ventricular mass is attributed to sustained abnormal pressure or volume loads and is a contributor to cardiovascular morbidity and mortality. Hypertension (LVH) occurs, in order to overcome the increased afterload Afterload Afterload is the resistance in the aorta that prevents blood from leaving the heart. Afterload represents the pressure the LV needs to overcome to eject blood into the aorta. Cardiac Mechanics.
  • Hypertrophic left ventricle leads to decreased compliance Compliance Distensibility measure of a chamber such as the lungs (lung compliance) or bladder. Compliance is expressed as a change in volume per unit change in pressure. Veins: Histology → ↑ left ventricular end diastolic pressure Ventricular end diastolic pressure Cardiac Mechanics (LVEDP)
  • LVH, ↑ LVEDP, and continuous valvular obstruction increase LV oxygen demand → ↑ 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 and myocardial fibrosis Fibrosis Any pathological condition where fibrous connective tissue invades any organ, usually as a consequence of inflammation or other injury. Bronchiolitis Obliterans
  • Changes result in decreased contractility and CO → 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)
  • Other complications:
    • Arrhythmias (e.g., atrial fibrillation Atrial fibrillation Atrial fibrillation (AF or Afib) is a supraventricular tachyarrhythmia and the most common kind of arrhythmia. It is caused by rapid, uncontrolled atrial contractions and uncoordinated ventricular responses. Atrial Fibrillation)
    • Pulmonary 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
Aortic stenosis heart sounds

Image demonstrates the relationship Relationship A connection, association, or involvement between 2 or more parties. Clinician–Patient Relationship between left ventricular pressure (green line) and aortic pressure Aortic pressure Cardiac Mechanics (red line) throughout the cardiac cycle Cardiac cycle The cardiac cycle describes a complete contraction and relaxation of all 4 chambers of the heart during a standard heartbeat. The cardiac cycle includes 7 phases, which together describe the cycle of ventricular filling, isovolumetric contraction, ventricular ejection, and isovolumetric relaxation. Cardiac Cycle. The circle corresponds with the point at which the aortic valve Aortic valve The valve between the left ventricle and the ascending aorta which prevents backflow into the left ventricle. Heart: Anatomy would normally open, beginning the ventricular ejection Ventricular ejection Cardiac Cycle phase. In aortic stenosis Stenosis Hypoplastic Left Heart Syndrome (HLHS), left ventricular pressure exceeds the aortic pressure Aortic pressure Cardiac Mechanics to overcome the stenotic valve. This leads to a systolic ejection murmur.

Image by Lecturio.

Clinical Presentation

Symptoms

  • Asymptomatic for years
  • Exertional 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 and fatigue Fatigue The state of weariness following a period of exertion, mental or physical, characterized by a decreased capacity for work and reduced efficiency to respond to stimuli. Fibromyalgia (initial symptoms)
  • Classic triad (late in the course of the disease):
    1. Exertional angina or chest pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways (from 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)
    2. 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:
      • On exertion (exercise-induced vasodilation Vasodilation The physiological widening of blood vessels by relaxing the underlying vascular smooth muscle. Pulmonary Hypertension Drugs, under the setting of obstruction with fixed CO, leads to 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)
      • At rest (from associated arrhythmias)
    3. 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)
      • Orthopnea Orthopnea Pulmonary Edema
      • Paroxysmal nocturnal 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
      • Pulmonary edema Edema Edema is a condition in which excess serous fluid accumulates in the body cavity or interstitial space of connective tissues. Edema is a symptom observed in several medical conditions. It can be categorized into 2 types, namely, peripheral (in the extremities) and internal (in an organ or body cavity). Edema

Signs

  • Unremarkable early in the course
  • Pulse and blood pressure:
    • Narrow pulse pressure with severe AS
    • Pulsus parvus et tardus (low-amplitude (parvus), delayed (tardus) peak in the carotid arterial pulse)
  • Cardiac inspection Inspection Dermatologic Examination and auscultation:
    • Hyperdynamic left ventricle leading to heave with a double or laterally displaced apical impulse
    • Heart sounds Heart sounds Heart sounds are brief, transient sounds produced by valve opening and closure and by movement of blood in the heart. They are divided into systolic and diastolic sounds. In most cases, only the first (S1) and second (S2) heart sounds are heard. These are high-frequency sounds and arise from aortic and pulmonary valve closure (S1), as well as mitral and tricuspid valve closure (S2). Heart Sounds may have:
    • Murmur:
      • Systolic low-pitched crescendo-decrescendo murmur heard best in the right upper sternal border and radiating to the carotids
      • Gallavardin effect: occasional downward 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 of AS murmur to the cardiac apex (may be confused with mitral regurgitation Mitral regurgitation Mitral regurgitation (MR) is the backflow of blood from the left ventricle (LV) to the left atrium (LA) during systole. Mitral regurgitation may be acute (myocardial infarction) or chronic (myxomatous degeneration). Acute and decompensated chronic MR can lead to pulmonary venous congestion, resulting in symptoms of dyspnea, orthopnea, and fatigue. Mitral Regurgitation murmur)
    • Provocative maneuvers: 
      • Decreased murmur: Valsalva maneuver Valsalva maneuver Forced expiratory effort against a closed glottis. Rectal Prolapse, standing (decreased intracardiac Intracardiac Total Anomalous Pulmonary Venous Return (TAPVR) volume) or sustained handgrip (increased afterload Afterload Afterload is the resistance in the aorta that prevents blood from leaving the heart. Afterload represents the pressure the LV needs to overcome to eject blood into the aorta. Cardiac Mechanics)
      • Increased murmur: leg Leg The lower leg, or just “leg” in anatomical terms, is the part of the lower limb between the knee and the ankle joint. The bony structure is composed of the tibia and fibula bones, and the muscles of the leg are grouped into the anterior, lateral, and posterior compartments by extensions of fascia. Leg: Anatomy raising, squatting, and after a premature Premature Childbirth before 37 weeks of pregnancy (259 days from the first day of the mother’s last menstrual period, or 245 days after fertilization). Necrotizing Enterocolitis ventricular beat (increased preload Preload Cardiac Mechanics)
Cardiac murmurs after correction

Phonocardiograms of abnormal heart sounds Heart sounds Heart sounds are brief, transient sounds produced by valve opening and closure and by movement of blood in the heart. They are divided into systolic and diastolic sounds. In most cases, only the first (S1) and second (S2) heart sounds are heard. These are high-frequency sounds and arise from aortic and pulmonary valve closure (S1), as well as mitral and tricuspid valve closure (S2). Heart Sounds caused by the following cardiac defects:
aortic regurgitation Aortic regurgitation Aortic regurgitation (AR) is a cardiac condition characterized by the backflow of blood from the aorta to the left ventricle during diastole. Aortic regurgitation is associated with an abnormal aortic valve and/or aortic root stemming from multiple causes, commonly rheumatic heart disease as well as congenital and degenerative valvular disorders. Aortic Regurgitation, mitral valve Mitral valve The valve between the left atrium and left ventricle of the heart. Heart: Anatomy prolapse, mitral stenosis Mitral stenosis Mitral stenosis (MS) is the narrowing of the mitral valve (MV) orifice, leading to obstructed blood flow from the left atrium (LA) to the left ventricle (LV). Mitral stenosis is most commonly due to rheumatic heart disease. Mitral stenosis leads to impaired LV diastolic filling, increased LA pressure, and LA dilation. Mitral Stenosis ( MS MS Multiple sclerosis (MS) is a chronic inflammatory autoimmune disease that leads to demyelination of the nerves in the CNS. Young women are more predominantly affected by this most common demyelinating condition. Multiple Sclerosis), aortic stenosis Stenosis Hypoplastic Left Heart Syndrome (HLHS) (AS), tricuspid regurgitation Tricuspid regurgitation Tricuspid regurgitation (TR) is a valvular defect that allows backflow of blood from the right ventricle to the right atrium during systole. Tricuspid regurgitation can develop through a number of cardiac conditions that cause dilation of the right ventricle and tricuspid annulus. A blowing holosystolic murmur is best heard at the left lower sternal border. Tricuspid Regurgitation, hypertrophic obstructive cardiomyopathy Cardiomyopathy Cardiomyopathy refers to a group of myocardial diseases associated with structural changes of the heart muscles (myocardium) and impaired systolic and/or diastolic function in the absence of other heart disorders (coronary artery disease, hypertension, valvular disease, and congenital heart disease). Cardiomyopathy: Overview and Types (HOCM), atrial septal defect Atrial Septal Defect Atrial septal defects (ASDs) are benign acyanotic congenital heart defects characterized by an opening in the interatrial septum that causes blood to flow from the left atrium (LA) to the right atrium (RA) (left-to-right shunt). Atrial Septal Defect (ASD) ( ASD ASD Autism spectrum disorder (ASD) is a neurodevelopmental disorder marked by poor social skills, restricted interests/social interactions, and repetitive/stereotyped behaviors. The condition is termed a “spectrum” because of the wide variability in the severity of symptoms exhibited. Autism Spectrum Disorder), ventricular septal defect Ventricular Septal Defect Tetralogy of Fallot (VSD), and patent ductus arteriosus Ductus arteriosus A fetal blood vessel connecting the pulmonary artery with the descending aorta. Patent Ductus Arteriosus (PDA) ( PDA PDA The ductus arteriosus (DA) allows blood to bypass pulmonary circulation. After birth, the DA remains open for up to 72 hours and then constricts and involutes, becoming the ligamentum arteriosum. Failure of this process to occur results in patent ductus arteriosus (PDA), a condition that causes up to 10% of congenital heart defects. Patent Ductus Arteriosus (PDA))

Image by Lecturio.

Audio:

This audio clip is an example of severe aortic stenosis Stenosis Hypoplastic Left Heart Syndrome (HLHS). This is a harsh, crescendo-decrescendo murmur occurring between S1 S1 Heart Sounds and S2 S2 Heart Sounds. Due to the severity of the aortic stenosis Stenosis Hypoplastic Left Heart Syndrome (HLHS), the S2 S2 Heart Sounds heart sound is inaudible.

Heart sound by The Regents of the University of Michigan. License: CC BY-SA 3.0

Diagnosis

Transthoracic and Doppler Doppler Ultrasonography applying the doppler effect, with frequency-shifted ultrasound reflections produced by moving targets (usually red blood cells) in the bloodstream along the ultrasound axis in direct proportion to the velocity of movement of the targets, to determine both direction and velocity of blood flow. Ultrasound (Sonography) echocardiography Echocardiography Ultrasonic recording of the size, motion, and composition of the heart and surrounding tissues. The standard approach is transthoracic. Tricuspid Valve Atresia (TVA)

  • Diagnostic imaging of choice
  • Details provided:
    • Structure and function of the valve
    • Valvular findings: decreased aortic valve Aortic valve The valve between the left ventricle and the ascending aorta which prevents backflow into the left ventricle. Heart: Anatomy opening, valvular calcification, bicuspid valve
    • Other findings: LV hypertrophy Hypertrophy General increase in bulk of a part or organ due to cell enlargement and accumulation of fluids and secretions, not due to tumor formation, nor to an increase in the number of cells (hyperplasia). Cellular Adaptation, aortic wall abnormalities, systolic and diastolic function 
    • Systolic dysfunction Systolic dysfunction Dilated Cardiomyopathy or LV ejection fraction Ejection fraction Cardiac Cycle ( EF EF Cardiac Cycle) < 50%: important in determining AS management
  • Parameters of stenosis Stenosis Hypoplastic Left Heart Syndrome (HLHS) (from Doppler Doppler Ultrasonography applying the doppler effect, with frequency-shifted ultrasound reflections produced by moving targets (usually red blood cells) in the bloodstream along the ultrasound axis in direct proportion to the velocity of movement of the targets, to determine both direction and velocity of blood flow. Ultrasound (Sonography) echocardiography Echocardiography Ultrasonic recording of the size, motion, and composition of the heart and surrounding tissues. The standard approach is transthoracic. Tricuspid Valve Atresia (TVA)):
    • Transvalvular gradient Transvalvular gradient Tricuspid Stenosis (in mm MM Multiple myeloma (MM) is a malignant condition of plasma cells (activated B lymphocytes) primarily seen in the elderly. Monoclonal proliferation of plasma cells results in cytokine-driven osteoclastic activity and excessive secretion of IgG antibodies. Multiple Myeloma Hg)
    • 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 velocity with decreased valvular area 
    • Aortic valve Aortic valve The valve between the left ventricle and the ascending aorta which prevents backflow into the left ventricle. Heart: Anatomy area (in cm²):
      • Severe AS: valve area < 1 cm2
      • Moderate AS: valve area 1–1.5 cm2
      • Mild AS: valve area 1.5–2 cm2
  • Additional information provided:
    • Other coexisting valvular disease
    • Hypertrophic cardiomyopathy Cardiomyopathy Cardiomyopathy refers to a group of myocardial diseases associated with structural changes of the heart muscles (myocardium) and impaired systolic and/or diastolic function in the absence of other heart disorders (coronary artery disease, hypertension, valvular disease, and congenital heart disease). Cardiomyopathy: Overview and Types
    • Ascending aortic 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 associated with bicuspid valves
    • Coarctation of aorta Aorta The main trunk of the systemic arteries. Mediastinum and Great Vessels: Anatomy

Other tests

  • ECG ECG An electrocardiogram (ECG) is a graphic representation of the electrical activity of the heart plotted against time. Adhesive electrodes are affixed to the skin surface allowing measurement of cardiac impulses from many angles. The ECG provides 3-dimensional information about the conduction system of the heart, the myocardium, and other cardiac structures. Electrocardiogram (ECG):
    • Results vary and depend on associated structural abnormalities and arrhythmias.
    • May demonstrate left ventricular hypertrophy Left ventricular hypertrophy Enlargement of the left ventricle of the heart. This increase in ventricular mass is attributed to sustained abnormal pressure or volume loads and is a contributor to cardiovascular morbidity and mortality. Hypertension, left atrial enlargement, and left axis deviation
  • Chest X-ray Chest X-ray X-ray visualization of the chest and organs of the thoracic cavity. It is not restricted to visualization of the lungs. Pulmonary Function Tests:
    • On lateral views, aortic valve Aortic valve The valve between the left ventricle and the ascending aorta which prevents backflow into the left ventricle. Heart: Anatomy calcification can be seen.
    • Pulmonary congestion from LV failure can be visualized.
  • Exercise stress testing or exercise tolerance Tolerance Pharmacokinetics and Pharmacodynamics test (ETT):
    • Contraindicated in symptomatic severe AS 
    • Performed in select cases (e.g., unclear level of physical activity, low-gradient AS)
  • Cardiac catheterization Cardiac Catheterization Procedures in which placement of cardiac catheters is performed for therapeutic or diagnostic procedures. Cardiac Surgery and coronary arteriography:
  • Multidetector computed tomography (MDCT):

Management

General principles

  • Aortic valve Aortic valve The valve between the left ventricle and the ascending aorta which prevents backflow into the left ventricle. Heart: Anatomy replacement (AVR): mainstay of treatment of symptomatic AS
  • To determine candidates for AVR, the following details are obtained:
    • Symptom status
    • Severity of AS: 
      • Severe AS: aortic jet velocity ≥ 4 m/sec, mean Mean Mean is the sum of all measurements in a data set divided by the number of measurements in that data set. Measures of Central Tendency and Dispersion transvalvular gradient Transvalvular gradient Tricuspid Stenosis of ≥ 40 mm MM Multiple myeloma (MM) is a malignant condition of plasma cells (activated B lymphocytes) primarily seen in the elderly. Monoclonal proliferation of plasma cells results in cytokine-driven osteoclastic activity and excessive secretion of IgG antibodies. Multiple Myeloma Hg
      • Severe AS: typically with < 1 cm² area (but is not required)
    • LV systolic function: LVEF < 50% = systolic dysfunction Systolic dysfunction Dilated Cardiomyopathy
  • Indications for AVR:
    • Asymptomatic severe AS:
      • Abnormal ETT (decreased exercise tolerance Tolerance Pharmacokinetics and Pharmacodynamics)
      • With LVEF < 50%
      • Undergoing other 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
      • Rapid disease progression and low surgical risk
    • Symptomatic severe AS
  • For less severe or moderate AS, performing AVR depends on multiple factors:
    • Symptoms
    • Aortic valve Aortic valve The valve between the left ventricle and the ascending aorta which prevents backflow into the left ventricle. Heart: Anatomy area < 1 cm²
    • LVEF 
    • ETT, dobutamine Dobutamine A catecholamine derivative with specificity for beta-1 adrenergic receptors. Sympathomimetic Drugs stress echocardiography Echocardiography Ultrasonic recording of the size, motion, and composition of the heart and surrounding tissues. The standard approach is transthoracic. Tricuspid Valve Atresia (TVA)
    • If undergoing other 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

Surgical management

  • For patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship with life expectancy Life expectancy Based on known statistical data, the number of years which any person of a given age may reasonably expected to live. Population Pyramids > 1 year and if surgery is likely to improve quality Quality Activities and programs intended to assure or improve the quality of care in either a defined medical setting or a program. The concept includes the assessment or evaluation of the quality of care; identification of problems or shortcomings in the delivery of care; designing activities to overcome these deficiencies; and follow-up monitoring to ensure effectiveness of corrective steps. Quality Measurement and Improvement of life
  • Transcatheter aortic valve Aortic valve The valve between the left ventricle and the ascending aorta which prevents backflow into the left ventricle. Heart: Anatomy implantation Implantation Endometrial implantation of embryo, mammalian at the blastocyst stage. Fertilization and First Week (TAVI):
    • In patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship with intermediate-high surgical risk
    • In patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship with low surgical risk meeting feasibility for TAVI
  • Surgical aortic valve Aortic valve The valve between the left ventricle and the ascending aorta which prevents backflow into the left ventricle. Heart: Anatomy replacement (SAVR):
    • In patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship with low or intermediate risk and TAVI is not feasible
    • Presence of another indication for 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
  • Percutaneous aortic balloon valvuloplasty (PABV):
    • Not a substitute for valve replacement
    • Has high rate of re-stenosis
    • Consider as a bridge to TAVI or SAVR in severe symptomatic AS
    • Palliation for patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship who are not good candidates for AVR
    • Has a role for young and adolescent patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship

General recommendations for non-surgical management

  • Periodic monitoring: 
  • Activity:
    • Avoid strenuous physical activity and competitive sports in severe AS.
    • Avoid dehydration Dehydration The condition that results from excessive loss of water from a living organism. Volume Depletion and Dehydration (to protect against CO reduction).
  • Medications:
    • Endocarditis Endocarditis Endocarditis is an inflammatory disease involving the inner lining (endometrium) of the heart, most commonly affecting the cardiac valves. Both infectious and noninfectious etiologies lead to vegetations on the valve leaflets. Patients may present with nonspecific symptoms such as fever and fatigue. Endocarditis prophylaxis Prophylaxis Cephalosporins: with history of infective endocarditis Infective endocarditis Infective endocarditis (IE) is caused by infection or inflammation of the inner lining of the heart (endocardium), most commonly affecting the heart valves. Endocarditis
    • General guidelines: Start with low dose and slowly titrate.
    • Angiotensin-converting enzyme (ACE) inhibitors: may improve LV fibrosis Fibrosis Any pathological condition where fibrous connective tissue invades any organ, usually as a consequence of inflammation or other injury. Bronchiolitis Obliterans in addition to blood pressure control
    • Beta blockers:
      • Reduce contractility 
      • Continue with coexisting coronary artery disease Coronary artery disease Pathological processes of coronary arteries that may derive from a congenital abnormality, atherosclerotic, or non-atherosclerotic cause. Stable and Unstable Angina or atrial fibrillation Atrial fibrillation Atrial fibrillation (AF or Afib) is a supraventricular tachyarrhythmia and the most common kind of arrhythmia. It is caused by rapid, uncontrolled atrial contractions and uncoordinated ventricular responses. Atrial Fibrillation
      • For 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, consider a low dose but generally avoid with symptomatic AS and 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).
    • Diuretics Diuretics Agents that promote the excretion of urine through their effects on kidney function. Heart Failure and Angina Medication
      • Excessive decrease in preload Preload Cardiac Mechanics should be avoided.
      • Use with caution if the patient has symptomatic AS (because it reduces ventricular volume).

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

  • If untreated with surgery, 50% of patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship die within 3 years of symptom onset (angina, 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, or 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)). 
  • Surgical mortality rate Mortality rate 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 for valve replacement including the elderly is 2%5%.

Differential Diagnosis

  • Hypertrophic cardiomyopathy Cardiomyopathy Cardiomyopathy refers to a group of myocardial diseases associated with structural changes of the heart muscles (myocardium) and impaired systolic and/or diastolic function in the absence of other heart disorders (coronary artery disease, hypertension, valvular disease, and congenital heart disease). Cardiomyopathy: Overview and Types: a cardiac condition characterized by a thickened left ventricular wall leading to left ventricular outflow obstruction Ventricular Outflow Obstruction Occlusion of the outflow tract in either the left ventricle or the right ventricle of the heart. This may result from congenital heart defects, predisposing heart diseases, complications of surgery, or heart neoplasms. Tetralogy of Fallot and diastolic dysfunction Diastolic dysfunction Restrictive Cardiomyopathy. Patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship present with exertional 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, 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, and, in extreme cases, sudden cardiac death Sudden cardiac death Cardiac arrest is the sudden, complete cessation of cardiac output with hemodynamic collapse. Patients present as pulseless, unresponsive, and apneic. Rhythms associated with cardiac arrest are ventricular fibrillation/tachycardia, asystole, or pulseless electrical activity. Cardiac Arrest. The systolic murmur increases with the Valsalva maneuver Valsalva maneuver Forced expiratory effort against a closed glottis. Rectal Prolapse and standing. Diagnosis is by echocardiography Echocardiography Ultrasonic recording of the size, motion, and composition of the heart and surrounding tissues. The standard approach is transthoracic. Tricuspid Valve Atresia (TVA). Management includes negative inotropic agents with surgical options to reduce the LV outflow obstruction. An implantable defibrillator Implantable defibrillator Implantable devices which continuously monitor the electrical activity of the heart and automatically detect and terminate ventricular tachycardia and ventricular fibrillation. They consist of an impulse generator, batteries, and electrodes. Ventricular Fibrillation (V-fib) is placed for those at risk for sudden death.
  • 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: an acute blockage 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 supplying the heart, which can predispose to structural valvular incompetence. This condition commonly presents with chest pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways and is diagnosed with ECG ECG An electrocardiogram (ECG) is a graphic representation of the electrical activity of the heart plotted against time. Adhesive electrodes are affixed to the skin surface allowing measurement of cardiac impulses from many angles. The ECG provides 3-dimensional information about the conduction system of the heart, the myocardium, and other cardiac structures. Electrocardiogram (ECG) and cardiac enzyme tests.
  • Aortic regurgitation Aortic regurgitation Aortic regurgitation (AR) is a cardiac condition characterized by the backflow of blood from the aorta to the left ventricle during diastole. Aortic regurgitation is associated with an abnormal aortic valve and/or aortic root stemming from multiple causes, commonly rheumatic heart disease as well as congenital and degenerative valvular disorders. Aortic Regurgitation: characterized by the backflow of blood from the aorta Aorta The main trunk of the systemic arteries. Mediastinum and Great Vessels: Anatomy to the left ventricle, commonly caused by rheumatic heart disease Rheumatic Heart Disease Cardiac manifestation of systemic rheumatological conditions, such as rheumatic fever. Rheumatic heart disease can involve any part the heart, most often the heart valves and the endocardium. Rheumatic Fever, and congenital Congenital Chorioretinitis and degenerative valvular disorders. Examination shows an early diastolic high-pitched decrescendo murmur, heard best in the left sternal border. Diagnosis is by echocardiography Echocardiography Ultrasonic recording of the size, motion, and composition of the heart and surrounding tissues. The standard approach is transthoracic. Tricuspid Valve Atresia (TVA). The acute form is a medical emergency requiring immediate surgery.
  • Congestive heart failure Congestive heart failure Congestive heart failure refers to the inability of the heart to supply the body with normal cardiac output to meet metabolic needs. Echocardiography can confirm the diagnosis and give information about the ejection fraction. Congestive Heart Failure ( CHF CHF Congestive heart failure refers to the inability of the heart to supply the body with normal cardiac output to meet metabolic needs. Echocardiography can confirm the diagnosis and give information about the ejection fraction. Congestive Heart Failure) with systolic dysfunction Systolic dysfunction Dilated Cardiomyopathy: a chronic, progressive condition characterized by left ventricular dysfunction from impaired myocyte contractility. This leads to subsequent volume overload. Risk factors include 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, coronary artery disease Coronary artery disease Pathological processes of coronary arteries that may derive from a congenital abnormality, atherosclerotic, or non-atherosclerotic cause. Stable and Unstable Angina, and diabetes mellitus Diabetes mellitus Diabetes mellitus (DM) is a metabolic disease characterized by hyperglycemia and dysfunction of the regulation of glucose metabolism by insulin. Type 1 DM is diagnosed mostly in children and young adults as the result of autoimmune destruction of β cells in the pancreas and the resulting lack of insulin. Type 2 DM has a significant association with obesity and is characterized by insulin resistance. Diabetes Mellitus. Congestive heart failure Congestive heart failure Congestive heart failure refers to the inability of the heart to supply the body with normal cardiac output to meet metabolic needs. Echocardiography can confirm the diagnosis and give information about the ejection fraction. Congestive Heart Failure can develop with or without valvular abnormalities.

References

  1. Ahmed, S., & Bernath, G.A. (2017). Valvular heart diseases. Elmoselhi, A. (Ed.), Cardiology: An Integrated Approach. McGraw-Hill.
  2. Bashore, T.M., & Granger, C.B., & Jackson K.P., & Patel M.R. (2021). Aortic stenosis. Papadakis M.A., & McPhee S.J., & Rabow M.W.(Eds.), Current Medical Diagnosis & Treatment 2021. McGraw-Hill.
  3. Gaasch, W., Otto, C., & Yeon, S. (2020) Natural history, epidemiology, and prognosis of aortic stenosis. UptoDate. Retrieved 31 Oct 2020, from https://www.uptodate.com/contents/natural-history-epidemiology-and-prognosis-of-aortic-stenosis
  4. Grimard, B., Safford, R., & Burns, E. (2016) Aortic stenosis: Diagnosis and Treatment. Am Fam Physician. 2016 Mar 1;93(5):371-378.
  5. Mitchell, R., & Halushka, M. (2020) Blood vessels. In Kumar, V., Abbas, A., Aster, J. & Robbins, S. Robbins and Cotran Pathologic Basis of Disease (10th Ed., pp. 557-567). Elsevier, Inc.
  6. O’Gara, P.T., & Loscalzo, J. (2018). Aortic valve disease. Jameson J, & Fauci A.S., & Kasper D.L., & Hauser S.L., & Longo D.L., & Loscalzo J(Eds.), Harrison’s Principles of Internal Medicine, 20e. McGraw-Hill.
  7. Otto, C., Cooper, S., Gaasch, W., & Yeon, S. (2019) Medical management of symptomatic aortic stenosis. UpToDate. Retrieved 1 Nov 2020, from https://www.uptodate.com/contents/medical-management-of-symptomatic-aortic-stenosis
  8. Otto, C., Gaasch, W., & Yeon, S. (2019) Medical management of symptomatic aortic stenosis. UpToDate. Retrieved 1 Nov 2020, from https://www.uptodate.com/contents/medical-management-of-asymptomatic-aortic-stenosis-in-adults
  9. Ren, X., & O-Brien, T. (2019) Aortic stenosis, Medscape. Retrieved 31 Oct 2020, from https://emedicine.medscape.com/article/150638-overview#a5

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