Pulmonary Stenosis

Overview

Anatomy

Pulmonary (or pulmonic) valve:

• Semilunar valve between the right ventricle (RV) and pulmonary artery Pulmonary artery The short wide vessel arising from the conus arteriosus of the right ventricle and conveying unaerated blood to the lungs. Lungs: Anatomy (PA)
• Consists of 3 cusps: anterior, left, and right
• Opens during systole Systole Period of contraction of the heart, especially of the heart ventricles. Cardiac Cycle as the RV pressure exceeds the pulmonary trunk Pulmonary Trunk Truncus Arteriosus pressure
• Closes during diastole Diastole Post-systolic relaxation of the heart, especially the heart ventricles. Cardiac Cycle as the RV pressure drops ( S2 S2 Heart Sounds), preventing retrograde flow Retrograde flow Veins: Histology from the pulmonary trunk Pulmonary Trunk Truncus Arteriosus

Definition and Epidemiology

Definition

Pulmonary stenosis Stenosis Hypoplastic Left Heart Syndrome (HLHS) is the narrowing of the pulmonary valve Pulmonary valve A valve situated at the entrance to the pulmonary trunk from the right ventricle. Heart: Anatomy causing:

• An increased pressure gradient Pressure gradient Vascular Resistance, Flow, and Mean Arterial Pressure across the valve
• An obstruction to the 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 from the RV to the PA

• Affects 7% of children with congenital heart defects
• Mild PS PS Invasive Mechanical Ventilation: good 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, with no difference from unaffected population
• Severe PS PS Invasive Mechanical Ventilation:
  • Without treatment, advances to RV outflow obstruction
  • Intervention required by majority of affected patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship within 10 years of diagnosis

Etiology and Classification

Etiology

• Cases are often congenital:
  • Isolated valvular PS PS Invasive Mechanical Ventilation:
    • 10% of congenital heart disease
    • Valve is typically dome shaped.
  • Other congenital forms:
    • As part of Noonan syndrome Noonan syndrome A genetically heterogeneous, multifaceted disorder characterized by short stature, webbed neck, ptosis, skeletal malformations, hypertelorism, hormonal imbalance, cryptorchidism, multiple cardiac abnormalities (most commonly including pulmonary valve stenosis), and some degree of intellectual disability. The phenotype bears similarities to that of turner syndrome that occurs only in females and has its basis in a 45, X karyotype abnormality. Noonan syndrome occurs in both males and females with a normal karyotype (46, XX and 46, xy). Mutations in a several genes (ptpn11, kras, sos1, nf1 and raf1) have been associated the ns phenotype. Mutations in ptpn11 are the most common. Leopard syndrome, a disorder that has clinical features overlapping those of noonan syndrome, is also due to mutations in ptpn11. In addition, there is overlap with the syndrome called neurofibromatosis-noonan syndrome due to mutations in nf1. Hypogonadism:
      • 50% of cases are associated with the PTPN11 gene mutation Gene Mutation Myotonic Dystrophies.
      • Usually with dysplastic valves
    • Tetralogy of Fallot Tetralogy of Fallot Tetralogy of Fallot is the most common cyanotic congenital heart disease. The disease is the confluence of 4 pathologic cardiac features: overriding aorta, ventricular septal defect, right ventricular outflow obstruction, and right ventricular hypertrophy. Tetralogy of Fallot (TOF):
      • Pulmonary valve Pulmonary valve A valve situated at the entrance to the pulmonary trunk from the right ventricle. Heart: Anatomy stenosis Stenosis Hypoplastic Left Heart Syndrome (HLHS) 
      • Overriding aorta Overriding Aorta Tetralogy of Fallot
      • RVH
      • Ventricular septal defect Ventricular Septal Defect Tetralogy of Fallot (VSD)
    • Congenital rubella syndrome Congenital rubella syndrome Transplacental infection of the fetus with rubella usually in the first trimester of pregnancy, as a consequence of maternal infection, resulting in various developmental abnormalities in the newborn infant. They include cardiac and ocular lesions, deafness, microcephaly, mental retardation, and generalized growth retardation. Rubella Virus
• Acquired PS PS Invasive Mechanical Ventilation:
  • Carcinoid syndrome Carcinoid syndrome A symptom complex associated with carcinoid tumor and characterized by attacks of severe flushing of the skin, diarrheal watery stools, bronchoconstriction, sudden drops in blood pressure, edema, and ascites. The carcinoid tumors are usually located in the gastrointestinal tract and metastasize to the liver. Symptoms are caused by tumor secretion of serotonin, prostaglandins, and other biologically active substances. Cardiac manifestations constitute carcinoid heart disease. Carcinoid Tumors and Syndrome
  • 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 (rarely involves PS PS Invasive Mechanical Ventilation)
  • Previous cardiothoracic surgeries

Types of stenosis Stenosis Hypoplastic Left Heart Syndrome (HLHS)

• Valvular PS PS Invasive Mechanical Ventilation: 
  • Narrowed or thickened valve
  • Most common type
  • Associated with TOF, congenital rubella syndrome Congenital rubella syndrome Transplacental infection of the fetus with rubella usually in the first trimester of pregnancy, as a consequence of maternal infection, resulting in various developmental abnormalities in the newborn infant. They include cardiac and ocular lesions, deafness, microcephaly, mental retardation, and generalized growth retardation. Rubella Virus, Noonan syndrome Noonan syndrome A genetically heterogeneous, multifaceted disorder characterized by short stature, webbed neck, ptosis, skeletal malformations, hypertelorism, hormonal imbalance, cryptorchidism, multiple cardiac abnormalities (most commonly including pulmonary valve stenosis), and some degree of intellectual disability. The phenotype bears similarities to that of turner syndrome that occurs only in females and has its basis in a 45, X karyotype abnormality. Noonan syndrome occurs in both males and females with a normal karyotype (46, XX and 46, xy). Mutations in a several genes (ptpn11, kras, sos1, nf1 and raf1) have been associated the ns phenotype. Mutations in ptpn11 are the most common. Leopard syndrome, a disorder that has clinical features overlapping those of noonan syndrome, is also due to mutations in ptpn11. In addition, there is overlap with the syndrome called neurofibromatosis-noonan syndrome due to mutations in nf1. Hypogonadism, acquired PS PS Invasive Mechanical Ventilation from carcinoid syndrome Carcinoid syndrome A symptom complex associated with carcinoid tumor and characterized by attacks of severe flushing of the skin, diarrheal watery stools, bronchoconstriction, sudden drops in blood pressure, edema, and ascites. The carcinoid tumors are usually located in the gastrointestinal tract and metastasize to the liver. Symptoms are caused by tumor secretion of serotonin, prostaglandins, and other biologically active substances. Cardiac manifestations constitute carcinoid heart disease. Carcinoid Tumors and Syndrome
• Subvalvular infundibular PS PS Invasive Mechanical Ventilation:
  • Fibromuscular narrowing of the infundibular region, with normal valve
  • Rare
  • Can be found with other congenital lesions (TOF, VSD)
• Supravalvular (or peripheral) PS PS Invasive Mechanical Ventilation: 
  • Narrowing of the main PA or its branches, up to the periphery
  • Murmurs heard over the lungs Lungs Lungs are the main organs of the respiratory system. Lungs are paired viscera located in the thoracic cavity and are composed of spongy tissue. The primary function of the lungs is to oxygenate blood and eliminate CO2. Lungs: Anatomy
  • Mild form: nonpathologic, with murmur resolving by 6 months of age
  • Associated with congenital rubella syndrome Congenital rubella syndrome Transplacental infection of the fetus with rubella usually in the first trimester of pregnancy, as a consequence of maternal infection, resulting in various developmental abnormalities in the newborn infant. They include cardiac and ocular lesions, deafness, microcephaly, mental retardation, and generalized growth retardation. Rubella Virus or other anomalies (TOF, patent ductus arteriosus Ductus arteriosus A fetal blood vessel connecting the pulmonary artery with the descending aorta. Patent Ductus Arteriosus (PDA), VSD)

Pathophysiology and Clinical Presentation

Pathophysiology

• PS PS Invasive Mechanical Ventilation causes sustained outflow tract obstruction, which increases right ventricular afterload Right Ventricular Afterload Noninvasive Ventilation. 
• RV is less adaptive than the left ventricle, with early rises in pressures; so, with lower systolic pressures, RVH occurs.
• Right atrial (RA) pressure increases as a result of elevated RV pressure.
• Late in the disease: persistently increased RV strain → RV dysfunction occurs → eventual RV failure
• Other complications: arrhythmia, 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

Symptoms

• Commonly asymptomatic during mild-to-moderate disease (majority of patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship)
• Severe PS PS Invasive Mechanical Ventilation:
  • The more severe the obstruction is, the earlier it is detected.
  • 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 and 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 
  • Anginal chest pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways from oxygen supply-demand mismatch
  • 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 especially when accompanied by provoking factors (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, infection)

Signs

• Prominent a wave in jugular venous pulse (strong atrial contraction)
• 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:
  • A high-pitched crescendo-decrescendo (diamond-shaped) systolic ejection murmur heard at the left upper sternal border (2nd intercostal space)
  • Murmur preceded by a pulmonary ejection click, which decreases with inspiration Inspiration Ventilation: Mechanics of Breathing (the only right-sided sound that decreases with inspiration Inspiration Ventilation: Mechanics of Breathing)
  • P2 delayed (wide S2 S2 Heart Sounds splitting Splitting Defense Mechanisms)
  • Right-sided S3 S3 Heart Sounds, S4 S4 Heart Sounds (RV failure)
• Left parasternal lift (from RVH) in severe PS PS Invasive Mechanical Ventilation
• Cyanosis Cyanosis A bluish or purplish discoloration of the skin and mucous membranes due to an increase in the amount of deoxygenated hemoglobin in the blood or a structural defect in the hemoglobin molecule. Pulmonary Examination in those with a right-to-left shunt (e.g., 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))
• Very late in the course: peripheral edema Peripheral edema Peripheral edema is the swelling of the lower extremities, namely, legs, feet, and ankles. Edema, hepatomegaly, ascites Ascites Ascites is the pathologic accumulation of fluid within the peritoneal cavity that occurs due to an osmotic and/or hydrostatic pressure imbalance secondary to portal hypertension (cirrhosis, heart failure) or non-portal hypertension (hypoalbuminemia, malignancy, infection). Ascites

Diagnosis

• Transthoracic echocardiography Transthoracic Echocardiography Imaging of the Heart and Great Vessels ( TTE TTE Imaging of the Heart and Great Vessels) with 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):
  • 2-dimensional 2-Dimensional Imaging of the Heart and Great Vessels (2D) 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) echocardiogram Echocardiogram Transposition of the Great Arteries confirms the diagnosis.
  • Findings:
    • Pulmonary valve Pulmonary valve A valve situated at the entrance to the pulmonary trunk from the right ventricle. Heart: Anatomy thickening, doming of the valves
    • RVH, narrowed RV outflow tract
    • Post-stenotic dilation of the PA
    • Associated cardiac defects
    • Increased transvalvular gradient Transvalvular gradient Tricuspid Stenosis between the RV and the PA
  • Grading Grading Methods which attempt to express in replicable terms the level of cell differentiation in neoplasms as increasing anaplasia correlates with the aggressiveness of the neoplasm. Grading, Staging, and Metastasis:
    • Mild PS PS Invasive Mechanical Ventilation: peak 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) gradient < 30 mm Hg
    • Moderate PS PS Invasive Mechanical Ventilation: peak 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) gradient of 30–50 mm Hg
    • Severe PS PS Invasive Mechanical Ventilation: peak 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) gradient across the pulmonary valve Pulmonary valve A valve situated at the entrance to the pulmonary trunk from the right ventricle. Heart: Anatomy of > 50 mm Hg
• Transesophageal 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) ( 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):
  • Use when assessing for 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.
  • Not indicated for routine diagnosis of PS PS Invasive Mechanical Ventilation
• Electrocardiogram Electrocardiogram 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) ( 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)):
  • Right axis deviation, RVH, right atrial enlargement
  • Right bundle branch block Right bundle branch block Bundle Branch and Fascicular Blocks
• 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:
  • Frontal view Frontal View Imaging of the Spine and Spinal Cord:
    • Prominent PA from post-stenotic dilation
    • Lifting of the cardiac apex off the diaphragm Diaphragm The diaphragm is a large, dome-shaped muscle that separates the thoracic cavity from the abdominal cavity. The diaphragm consists of muscle fibers and a large central tendon, which is divided into right and left parts. As the primary muscle of inspiration, the diaphragm contributes 75% of the total inspiratory muscle force. Diaphragm: Anatomy
    • Prominent right heart border Right Heart Border Imaging of the Heart and Great Vessels from RA enlargement
  • Lateral view: filling of the retrosternal space by the enlarged RV
• Cardiac magnetic resonance Cardiac magnetic resonance Aortic Regurgitation imaging:
  • An option if TTE TTE Imaging of the Heart and Great Vessels is suboptimal
  • Evaluates severity of the valve abnormalities and branch PA 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
  • Delineates anatomy of the PA and right heart
• Cardiac catheterization Cardiac Catheterization Procedures in which placement of cardiac catheters is performed for therapeutic or diagnostic procedures. Cardiac Surgery and pulmonary angiography Angiography Radiography of blood vessels after injection of a contrast medium. Cardiac Surgery:
  • Not necessary for the diagnosis of PS PS Invasive Mechanical Ventilation
  • Performed if clinical findings and echocardiographic findings are inconclusive
  • Provides information about concomitant congenital abnormalities Congenital Abnormalities Malformations of organs or body parts during development in utero. Omphalocele

Management

• Monitoring:
  • Asymptomatic, with peak 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) gradient < 30 mm Hg: physical examination, 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), 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) every 5 years 
  • Asymptomatic, with peak 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) gradient > 30 mm Hg: 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) every 2–5 years
• Diuretics Diuretics Agents that promote the excretion of urine through their effects on kidney function. Heart Failure and Angina Medication: for symptoms of RV overload
• Percutaneous balloon valvotomy Balloon valvotomy Percutaneous procedure to separate and stretch the valve leaflets to increase the valve opening. Tricuspid Stenosis:
  • Symptomatic patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship with a domed valve and a peak gradient > 50 mm Hg (or a mean gradient > 30 mm Hg)
  • Asymptomatic patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship with a peak gradient > 60 mm Hg (or a mean gradient > 40 mm Hg)
• Surgical valvotomy for severe PS PS Invasive Mechanical Ventilation associated with:
  • Hypoplastic pulmonary annulus
  • Severe pulmonary regurgitation Regurgitation Gastroesophageal Reflux Disease (GERD)
  • Subvalvular PS PS Invasive Mechanical Ventilation
  • Most dysplastic valves
  • Severe tricuspid regurgitation Regurgitation Gastroesophageal Reflux Disease (GERD)
  • Surgical cardiac condition requiring operative intervention

Clinical Relevance

• TOF: cyanotic congenital heart disease characterized by the tetrad of RVH, an overriding aorta Overriding Aorta Tetralogy of Fallot, pulmonary valve Pulmonary valve A valve situated at the entrance to the pulmonary trunk from the right ventricle. Heart: Anatomy stenosis Stenosis Hypoplastic Left Heart Syndrome (HLHS), and a ventricular septal defect Ventricular Septal Defect Tetralogy of Fallot. Surgically corrected TOF is a common cause for subsequent pulmonary regurgitation Regurgitation Gastroesophageal Reflux Disease (GERD).
• Pulmonary atresia Atresia Hypoplastic Left Heart Syndrome (HLHS): a rare congenital cyanotic heart disease characterized by the failed formation of the pulmonary valve Pulmonary valve A valve situated at the entrance to the pulmonary trunk from the right ventricle. Heart: Anatomy, leading to subsequent RV hypoplasia Hypoplasia Hypoplastic Left Heart Syndrome (HLHS). Pulmonary atresia Atresia Hypoplastic Left Heart Syndrome (HLHS) may occur as part of the most severe form of TOF (with VSD), where the entire RV outflow enters the aorta Aorta The main trunk of the systemic arteries. Mediastinum and Great Vessels: Anatomy.
• Carcinoid syndrome Carcinoid syndrome A symptom complex associated with carcinoid tumor and characterized by attacks of severe flushing of the skin, diarrheal watery stools, bronchoconstriction, sudden drops in blood pressure, edema, and ascites. The carcinoid tumors are usually located in the gastrointestinal tract and metastasize to the liver. Symptoms are caused by tumor secretion of serotonin, prostaglandins, and other biologically active substances. Cardiac manifestations constitute carcinoid heart disease. Carcinoid Tumors and Syndrome: small, slow-growing neuroendocrine tumors Neuroendocrine tumors Tumors whose cells possess secretory granules and originate from the neuroectoderm, i.e., the cells of the ectoblast or epiblast that program the neuroendocrine system. Common properties across most neuroendocrine tumors include ectopic hormone production (often via apud cells), the presence of tumor-associated antigens, and isozyme composition. Gastrinoma. The tumors are associated with unregulated vasoactive hormone production, inducing the development of fibrous Fibrous Fibrocystic Change endocardial plaques and leading to pulmonary and tricuspid valve Tricuspid valve The valve consisting of three cusps situated between the right atrium and right ventricle of the heart. Heart: Anatomy abnormalities.
• Rheumatic fever Rheumatic fever Acute rheumatic fever (ARF) is an autoimmune inflammatory process that usually follows Streptococcal pharyngitis. Acute rheumatic fever usually occurs 2-4 weeks after an untreated infection and affects the heart, skin, joints, and nervous system. Rheumatic Fever: a late complication of untreated streptococcal pharyngeal infection characterized by valvular abnormalities, most commonly of the left heart. While rare, the pulmonary valve Pulmonary valve A valve situated at the entrance to the pulmonary trunk from the right ventricle. Heart: Anatomy can be affected concurrently with the mitral valve Mitral valve The valve between the left atrium and left ventricle of the heart. Heart: Anatomy.