Valvular Dysfunctions

Objectives - Differentiate valvular stenosis, regurgitation, and prolapse.

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Three Patterns of Valve Dysfunction

Aortic Stenosis

Aortic stenosis occurs when the aortic valve narrows from malformation or calcification. This reduces blood flow from the left ventricle through the aorta and to the rest of the body. Severe aortic stenosis can lead to death without treatment.

Causes include:

• Calcific aortic valve, listed as the most common cause in adult patients
• Hyperlipidemia
• Hypertension
• Rheumatic aortic stenosis from rheumatic fever
• Bicuspid aortic valve that leads to obstruction and calcification of the outflow tract

Pathophysiology includes:

• Increased left ventricular filling pressures
• Left ventricular hypertrophy
• Increased left atrial pressures
• Left atrial dilation
• Decreased oxygen supply to the heart, which may worsen ischemia
• Progression to CHF

Symptoms include syncope, angina, dyspnea, weak pulses, decreased pulse pressure, systolic murmur, and arrhythmias such as atrial fibrillation.

Mitral Stenosis

Mitral stenosis is narrowing of the mitral valve. The valve does not open properly, reducing blood flow into the left ventricle.

Causes include:

• Rheumatic fever, listed as the most common cause
• Calcium deposits from aging
• Radiation therapy for cancer
• Rare causes such as congenital defect and autoimmune disease such as lupus

Pathophysiology includes:

• Left atrial enlargement
• Pulmonary hypertension
• Pulmonary edema
• Heart failure
• Atrial fibrillation
• Blood clots from atrial fibrillation, including stroke

Symptoms include murmur, shortness of breath with activity or lying down, fatigue during activity, chest discomfort or chest pain, peripheral edema, palpitations, arrhythmias, atrial fibrillation, coughing up blood, dizziness, syncope, pulmonary hypertension, and pulmonary edema.

Tricuspid Stenosis

Tricuspid stenosis is narrowing or calcification of the valve between the right atrium and right ventricle. It reduces blood flow across the valve.

The source states this condition causes decreased pulmonary vascular resistance and increased systemic vascular resistance, leading to symptoms such as ascites and jugular vein distention.

Causes include rheumatic heart disease, rheumatic fever, and carcinoid syndrome. The source notes that rheumatic disease also affects the mitral and pulmonic valves.

Pathophysiology includes:

• Increased right atrial volume and pressure
• Right atrial dilation
• Right heart failure
• Jugular venous distension
• Ascites
• Hepatomegaly
• Pedal edema
• Atrial fibrillation or atrial flutter
• Clotting leading to pulmonary embolism

Pulmonic Stenosis

Pulmonic stenosis is narrowing, calcification, or malformation of the valve between the right ventricle and pulmonary arteries. It reduces blood flow across the valve.

Causes include:

• Congenital pulmonic stenosis, listed as the most common form
• Tetralogy of Fallot or bicuspid valve
• Rheumatic fever
• Rubella
• Carcinoid cancer
• Carcinoid heart disease with fibrous plaque deposition on cardiac valves and chambers

Pathophysiology includes reduced blood flow to the lungs, right ventricular hypertrophy, right ventricular dilation, and heart failure.

Symptoms include abnormal heart sounds or murmur, fatigue, shortness of breath during activity, chest pain, and syncope.

Aortic Regurgitation

Aortic regurgitation occurs when the valve between the left ventricle and aorta does not close properly. Blood leaks backward into the left ventricle.

Causes include:

• Aortic root calcification, listed as most common
• Congenital valve defects such as bicuspid valve
• Infective endocarditis
• Rheumatic fever
• Trauma to the heart

Pathophysiology includes backflow of blood into the left ventricle, increased left ventricular end-diastolic volume, left ventricular hypertrophy and enlargement, increased myocardial force and oxygen requirements to maintain stroke volume, and heart failure.

Symptoms include fatigue, shortness of breath, syncope, and widened pulse pressure.

Mitral Regurgitation

Mitral regurgitation occurs when the valve between the left ventricle and left atrium does not close properly. Blood leaks backward into the left atrium.

Causes include:

• Mitral valve prolapse
• Rheumatic fever
• Heart attack
• Congenital heart defect
• Cardiomyopathy
• Damaged chordae tendineae
• Endocarditis

Pathophysiology includes dilation of the left atrium, atrial fibrillation, pulmonary hypertension, CHF in severe cases, and increased work by the heart to pump blood to the body. The extra effort can cause the left ventricle to hypertrophy, and untreated weakness can lead to heart failure.

Tricuspid and Pulmonic Regurgitation

Tricuspid regurgitation occurs when the valve between the right ventricle and right atrium does not close properly. Blood leaks backward into the right atrium.

Causes include other heart dysfunctions, tricuspid stenosis, pulmonary hypertension, right ventricular dysfunction, myocardial infarction with damaged papillary muscles or chordae tendineae, IV drug abuse with endocarditis from S. aureus infection, and congenital heart defects such as Ebstein anomaly.

Pathophysiology includes increased right atrial volume, right atrial dilation, right heart failure, and arrhythmias such as atrial fibrillation or atrial flutter. Symptoms may be absent until severe and can include fatigue, shortness of breath, arrhythmias, ascites, peripheral edema, and JVD.

Pulmonic regurgitation is found mostly in patients with congenital heart diseases or surgeries. It can also come from congenital malformations, trauma, infective endocarditis, and leaflet anomalies. Pathophysiology includes increased right ventricular volume, right ventricular dilation, right heart failure, and arrhythmias such as atrial fibrillation or atrial flutter.

Mitral Valve Prolapse

Mitral valve prolapse is primarily a problem of the valves between the atria and ventricles, most commonly the mitral valve. It is also called Barlow syndrome.

Causes include damage to left ventricular anatomical structures, dysfunction of the leaflets, chordae tendineae, papillary muscles, genetic factors, Ebstein anomaly, Marfan syndrome, Graves disease, and Ehlers-Danlos syndrome.

Mitral valve prolapse may eventually lead to regurgitation into the left atrium. Severity depends on valve dysfunction. Most patients are asymptomatic until they are older.

Diagnostics and Treatment

Diagnostics for valvular dysfunction include:

Medication management may include diuretics, anticoagulants, heart rate control, antiarrhythmics for atrial fibrillation, and antibiotics for rheumatic fever.

Treatment options include:

• Balloon valvuloplasty
• Valve replacement
• Right heart failure treatment with fluid restriction and diuretics
• Symptom management for mitral valve prolapse

Valve replacement options include mechanical valves and bioprosthetic valves. Mechanical valves are listed for patients under 65, patients with atrial fibrillation, and patients who must remain on anticoagulants for life. Bioprosthetic valves are listed for patients over 65 and may be bovine, porcine, or cadaver valves. Patients may need antibiotics to prevent valve infections.