B.34 Mitral Valve Stenosis

Question 1

B.34 Mitral Valve Stenosis

define

Answer 1

Mitral stenosis (MS) is a valve condition affecting the mitral valve, which results in a blockage of blood flow into the left ventricle.

Question 2

B.34 Mitral Valve Stenosis
etiology

Answer 2

Etiology

• Primarily caused by rheumatic fever
• Associated with autoimmune diseases such as systemic lupus erythematosus (SLE) and rheumatoid arthritis
• May be congenital in nature
• Certain conditions can resemble mitral stenosis, including:
• Bacterial endocarditis of the mitral valve with significant vegetation
• Left atrial myxoma
• Degenerative aortic stenosis can also contribute.

Question 3

B.34 Mitral Valve Stenosis

pathophys

Answer 3

Mitral valve stenosis leads to an obstruction of blood flow into the left ventricle (LV), resulting in:
- Limited diastolic filling of the LV
- Decreased stroke volume
- Reduced cardiac output (forward heart failure)

Mitral valve stenosis also causes:
- Increased left atrial pressure
- Backup of blood into the lungs
- Elevated pulmonary capillary pressure, leading to:
- Cardiogenic pulmonary edema
- Pulmonary hypertension
- Outcome of heart failure and right ventricular hypertrophy.

Question 4

B.34 Mitral Valve Stenosis

clinical

Answer 4

Initially Asymptomatic: Symptoms may not appear for up to 10 years following acute rheumatic carditis.

• Dyspnea: Patients often experience paroxysmal nocturnal dyspnea and orthopnea, particularly when lying flat.
• Hemoptysis
• Hoarseness
• Dysphagia
• Mitral Facies: Characteristic facial appearance.
• Atrial Fibrillation and Embolic Complications
• Later Stages: Signs and symptoms of right heart failure (RHF) may develop.

Question 5

B.34 Mitral Valve Stenosis

auscultation

Answer 5

Opening Snap:
- Follows the second heart sound (S2) due to a sudden halt in leaflet motion during diastole, occurring after the rapid opening of the valve leaflets.

• The interval between S2 and the opening snap (OS) relates to the severity of the stenosis.

Delayed Rumbling Mid-to-Late Diastolic Murmur:

Increased Intensity with Increased Preload:
- Notably heard during passive leg raises and squatting.

Decreased Intensity with Decreased Preload:
- Notably heard during the Valsalva maneuver; increased intensity occurs with inspiration due to greater venous return.

• Loudest when Patient is in Left Lateral Position:
• Best auscultated while the patient lies on their left side.
• Prominent First Heart Sound (S1)

Question 6

B.34 Mitral Valve Stenosis

CXR

Answer 6

PA Image:
- Left Atrial Enlargement: Notable enlargement of the left atrium with a prominent left atrial appendage, leading to a straightening of the left cardiac border.

Signs of Pulmonary Congestion: Indicators of fluid accumulation in the lungs.

Lateral Image:
- Esophageal Displacement: Dorsal displacement of the esophagus, observable in a barium swallow test.

• Signs of Right Ventricular Hypertrophy: Evidence of thickening in the right ventricular wall.

Question 7

B.34 Mitral Valve Stenosis

ECG

Answer 7

• P Mitrale: Indication of left atrial enlargement.
• Atrial Fibrillation (A.fib): Presence of irregular heart rhythm.
• Signs of Right Ventricular Hypertrophy (RVH): Evidence suggesting thickening of the right ventricle.

Question 8

B.34 Mitral Valve Stenosis

imaging

Answer 8

Echocardiography
The primary diagnostic tool for identifying and evaluating valvular abnormalities, it helps assess the mitral valve’s structure, function, and severity of stenosis:

• Leaflet Thickening and Rigidity
• Calcification
• Subvalvular Thickening
• Decreased Mitral Valve Area (MVA)
• An MVA of ≤ 1.5 cm² is classified as severe mitral stenosis (MS).
• Assessment for Left Atrial (LA) Thrombus and concurrent mitral regurgitation.

Coronary Angiography
- May be performed before surgical interventions to evaluate any associated coronary artery disease.

Question 9

B.34 Mitral Valve Stenosis
conservative TX

Answer 9

Management of Heart Failure: Only diuretics may be administered.

• Medications:
• Beta Blockers or Calcium Channel Blockers: Decrease heart rate (HR) and cardiac output (CO) in patients with atrial fibrillation or sinus rhythm.
• Endocarditis Prophylaxis: Recommended for high-risk patients, such as those with a history of infective endocarditis (IE) or prosthetic valves.
• Anticoagulation Considerations: Important in cases of atrial fibrillation (A.fib).

Question 10

B.34 Mitral Valve Stenosis
Interventional TX

Answer 10

Indication: Severe mitral stenosis (MVA ≤ 1.5 cm²) or symptomatic mitral stenosis.

• First-Line Procedure: Percutaneous Balloon Commissurotomy (PMBC) if the following criteria are met:
• Favorable valve morphology (e.g., no valvular calcifications)
• Absence of left atrial thrombus
• Mild or no mitral regurgitation
• Alternatives: Open commissurotomy and surgical valve replacement (mechanical prosthetic valve or biological prosthetic valve).

Note: ACE inhibitors and other afterload-reducing drugs are contraindicated due to the risk of peripheral blood vessel dilation, which may lead to cardiovascular decompensation.

Question 11

B.34 Mitral Valve Stenosis

complications

Answer 11

• Atrial Fibrillation (A.fib): Risk of thromboembolic events.
• Pulmonary Issues: Progressive lung congestion, pulmonary edema, and pulmonary hypertension.
• Congestive Heart Failure: Develops as a significant complication.
• Rare Complication: Enlargement of the left atrium may lead to esophageal compression and recurrent laryngeal nerve palsy.