Mitral Stenosis - Case Study With Questions & Answers

A 32-year-old woman who recently moved to the United States from Mexico is seen because of the recent onset of palpitations associated with dyspnea on exertion, orthopnea, and paroxysmal nocturnal dyspnea with hemoptysis.
On physical examination, her blood pressure is 112/90 mm Hg and her heart rate is 120 per minute and irregularly irregular. Jugular venous distention to 10cm H2O with a prominent V w ave is noted, as are diminished arterial pulses and bibasilar rales (up to half of the lung fields bilaterally). Additional findings include a nondisplaced apex beat, a right ventricular heave palpable in the left
parasternal region, a palpable pulmonic closure sound in the second left intercostal space, an accentuated S4, a loud pulmonic second sound (P2) over the left ventricular apex, a snapping sound over the left ventricular apex impulse just after the second heart sound, and a grade 3/4, low -pitched,
rumbling, nearly holodiastolic murmur heard best at the cardiac apex. There is 1 to 2+ pitting edema noted in the lower extremities and presacral area.

1. What is the most likely valvular lesion in this patient?
2. What is the most common cause of mitral stenosis in adult patients?
3. What is the mortality rate associated with medically treated mitral stenosis?
4. What are the major complications of mitral stenosis?
5. What is the best treatment for symptomatic patients with mitral stenosis?

Answers:



1. What is the most likely valvular lesion in this patient?
The clinical picture exhibited by this patient is characteristic of severe mitral stenosis with secondary pulmonary hypertension and cor pulmonale.

The severity of the mitral stenosis is indicated by the mitral opening snap, which closely follows the second heart sound and the holodiastolic rumble. The
mitral opening snap is a characteristic sign of mitral stenosis and appears to be due to a sudden tensing of the valve leaflets after the valve cusps have completed their opening excursions, and occurs shortly after (0.08 to 0.12 second) the aortic component of the second heart sound. The mitral opening snap moves closer to the second heart sound as the pressure between the left atrium and left ventricle increases. The rumbling, low -pitched diastolic murmur heard at the apex is characteristic of mitral stenosis. The duration of the murmur throughout diastole indicates that there is a pressure gradient across the mitral valve throughout diastole.

Pulmonary hypertension is indicated by the loud pulmonic component of the second heart sound and right ventricular heave. A P2 that can be heard at the left ventricular apex indicates pulmonary hypertension.

Cor pulmonale is reflected by the elevated neck veins, and peripheral edema. The large V wave indicates tricuspid regurgitation—a result of the pulmonary hypertension and cor pulmonale. Paroxysmal nocturnal dyspnea with hemoptysis is a major clue to this diagnosis and reflects a sudden increase in pulmonary capillary pressure with intraalveolar edema and hemorrhage such as might occur with exercise or new onset of atrial fibrillation.

2. What is the most common cause of mitral stenosis in adult patients?
Mitral stenosis in adults is almost exclusively due to rheumatic heart disease. This patient described a prolonged illness at 12 years of age consistent with acute rheumatic fever but half of all patients with rheumatic mitral stenosis will not have a clear childhood history of rheumatic fever.

3. What is the mortality rate associated with medically treated mitral stenosis?
From the time of the initial diagnosis, patients w ith medically treated mitral stenosis can expect a mortality rate of 20% at 5 years and 40% at 10 years.
This patient faces a much less favorable prognosis because of her pulmonary hypertension and right ventricular HF. How ever, the risk is significantly reduced if she undergoes valve replacement, commissurotomy, or mitral balloon valvotomy.

4. What are the major complications of mitral stenosis?
In patients with uncorrected mitral stenosis, there is a 20% lifetime risk of thromboembolism. This is often a devastating complication because the embolus most often travels to the brain, resulting in a stroke. Eighty percent of patients with systemic emboli are in atrial fibrillation. This risk is decreased by the use of anticoagulant therapy with sodium warfarin.
Infective endocarditis occurs less frequently but may be a disastrous complication.
Atrial fibrillation is a common complication of mitral stenosis. The left atrium is often very large due to a combination of rheumatic involvement of the atrial muscle and the high left atrial pressures, predisposing to atrial fibrillation.

5. What is the best treatment for symptomatic patients with mitral stenosis?
Options for correction of mitral stenosis include percutaneous transvenous mitral valvuloplasty, surgical mitral commissurotomy, or mitral valve repair.

In balloon valvuloplasty, the balloon is passed from the femoral vein to the right atrium, across the atrial septum, and across the mitral valve. The balloon is inflated, cracking open the valve. This is the preferred procedure in experienced hands if the valve anatomy is favorable and there are no
contraindications.

Results are also good with surgical commissurotomy or mitral valve replacement.