Mitral Stenosis - Treatment
The treatment of mitral stenosis relies on the prevention or early recognition of rheumatic heart disease.
Prophylactic penicillin treatment of patients known to have rheumatic heart disease successfully reduces exacerbations and will limit the damage done to the mitral valve. Anticoagulation is of great importance to prevent the formation of a left atrial thrombus and embolic events. Even in the absence of atrial fibrillation, patients with certain risk factors including hypertension or hypercoagulable states should be anticoagulated. Antibiotic prophylaxis before dental procedures and certain surgeries is no longer recommended to prevent bacterial endocarditis unless a prosthetic valve is present.
Preload reduction with diuretics and salt restriction can relieve symptoms if mitral stenosis if pulmonary hypertension is present. Many patients experience symptoms only when the heart rate is elevated, since tachycardia decreases diastolic filling time significantly. Thus the use of beta-blockers can be beneficial at times, especially in patients with predominantly exertional symptoms.
Definitive treatment includes Percutaneous Balloon Mitral Valvotomy (PBMV). In this procedure, a catheter is inserted through the interatrial septum and into the stenotic mitral valve. A balloon is then inflated that fractures the calcium deposits and relieves the stenosis. Unlike valvuloplasty in the setting of aortic stenosis, PBMV is highly successful with a low rate of restenosis. Complications include residual mitral regurgitation, a persistent atrial septal defect, and rarely calcium embolization. PBMV is indicated for patients who are symptomatic with moderate to severe mitral stenosis in the absence of a pre-existing LA thrombus and mitral regurgitation. PBMV is also indicated for patients who are asymptomatic with severe mitral stenosis and a Wilkins (Abascal) echocardiographic score of 8 or less.
Surgical approaches to the management of mitral stenosis include closed commissurotomy, open commissurotomy, and mitral valve replacement. Closed commissurotomy is similar to PBMV in that the mitral valve is not directly visualized and a balloon is used to dilate the stenotic mitral valve. The same criteria that are used for PBMV are also used to assess which patients may benefit from closed commissurotomy.
Open commissurotomy requires the use of a cardiopulmonary bypass machine which significantly increases both the cost and complication rate of the procedure. However the surgeon is able to debride calcifications on the mitral valve, remove left atrial thrombi if found, and remove the left atrial appendage, which is a common site for the formation of thrombi. Open commissurotomy is the treatment of choice in patients with known left atrial thrombi or mitral stenosis with concurrent severe mitral valve calcifications.
Mitral valve replacement is also an option for patients with symptomatic or severe mitral stenosis requiring definitive therapy. This is usually reserved only for patients that are not a candidate for PBMV or commissurotomy due to the long-term complications associated with prosthetic valves. Patients with mitral stenosis along with moderate to severe mitral regurgitation can benefit greatly from mitral valve replacement.