Mitral Stenosis Treatment & Management

The goal of medical treatment for mitral stenosis is to reduce recurrence of rheumatic fever, provide prophylaxis for infective endocarditis, reduce symptoms of pulmonary congestion (eg, orthopnea, paroxysmal nocturnal dyspnea), control the ventricular rate if atrial fibrillation is present, and prevent thromboembolic complications. ^[12]

Because rheumatic fever is the primary cause of mitral stenosis, secondary prophylaxis against group A beta-hemolytic streptococci (GAS) is recommended. ^[13] Duration of prophylaxis depends on the number of previous attacks, the time elapsed since the last attack, the risk of exposure to GAS infections, the age of the patient, and the presence or absence of cardiac involvement. Penicillin is the agent of choice for secondary prophylaxis, but sulfadiazine or a macrolide or azalide are acceptable alternatives in individuals allergic to penicillin (Tables 1 and 2).

A European study involving 315 patients with rheumatic mitral stenosis showed a significantly slower progression of rheumatic mitral stenosis in patients treated with statins compared with patients not taking statins. These findings could have an important impact in the early medical therapy of patients with rheumatic heart disease. ^[14]

Initial symptoms of pulmonary congestion can be safely treated by diuretics. Dietary sodium restriction and nitrates decrease preload and can be of additional benefit. Careful use of beta-blockers in patients with a normal sinus rhythm can prolong the diastolic filling time and thus decrease in left atrial pressure. In general, afterload reduction should be avoided as it can cause hypotension.

In a randomized crossover study, Saggu et al investigated the comparative efficacy of ivabradine and metoprolol on symptoms, hemodynamics, and exercise parameters in 33 patients with mild-to-moderate mitral stenosis (mitral valve area, 1-2 cm) in normal sinus rhythm. They found evidence that metoprolol and ivabradine reduced patients’ symptoms and improved hemodynamics significantly from baseline with a similar efficacy. The investigators concluded that ivabradine can be used safely and effectively in patients with mitral stenosis in normal sinus rhythm who are intolerant to or contraindicated for beta-blocker therapy. ^[15]

Atrial fibrillation is common in mitral stenosis and often leads to a rapid ventricular rate with reduced diastolic filling time and increased left atrial pressure. Although patients with mitral stenosis have a reduced average early diastolic strain in the presence of atrial fibrillation compared to normal sinus rhythm, those with mitral stenosis and atrial fibrillation show a loss of atrial late diastolic contraction as well as a reduction in early diastolic shortening of the left atrial myocardium.​ ^[16]

The ventricular rate of atrial fibrillation can be slowed acutely by the administration of intravenous beta-blocker or calcium channel blocker therapy (diltiazem or verapamil). The rate and/or rhythm can be controlled long-term with oral beta-blockers, calcium channel blockers, amiodarone, or digoxin.

In the patient with mild mitral stenosis and recent-onset (< 6 mo) atrial fibrillation, conversion to sinus rhythm can be accomplished with pharmacologic agents or electrical cardioversion. In this circumstance, anticoagulation therapy should be given for at least 3 weeks prior to cardioversion. Alternatively, a TEE can be performed to exclude the presence of left atrial thrombus, prior to cardioversion. Patients who are successfully converted to sinus rhythm should receive long-term anticoagulation and antiarrhythmic drugs. Warfarin should be used for anticoagulation. The novel anticoagulants dabigatran and rivaroxaban was approved for nonvalvular atrial fibrillation; these drugs have not been evaluated in patients with heart valve disease. ^[17]

Surgical correction of the mitral stenosis is indicated if embolization is recurrent, despite adequate anticoagulation therapy.

In a retrospective study (2001-2015) of 318 patients with late onset of atrial fibrillation following mitral valve repair for type II dysfunction, significant risk factors for late atrial fibrillation were small ring annuloplasty, left atrial diameter, and pressure half-time. ^[18] In addition, affected patients developed recurrent myocardial infarction more often than those without late-onset atrial fibrillation.

Table 1. Duration of Secondary Rheumatic Fever Prophylaxis (Open Table in a new window)

Table 2. Secondary Prevention of Rheumatic Fever (Prevention of Recurrent Attacks) (Open Table in a new window)

Diet and activity

The patient should start a low-salt diet if pulmonary vascular congestion is present.

In most patients with mitral stenosis, recommendations for exercise are symptom limited. Patients should be encouraged to pursue a low-level aerobic exercise program for maintenance of cardiovascular fitness.

Surgical therapy for mitral stenosis consists of mitral valvotomy (which can be either surgical or percutaneous) or mitral valve replacement. The surgical mitral valvotomy approach can be through an closed or open technique; the latter technique is rarely used, except in developing countries, and has largely been replaced by the percutaneous balloon commissurotomy. ^[8]

Asymptomatic patients with moderate or severe mitral stenosis (mitral valve area < 1.5 cm²) and a suitable valve should be considered for percutaneous balloon commissurotomy if the pulmonary arterial systolic pressure is ≥50 mm Hg at rest or ≥60 mm Hg with exercise, or pulmonary capillary wedge pressure is ≥25 mm Hg with exercise. ^[19]

Symptomatic patients with moderate or severe mitral stenosis (mitral valve area < 1.5 cm²) and suitable valve are also candidates for percutaneous balloon commissurotomy.

If percutaneous balloon commissurotomy is not an option, patients should be referred for surgical repair or mitral valve replacement.

Some patients may have recurrent moderate mitral regurgitation after repair; there appears to be an increased likelihood of having a recurrent mitral regurgitation of 2+ or higher within 1 year after the repair in patients who required a subsequent mitral valve reoperation. ^[20]

Percutaneous balloon valvuloplasty/percutaneous mitral commissurotomy (PMC)

PMC is the procedure of choice for patients with uncomplicated mitral stenosis. Patients with pliable, mobile, relatively thin, minimally calcified mitral leaflets with minimal or no subvalvular stenosis are good candidates for this procedure. A TEE should be performed prior to commissurotomy to clearly define the valve anatomy and exclude the presence of a left atrial thrombus.

The echocardiographic scoring system (Wilkins score) has been used as a valuable tool for patient selection. Leaflet mobility, valvular thickening, valvular calcification, and subvalvular disease are each given a score of 0-4, with higher scores indicating more severe involvement. A total score of less than 8 results in good short- and long-term outcome with balloon valvuloplasty.

With PMC, a catheter is directed into the left atrium after transseptal puncture, and a balloon is directed across the valve and inflated in the orifice. This results in separation of the mitral leaflets. The valve size can be increased up to 2-2.5 cm².

Improvement in symptoms is noted immediately following the procedure. If symptoms do not improve, the commissurotomy was either ineffective or resulted in mitral regurgitation.

In a prospective study of 56 patients with critical mitral stenosis in normal sinus rhythm and 37 healthy controls that used transthoracic echocardiography to measure aortic stiffness before percutaneous mitral balloon valvuloplasty (PMBV), 24-48 hours postprocedure, and 1 year postprocedure, investigators found that mitral valve stenosis was associated with impaired aortic stiffness. ^[21] Following PMBV, aortic stiffness decreased during the acute and intermediate periods.

The short- and long-term prognoses are favorable compared with surgical valvotomy.

PMC offers certain advantages over surgical valvotomy, including avoidance of a thoracotomy and general anesthesia and their attendant complications.

The major contraindications to balloon commissurotomy are the presence of thrombus in the left atrium or its appendage, moderate-to-severe mitral regurgitation, and an unfavorable valve morphology (ie, high Wilkins echo score).

Complications of a PMC include embolization, mitral regurgitation, ventricular rupture, residual atrial septal defect, stroke, and death.

Surgical valvotomy/valve replacement

Open surgical commissurotomy allows direct visualization of the mitral valve.

Using current techniques, even severe regurgitant or stenotic valves can often be repaired, with good long-term results. Valves that are not suitable for repair can be replaced using either bioprosthetic or metallic prosthetic valves.

With bioprosthetic valves, the patient does not require anticoagulation, as long as he or she remains in sinus rhythm; however, 20-40% of these valves fail within 10 years, secondary to structural deterioration.

Mechanical valves are placed in young patients who do not have any contraindications for anticoagulation, and these valves are associated with good long-term durability.

Patients who have chronic atrial fibrillation and who undergo mitral valve surgery can have simultaneous Cox Maze procedure or pulmonary vein ablation, which helps to maintain sinus rhythm in up to 80% of the cases during the postoperative period.

Balloon-expandable valve implantation

Early results of direct transatrial implantation of a balloon-expandable valve in the mitral position in 6 patients with symptomatic severe mitral annular calcification considered to be high-risk surgical candidates indicates that although this approach appears to be feasible, the technique requires further refinement due to significant morbidity and mortality. ^[22] Although no left ventricular outflow tract obstruction was noted, 3 patients had severe mitral valve periprosthetic regurgitation and 1 had moderate to severe mitral valve periprosthetic regurgitation, and in-hospital death occurred in 3 other patients (noncardiac cause, 1 patient; cardiogenic shock, 2 patients). ^[22]

Key members of a multidisciplinary team for structural heart valve disease management include primary cardiologists, interventional cardiologists, cardiac surgeons, noninvasive and heart failure cardiologists, echocardiographers and cardiac imaging specialists, cardiac anesthesiologists, nurse practitioners, physician assistants, research coordinators, administrators, dietary and rehabilitation specialists, and social workers. Each component will need to develop and implement specific protocols depending on the individual patient and specific technical procedure. ^[23]

Primary prevention of acute rheumatic fever is summarized in Table 3 below. ^[13]

For secondary prevention of rheumatic fever and for infective endocarditis prophylaxis, see Medical Care.

Table 3. Primary Prevention of Rheumatic Fever (Treatment of Streptococcal Tonsillopharyngitis*) (Open Table in a new window)

Serial follow-up testing of a patient with mitral stenosis should be based on whether the results of a test will dictate either a change in therapy or a recommendation for a procedure.

All patients should be informed that any change in symptoms warrants re-evaluation.

In the asymptomatic patient, yearly re-evaluation is recommended; history, physical examination, chest radiograph, and electrocardiogram (ECG) should be obtained.

An echocardiogram is not recommended yearly unless there is a change in clinical status or the patient has severe mitral stenosis.

Ambulatory ECG monitoring (Holter or event recorder) to detect paroxysmal atrial fibrillation is indicated in patients with palpitations.