Approach Considerations
Intravenous diuretics may be used in patients with severe or refractory symptoms.
Oxygen administration or endotracheal intubation and mechanical ventilation may be necessary in patients with respiratory compromise due to pulmonary edema.
Patients with unstable tachyarrhythmias should undergo direct current (DC) cardioversion. Medical cardioversion can be attempted in patients who are hemodynamically stable. Echocardiography must be accomplished prior to cardioversion in order to assess the left atrium and its appendage for thrombi.
Medical Care
Asymptomatic patients with mild mitral stenosis (MS) require yearly follow-up care to monitor for disease progression. Yearly evaluation should include physical examination, chest radiography, and echocardiography.
Critically ill inpatients or those unable to receive oral medications may be treated intravenously.
For the patient with signs or symptoms of CHF, diuretics may provide benefit.
Tachyarrhythmias, such as atrial flutter and atrial fibrillation, usually require medical treatment aimed at restoration and maintenance of sinus rhythm. If this is not possible, therapy may be aimed at decreasing ventricular response and maintaining an acceptable heart rate. Pharmacotherapy may include the following:
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Digoxin, beta-blockers, and calcium channel blockers have all been used to slow atrioventricular (AV) node conduction and decrease ventricular rate response.
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Antiarrhythmics from class I (eg, procainamide, flecainide, propafenone) and class III (eg, sotalol, amiodarone) have been used with variable success in converting to and maintaining sinus rhythm.
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Thromboembolic complication from chronic atrial arrhythmia can be reduced with anticoagulation using warfarin.
Electrophysiologic ablation of atrial fibrillation or flutter circuits may be performed in the catheterization laboratory.
Surgical ablation via a Cox-Maze procedure during mitral valve repair or replacement has been shown to be an effective treatment for atrial fibrillation with freedom from atrial fibrillation recurrence of nearly 80% after 10 years. [13]
Percutaneous mitral balloon valvuloplasty for acquired MS was first described in 1984 and approved by the US Food and Drug Administration in 1994. Indications for this procedure are similar to those for surgery, including CHF unresponsive to medical management and in asymptomatic patients with a pulmonary artery (PA) systolic pressure of 50 mmHg or greater at rest or greater than 60 mmHg with exercise in the absence of a left atrial thrombus or moderate to severe MR. [14] In some centers, the procedure is successful in 80-90% of selected cases. The procedural mortality rate is 1-2%.
Hydroxymethylglutaryl-coenzyme A reductase inhibitors (statins) have reportedly slowed the progression of rheumatic MS. [15, 16]
Consultations
Consult a cardiologist and a cardiothoracic surgeon.
Transfer
Transfer patients to an ICU when general status is unstable because of CHF with pulmonary edema or serious cardiac dysrhythmia.
Once medically stabilized, surgical or transcatheter intervention should be considered.
Diet and activity
Salt intake should be restricted and excessive fluid intake minimized to avoid exacerbating signs and symptoms of CHF.
Patients with more severe than mild MS should avoid strenuous exertion. Increased heart rate may result in decreased diastolic filling, thereby decreasing cardiac output. Coexistent atrial arrhythmias result in loss of atrial augmentation of LV filling and may further impair cardiac output.
Surgical Care
Surgical intervention is indicated in symptomatic (New York Heart Association [NYHA] functional class III-IV) moderate or severe mitral stenosis (MS) when percutaneous mitral valve (MV) balloon valvuloplasty is unavailable or contraindicated because of left atrial thrombus despite anticoagulation or concomitant moderate to severe mitral regurgitation (MR), or when valve morphology is unfavorable for valvotomy. [8, 17]
Although pediatric mitral vavle repair may be challenging owing to the various types of lesions and anticipated patient growth, it is an effective intervention option for children younger than 10 years, whether the mitral stenosis is congenital or acquired. [18] However, mitral valve repair may delay time to valve replacement.
Mitral valvotomy
Commissurotomy consists of an incision of fused mitral valve commissures and shaving of thickened mitral valve leaflets. Fused chordae tendineae and papillary muscles can be divided to relieve subvalvular stenosis.
Supravalvular tissue contributing to the MS should be resected.
Combined valvuloplasty with prosthetic ring annuloplasty is also used with reportedly good results. [19]
Percutaneous mitral valvotomy during pregnancy appears to be safe and provides symptomatic relief and hemodynamic improvement, even in gravida with severe mitral stenosis. [20]
Following percutaneous balloon mitral valve valvuloplasty in patients with rheumatic mitral stenosis, elevations of plasma levels of atrial (ANP) and B-type (BNP) natriuretic peptides may occur and then fall thereafter. [21]
Mitral valve replacement with mechanical valve or bioprosthesis
This procedure is reserved for patients in whom mitral valvotomy is considered unlikely to achieve a satisfactory result, such as in those with moderate to severe MR.
Mechanical mitral valve replacement is performed frequently in adolescents and adults in whom anticoagulation with warfarin (Coumadin) is not contraindicated. In older patients in whom warfarin therapy may be relatively contraindicated or in patients who have other contraindications to warfarin therapy, mitral valve replacement can be performed using a bioprosthesis, although these are less durable than mechanical prostheses.
Weigh the risk of warfarin therapy against that of bioprosthetic valve deterioration resulting in the need for reoperation. Warfarin is contraindicated during pregnancy.
Complications after mitral valve replacement include anticoagulation-related complications, valve thrombosis, valve dehiscence, infective endocarditis, valve malfunction, and embolic events.
Hemolytic anemia when mild-to-moderate paravalvular leakage is present predicts poor clinical outcome in patients who have undergone mitral valve replacement. [22]
Prevention
Antibiotics for endocarditis prophylaxis are required for patients with certain cardiac conditions, such as mitral stensosis. MS, before performing procedures that may cause bacteremia. For more information, see the American Heart Association's Webpage on infective endocarditis.
See the American Heart Association (AHA) and/or American College of Cardiology (ACC) guidelines on:
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Prevention of infective endocarditis in childhood (2015 update)
See also the Medscape Drugs and Diseases topic Antibiotic Prophylactic Regimens for Endocarditis.
Long-Term Monitoring
Follow-up visits to the pediatrician and/or generalist are needed to monitor general health status.
Follow-up clinical visits to the pediatric cardiologist are needed to monitor antiarrhythmic drug levels and anticoagulation drug effectiveness by measuring prothrombin time (PT) and/or international normalized ratio (INR).
Serial echocardiography is indicated to monitor progression of mitral stenosis (MS). The frequency of these studies varies according to the patient's general health status and according to the cardiologist's criteria. Stress echocardiography may provide additional hemodynamic information.
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Acquired Mitral Stenosis. Hemodynamic changes in severe mitral valve stenosis (MS). MS causes an obstruction (in diastole) to blood flow from the left atrium (LA) to the left ventricle (LV). Increased LA pressures are transmitted retrograde to pulmonary veins and pulmonary capillaries, resulting in capillary leak with subsequent development of pulmonary edema. To overcome pulmonary edema, the arterioles constrict, increasing pulmonary pressures. Over time, capillaries develop intimal thickening, causing fixed (permanent) pulmonary hypertension. The right ventricle (RV) hypertrophies to generate enough pressure to overcome the increased afterload. Eventually, the RV fails, which manifests as hepatomegaly and/or ascites, edema of the extremities, and cardiomegaly on radiography.
