Medical Care: The goals of medical treatment are to reduce the recurrence of rheumatic fever, provide prophylaxis for infective endocarditis, reduce the symptoms of pulmonary congestion (eg, orthopnea, paroxysmal nocturnal dyspnea), control the ventricular rate in patients with atrial fibrillation, and prevent thromboembolic complications.
" Asymptomatic patients with mitral valve disease must receive secondary prophylaxis against beta-hemolytic streptococci (benzathine penicillin G 1.2 million U IM q3-4 wk) for their lifetime to prevent the recurrence of rheumatic fever. They also need to receive prophylaxis for infective endocarditis prior to surgical or dental procedures.
" Initial symptoms of pulmonary congestion are secondary to increased left atrial pressure, which can be safely reduced by diuretics. Dietary sodium restriction and nitrates that can decrease preload can be of additional use. Careful use of beta-blockers in patients with a normal sinus rhythm can prolong the diastolic filling time and thus decrease left atrial pressure. Do not use afterload reducers because they can cause hypotension mainly due to the inability to compensate through an increase in cardiac output through a stenotic valve.
" Atrial fibrillation is common in mitral stenosis and leads to a rapid ventricular rate. An increased ventricular rate in atrial fibrillation markedly reduces diastolic filling time and increases left atrial pressure. It can be controlled by intravenous beta-blocker or calcium channel blocker therapy (diltiazem or verapamil). The rate can be controlled long-term with beta-blockers, calcium channel blockers, or digoxin.
" Recent-onset atrial fibrillation (<6 mo) in a patient with mild mitral stenosis and normal atrial size can be easily converted to a sinus rhythm either pharmacologically or with electrical counter shock. For this purpose, anticoagulation therapy should be given for at least 3 weeks prior to cardioversion or an abbreviated route can be used once the patient is anticoagulated. A TEE can be performed to exclude the presence of left atrial thrombus. If no thrombus is present, immediate cardioversion can be performed.
" Patients who are successfully converted to sinus rhythm need to receive long-term anticoagulation and antiarrhythmic drugs.
" Patients who are in sinus rhythm and have systemic embolization receive anticoagulation for at least 1 year, and patients with atrial fibrillation receive anticoagulation for life.
" Surgical correction of the mitral valve is indicated if embolization is recurrent.
Surgical Care: Surgical therapy for mitral stenosis consists of mitral valvotomy, which can be either surgical or percutaneous. The surgical approach can be through an open or closed technique; however, currently, the latter is rarely used and has been replaced by the percutaneous technique.
Asymptomatic patients with moderate or severe mitral stenosis (mitral valve area <1.5 cm2) with a suitable valve should be considered for percutaneous valvotomy if the pulmonary pressure is 50 mm Hg and above at rest or 60 mm Hg and above with exercise, or pulmonary capillary wedge pressure is 25 mm Hg and above with exercise.
Symptomatic patients with moderate or severe mitral stenosis (mitral valve area <1.5 cm2) who have suitable valves are candidates for percutaneous valvotomy.
If percutaneous valvotomy is not an option, patients should be referred for surgical repair or mitral valve replacement when they develop class III or IV symptoms.
" Percutaneous balloon valvotomy
o Percutaneous valvotomy 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 valvotomy to clearly define the anatomy.
o 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 is increased by approximately 2 cm2.
o Improvement in symptoms is dramatic immediately following the procedure. When only a little symptomatic improvement occurs after valvotomy, the valvotomy was likely ineffective or mitral regurgitation was present.
o The short- and long-term prognoses are good compared with surgical valvuloplasty. Even the long-term prognosis is good. Nearly half of all patients who undergo valvotomy require reoperation within 10 years.
o Balloon valvotomy offers certain distinct advantages to surgical commissurotomy, which include avoidance of thoracotomy, general anesthesia, and blood transfusion.
o The major contraindications are the presence of thrombus in the left atrium or its appendage and patients with mitral regurgitation that is more severe than grade 2.
o Complications of a balloon mitral valvotomy include embolization, mitral regurgitation, ventricular rupture, residual atrial septal defect, and death.
" Surgical valvotomy
o Open surgical commissurotomy has no advantages over closed commissurotomy.
o Surgery allows direct visualization of the mitral valve that must be repaired or replaced.
o Using current techniques, even severe regurgitant or stenotic valves can be repaired, with good long-term results. Valves that are not suitable for repair can be replaced using either bioprosthetic or prosthetic valves.
o With bioprosthetic valves, the patient does not require anticoagulation; however, 20-40% of these valves fail within 10 years, secondary to structural deterioration.
o 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.
o Patients who have chronic atrial fibrillation and who undergo mitral valve surgery can have simultaneous cox maze procedure, which helps to maintain sinus rhythm in up to 80% of the cases during the postoperative period.
DRUG TREATMENT :
1. ANTIARRYTHMICS :
- DIGOXIN
- AMIODARONE
3. CALCIUM CHANNEL BLOCKERS :
- DILTIAZEM
4. ANTICOAGULANTS :
- WARFARIN
- HEPARIN
5. BETA BLOCKERS :
- METOPROLOL
6. ANTIBIOTICS :
- PENICILLIN G BENZATHINE
7. DIURETICS :
- FRUSEMIDE
ALTERNATIVE DRUGS : Erythromycin for rheumatic fever prophylaxis; Clindamycin for bacterial endocarditis prophylaxis
PATIENT MONITORING : Close regular visits for assessment of the gradually progressive symptoms
PREVENTION/AVOIDANCE:
β’ Bacterial endocarditis prophylaxis for dental and invasive procedures continued for life
β’ Strep throat - treat appropriately when it occurs
β’ Rheumatic fever prophylaxis when indicated (See General Measures)
POSSIBLE COMPLICATIONS :
β’ Thromboembolism from mitral stenosis is a major potential complication (anticoagulation therapy has lessened this risk substantially)
β’ Recurrent rheumatic fever
β’ Bacterial endocarditis
β’ Pulmonary hypertension
β’ Pulmonary edema
EXPECTED COURSE/PROGNOSIS :
β’ Although a milder course is now seen in North America, the classic mitral stenosis history is 10 years from
the episode of rheumatic fever to the development of a murmur, another 10 years until symptomatic and
another 10 years for the patient to develop serious disability
β’ Operative mortality 1-2% for mitral commissurotomy; 2-5% for mitral valve replacement
AGE-RELATED FACTORS :
Geriatric:
β’ Atrial fibrillation and complicating arterial embolism more common
β’ Though there is an increased risk for bleeding, anticoagulation therapy recommended (unless specifically
contraindicated) due to high risk of embolism and valve thrombosis (especially if atrial fi brillation present)