RISK FACTORS: Positive family history, Disorder of connective tissue/collagen, Increased risk of complications:- Male sex and age over 50, Posterior leaflet prolapse (associated with holosystolic murmur), Mitral regurgitation
Medical Care:
" Asymptomatic patients with minimal disease
o These patients should be strongly reassured of their benign prognosis.
o They should undergo initial echocardiography for risk stratification. If no clinically significant mitral regurgitation is identified with thin leaflets, clinical examinations and echocardiographic studies can be scheduled every 3-5 years.
o These patients are encouraged to pursue a normal, unrestricted lifestyle, including vigorous exercise.
" Patients with symptoms of autonomic dysfunction
o A trial of beta-blockers for symptomatic relief can be tried.
o They are also recommended to abstain from stimulants such as caffeine, alcohol, and cigarettes. An ambulatory 24-hour monitor may be useful to detect supraventricular and/or ventricular arrhythmias. If frequent ventricular ectopy or VT is identified, electrophysiology studies may be indicated to identify the small risk of sudden cardiac death.
" Patients with evidence of or progression to severe mitral regurgitation
o Close follow-up and referral for surgical repair are indicated early, before left ventricular dilatation and systolic dysfunction develop.
o Asymptomatic patients with moderate-to-severe mitral regurgitation and left ventricular enlargement, especially those with atrial fibrillation and/or pulmonary hypertension, should undergo surgery soon, before left ventricular dysfunction becomes poor.
o If the physician is unsure if the patient is asymptomatic, a treadmill stress test for exercise tolerance should be performed. That is, have the patient demonstrate that he or she can walk vigorously without symptoms.
" Patients with MVP and neurologic findings
o After atrial fibrillation and left atrial thrombus are excluded, these patients should be given daily aspirin therapy at a dosage of 80-325 mg/d.
o Daily aspirin is also recommended for patients with transient ischemic attacks (TIAs) and patients <65 years with atrial fibrillation and no history of mitral regurgitation, hypertension or heart failure (ie, lone atrial fibrillation).
o Patients should stop smoking and using oral contraceptives to help prevent a hypercoagulable state.
o Warfarin should be used when patients older than 65 years have atrial fibrillation, especially if they have associated risk factors of a previous stroke or TIA, clinically significant valvular heart disease, hypertension, diabetes, left atrial enlargement, or a history and/or findings of heart failure.
" Patients with a mid-systolic click and late-systolic mitral regurgitation murmur
o Seriously consider antibiotic prophylaxis in these patients, including those with increased leaflet thickening or redundancy, left atrial enlargement, and left ventricular dilatation, even in the absence of correlated clinical findings.
o Most clinicians and textbook authors usually consider an isolated mid-to-late systolic click without a murmur a low-risk condition. However, if the echocardiographic findings of redundancy and leaflet thickness are impressive, some cardiologists still offer prophylactic antibiotics.
Surgical Care: See the surgical management discussion in Mitral Regurgitation.
Further Outpatient Care:
" Depending on its severity, patients with MVP may be monitored regularly with history taking, physical examination, and echocardiography when indicated.
" If symptoms or physical findings change during outpatient care, echocardiography or a combination of studies may be indicated.
Complications:
" Severe mitral regurgitation
o This is the most common complication and the cause of isolated mitral regurgitation requiring mitral valve surgery in the United States.
o Severe mitral regurgitation is most frequently due to rupture of the chordae tendineae.
o The risk increases with the following factors: patients older than 50 years, male individuals, history of hypertension, increased BMI, increased mitral valve thickness or redundancy, or left atrial and left ventricular dilatation.
" Infective endocarditis
o The main mechanism for increased risk includes leaflet thickness or redundancy and the severity of mitral regurgitation resulting in a turbulent flow state.
o The risk increases 3- to 8-fold.
o The main predictors are age older than 50 years, male sex, history of hypertension, increased BMI, left atrial and ventricular enlargement, or increased mitral valve thickness or redundancy.
o If an isolated mid-to-late systolic click is present, it is generally thought to be low risk, but universal agreement is lacking.
" Sudden cardiac death and cerebrovascular ischemic events
o The association between sudden cardiac death and MVP is not well understood. Data suggest that MVP alone does result in excessive atrial or ventricular arrhythmias, which are most likely due to autonomic dysfunction. Patients with these findings have been said to have MVP syndrome.
o The risk is increased when patients have evidence of left ventricular dilatation and dysfunction, severe mitral regurgitation, and increased mitral leaflet thickness or redundancy.
o In the presence of QT prolongation and frequent ventricular ectopy, especially nonsustained ventricular or sustained ventricular tachycardia, an electrophysiologic study may be indicated to quantitate the risk of inducible ventricular tachycardia and/or ventricular fibrillation and sudden arrhythmic death.
o In regard to cerebrovascular ischemic events, recent studies yielded mixed findings in terms of the association between the increased prevalence of cerebrovascular events and MVP in young patients without evidence of cerebrovascular disease.
" Gilon et al (1999) describes the lack of an association between MVP and stroke in young patients in a large case-control study.
" The hypothesized mechanism is the formation of platelet fibrin thrombi on the denuded, damaged myxomatous valves resulting in embolization. Data have again suggested that the prevalence of this mechanism is based on the degree of mitral regurgitation.
o The major risk factors for cerebrovascular events include age older than 50 years, thickened mitral valve leaflets, atrial fibrillation, and a need for mitral valve surgery.
Prognosis:
" Most patients with MVP are asymptomatic and have a benign course.
" Patients with high-risk characteristics and/or progressive mitral regurgitation are at increased risk for complications.
Surgical Care:
" Indications for surgical intervention
o Acute mitral regurgitation (MR) with congestive heart failure or cardiogenic shock
o Acute endocarditis
o Class III/IV symptoms (ie, patient symptomatic while at rest or with minimal activity)
o Class I/II (few or no) symptoms with evidence of deteriorating LV function as evidenced by (1) an ejection fraction less than 0.55, (2) fractional shortening less than 30%, and (3) either the end-diastolic diameter approaching 75 mm or the end-systolic diameter approaching 50 mm
o Systemic emboli
o End-systolic volume index greater than 60 mL/m2 - Most commonly used parameter
" Surgical options
o Mitral valve reconstruction with mitral annuloplasty, quadratic segmental resection, shortening of the elongated chordae, or posterior leaflet resection
o Mitral valve replacement with either a mechanical valve (requiring lifelong anticoagulation) or a bioprosthetic porcine valve.
DRUG TREATMENT :
1. BETA BLOCKERS : DRUG OF CHOICE FOR PTS WITH MVP & PALPITATION
2. DIURETICS :
- FRUSEMIDE
3. ACE INHIBITORS : TO REDUCE BLOOD PRESSURE & REGURGITATION IN THE APPROPRIATE CLINICAL SETTING BUT SHOULD NOT BE USED IN THE PRESENCE OF SEVERE MITRAL REGURGITATION & LT. VENTRICULAR REMODELING WITHOUT CONSIDERATION OF MITRAL VALVE REPAIR.
- CAPTOPRIL
- ENALAPRIL
- LISINOPRIL
4. NITRATES :
- NITROGLYCERINE
5. HYDRALAZINE : HYDRALAZINE & NITRATES IN COMBINATION FOR AFTERLOAD REDUCTION
6. INOTROPICS :
- DIGOXIN
7. ANTIBIOTICS : AS PROPHYLACTIC
- AMPICILLIN
- AMOXYCILLIN
- CLINDAMYCIN
- GENTAMYCIN
- VANCOMYCIN
- ERYTHROMYCIN
- AZITHROMYCIN
- CLARITHROMYCIN
- CEFAZOLIN
PREVENTION/AVOIDANCE:
. Endocarditis prophylaxis for auscultatory murmur or redundant, thickened leafl ets by echocardiogram.
Prophylaxis not needed in MVP without a murmur.
. Good dental hygiene
. Anticoagulation in patients with atrial fibrillation and atrial enlargement
POSSIBLE COMPLICATIONS :
. Complication rate approximately 2% per year
. Sudden death - rare. Some cases of MVP associated with proteoglycan deposition (valves as well as
extravalvular) and with small vessel disease, causing ventricular arrhythmias and sudden death.
. Uncommon and related to advancing age, male sex, atrial/ventricular size rather than to presence/absence
of valvular prolapse:
. Infective endocarditis
. TIA
. Stroke
. Congestive heart failure
. Heart block
. Severe mitral regurgitation
. Syncope
EXPECTED COURSE/PROGNOSIS :
. 75% excellent with same morbidity/mortality as agematched controls
. 25% progressive mitral regurgitation with a long (25 year) asymptomatic phase followed by rapid deterioration requiring valvular repair within a year once symptoms occur