A 58-year-old computer engineer is evaluated for a murmur heard during a routine physical. He has no symptoms and no significant medical history. Specifically, he has no dyspnea, chest pain, syncope, or lower extremity swelling. The patient smokes a cigar and drinks a glass of brandy every Friday night. His lifestyle is mostly sedentary, but he walks for several miles on weekends. Blood pressure is 122/69 mm Hg and pulse is 72/min. There is no jugular venous distension. Vesicular breath sounds are auscultated bilaterally. There is a 3/6 holosystolic murmur best heard at the apex. Echocardiogram shows the mitral valve cusps bulging into the left atrium during systole, and there is severe mitral regurgitation. The left ventricle is dilated with ejection fraction of 52%. Which of the following is the most appropriate management of this patient?
Surgical indications for severe chronic mitral valve regurgitation | |
Primary MR |
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Secondary MR |
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| *When possible, durable valve repair is favored over replacement because replacement necessitates lifelong anticoagulation & repeat replacement is often needed after ~10 yr. LVEF = left ventricular ejection fraction; MR = mitral regurgitation. | |
Primary mitral regurgitation (MR) is that caused by an intrinsic defect of the mitral valve apparatus (eg, leaflets, chordae tendineae) and is differentiated from secondary MR, which results from other cardiac disease (eg, myocardial ischemia, dilated cardiomyopathy). This patient's echocardiogram reveals severe MR due to mitral valve prolapse, a primary defect resulting from myxomatous degeneration of the mitral valve (manifesting on echocardiography as mitral valve cusps bulging into the left atrium during systole).
Chronic, severe primary MR is best treated with surgical repair, and the timing of surgery should precede the development of significant LV dysfunction. An important consideration is that measured LV ejection fraction (LVEF) overestimates LV function in severe MR because regurgitant flow accounts for a large amount of the stroke volume. Therefore, LVEF 30%-60% (as in this patient) is an indication for surgical repair (or replacement if repair is not possible) in patients with primary chronic severe MR, regardless of symptoms.
Because a progressive decline in LV function is expected in all patients, preemptive surgery should be considered in asymptomatic patients with LVEF >60% who are excellent candidates for successful valve repair (rather than replacement). Symptomatic patients with LVEF <30% have likely progressed to life-limiting, permanent systolic dysfunction; therefore, surgery is considered only when there is a high likelihood of successful valve repair.
(Choices A and B) Treatment with angiotensin receptor blockers (eg, losartan) and/or beta blockers (eg, metoprolol) can be beneficial for chronic severe MR that is secondary to dilated cardiomyopathy (ie, the MR is due to LV dilation and the mitral valve itself is normal). However, pharmacologic therapy is of limited benefit in patients with chronic severe MR of primary etiology; timely surgical repair is most effective.
(Choices D and E) Referral to an exercise program or repeat echocardiography in 6 months can be appropriate for patients with primary chronic severe MR and LVEF >60%. However, even patients with LVEF >60% may be considered for surgery if they have a high likelihood of successful and durable mitral valve repair.
Educational objective:
Timely surgical repair is the best treatment for chronic severe mitral regurgitation (MR) of primary etiology. The measured left ventricular ejection fraction (LVEF) significantly overestimates the effective LVEF in patients with severe MR; therefore, surgery is indicated for both symptomatic and asymptomatic patients with LVEF ≤60%.