- Clinical science
Mitral regurgitation (MR) refers to the leakage of blood from the left ventricle to the left atrium due to incomplete closure of the mitral valve. The most common causes are primary diseases of the valve (e.g., mitral valve prolapse), although damage may also result secondary to other heart conditions such as left ventricular dilation and myocardial infarction. Symptoms such as palpitations or dyspnea appear late in the course of chronic compensated MR in which cardiac output can still be maintained. In acute or chronic decompensated MR, pulmonary edema and pulmonary hypertension often cause dyspnea, coughing, jugular venous distention, and pitting edema. Echocardiography is the most important diagnostic tool and allows for assessment of severity. It may also be used for preoperative evaluation. Treatment options include surgical mitral valve repair or replacement and percutaneous reconstruction. Early intervention is favored in most cases of MR with evidence of left ventricular dysfunction, regardless of symptoms.
- Primary MR
- Secondary (functional) MR
- Acute MR → ↑ LV end-diastolic volume → rapid ↑ LA and pulmonary pressure → pulmonary venous congestion → pulmonary edema
- Chronic (compensated) MR: : progressive dilation of the LV (via eccentric hypertrophy) → ↑ volume capacity of the LV (preload and afterload return to normal values) → ↑ end-diastolic volume → maintains ↑ stroke volume (normal EF)
- Chronic (decompensated) MR: progressive LV enlargement and myocardial dysfunction → ↓ stroke volume → ↑ end-systolic and end-diastolic volume → ↑ LV and LA pressure → pulmonary congestion, possible acute pulmonary edema, pulmonary hypertension, and right heart strain
- See “”
- Quiet first heart sound (S1)
- S3 gallop in advanced stages of disease
- Holosystolic murmur
- Cardiac impulse is often prominent
- Chest X-ray
Echocardiography: most important diagnostic method for detecting and assessing valvular abnormalities
- Valve apparatus (e.g., dimensions of valve opening area, calcification, rupture of the chordae tendineae) and mobility
- LV and LA size and function
- Coronary angiography: prior to surgical intervention
Myocardial infarction must be ruled out in patients presenting with acute MR!
- Acute mitral regurgitation
Chronic mitral regurgitation
- Asymptomatic patients
- Symptomatic patients
- Without evidence of severe LV dysfunction (EF > 30%): early valve repair or replacement ( or )
- With severe LV dysfunction (EF < 30%): surgical valve repair or replacement only if the patient is hemodynamically stable ;
- Alternatives for severe LV dysfunction:
- Percutaneous reconstruction
- Medical management of heart failure
- Initiate hemodynamic support for patients with unstable vitals.
- Cardiology and cardiac surgery consult
- Consider TEE
- If TTE is inconclusive
- For preoperative planning
- Identify and treat the underlying cause (e.g., endocarditis, acute MI).
- Consider definitive management options based on the underlying cause.
- Organic causes with disrupted valve structure : immediate surgical treatment
- Functional causes
- Myocardial ischemia: PCI or operative revascularization with valve repair/replacement
- Cardiomyopathy: medical therapy for heart failure (see acute management checklist for heart failure exacerbation), consider intra-aortic balloon pump
- If conservative treatment fails, surgical repair/replacement is indicated.
- Continuous cardiac monitoring
- Continuous pulse oximetry
- Transfer to OR or ICU.