Mitral Regurgitation: Clinical Overview and Management

Definition and Anatomy

The mitral valve consists of two leaflets (anterior and posterior), each divided into three scallops, with the posterior leaflet attached to two-thirds of the annular plane 1
Normal valve function requires perfect coordination between the mitral leaflets, subvalvular apparatus, mitral annulus, and left ventricle 1

Primary MR results from direct pathology of the mitral valve apparatus itself, with the valve being the diseased structure 2
Mitral valve prolapse and Barlow disease represent the most common causes of primary MR in developed countries, characterized by myxomatous degeneration with excessive leaflet tissue 1, 2
Secondary MR develops despite structurally normal valve leaflets, resulting from dysfunction of surrounding cardiac structures—this is a disease of the left ventricle, not the valve 2

Echocardiography plays the key role in assessment and management of patients with MR, answering four critical questions: mechanism, severity, cardiac effects, and suitability for intervention 1, 6
Transthoracic echocardiography accurately assesses mitral valve morphology using parasternal long-axis and short-axis views to identify all six scallops and determine the Carpentier classification 1
Color Doppler imaging localizes the origin of the regurgitant jet to identify prolapsing or flail segments 1

Surgery is the only treatment proven to improve symptoms and prevent heart failure in severe MR 5
Valve repair improves outcome compared with valve replacement and reduces mortality in patients with severe organic MR by approximately 70% 5
Emergency surgery is required for acute severe MR with cardiogenic shock or pulmonary edema, particularly with papillary muscle rupture 5

Acute papillary muscle rupture causes sudden hemodynamic deterioration with cardiogenic shock and pulmonary edema 4, 3, 5
Chordal rupture in degenerative disease presents as acute decompensation in previously stable patients 3
Infective endocarditis can cause rapid valve destruction with acute severe MR and high risk of embolism 3

Any new murmur in a patient with acute cardiorespiratory symptoms mandates immediate echocardiography—do not wait 4, 3
Suspect papillary muscle rupture in any post-MI patient with sudden hemodynamic deterioration, even if the murmur is soft or absent 4, 3, 5
Intra-aortic balloon pump placement is the most effective bridge to surgery in acute severe MR with cardiogenic shock—place early while preparing for definitive intervention 5