Although the clinical significance of mitral regurgitation (MR) due to prolapse or chordae rupture with myxomatous degeneration (MD) is increasing significantly, clinical features of patients with MD in Korea are not characterized.

Retrospective analysis of clinical data of 90 patients who underwent surgical correction of significant MR due to MD was performed. Lesion sites of MD were confirmed during surgery; anterior (A) and posterior (P) mitral leaflets were divided into lateral (A1 & P1), middle (A2 & P2), and medial segments (A3 & P3).

Mean age was 5114 years and male / female ratio was 1; age distribution showed typical bimodal pattern with two peaks at the mid-thirties and the mid-fifties each. MD was confined to P leaflet in 36 (40%), A leaflet in 20 (22%), and both leaflets in 34 patients (38%). Forty-six patients (51%) showed MD in a single segment, and 37 (41%) in 2 segments; 7 patients (8%) showed MD in more than 2 segments. In 90 patients, pathologic MD was confirmed in 139 mitral segments; among them, P3 was the most commonly involved segment (30%), followed by A3 (17%), P2 (14%), A2 (14%), A1 (14%), and P1 (12%). Hypertension (HT) was more frequently observed in female patients (42%) than in male patients (16%) (p<0.05). Chordae rupture was observed in 71 patients (79%), which was associated with HT. Younger patients (age<45 years, N=31) showed lower prevalence of HT and higher incidence of MD involving multiple segments. Valve repair was successful in 83 patients (92%), which was not associated with lesion sites or numbers of MD. Three-year event free survival rate was 865% and independent on sites and numbers of MD.

MD develops preferentially in the medial part of the mitral valve, and patterns of clinical presentation can change according to the age and existence of HT in these selected patients with significant MR. However, the morphologic characteristics of MD do not seem to affect the feasibility of repair and long-term prognosis.