Effect of systematic downsizing rigid ring annuloplasty in patients with moderate ischemic mitral regurgitation

Functional ischemic mitral regurgitation (FIMR) increases mortality independently of the baseline characteristics and ventricular function. The effect of treating FIMR with annuloplasty is unclear when mitral regurgitation is moderate. Myocardial revascularization alone has been shown to improve mitral valve function.

We randomized 31 patients with moderate (grade 2-4) FIMR to receive either coronary artery bypass grafting (CABG) alone or CABG plus downsizing mitral ring annuloplasty. The patients were followed up for clinical outcomes and echocardiographic assessment of mitral valve function and left ventricular dimensions at 3 and 12 months. Clinical improvement was assessed using the Minnesota quality-of-life questionnaire, 6-minute walk test, and brain natriuretic peptide levels.

The clinical course was similar in the 2 groups of patients during the study period. FIMR was perfectly corrected intraoperatively in the ring group. Echocardiographic follow-up at 3 months showed no difference in the FIMR grade between the 2 groups (66% less than grade 2 in the CABG alone and 86% in the CABG plus ring group; P = .316). The improvement in the CABG alone group was even more marked at 12 months (85% less than grade 2 in the CABG group and 85% in the CABG plus ring group). The left ventricular ejection fraction was significantly better at 3 months in the CABG alone group, although at 12 months, the left ventricular ejection fraction in the 2 groups had improved similarly.

Although initially effective at reducing moderate FIMR, the addition of a ring did not change the clinical course after CABG surgery. At 12 months, no echocardiographic difference was found in terms of residual mitral regurgitation, left ventricular dimensions and function, or clinical outcomes.