Importance of mitral regurgitation inpatients undergoing percutaneous coronary intervention for acute myocardial infarction: the Controlled Abciximab and Device Investigation to Lower Late Angioplasty Complications (CADILLAC) trial.

OBJECTIVES: We sought to determine the prognostic importance of mitral regurgitation (MR) in patients undergoing percutaneous coronary intervention for acute myocardial infarction (AMI).

BACKGROUND: Mitral regurgitation has been associated with a poor prognosis in patients treated with thrombolytic therapy for AMI. The prognostic significance of MR in patients undergoing mechanical reperfusion therapy for AMI is unknown.

METHODS: Left ventriculography was performed during the index procedure in 1,976 (95%) of 2,082 non-shock patients enrolled in a prospective, multicenter, randomized trial of mechanical reperfusion strategies in AMI. The severity of operator-assessed MR was divided into four strata: none (n = 1,726), mild (n = 192), and moderate/severe (n = 58).

RESULTS: Patients with progressively more severe MR were older (p < 0.0001), were more often women (p < 0.0001), and had higher Killip class (p = 0.0007). More severe grades of MR correlated with triple-vessel disease (p < 0.0001) and lower left ventricular ejection fraction (LVEF) as measured during the index procedure (p = 0.0004). Increasingly severe MR was strongly associated with a higher mortality at 30 days (1.4% vs. 3.7% vs. 8.6%, respectively; p < 0.0001) and at one year (2.9%, 8.5%, 20.8%, respectively; p < 0.0001). By multivariate analysis, the presence of even mild MR was an independent predictor of long-term mortality (mild MR, relative risk [RR] = 2.40, p = 0.005; moderate/severe MR, RR = 2.82, p = 0.006).

CONCLUSIONS: Mitral regurgitation of any degree present on the baseline left ventriculogram during the index procedure is a powerful, independent predictor of mortality in patients undergoing mechanical reperfusion therapy for AMI. The presence of MR identifies high-risk patients in whom close out-patient follow-up is warranted, and who may benefit from aggressive adjunctive medical or surgical therapies.