Abstract 1752: Impact of Early Mitral Regurgitation on Left Ventricular Remodeling and Heart Failure After Successful Angioplasty for Acute Myocardial Infarction
Background: The mechanisms by which mitral regurgitation (MR) may leads an adverse prognosis after reperfused acute myocardial infarction (AMI) have not been yet fully investigated. We hypothesized that in the early phase of AMI MR may leads to progressive left ventricular (LV) remodeling and subequent heart failure.
Methods and results: A series of 184 patients with AMI successfully treated with primary percutaneous intervention underwent serial 2-D echocardiography from admission to 1 and 6 months, and 6-month angiography. Mean follow-up was 18 ± 7 months. On the basis of color Doppler, MR was graded from 0 (none) to 4 (severe). Patients were divided into two groups: those with MR grade ≤ 1 (group 1, n = 146) and those with grade ≥ 2 (group 2, n = 38). The regurgitant volume and the effective regurgitant orifice (ERO) area of MR were significantly higher in group 2 than in group 1 pts (36.7 ± 12.9 mL/beat vs 4.67 ± 3.2 mL/beat, P < 0.0001; 22.5 ± 7.6 mm2 vs 5.8 ± 5.7 mm2, P < 0.0001, respectively). No significant difference was found between the two groups regarding enzymatic infarct size, baseline angiographic and echocardiographic characteristics, 6-month patency/restenosis in the infarct vessel. LV end diastolic volume (EDV) progressively increased in group 2 and was significantly higher than in group 1 at 6 months (113.8 ± 31.8 mL vs 96.9 ± 34.1 mL, P = 0.0002), with a higher rate of LV remodeling (66% vs 22%, P < 0.0001) and a lower recovery of LV global and regional systolic function (P = 0.00002 for both). At 2 years, the incidence of heart failure was higher in the group 2 (39% vs 12%, P = 0.0001). A significant correlation was found between ERO area of MR and baseline to 6-month change of LV EDV (P = 0.001). By stepwise multivariate regression analysis ERO area of MR was an independent predictor of LV remodeling (P = 0.001), and at Cox analysis ERO area of MR was a strong independent predictor of heart failure (HR:1.069 CI 1.033–1.106, P < 0.0001).
Conclusion: In reperfused AMI, early high degree MR is an important predictor of both LV remodeling and subsequent heart failure.