Background: The presence of ischemic mitral regurgitation (IMR) after ST-segment elevation myocardial infarction (STEMI) portends a poorer prognosis. The possible influence of reperfusion therapy in restoring mitral valve competence in inferoposterior STEMI has not been well elucidated.
Methods and results: We studied 423 consecutive patients with a first inferoposterior STEMI and determined the presence of IMR in patients treated with reperfusion therapy versus medical therapy. A primary percutaneous coronary intervention (PCI) was performed in 186 patients; 74 patients underwent thrombolysis, 63 patients had rescue PCI whereas 54 patients were treated medically. The mean time interval between STEMI presentation and echocardiography was 14 ± 27 days. Patients receiving reperfusion therapy had less moderate or severe IMR (2.5 vs. 11.1%, P=0.001). The presence of IMR between the primary PCI and the thrombolytic groups was similar (52.2 vs. 60.8%, P=NS). Left ventricular ejection fraction (47.7 ± 10.3 vs. 53.1 ± 11.4%, P<0.001) and infarct size (mean CK-MB) (271 ± 168 vs. 222 ± 151 U/l, P<0.001) were significantly worse in patients with IMR. Dominance of the coronary artery system, involvement of the right or the left coronary arteries, and the presence of triple-vessel disease did not correlate with the presence of IMR. After adjustment for age and left ventricular ejection fraction, there was a trend toward poorer survival and recurrent admission for heart failure at 1 year in patients with IMR (hazard ratio=2.4, 95% confidence interval 0.91-6.2, P=0.08).
Conclusion: Both thrombolytic therapy and primary PCI were associated with decreased incidences of IMR following inferoposterior STEMI.