Improvement of global and regional left ventricular function by percutaneous transluminal coronary angioplasty after myocardial infarction.

OBJECTIVES: This study was designed to evaluate how elective percutaneous transluminal coronary angioplasty of the infarct-related vessel after acute myocardial infarction affects global ejection fraction and regional wall function.

BACKGROUND: The severity of the residual stenosis of the infarct-related artery after thrombolysis is an important predictor of changes in left ventricular function; however, the optimal time to restore complete perfusion in the infarct area has not been determined.

METHODS: We prospectively evaluated patients with a first myocardial infarction, postinfarction ischemia and residual high grade stenosis with reduced flow in the infarct-related artery who underwent successful coronary angioplasty. The group comprised 74 patients (61 men, 13 women with a mean age +/- SD of 55.9 +/- 9.9 years). Global ejection fraction and infarct region function (expressed as area ejection fraction) were angiographically measured before coronary angioplasty (3.9 +/- 2.1 weeks after infarction) and on routine follow-up study 6 +/- 1 months after angioplasty.

RESULTS: Restenosis with reduced flow occurred in 15 patients (20%). The global ejection fraction in patients with complete flow at follow-up increased significantly from 56.8% +/- 12% to 62.3% +/- 12.5% (p < 0.001). Regional wall motion of the infarct area increased from 12.1% to 22.5% (p = 0.001) in patients with anterior wall infarction and from 20.4% to 28.5% (p = 0.002) in those with inferior wall infarction. In patients with restenosis there was no difference at follow-up either in global ejection fraction (from 47.7% +/- 7.7% to 47.1% +/- 12.7%, p = 0.57) or in regional wall motion of the infarct area.

CONCLUSIONS: Global and regional myocardial dysfunction due to postinfarction ischemia lessens significantly after successful coronary angioplasty of the infarct-related coronary artery with long-term sustained normal, complete flow. In contrast, restenosis with reduced flow prevents long-term improvement of left ventricular function.