The effect of early postinfarction revascularization of asymptomatic patients on left ventricular remodeling.

BACKGROUND: Patients with angina after a Q-wave myocardial infarction benefit from elective revascularization, but it is not known whether asymptomatic patients, including those with a totally occluded infarct-related artery, improve after revascularization.
OBJECTIVE: To determine the effect of early postinfarction revascularization of asymptomatic patients on left ventricular remodeling.
METHODS: We prospectively studied 31 consecutive asymptomatic patients (aged 57 +/- 2 years, 24 with anterior infarcts) after Q-wave myocardial infarction with > or = 70% stenosis of the infarct-related artery (IRA) who underwent early elective revascularization (days 4-10 after myocardial infarction). Group I consisted in patients with a totally occluded IRA (n = 10), and group II consisted in patients with a patent, though stenosed, IRA (n = 21). Resting echocardiography and low-dose dobutamine echocardiography were performed at baseline (day 3 +/- 1), and rest echocardiography was repeated after an 8-week follow-up. Significant myocardial viability was defined as > or = 2 wall segments improved (in a 16-segment model of left ventricle) versus baseline, and significant functional recovery as > or = 2 segments improved versus baseline on follow-up examination. Left ventricular end-systolic volume indices (ESVI) and end-diastolic volume indices and ejection fractions were measured by using a modified version of Simpson's rule (using apical two-chamber and four-chamber views).
RESULTS: The left ventricular ESVI of patients in group I had decreased by 4.2 +/- 1.9 ml/m2, whereas for patients in group II the left ventricular ESVI had increased by 4.2 +/- 1.7 ml/m2 (P = 0.006). Similarly, the left ventricular end-diastolic volume index had decreased by 0.7 +/- 2.4 ml/m2 versus baseline at follow-up for patients in group I and increased by 7.8 +/- 2.1 ml/m2 for patients in group II (P = 0.02). The left ventricular ejection fraction increased by 7.3 +/- 3% for patients in group I and decreased by 0.4 +/- 2% for patients in group II (P = 0.04).
CONCLUSION: There is less global left ventricular remodeling, a potentially deleterious process, after elective revascularization early after Q-wave myocardial infarction in asymptomatic patients who had had a totally occluded IRA before revascularization than there is in patients who had already had a patent, though stenosed, IRA before revascularization. These results suggest that restoration of patency of IRA after a Q-wave myocardial infarction is beneficial even for asymptomatic patients.