Effect of the stenosis location and severity on left ventricular function after single-vessel anterior wall myocardial infarction

Background The purpose of the current study was to determine how the locati on of the infarct-related lesion (IRL) and the degree of stenosis during th e acute and chronic phases of infarction might affect left ventricular (LV) function in patients with acute anterior wall myocardial infarction. Methods Ninety consecutive patients with a First single-vessel anterior wal l myocardial infarction (male/female ratio 75:15, mean age 60 +/- 9 years) underwent coronary angiography (CAG) immediately and 1 month after infarcti on. Patients were grouped according to IRL location (proximal [Coronary Art ery Surgery Study (CASS) No. 12] or distal [CASS No. 13] to the first diago nal branch of the left anterior descending artery) and according to the sev erity of stenosis at 1 month (severe stenosis [IRL >75%] and mild stenosis [IRL less than or equal to 75%]). At the time of infarction and 1 month and 1 year after infarction, total wall motion index (TWMI), left ventricular end-diastolic dimension (LVDd), left ventricular end-systolic dimension (LV Ds), and fractional shortening (FS) were determined. Results TWMI was greater and FS was lower For CASS No. 12 lesions than for CASS No. 13 lesions. CASS No. 12 lesions were associated with a greater LVD d at 1 year and a greater LVDs throughout 1 year of observation. The patien ts with mild stenoses had significant improvements in TWMI and FS over time , whereas those with severe stenoses showed no improvement. Multivariate an alysis showed that the independent factors predicting left ventricular func tion were IRL location at CASS No. 12, initial TIMI 0-1 flow in the IRL at emergency coronary artery graft, and he presence of a severe stenosis at I month. Conclusions In patients with severe stenoses at 1 month at CASS No. 12, lef t ventricular functional recovery is delayed and the left ventricular chamb er is enlarged. In patients with CASS No. 13 lesions, left ventricular func tion is preserved well, regardless of the severity of residual stenosis.