RESUMEN
The long-term outcome of a moderately diseased left main coronary artery (LMCA) remains unknown. One hundred and fourteen patients who underwent angiographic and intravascular ultrasound (IVUS) evaluation for moderate LMCA disease (< 50% diameter stenosis) without intervention were followed for 5 years. There were 11 patients who underwent coronary artery bypass graft surgery (CABG) within 30 days of IVUS analysis based on IVUS findings and 3 patients who died of noncardiac diseases during the follow-up period. These 14 patients were excluded from the cohort, and 100 patients comprised the study group. Six patients (6%) died (1 of cardiac causes and 5 of unknown causes) at a follow up of 31.5 +/- 17.0 months post-IVUS assessment. Two patients (2%) underwent CABG at a follow up of 19.0 +/- 7.1 months. There were no percutaneous LMCA interventions and no myocardial infarctions. Univariate predictors for events were age, mean plaque and media (P&M) area and plaque burden over the entire length of the LMCA lesion, and minimum luminal area (MLA), P&M area, plaque burden, and arc of calcium > 90 degrees at the MLA site. By multiple logistic regression analysis, plaque burden at the MLA (odds ratio = 1.34, 95% confidence interval 1.04-1.73; p = 0.025) was the only independent predictor of events. In conclusion, moderately diseased LMCAs had a 5- year event rate of 8%. The occurrence of future events in moderate diseased LMCAs is dependent on the amount of disease at the MLA site.