One-year follow-up after intravascular ultrasound assessment of moderate left main coronary artery disease in patients with ambiguous angiograms

OBJECTIVES The purpose of this study was to correlate angiographic and intravascular ultrasound (IVUS) findings in left main coronary artery (LMCA) disease and identify the predictors of coronary events at one year in patients with LMCA stenoses. BACKGROUND Significant (≥50% diameter stenosis [DS]) LMCA disease has a poor long-term prognosis. METHODS One hundred twenty-two patients who underwent angiographic and IVUS assessment of the severity of LMCA disease and who did not have subsequent catheter or surgical intervention were followed for one year. Standard clinical, angiographic and IVUS parameters were collected. RESULTS The quantitative coronary angiography (QCA) reference diameter (3.91 ± 0.76 mm, mean ± 1 SD) correlated moderately with IVUS (4.25 ± 0.78 mm, r = 0.492, p = 0.0001). The lesion site minimum lumen diameter (MLD) (2.26 ± 0.82 mm) by QCA correlated less well with IVUS (2.8 ± 0.82 mm, r = 0.364, p = 0.0005). The QCA DS measured 42 ± 16%. During the follow-up period, 4 patients died, none had a myocardial infarction, 3 underwent catheter-based LMCA intervention and 11 underwent bypass surgery. Univariate predictors of events (p < 0.05) were diabetes, presence of another lesion whether treated with catheter-based intervention or untreated with DS > 50% and IVUS reference plaque burden and lesion lumen area, maximum lumen diameter, MLD, plaque area and area stenosis. Using logistic regression analysis diabetes mellitus, an untreated vessel (with a DS > 50%) and IVUS MLD were independent predictors of cardiac events. CONCLUSIONS In selected patients assessed by IVUS, moderate LMCA disease had a one-year event rate of only 14%. Intravascular ultrasound MLD was the most important quantitative predictor of cardiac events. For any given MLD, the event rate was exaggerated in the presence of diabetes or another untreated lesion (>50% DS).