Grade of left main coronary artery stenosis does not influence long-term mortality after coronary artery bypass surgery.

Objective: To assess if grade of left main coronary artery (LMCA) stenosis influences early or long-term mortality after coronary artery bypass grafting (CABG).

Design: Among all 1 384 patients with LMCA stenosis at Karolinska Hospital, Stockholm, Sweden during 1990-1999, 131 deaths occurred within 5 years of surgery (cases). Matched controls (n=146) were randomly selected from all surviving LMCA patients taking gender, age and year of surgery into account. Angiographies were classified for grade of LMCA stenosis before the operation.

Results: High-grade LMCA stenosis was equally common among cases and controls (50 vs. 45%). The odds ratio (OR) of mortality 5 years after the operation in patients with high-grade versus low-grade LMCA stenosis based on the matched pairs was 1.2 (95% confidence interval (CI) 0.7-2.0) and after multivariable adjustment using information on all subjects the OR was 1.0 (95% CI 0.6-1.7). For early and one year mortality similar odds ratios were observed but with wide confidence intervals.

Conclusions: Grade of LMCA stenosis does not appear to influence early or long-term mortality after CABG performed during 1990-1999.