Complexity of coronary artery disease affects outcome of patients undergoing coronary artery bypass grafting with impaired left ventricular function.

OBJECTIVE

To determine whether the SYNTAX score can predict the outcomes of patients with left ventricular dysfunction undergoing coronary artery bypass grafting.

METHODS

We studied a consecutive series of 191 patients (mean age, 67 ± 10 years) with a left ventricular ejection fraction of 40% or less who were undergoing isolated coronary artery bypass grafting. All patients were stratified according to their SYNTAX score, indicating coronary artery disease complexity: low, 0 to 22; intermediate, 23 to 32; and high, 33 or more. The primary outcome was all-cause mortality. Secondary outcomes included the late occurrence of major adverse cardiac and cerebrovascular events, left ventricular function, and New York Heart Association functional class.

RESULTS

The mean SYNTAX score was 32 ± 13, and the mean preoperative left ventricular ejection fraction was 35% ± 6%. At a median follow-up of 43 months, the primary outcome had occurred in 46 of 191 patients (24%). Kaplan-Meier analysis showed a survival of 81% ± 15% for low, 77% ± 7% for intermediate, and 53% ± 7% for high coronary artery disease complexity (χ(2), 29.4; P = .001). The rate of major adverse cardiac and cerebrovascular events was significantly greater in patients with a SYNTAX score of 33 or more (P = .002). Greater degrees of left ventricular ejection fraction improvement were found in patients with a SYNTAX score of 32 or less (+15% ± 10% vs +4% ± 11%; P = .17) and translated into a better New York Heart Association functional class among patients with a lower SYNTAX score (P = .01). Receiver operating characteristic curve analysis showed the SYNTAX score (area under the curve, 0.70; 95% confidence interval, 0.63-0.77) to have the best predictive power for late mortality with respect to the preoperative left ventricular ejection fraction (area under the curve, 0.59; difference, P = .04) and incomplete revascularization (area under the curve, 0.55; difference, P = .02).

CONCLUSIONS

The results of the present study have shown a direct relationship between coronary artery disease complexity and late outcomes of patients with left ventricular dysfunction who are undergoing coronary artery bypass grafting. Additional studies are needed to confirm these findings.