Effect of diastolic dysfunction on early outcomes during elective off-pump coronary artery bypass grafting: a prospective observational study

Abstract

BACKGROUND: Left ventricular diastolic dysfunction (DD) causes adverse outcomes after cardiac surgery; however, the effects of DD during off-pump coronary artery bypass grafting (OPCAB) are not well understood. We aimed to assess the influence of DD on early mortality and morbidity of patients undergoing OPCAB.

METHODS: This prospective observational study included 1,256 patients scheduled for elective OPCAB. The DD of the patients was assessed by transthoracic echocardiography and tissue Doppler imaging. The cohort was classified into four DD groups; normal, mild (relaxation abnormality), moderate (pseudonormal dysfunction), and severe (restrictive abnormality). Study endpoints were major adverse cardiac events and other complications. Multivariate logistic regression was used to evaluate the independent effect of DD on surgical outcomes.

RESULTS: The 1,256 patients were grouped as follows: normal diastolic function (n=55, 4.4%), mild DD (n=995, 79.2%), moderate DD (n=169, 13.5%), and severe DD (n=37, 2.9%). Operative strategy did not differ among groups. The prevalence of hypertension, diabetes mellitus, renal failure, low ejection fraction (<35%), myocardial infarction within 30 days, and European System of Cardiac Operative Risk Evaluation score greater than 5 increased significantly with more severe DD. No significant difference was found in 30-day major adverse cardiac events (normal, 1.8%; mild DD, 3.6%; moderate DD, 6.5%; severe DD, 5.4%; p=0.23); however, postoperative renal failure, respiratory complications, respiratory failure, and prolonged hospitalization (more than 12 days: 75th percentile of the study cohort) increased with the severity of DD (p<0.01). Multivariate analysis revealed that severe DD independently predicted respiratory complications (odds ratio 3.68, 95% confidence interval: 1.84 to 20.36, p=0.01) and prolonged hospitalization (odds ratio 5.75, 95% confidence interval: 1.81 to 13.23, p<0.01).

CONCLUSIONS: Diastolic dysfunction does not affect 30-day major adverse cardiac events after elective OPCAB. However, severe DD independently predicts respiratory complications and prolonged hospitalization.