Impact of low cardiac function and diabetes mellitus on survival and causes of death following coronary artery surgery.

OBJECTIVES

To determine the differential impact of low cardiac function (ejection fraction [EF] ≤ 35%) and diabetes mellitus (DM) on survival and to identify causes of death after coronary artery bypass grafting (CABG).

METHODS

Overall, 1036 patients who underwent isolated CABG between 2009 and 2022 were divided into four groups based on EF and DM. Kaplan-Meier analysis was performed to calculate each group's estimated survival. Inter-group multivariate Cox regression was performed with the reference group showing EF > 35% and DM (-). Additional Cox regressions were performed to investigate the associations of EF ≤ 35% and DM (+) with death from heart failure, myocardial infarction, cancer, pneumonia, cerebrovascular disease and renal failure.

RESULTS

Off-pump techniques were used in 980 patients (95%). Patient population and estimated 10-year postoperative survival were as follows: EF > 35% DM (-), 430, 75.1%; EF > 35% DM (+), 456, 66.3%; EF ≤ 35% DM (-), 73, 62.5%; and EF ≤ 35% DM (+), 77, 53.5%. Hazard ratios (HRs) (P values) for the three groups were as follows: EF > 35% DM (+), 1.53 (0.006); EF ≤ 35% DM (-), 1.84 (0.017); and EF ≤ 35% DM (+), 2.23 (0.001). For death from heart failure, HR (P value) for EF ≤ 35% versus EF > 35% was 3.62 (0.012). For deaths from cancer and pneumonia, HRs (P values) for DM (+) versus DM (-) were 1.73 (0.097), and 2.72 (0.046), respectively.

CONCLUSIONS

EF ≤ 35% and DM (+) are associated with worse post-CABG survival. Each is associated with specific causes of death.