The effect of ejection fraction on mortality in Coronary Artery Bypass Grafting (CABG) patients

Background and Objectives: Patients with low ejection fraction undergoing isolated CABG surgery are at a higher risk for postoperative complications and mortality. This study was conducted to evaluate the impact of ejection fraction on the outcome of isolated Coronary Artery Bypass Grafting (CABG).

Methods: Between July, 2017 to May, 2019 total 1214 patients underwent isolated CABG. Patients were divided into three groups based on their pre-operative Ejection Fraction (EF). Group-I included 625 patients with EF >50% [Normal EF], Group-II included 484 patients with EF 35-50% [Mild to Moderately Reduced EF], and Group 3 included 105 patients with EF <35% [Severely Reduced EF].

Results: The mean age of Group-I was 57.58 ± 9.206, Group-II was 58.38±9.124 and Group-III was 58.81± 8.663.The male gender was the predominant gender in all three groups: 194(41.1%) in Group-I, 201(52.6%) in Gp2, 52 (61.9%) in Group-III. 231(36.9) patients in Group-I, 234(48.3)in Group-II and 59(56.2) in Group-III had raised creatinine pre operatively. 5(0.8%) patients in Group-I, 2(0.4%) in Group-II and 3(2.9%) in Group-III had history of CVA. Hypertension was present in approximately 60% of all our patients. In the per-operative period 20(3.2%) patients in Group-I required an IABP as compared to 73(15.1%) in Group-II and 41(39.0%) in Group-III. The mean post-operative mortality in Group-I was 19 (3%), Group-II was 24(5.0%) and low EF group was 9(8.6%).

Conclusions: The results clearly indicate that worsening pre-operative ejection fraction is associated with a higher mortality post-operatively in patients undergoing isolated CABG. In addition, use of IABP increases as pre-operative LVEF decreases.

Definitions: *PERFUSION TIME: total time on CPB machine. *CROSS CLAMP TIME: Total time that ascending aorta was CROSS clamped. *STROKE: Defined as presence of neurological deficit, findings on CT scan and confirmed by a Neurology consultant. *RE-OP: Re-operation during index admission.