Abstract Introduction:

Preoperative renal insufficiency is an independent predictor of mortality after coronary artery bypass graft (CABG) surgery. However, there are few reports aimed to evaluate the impact of mild preoperative renal insufficiency on long-term follow-up outcomes after isolated CABG surgery. This study investigates the effect of mild preoperative renal insufficiency on long-term follow-up outcomes of patients after CABG.

Methods:

Five hundred eighty-four patients' data that underwent CABG between 1 January 2009 and 1 December 2016 were retrospectively analyzed.

They were divided into two groups:

normal group [Estimated glomerular filtration rate (eGFR) ≥ 90 ml/min/1.73 m2, n=304] and mild group (eGFR ranges from 60 to 89 ml/min/1.73 m2, n=280). Clinical material and long follow-up outcomes were compared inthe two groups.

Results:

Two groups had similar baseline and intraoperative data except eGFR. Six (0.01%) patients died in hospital, 15 in normal group and 28 in mild group during the long-term follow-up, which had statistical significance (P<0.05). Univariate factor analysis displayed that the two groups had similar in-hospital outcomes. Kaplan-Meier curves showed a better long-term survival in patients with normal preoperative renal function compared to mild preoperative renal insufficiency (x 2=4.255, P=0.039). Cox proportional model presented the hazard ratio of long-term mortality in patients with mild preoperative renal insufficiency compared to normal preoperative renal function was 1.79 (95% CI 1.17-2.88, P=0.027).

Conclusions:

Patients with mild preoperative renal insufficiency had a higher mortality rate than normal patients in long-term survival, whereas no evidence of worse in-hospital mortality rate was found. Patients with mild preoperative renal insufficiency showed a higher mortality rate than other studies.