Hypothesis: Renal insufficiency (RI) is associated with an increased risk of morbidity and mortality following coronary artery bypass graft (CABG) operations, particularly among patients who are dependent on dialysis.
Design and setting: A retrospective analysis of data collected at a tertiary care center.
Patients: One hundred eighty-four consecutive patients with RI who underwent CABG surgery between 1992 and 2004. This group consisted of 152 patients with serum creatinine levels of ≥ 1.7 mg/dL (group I) and 32 kidney transplant recipients (group II). Of the patients in group I, 90 were dialysis-free (subgroup IA) and 62 were dialysis-dependent (subgroup IB).
Main outcome measures: Demographics, perioperative data, and outcomes for each of the three groups were evaluated and compared.
Results: Fifty-four percent of the patients were in New York Heart Association classes III and IV, 36% had unstable angina, and 21% had left main coronary disease. The mean ejection fraction was 38%. The median postoperative length of stay in the hospital was 10 days. Of the patients in group IB, 8% required reexploration for bleeding compared to 3% in groups IA and II (p < 0.05). Dialysis was needed postoperatively in five patients in group IA and two patients in group II (5.7%). The raw operative mortality rate was 7.6% and was higher in group IB (9.7%) compared to groups IA and II (6.7% and 6.2%, respectively; p < 0.05). The actuarial 5-year survival rate was higher in group II compared to group I (79% vs 59%, respectively; p < 0.05). The difference in survival rates was more apparent between groups II and IB (79% vs 57%, respectively; p < 0.005).
Conclusions: CABG is associated with an increased rate of perioperative complications and mortality in patients with RI. Dialysis dependence is a major risk factor for patients undergoing CABG surgery. However, with acceptable surgical results, dialysis patients should not be denied CABG surgery. A survival advantage is demonstrated among patients with previous kidney transplants compared to those patients who are dependent on dialysis.