Impact of the interval between coronary angiography and off-pump coronary bypass surgery on postoperative renal function

Background: Postoperative acute kidney injury (AKI) is a significant complication after coronary artery bypass surgery. Prior coronary angiography increases the likelihood of AKI due to the use of a radiocontrast dye. This study examined the effect of coronary angiography on the postoperative renal function after off-pump coronary artery bypass surgery (OPCAB). Methods: The records of 110 patients who required OPCAB were reviewed. These patients also had at least two of the following conditions: chronic kidney disease, hypertension, diabetes mellitus, emergency surgery, congestive heart failure, age >75 years, hematocrit <30%, a left ventricular ejection fraction <40%, or the use of angiotensin-converting enzyme inhibitors or angiotensin receptor blockers. The patients were divided into two groups; coronary angiography performed within two days of OPCAB (Control group, n = 55), and coronary angiography performed more than two days before OPCAB (Angio group, n = 55). The serum creatinine (SCr) and serum cystatin C levels were measured on the day before surgery, as well as on postoperative days 1, 2, 3 and 7. The estimated glomerular filtration rate (eGFR) was also obtained on those days. AKI was defined as an increase in Cr ≥50% or ≥0.3 mg/dl within 48 hours. Results: The postoperative changes in the SCr, cystatin C and eGFR were similar in the two groups. The incidence of AKI and renal replacement therapy were similar in the two groups. Conclusions: Coronary angiography performed within two days of OPCAB does not affect the postoperative renal function. (Korean J Anesthesiol 2010; 58: 142-147)