The effect of pulsatile Versus nonpulsatile cardiopulmonary bypass on renal function in patients undergoing coronary artery bypass graft surgery, a randomized controlled trial

Background Coronary artery bypass grafting is of the most major surgeries performed around the world. Even though advances are achieved in the surgical technique, a relatively high complication rate regarding circulation is still observed. These complications are believed to be related to cardiopulmonary bypass flow types, pulsatile and nonpulsatile. With renal complications being one of the most important ones, we aim to evaluate the effect of choice of these two flow types on patients’ renal function in a randomized controlled trial. Method The study is a double blind randomized clinical trial. Patients with left ventricular dysfunction who were candidates for CABG and were between the ages of 40 to 75 were included in this study. The patients then were randomly assigned into two groups of intraoperative pulsatile and nonpulsatile flow type. The patients renal function markers such as 24-hour urine output, blood urea nitrogen and serum creatinine levels and creatinine clearance were evaluated before and CABG and afterwards in the ICU ward. The results were then analyzed using SPSS 23 software. Results of the initial 80 patients enrolled in this study, 16 patients were dropped due to unwillingness to continue follow-up and limitation of data gathering. Patients demographic data between two groups did not differ significantly. No statistically significant difference was observed between the 24 patients undergoing surgery with pulsatile flow and 40 with nonpulsatile flow regarding renal function. Both groups had a decrease in creatinine clearance during their ICU stay. Patients in the pulsatile flow group had less intubation time, less need for blood transfusion but more bleeding after the surgery. Conclusion Our study indicated that there is no difference between the use of pulsatile versus nonpulsatile flow regarding patients’ renal outcome. Our participants had a relatively broader age range than similar studies, including younger patients. This plus having an acceptable number of patients evaluated may illustrate that the differences in these two flow types may be dependent on other risk factors depending on the studied population. Further investigations with focal groups could lead us towards a better understanding how these two flow types differ.