Minimized Extracorporeal Circulation Cannot Prevent Acute Kidney Injury but Attenuates Early Renal Dysfunction After Coronary Bypass Grafting
We studied the impact of minimized extracorporeal circulation (MECC) on acute kidney injury (AKI) after coronary bypass grafting. A retrospective, observational study with 1,685 patients with MECC and 3,046 patients with conventional bypass was done. Primary outcome was AKI defined as a decline ≥50% in estimated glomerular filtration rate (eGFR) within 48 hours after surgery. Secondary outcome was temporary dialysis. MECC exerts beneficial hemodynamic effects but does not prevent AKI. Fewer patients developed a decline in eGFR <60 mL/min/1.73 m2 (MECC) compared with conventional extracorporeal circulation (ECC) (30.7% versus 45.5%, p < 0.001). The incidence of eGFR decrease by ≥50% did not differ (1.8% versus 2.7%, p = 0.20). Temporary dialysis was required in 61 patients with ECC (2%) and in 16 patients with MECC (0.9%, p < 0.001). A preoperative eGFR <60 mL/min/1.73 m2 increased in both groups the risk for mortality compared with patients with an eGFR >60 mL/min/1.73 m2 (ECC: odds ratio 3.6, 95% confidence interval 2.6–4.9; MECC: odds ratio 4.9, 95% confidence interval 2.8–8.6). MECC is renoprotective in the early postoperative period but cannot prevent AKI. An impaired preoperative eGFR increases the risk for mortality irrespective of the cardiopulmonary bypass system used.