Cardiopulmonary Bypass Blood Flow Rates and Major Adverse Kidney Events in Cardiac Surgery: A Propensity Score-adjusted Before–After Study

Cardiac surgery associated-acute kidney injury is a common and serious postoperative complication of cardiac surgery, which is associated with increased postoperative morbidity and mortality. This study aimed to explore the association between cardiopulmonary bypass (CPB) blood flow rate (BFR), and major adverse kidney events (MAKEs) at day 30. Retrospective single-center before–after observational study. Patients were divided in 2 groups according to CPB flow rates: a first group with an institutional protocol targeting a CPB-BFR of >2.2 L/min/m² (low CPB-BFR group), and a second group with a modified institutional protocol targeting a CPB-BFR of >2.4 L/min/m² (high CPB-BFR group). The primary outcome was MAKE at 30 days, defined as the composite of death, renal replacement therapy or persistent renal dysfunction. The data were collected from clinical routines in university hospital. Adult patients who underwent elective and urgent cardiac surgery without severe chronic renal failure, for whom CPB duration was ≥90 minutes. We included 533 patients (low CPB-BFR group, n = 270; high CPB-BFR group, n = 263). A significant decrease in MAKE at 30 days was observed in the high CPB-BFR group (3% v 8%; odds ratio [OR], 0.779; 95% confidence interval [CI], 0.661-0.919; p < 0.001) mainly mediated by a lower 30-day mortality in the high CPB-BFR group (1% v 5%; OR, 0.697; 95% CI, 0.595-0.817; p = 0.001), as was renal replacement therapy (1% v 4%; OR, 0.739; 95% CI, 0.604-0.904; p = 0.016). In patients undergoing cardiac surgery, increased CPB-BFR was associated with a decrease in MAKE at 30 days including mortality and renal replacement therapy. [Display omitted]