Elevated Serum Renin Before Liver Transplantation Is Associated With Increased Intraoperative Vasopressor Requirements and Posttransplant Acute Kidney Injury

BACKGROUND: Derangements of the renin-angiotensin-aldosterone system may contribute to circulatory dysfunction in cirrhosis. We hypothesized that renin is elevated in patients undergoing liver transplantation (LT) and is associated with vasopressor requirements and postoperative organ dysfunction. METHODS: We collected serum from 138 patients before LT and measured renin by enzyme-linked immunosorbent assay. Eligible patients were adults with cirrhosis undergoing LT from a deceased or living donor. Detailed clinical data were obtained from a perioperative data warehouse. The primary outcome was vasopressor dosage during the dissection phase of LT. The secondary outcomes were postoperative acute kidney injury (AKI) and early allograft dysfunction. RESULTS: Renin was elevated up to 100-fold above normal and strongly correlated with Model for End-Stage Liver Disease sodium. A 10-fold increase in renin was associated with a 0.03 µg/kg/min (95% confidence interval [CI], 0.01-0.05) higher vasopressor dose during dissection measured in norepinephrine equivalents. Renin was unassociated with early allograft dysfunction but strongly associated with AKI. A 10-fold increase in renin was associated with an odds ratio of 1.77 (95% CI, 1.12-2.77) for AKI. The association with AKI persisted in a sensitivity analysis limited to 105 patients with preoperative estimated glomerular filtration rate of 60 mL/min/1.73 m2 (odds ratio, 1.74; 95% CI, 1.05-2.88). CONCLUSIONS: Renin-angiotensin-aldosterone system perturbations may contribute to negative outcomes after LT. Elevated renin may help predict postoperative AKI even when kidney function is preserved before LT. As renin is associated with increased vasopressor requirements, measuring renin may help identify patients for consideration of treatment with infusion of the vasopressor angiotensin II during LT.