The impact of intraoperative bleeding on the risk of chronic kidney disease after nephron-sparing surgery

Purpose: The current literature regarding the effect of blood loss (eBL) after nephron-sparing surgery (NSS) on long-term renal function is scarce. We tested the effect of eBL on the risk of developing chronic kidney disease (CKD) after NSS. Methods: Within an institutional prospectively maintained database, we identified 215 patients treated with NSS for cT1N0M0 renal mass at one European high-volume center. Multivariable logistic regression models tested the effect of eBL on the risk of developing CKD, after accounting for surgical complexity, individual clinical characteristics, and surgical experience. Multivariable linear regression models identified predictors of eBL. Results: After a median follow-up of 36 months, 55 (25.6%) patients experienced CKD after surgery. At multivariable analyses, eBL independently predicted higher risk of CKD after NSS (odds ratio [OR]: 1.16; 95% confidence intervals [CI] 1.04–1.30; p < 0.01). Specifically, the relationship between eBL and probability of CKD emerged as nonlinear, with a plateau from 0 to 500 mL of eBL and an increase afterward. When multivariable linear regression analyses investigated predictors of eBL, hypertension (Est: 127, 95% CI 12–242; p = 0.03), clinical size (Est: 47, 95% CI 7–87; p = 0.02), and PADUA score (Est: 42; 95% CI 4–80 p = 0.03) achieved independent predictor status for higher intraoperative eBL. Conversely, surgical experience was associated with lower eBL (p = 0.01). Conclusions: Intraoperative bleeding is independently associated with the risk of developing CKD after surgery, even after adjustment for well-known predictors of renal failure and tumor complexity. Hence, strategies aimed at maximally reducing such adverse events deserve special consideration.