Intraoperative blood loss and warm ischemia time as independent predictors of positive surgical margins following partial nephrectomy

Abstract

Introduction. The presence of a positive surgical margin (PSM; R1 resection) following partial nephrectomy is associated with inferior oncological outcomes. Identification of risk factors for PSM and targeted optimization of modifiable variables may improve the surgical management of renal cell carcinoma and enhance long-term oncological outcomes. Objective. To identify risk factors for PSM following partial nephrectomy performed under warm ischemia, determine which of these factors are potentially modifiable, and evaluate the potential for reducing the incidence of PSM through targeted perioperative management. Materials & methods. A retrospective single-center study was conducted including 570 patients with localized renal cell carcinoma (clinical stages cT1–T2) who underwent partial nephrectomy between 2023 and 2025. Procedures were performed under warm ischemia using laparoscopic, retroperitoneoscopic, open, or robot-assisted approaches. Demographic, clinical, and pathological characteristics, the R.E.N.A.L. nephrometry score, surgical complexity, and key perioperative parameters—including warm ischemia time, estimated blood loss, incidence of collecting system injury, and PSM rate—were analyzed. Multivariable logistic regression, multivariable linear regression, and receiver operating characteristic (ROC) curve analyses were performed to identify independent predictors. Results . The overall incidence of PSM was 6.3% (n = 36). On univariable analysis, PSM was associated with larger tumor size, clinical stage cT1b, a higher R.E.N.A.L. nephrometry score, greater surgical complexity, prolonged warm ischemia time, and increased intraoperative blood loss. Multivariable analysis identified warm ischemia time and intraoperative blood loss as independent predictors of PSM. Threshold values associated with an increased risk of PSM were 28 minutes for warm ischemia time and 100 mL for intraoperative blood loss. Blood loss ≥100 mL was also associated with an increased risk of collecting system injury. Independent predictors of increased intraoperative blood loss included tumor size, the presence of atherosclerosis, operative time, warm ischemia time, surgical maneuver (tumor resection), and the renal artery-to-aorta diameter ratio (RA/Ao). An RA/Ao ratio ≥29% was found to predict intraoperative blood loss ≥100 mL. Conclusions. Warm ischemia time and intraoperative blood loss are independent predictors of PSM following partial nephrectomy performed under warm ischemia. Among these, intraoperative blood loss represents the only modifiable risk factor, underscoring the importance of meticulous preoperative planning and rigorous intraoperative hemostatic control. Attention should be paid to patients with atherosclerosis and an RA/Ao ratio ≥29%, as they are at increased risk of significant blood loss. Implementation of these strategies may reduce the incidence of PSM and improve oncological outcomes following partial nephrectomy. Further validation of these findings in prospective multicenter studies is warranted.