Impact of Ischemia Time on Kidney Function in Patients with Microcirculation Impairment during Partial Nephrectomy (PN) for Kidney Cancer

Background: The role of onco-nephrologists in renal cancer patients (RCC) is crucial due to the risk of surgical AKI and CKD. Despite the benefits of partial nephrectomy (PN) in preserving renal function, arterial clamping during surgery could lead to AKI and CKD, especially in RCC patients with comorbidities like hypertension, diabetes, or vascular diseases. This study aims to investigate the impact of PN on RCC patients with microcirculation impairment (MI) Methods: Data are from 186 patients with microcirculation impairment undergoing elective partial nephrectomy (PN) for cT1-2 cN0 cM0 RCC. Impairments included hypertension, diabetes, peripheral vasculopathy, or vascular nephropathy. Ischemia time was the duration of clamping the renal artery without refrigeration. Primary outcome was the effect of warm ischemia time (WIT) on renal function postoperatively, at 6 months, and long term. Secondary outcome was hemorrhagic risk, defined as estimated blood loss (EBL) or peri-operative transfusions. Multivariable regression analyses were used Results: A total of 139 patients (75%) underwent PN with WIT and 47 (25%) without. The baseline median eGFR was 71 mL/min/1.73m2 for the on-clamp population and 61.4 mL/min/1.73m2 for the off-clamp population. At multivariable analyses predicting renal function, longer WIT was associated with decreased postoperative eGFR (Est:−0.23, [P<0.001]). Conversely, no association between WIT and eGFR was recorded at 6-month or long-term follow-up (all P>0.1). At multivariable analyses predicting hemorrhagic risk, clampless resection with no ischemia time and PN with short WIT was associated with an increased EBL (Est:−25.77, [P=0.03]) and peri-operative transfusion rate (Est:−0.017, [P=0.04]) Conclusion: Patients and clinicians should know that performing partial nephrectomy (PN) with limited or zero warm ischemia time (WIT) in patients with microcirculation impairment does not improve long-term renal function and increases bleeding and transfusion risk. Our findings support hilum clamping even in these patients