Impact of ischaemia duration and clamping strategy in patients with solitary kidney undergoing partial nephrectomy

Abstract

Objectives To explore the effects of ischaemia time (IT) in a multicentre cohort of patients with solitary kidney (SK), treated with partial nephrectomy (PN) for a renal mass, on short- and long-term kidney function, haemorrhagic risk and pathological outcomes. Methods This is an observational study of 426 patients with SK treated with on- and off-clamp PN for a single cT1-3 N0M0 renal mass from 2000 to 2023 at 19 global institutions. The primary outcomes were postoperative and 1-year renal function. The secondary outcomes of the study were haemorrhagic risk, defined as estimated blood loss (EBL) and peri-operative transfusions, and presence of positive surgical margins. The effect of IT and arterial clamping strategy was estimated using linear and logistic regressions for continuous and categorical outcomes, respectively. Results On-clamp PN was performed in 56% of patients (n = 237). The median (interquartile range [IQR]) age, body mass index, preoperative estimated glomerular filtration rate (eGFR), clinical size and PADUA score were 65 (58-71) years, 27 (24-29) kg/m(2), 58 (45-46) mL/min, 3 (2-4.2) cm and 8 (7-10), respectively. The median (IQR) duration of IT was 19 (13-25) min. In multivariable linear and logistic regression analyses (MVA), IT was not associated with decreased postoperative eGFR (estimate -0.08 mL/min; P = 0.3) or 1-year eGFR (estimate -0.1 mL/min; P = 0.2). No association between on-clamp strategy and eGFR decline was recorded either postoperatively (estimate -3.11 mL/min; P = 0.1) or at 1 year (estimate -3.12 mL/min; P = 0.1). The median (IQR) EBL was lower in the on-clamp group at 200 (100-400) mL vs 300 (145-500) mL in the off-clamp group. In MVA predicting haemorrhagic risk, arterial clamping was associated with lower risk of transfusions (odds ratio 0.45; P = 0.01). Conclusions In patients with SK, on-clamp PN did not affect long-term renal function and was associated with a modestly lower need for peri-operative transfusion. The routine use of the off-clamp technique is therefore not supported by these findings, although its selective application may remain appropriate in cases with a high risk of renal function decline.