Prolonged ischaemia during partial nephrectomy: impact of warm vs cold

Area of Science:

• Nephrology
• Urology
• Surgical Innovation

Background:

• Partial nephrectomy (PN) is standard for kidney tumors, but ischaemia time's impact on recovery is understudied.
• Understanding ischaemia's effect is vital for optimizing surgical outcomes and preserving renal function.
• Prolonged ischaemia can lead to irreversible kidney damage, necessitating careful surgical planning.

Purpose of the Study:

• To evaluate the impact of prolonged ischaemia during on-clamp partial nephrectomy (PN).
• To assess the relationship between ischaemia duration, type (warm vs. cold), and kidney function recovery.
• To identify thresholds for prolonged ischaemia that significantly affect post-operative renal outcomes.

Main Methods:

• Retrospective analysis of 759 patients undergoing on-clamp PN (2011-2014).
• Calculation of recovery from ischaemia (Rec_ischaemia) using preserved ipsilateral GFR normalized by preserved parenchymal volume (PPVP).
• Pearson correlation and multivariable linear regression used to analyze associations between Rec_ischaemia and ischaemia characteristics.

Main Results:

• Median warm ischaemia time was 22 min, cold ischaemia was 30 min; Rec_ischaemia was 96% overall.
• Rec_ischaemia declined significantly after approximately 30 min of warm ischaemia, but not with hypothermia.
• Prolonged warm ischaemia (>30 min) was associated with reduced Rec_ischaemia (3.9% decrease per 10 min beyond 30 min).

Conclusions:

• Kidney function recovery (Rec_ischaemia) significantly declines after 30 min of warm ischaemia during PN.
• Hypothermia demonstrates a protective effect against ischaemia-induced kidney damage.
• Prioritizing avoidance of prolonged warm ischaemia is essential for patients with solitary kidneys or pre-existing chronic kidney disease.