Correlation of vasoconstriction and kidney protection during shock wave lithotripsy

Abstract

Kidney injury in lithotripsy can lead to long‐term adverse effects, so minimizing injury is beneficial. We have found that injury is significantly reduced when shock wave (SW) administration is halted briefly‐ 3‐minutes‐early in treatment. Previous studies have shown that SWs stimulate renal blood vessels to constrict. Therefore, we tested the idea that vasoconstriction mediates SW‐induced protection of the kidney. Doppler ultrasound was used to measure resistive index (RI), a ratio of systolic and diastolic velocities, indicating vasoconstriction. RI was determined for single intralobar arteries in targeted porcine kidneys treated by standard versus protection protocols (2,000SW, uninterrupted vs 500SW‐3‐min pause‐2,000SW) using a Dornier‐HM3 lithotripter (2Hz, 24kV). Significant differences in RI from baseline within a group and between groups at various time points were determined using mixed‐effect models for repeated measures with Holm's step‐down method for multiple comparison adjustment. All animals had similar baselines. Sham pigs (no‐SWs) showed no significant change in RI. The protection protocol produced a significant rise (p<0.05, n=8) in RI 15 minutes into treatment, while the standard protocol did not yield a significant rise (p<0.05, n=7) until 45 minutes after treatment. Thus, the treatment protocol shown to protect against injury, induces early vasoconstriction. [NIH‐DK43881, NSBRI‐SMS00402]