Impact of ureteral access sheath size on intrarenal pressure evaluated by LithoVue™ elite single use ureteroscope.

Objective: We aimed to assess the impact of ureteral access sheath (UAS) size on intrarenal pressure (IRP) using LithoVue^™ Elite (LVE) ureteroscope (Boston Scientific) during lithotripsy and to identify factors contributing to increased IRP.

Methods: A single-arm prospective study was conducted on 21 consecutive patients who underwent ureteroscopic lithotripsy using the LVE at a single center between April 2023 and April 2024. 11/13 Fr or 13/15 Fr UAS was placed in all cases based on the physician's discretion. We analyzed baseline, median, and maximum IRPs and factors associated with increased IRP (≥ 30 mmHg).

Results: Median age was 61 (IQR: 48-66) years. Baseline, median, and maximum IRPs were 11 (IQR: 5-16), 32 (IQR: 18-67), and 159 (IQR: 111-222) mmHg, respectively. 11/13Fr and 13/15Fr UAS were utilized in 10 and 11 patients, respectively, with no significant difference in patient demographics between the two groups. The baseline, median, and maximum IRPs were significantly lower in the 13/15Fr UAS group: 5 vs. 18.5 mmHg (p = 0.001), 21 vs. 57 mmHg (p = 0.02), and 111 vs 177.5 mmHg (p = 0.01). The use of 11/13 UAS was the factor associated with an increased median IRP (≥ 30 mmHg). Sex, comorbidities, the presence of hydronephrosis, stone location, the shape of the renal pelvis, and laser size were not.

Conclusions: Measurement and monitoring of IRPs using LVE during lithotripsy are technically feasible. Our study confirmed that the use of larger UAS can decrease IRP. Further investigation is needed to clarify the clinical impact of IRP during URS.