# Safety and efficacy of Rezūm water vapour energy therapy in BPH patients receiving antithrombotic therapy: A Japanese single‐centre experience

## TL;DR

This study shows that Rezūm water vapor therapy for enlarged prostate is safe for patients on blood thinners, with most complications managed without surgery.

## Contribution

The study introduces a modified classification system for grading hematuria and confirms the safety of continuing antithrombotic therapy during WAVE.

## Key findings

- 21.6% of patients on antithrombotic therapy experienced clinically significant hematuria, compared to 4.7% without.
- All hematuria cases were managed conservatively without transfusion or surgery.
- Antithrombotic therapy was the only independent risk factor for significant hematuria.

## Abstract

The objective of this study is to evaluate the safety and efficacy of Rezūm water vapour energy therapy (WAVE) in Japanese patients with benign prostatic hyperplasia (BPH) continuing antithrombotic therapy and to validate the Okayama University Modified Clavien‐Dindo classification (OU‐mCD) for perioperative hematuria.

We retrospectively analysed 80 consecutive patients who underwent WAVE from August 2023 to July 2024, including 37 (46.2%) continuing antithrombotic therapy perioperatively. Hematuria within 30 days was graded using conventional Clavien‐Dindo classification and the OU‐mCD, a novel classification focusing on intervention necessity. We assessed clinically significant hematuria (Grade ≥ Ib), catheter‐free rate, prostate volume reduction and haemoglobin change.

Clinically significant hematuria occurred in 21.6% (8/37) of patients continuing antithrombotic therapy versus 4.7% (2/43) without (p = 0.038). All 10 Grade ≥ Ib cases occurred during hospitalization with the catheter in place and were managed conservatively with continuous bladder irrigation (median 1 day); none required transfusion or surgical reintervention. Only one patient required temporary drug discontinuation. Treatment efficacy did not differ by antithrombotic status: 86.2% achieved PVR < 50 ml with 44% mean prostate volume reduction. Multivariate analysis identified antithrombotic therapy as the sole independent risk factor for Grade ≥ Ib hematuria (OR 5.46, 95% CI 1.06–28.16, p = 0.042).

WAVE can be safely performed with continued antithrombotic therapy. Whereas Grade ≥Ib hematuria occurred in 25% of antiplatelet/anticoagulant users (vs. 5% without), 75% had no significant bleeding, and all complications were managed conservatively without transfusion. The OU‐mCD provides precise complication stratification. These findings suggest outpatient procedures may be feasible with appropriate patient selection.