Abstract Objectives 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. Patients and Methods 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. Results 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). Conclusion 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.
Moriwake et al. (2026) studied this question.