Authors (including presenting author) :
Brian W.H. Siu(1), Steffi K.K. Yuen(1), Jeremy M.H. Ho(1), Henry Y.H. Meng(1), Chi Ho Leung(1), David K.W. Leung(1), Alex Q. Liu(1), Chris H.M. Wong(1), Ivan C.H. Ko(1), Francis C.H. Wong(1), Mandy H.M. Tam(1), Chi Hang Yee(1), Jeremy Y.C. Teoh(1), Hilda Kwok(1), Irene Wu(1), Chi Fai Ng(1), Peter K.F. Chiu(1) and Ka Lun Lo(1)
Affiliation :
SH Ho Urology Centre, Department of Surgery, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong, China.
Introduction :
Benign prostatic hyperplasia (BPH) is a prevalent histological condition for men from their middle age, occurring up to 50% and 80%, in their 6th and 9th decade respectively. BPH is the most common cause for Lower Urinary Tract Symptoms (LUTS) for men, progression of BPH can lead to acute urinary retention (AUR). From the Olmsted County Study, the overall risk of AUR has been estimated as 23% for an average 60 year old man if he survives another 20 years. With regards to refractory retention due to BPH, transurethral resection of the prostate (TURP) to date is still the surgical gold standard. TURP must be performed under general or spinal anaesthesia, whereas some options of minimally invasive surgical therapy (MIST) for BPH can be carried out under ambulatory settings with local anesthesia [5]. For example, safe implementation of Prostatic Artery Embolization [6][7] and Rezūm [8] as procedures under pure local anaesthesia have been reported. In more practical terms, Hong Kong’s service for operations requiring general/spinal anesthesia had been severely impacted in the COVID era, especially for benign conditions. Such MIST options can offer timely relief to the patient, as well as the medical system. The Rezūm System (Boston Scientific Company Inc., Marlborough, MA, USA) was approved by the Food and Drug Adminstration in 2015 based on the Rezūm II randomized control trial (NCT01912339) on BPH/LUTS patients [5]. Rezūm Transurethral Water Vapour Therapy utilizes radiofrequency generator heating water into steam, causing cell death in prostate tissues by thermal energy. From Rezūm II randomized controlled trial, it improved International Prostate Symptoms Score (IPSS), peak flow rate (Qmax), post void residual urine (PVRU) significantly compared to Sham procedure. It has been approved by the FDA as a surgical option for relieving LUTS secondary to BPH. As a day procedure requiring only local anesthesia, with the upside of causing minimal impact on sexual function, Rezūm has gained popularity in recent years as a MIST for LUTS. However, high level evidence of Rezūm on catheter dependent urinary retention is scarce. There has been only one systematic review of Rezūm on catheter dependent patients, 4 retrospective studies and 1 prospective study were included, high catheter free rates ranging from 70.3 to 100% were reported. However, urinary retention with obstructive uropathy (acute renal impairment) is classically regarded as an absolute indication of TURP or prostate enucleation, and a contraindication to TWOC (Trial without Catheter).
Objectives :
In this prospective, multicentre cohort study, we will further extend the indication of MIST - to evaluate the safety and efficacy of Rezūm on patients with refractory retention and obstructive uropathy (acute renal impairment).
Methodology :
This is a prospective cohort study of Rezūm for acute urinary retention complicated by obstructive uropathy. The 3 month follow up data of the first 20 cases are presented in this manuscript. Obstructive uropathy was defined with reference to the KDIGO definition of Acute Kidney Injury (AKI). After urethral catheter insertion, Rezūm was scheduled within 4-8 weeks of retention. Serum creatinine was taken at the preoperative clinic. This was to confirm eligibility for the study, and to define the baseline level after elimination of bladder outlet obstruction by urethral catheter for at least 4 weeks. Under local anaesthesia via periprostatic block, Rezūm water vapour therapy was performed as previously described in literature. Two extra treatment cycles were performed at the region that was considered ‘most obstructive’ by the operating surgeon. Patients were discharged with a Fr 16 Silicon Foley’s catheter within the same day. After surgery, the patient would be followed according to our standardized protocol, including (1) A nurse led phone consultation scheduled at post op six weeks, enquiring on symptoms, complications (e.g. hematuria, dysuria, incontinence) and voiding symptom score (e.g. International Prostate Symptoms Score IPSS, International Prostate Symptoms Score Quality of Life Score IPSS QoL); (2) A physical follow up at post op three months, with questionnaires assessment, uroflowmetry and PSA testing; (3) A follow up visit at one year after surgery. The first Trial Without Catheter (TWOC) was scheduled at 4 weeks post operatively. If the patient failed TWOC, he would be scheduled for another TWOC 2 weeks later, and so on until 3 months post operatively. Serum creatinine would be taken 2 weeks after successful TWOC, monitoring for any rebound to signify recurrence of obstructive uropathy. Prostate Specific Antigen (PSA) was taken as appropriate at 3 months follow up, according to EAU guidelines for prostate cancer screening. [7] All baseline characteristics, preoperative voiding condition and perioperative details were prospectively documented in the registry. The primary outcome of this study was the proportion of patients who were catheter free at 3 months follow up, with serum creatinine NOT exceeding +0.3mg/dL or 1.5 times the baseline (in line with the KDIGO definition, except that urine output monitoring was omitted in the outpatient setting). Secondary outcomes included time to successful TWOC, same day discharge rate, 30 day readmission rate, change in prostate size.
Result & Outcome :
Twenty consecutive patients with acute urinary retention and obstructive uropathy were recruited from August 2023 to February 2024. Median age was 71 years (interquartile range:66-78 years), the median ECOG/WHO performance score was 2 (1-3). The median prostate size was 57.8 ml (46.4-69.0ml). The median operation time was 18.0 minutes (16.0-23.8 minutes). A median of 10 (8-11) treatment cycles were performed; 5 (25%) patients received treatments on their median lobes (1.4 treatment cycles per patient). Procedure was well tolerated by patients, with a median pain score (visual analogue scale) of 4 (3-6) and 3 (3-6) during LA infiltration and treatment cycles respectively. All patients were discharged on the same day, the median admission time was 7.5 hours (7-9 hours); no bladder irrigation nor blood transfusion was required.
Ninety five percent of men (19 out of 20) were able to successfully wean off catheter and void spontaneously, also fulfilling the serum creatinine requirement of the primary outcome. The median worst creatinine level during index episode of retention was 319 µmol/L (216-728 µmol/L); the median creatinine level at 3 months was 99 µmol/L (79-113 µmol/L). Median time to successful TWOC was 33 days (27-42 days). The patient who failed TWOC was a 91 year old gentleman. He was wheelchair bound preoperatively, with an ECOG performance score of 4 and an ASA grade of 4. He had an uneventful Rezūm procedure (67ml prostate with 12 cycles performed) and was discharged same day. He failed TWOC at 4 weeks and 6 weeks. Eventually he was admitted to the medical ward at 8 weeks postoperatively for severe pneumonia and succumbed. All patients that weaned off catheter successfully, also fulfilled the serum creatinine requirement of the primary outcome. The same day discharge rate was 100%. There were three 30-day readmissions. two were related to the procedure (UTI and hematuria respectively) (Clavien Dindo grade 1-2 complications); one was unrelated to the procedure (flare up of gouty arthritis). At 3 months follow up, there was no recurrent urinary retention. The median prostate size dropped from 57.8 ml (interquartile range: 46.4 69.0ml) to 35.6 ml (26.5 48.5 ml) (p< 0.001); the median PSA dropped from 4.8 ng/ml (3.9–6.1 ng/ml) to 2.7ng/ml (1.8 4.6) (p=0.09). The median Qmax was 10.3 ml/s (6.7–16.7 ml/s), with residual urine of 80 ml(60–143 ml). The median IPSS was 4 (2-7).
