Aquablation for BPH

An urologist  Stephan Madersbacher has commented on aquablation in a paper, entitled 

"Re: WATER: A Double-blind, Randomized, Controlled Trial of Aquablation vs Transurethral Resection of the Prostate in Benign Prostatic Hyperplasia".

This is a paper written by Peter Gilling (one of the two principal investigators of the multi-continents trial on Aquablation) and other urologists who participated in the trial reporting the results of the trial, published on Journal of Urology, May, 2017.

 Madersbacher's view of the short comings of Aquablation is given below.

[Note: to show the important points, I capitalized some of the words and also put in quotation marks.]

"The data are encouraging and interesting. Although aquablation allows very rapid resection of BPH tissue, HAEMOSTASIS seems to be an issue: many patients require post-interventional endoscopic coagulation (the exact number was not provided) and the risk of postoperative BLEEDING was higher than after TURP. Furthermore, the rates of postoperative DYSURIA and RETENTION were higher after aquablation, suggesting less immediate tissue removal. The 6-mo functional data, however, are excellent, with comparable outcomes for subjective and objective parameters. Of interest is the marked difference in ANEJACULATION despite similar functional outcomes, suggesting that the concept of tissue removal at the area of the verumontanum is debatable, at least in some patients. Provided that the data are durable, the main issue is the positioning of this innovative device: as it requires general or spinal anaesthesia; the main competitors are monopolar or bipolar TURP, enucleation techniques, and laser or electrocautery vaporisation. "Given the lack of obvious intraoperative or perioperative advantages and the comparable subjective and functional outcomes, the main difference is the lower rate of anejaculation", yet there are no clinically relevant advantages for any other sexual outcome parameter. A potential further advantage might be the avoidance of the TURP learning curve (particularly for larger sized prostates), although postoperative coagulation probably requires surgical expertise as well. "It remains debatable whether these few pros—given the current available armamentarium—are sufficient to convince urologists, payers, and patients". Intermediate- and long-term data are awaited with great interest." 

Aquablation or water jet is the newest BPH procedure. Currently all the important information is from clinical trials. To fully understand Aqua, the best way is to read the reports of the trials published  in scientific journals.

For those readers , who are investigating aquablation as a candidate for their BPH surgeries, I would like to share a paper, "New Technology and Techniques Aquablation of the Prostate for Symptomatic Benign Prostatic Hyperplasia: 1-Year Results" by Peter Gilling, Paul Anderson, AndrewTan, published in journal of urology in June, 2017.

This paper describes the results for the earliest trial of aquablation and is the forerunner of the current Multicentre, multi continent trial (US, United Kingdom, Newzeland and Australia). "It was a single arm, multicenter trial at a total of 3 centers in Australia and New Zealand with 1-year followup. Participants were men 50 to 80 years old with moderate to severe lower urinary tract symptoms as determined by urodynamics. All patients underwent aquablation." The short coming of this trial is that the number of patients was only 21. But if the aquablation as a technology had a problem, it would show up in a lot of the patients.

Why this paper is useful? (1) It explains how the aquabeam system worked, (2) explains the details of the operation, (3) shows the profile of the cut (tissue removal) in the plane both perpendicular and parallel  to the bladder neck, (4) shows pictures of the prostatic urethra before and after aquablation , and (5) show that functional outcomes at month 1 are sustained throughout month 1 to month 12. 

The authors pointed out the problems of TURP, the gold standard: "Although it is effective, complications from TURP can be significant, including postoperative bleeding, urinary retention, urinary incontinence, erectile dysfunction and retrograde ejaculation.8, 9, 10, 11, 12" (numbers are the ref number in the original paper).  So we really want to know if aquablation is a "treatment  that preserve the effectiveness of TURP but have a more acceptable risk profile." As potential early uses of this theology, we want to know what are the RICKs.

Right now, as far as I'm concerned, I don't have any problem accepting that Aquablation produces functional outcomes(IPSS, Qmax, PVR)  between TURP's and HoLEP's and that it preserves ejaculation with a success rate of 80-90%. What we don't know is what the complications are. So we should pay great attention to complications.

The Goal of The Trial 

""The primary safety end point was the perioperative complication rate. Secondary end points included the change from baseline in I-PSS and IIEF, and the change from baseline in the peak urinary flow rate, PVR and PDet at Qmax. Other assessments included ISI (first 6 months only) and laboratory evaluation (PSA and creatinine measurements) as well as repeat cystoscopy, TRUS and urodynamic studies at 6 months........ Detrusor pressure at maximum flow was only measured at 6 months."

Results (only a portion of the results will be given below.)

"No adverse events occurred during the procedure. Postoperative events (those developing before day 30) were consistent with expectations for a minimally invasive transurethral procedure (table 2). Six patients (~30%) had at least 1 adverse event, including grade 1 complications (self-resolving dysuria and hematuria, and catheter reinsertion for retention) and grade 2 complications (medically treated urinary tract infections). Of the patients requiring recatheterization, each passed subsequent voiding trials with successful catheter removal. Incontinence, the need for blood transfusions or reoperations were not required."

"At 12 months, the mean I-PSS score had improved by 16.2 points (from 22 to 6). The I-PSS QOL component improved by 3.3 points. Mean maximum urinary flow improved from 8.7 ml per second at baseline to 18.3 ml per second for an improvement of 9.7 ml per second and PVR improved from 136 to 54 ml for an improvement of 89 ml . " (I removed the p values.)

"Table 2. Adverse events occurring within 30 days after aquablation

Adverse Event       No. of Events

Dysuria    1

Hematuria    1

Urinary retention    3

Urinary tract infection + 30-day treatment    1

Bladder spasm    1

Meatal stenosis    1

To catheter removal    1.0 ± 0.2 (1–2) days

To hospital discharge  1.1 ± 0.5 (1–3) days"

"The mean improvement in I-PSS after aquablation (16 points) was similar in size to that observed in randomized trials of TURP21, 22 and slightly larger than after laser vaporization (14 points),23 prostatic urethral lift (11 points),21 transurethral microwave thermotherapy and transurethral needle ablation (10 or 11 points),3 and convective water vapor energy (11 points)13 ."

(Note that in this trial, after aquablation, a heated TURP electrode was used to cauterize the bleeding. This step is inconsistent with the so called "heartless" aquablation. In later trials, the heated TURP electrode was no longer used. As a result, anejaculation rate decreased. This proves that HEAT generated by the operation could cause more anejaculation.)

"Decreases in sexual function, especially retrograde ejaculation, are common after TURP.25 Although the number of sexually active patients in our cohort was small, our data suggest that aquablation may not negatively affect sexual function. Improvement in intercourse satisfaction was observed, although this is but 1 component of the several IIEF-15 subdomains. It is possible that some men with BPH experience decreased sexual desire due to physical or psychological factors. It is plausible that reducing LUTS symptoms without introducing further sexual dysfunction may allow for a reversal in libido changes and an improvement in overall sexual function. "

Impression After Reading The Paper

I feel that GIlling must have felt that aquablation is a "treatment  that preserve the effectiveness of TURP but have a more acceptable risk profile" because he became one of the two principal investigators of two muti continent muti center trials and have a financial relation with the aquabeam company.

We shall see if the above results still hold in the later better designed and larger trials.