Aquablation of the Prostate: Surgical Technique and Role in the Management of BPH

Educational Objectives

The goal of this program is to improve diagnosis and treatment of benign prostatic hyperplasia. After hearing and assimilating this program, the clinician will be better able to:

1. Summarize the findings of the WATER and WATER II studies of aquablation therapy.

2. List techniques that may reduce bleeding in patients undergoing aquablation for benign prostatic hyperplasia.

Summary

Aquablation: device features cavitating water jet in saline environment; high pressure ablates tissue as nozzle moves back and forth like windshield wiper; unlike laser, which may leave behind areas of coagulative necrosis that promote storage symptoms and dystrophic calcification, aquablation uses no thermal energy; margins of ablated area sharp and re-epithelialize quickly

Equipment: nozzle size 150 μ (size of single hair); flexible Kevlar tubing must be controlled to prevent movement; treatment unit has tower with viewing screen for ultrasonographic images and conformal planning unit used to plan surgical procedure; ultrasonographic and endoscopic guidance available; 24F handpiece has sapphire nozzle; ports available for aspirating fluid and tissue, and for ultrasonic unit

Surgical planning: longitudinal view shows prostate, bladder neck, and bladder; surgeon demarcates area to be ablated, which can be modified; depth and width can be controlled; ablation time short (1.5-3.0 min); length (but not width or height) of prostate affects ablation time; surgeon has option to perform 1 or 2 runs

Development: Gilling et al conducted nonrandomized trial in men 50 to 80 yr of age; mean size of prostate 57 g; some glands had median lobes; operative time 30 min; resection time 5 min; urodynamic assessment showed substantial reduction in detrusor pressure at maximum flow rate (Qmax), from 65 to 39 cm H2O; photographs taken before and immediately after cystoscopy and at 1 mo confirmed rapid epithelialization

WATER study: randomized trial that led to approval of device by US Food and Drug Administration; 275 patients randomized (in 2:1 ratio) to aquablation vs transurethral resection of prostate (TURP); safety and efficacy assessed at 3 and 6 mo; WATER designed to confirm noninferiority (for efficacy) and superiority (for safety); mean volume of prostate 50 g; in many patients, intravesical lobe ablated concomitantly; at baseline, population exhibited typical Qmax and symptoms

Outcomes of WATER: primary and secondary safety outcomes show aquablation superior to TURP; on ejaculation domain of Male Sexual Health Questionnaire, lower scores seen after TURP and slight increase in scores seen after aquablation; incontinence initially increased but subsequently improved; efficacy assessment confirmed noninferiority (by margin of ≤3 points); efficacy analysis favored aquablation, but aquablation not statistically superior to TURP; when symptoms assessed, most differences between groups unremarkable; however, storage symptoms significantly better in aquablation group at 6 mo; Qmax improved in both groups (no differences between groups at 3 or 6 mo)

Outcomes of WATER at 1 yr: 3 patients withdrew from trial; ejaculatory function unchanged in aquablation group; symptom scores similar; improvement in Qmax maintained at 1 yr (19.8 mL/sec in both groups); in preplanned analysis of men with prostates ≥50 g, safety of aquablation even more apparent, and improvements in symptom score greater than in men with smaller glands (-17 points vs -13 points)

Intraoperative outcomes: duration of procedure — operative and resection times same in TURP group; in aquablation group, treatment planning included in operative time, and resection time independent of size of gland; resection time usually <5 min for aquablation; blood loss — decrease in hemoglobin 1.9 g/dL in aquablation group (less in TURP group)

Reduction in prostate-specific antigen (PSA): may be considered measure of ablation of tissue; findings favored neither group; reduction in PSA greater in patients treated with TURP or aquablation than those treated with potassium titanyl phosphate laser or water vapor therapy (Rezum); however, observed decrease in PSA after aquablation less than that expected after HoLEP or open prostatectomy

Retreatment: at 1 yr, retreatment rates 1.5% [in TURP group] vs 2.6% [in aquablation group]

WATER II follow-up study: single-arm trial conducted in 114 men; mean size of prostate 107 g; most patients had intravesical lobe; baseline PSA higher than in previous study (7 ng/mL) and Qmax lower; mean of 1.8 passes made with aquablator, leading to increased resection time

Hemostasis: attempts to overcome problem of hemostasis in patients treated with aquablator have involved double-balloon catheters, use of hemostatic matrix (Floseal), touch point coagulation, and catheter tensioning device (CTD) that applies traction to perineum (mean duration of traction with CTD 18 hr; device complicates mobilization and ambulation)

Outcomes in WATER II: primary safety end point (Clavien-Dindo classification and persistent complications) met; bleeding events included 10 transfusions among 101 patients (4 transfusions performed after discharge); some patients returned to operating room; symptomatic improvement similar to that observed in WATER study; patients had 16-point decrease [in symptoms] and remarkable improvement in Qmax; overall, efficacy similar to that seen in WATER, but surgeons encountered more difficulties with control of bleeding; reduction in volume of prostate 44% at 3 mo; in men with large prostates treated with simple open prostatectomy, risk for transfusion 5% to 20%

Other data on aquablation: in series of consecutive patients, Bach et al treated 118 men; authors reported operative time of 20 min; volume of prostate decreased by 65% (better than outcome achieved in WATER II); sparing bladder neck allowed 73% of patients to maintain ejaculation

Guidelines: trials on aquablation not yet covered in guideline from American Urological Association

Readings

Bach T et al: Aquablation of the prostate: single-center results of a non-selected, consecutive patient cohort. World J Urol 2018 Oct 4 [Epub ahead of print]; Desai M et al: Aquablation for benign prostatic hyperplasia in large prostates (80-150 mL): 6-month results from the WATER II trial. BJU Int 2019 Feb 8 [Epub ahead of print]; Desai M et al: WATER II (80-150 mL) procedural outcomes. BJU Int 2019 Jan;123(1):106-12; Gilling P et al: WATER: A double-blind, randomized, controlled trial of Aquablation(®) vs transurethral resection of the prostate in benign prostatic hyperplasia. J Urol 2018 May;199(5):1252-61; Gilling P et al: Aquablation of the prostate for symptomatic benign prostatic hyperplasia: 1-year results. J Urol 2017 Jun;197(6):1565-72; Gilling PJ et al: Randomized controlled trial of aquablation versus transurethral resection of the prostate in benign prostatic hyperplasia: one-year outcomes. Urology 2019 Mar;125:169-73; Plante M et al: Symptom relief and anejaculation after aquablation or transurethral resection of the prostate: subgroup analysis from a blinded randomized trial. BJU Int 2019 Apr;123(4):651-60.

Disclosures

For this program, members of the faculty and planning committee reported nothing to disclose.

Acknowledgements

Dr. Roehrborn was recorded at the 2nd Annual Jefferson Urology Symposium: Emerging Technologies for the Treatment of BPH, presented by Thomas Jefferson University, and held February 1, 2019, in Philadelphia, PA. For more information on upcoming CME meetings presented by Sidney Kimmel Medical College at Thomas Jefferson University, please visit  cme.jefferson.edu. The Audio Digest Foundation thanks the speakers and Thomas Jefferson University for their cooperation in the production of this program.

CME/CE INFO

Accreditation:

The Audio- Digest Foundation is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians.

The Audio- Digest Foundation designates this enduring material for a maximum of 0 AMA PRA Category 1 Credits™. Physicians should claim only the credit commensurate with the extent of their participation in the activity.

Audio Digest Foundation is accredited as a provider of continuing nursing education by the American Nurses Credentialing Center's (ANCC's) Commission on Accreditation. Audio Digest Foundation designates this activity for 0 CE contact hours.

Lecture ID:

UR421202

Expiration:

This CME course qualifies for AMA PRA Category 1 Credits™ for 3 years from the date of publication.

Instructions:

To earn CME/CE credit for this course, you must complete all the following components in the order recommended: (1) Review introductory course content, including Educational Objectives and Faculty/Planner Disclosures; (2) Listen to the audio program and review accompanying learning materials; (3) Complete posttest (only after completing Step 2) and earn a passing score of at least 80%. Taking the course Pretest and completing the Evaluation Survey are strongly recommended (but not mandatory) components of completing this CME/CE course.

Estimated time to complete this CME/CE course:

Approximately 2x the length of the recorded lecture to account for time spent studying accompanying learning materials and completing tests.