WATER versus WATER II 2-Year Update: Comparing Aquablation Therapy for Benign Prostatic Hyperplasia in 30-80-cm3 and 80-150-cm3 Prostates

Background

Surgical options are limited when treating large (>80 cm³) prostates for lower urinary tract symptoms (LUTS) due to benign prostatic hyperplasia (BPH). Open simple prostatectomy remains the most common procedure performed for large prostates. There is a need for novel surgical approaches with shorter learning curves and effective treatment. Aquablation could be this novel tool.

Objective

To compare the outcome of Aquablation for 30-80-cm³ prostates with the outcome for 80-150-cm³ prostates at 2-yr follow-up.

Design setting and participants

We used data from two trials. WATER is a prospective, double-blind, multicenter, international clinical trial comparing the safety and efficacy of Aquablation and transurethral resection of the prostate in the treatment of LUTS/BPH in men aged 45-80 yr with a prostate of 30-80 cm³. WATER II is a prospective, multicenter, single-arm international clinical trial of Aquablation in men with a prostate of 80-150 cm³.

Intervention

Aquablation, an ultrasound-guided, robotically executed waterjet ablative procedure.

Outcome measurements and statistical analysis

We compared 24-mo outcomes between 116 WATER and 101 WATER II study subjects. Student's t test or a Wilcoxon test was used to compare continuous variables and Fisher's test for categorical variables.

Results and limitations

The International Prostate Symptom Score (IPSS) reductions at 24 mo was 14.5 points for WATER and 17.4 points for WATER II (p = 0.31). At baseline, the maximum urinary flow rate (Q_max) was 9.4 and 8.7 cm³/s in WATER and WATER II, improving to 20.5 and 18.2 cm³/s, respectively (p = 0.60) at 24 mo. Improvements in both IPSS and Q_max were immediate and sustained throughout follow-up. At 2 yr, the surgical retreatment rate was 4% in WATER and 2% in WATER II.

Conclusions

Aquablation is effective in patients with a prostate of 30-80 cm³ and patients with a prostate of 80-150 cm³ treated for LUTS/BPH, with comparable outcomes in both groups. It has low complication and retreatment rates at 2 yr of follow-up, with durable improvements in functional outcome.

Patient summary

Outcomes of Aquablation for both small-to-moderately-sized and large prostates are similar and sustainable at 2 yr of follow-up.

Waterjet Ablation Therapy for Endoscopic Resection of prostate tissue trial (WATER) vs WATER II: comparing Aquablation therapy for benign prostatic hyperplasia in 30-80 and 80-150 mL prostates

Objective

To compare the outcomes of Aquablation in 30–80 mL prostates with those in 80–150 mL prostates. Surgical options, especially with short learning curves, are limited when treating large prostates for lower urinary tract symptoms (LUTS) due to benign prostatic hyperplasia (BPH). Aquablation (AquaBeam System, PROCEPT BioRobotics Inc., Redwood City, CA, USA) could solve this issue with global reproducibility, independent of prostate volume.

Patients and Methods

Waterjet Ablation Therapy for Endoscopic Resection of prostate tissue (WATER [W‐I]; NCT02505919) is a prospective, double‐blind, multicentre, international clinical trial comparing Aquablation and transurethral resection of the prostate (TURP) for the treatment of LUTS/BPH in prostates between 30 and 80 mL. WATER II (W‐II; NCT03123250) is a prospective, multicentre, single‐arm international clinical trial of Aquablation in prostates between 80 and 150 mL. We compare baseline parameters and 12‐month outcomes in 116 W‐I and 101 W‐II study patients. Students’ t‐test or Wilcoxon tests were used for continuous variables and Fisher’s test for binary variables.

Results

The mean (SD) operative time was 33 (17) and 37 (13) min in W‐I and W‐II, respectively. Actual treatment time was 4 and 8 min in W‐I and W‐II, respectively. The mean change in the International Prostate Symptom Score was substantial averaging (at 12 months) 15.1 in W‐I and 17.1 in W‐II (P = 0.605). By 3 months, Clavien–Dindo grade ≥II events occurred in 19.8% of W‐I patients and 34.7% of W‐II patients (P = 0.468).

Conclusion

Aquablation clinically normalises outcomes between patients with 30–80 mL prostates and patients with 80–150 mL prostates treated for LUTS/BPH, with an expected increase in the risk of complications in larger prostates. Long‐term outcomes of procedure durability are needed.

Renal histopathology of stone-forming patients with distal renal tubular acidosis

To define the renal tissue changes in stone-forming patients with distal renal tubular acidosis (dRTA), we performed intra-operative papillary and cortical biopsies in five patients. The main abnormalities were plugging of inner medullary collecting ducts (IMCD) and Bellini ducts (BD) with deposits of calcium phosphate in the form of apatite; epithelial cell injury and loss was marked. Plugged ducts were surrounded by interstitial fibrosis, but the fibrosis was generalized, as well, and was a main feature of the histopathology even when plugging was not present. In contrast, common idiopathic calcium oxalate stone formers (SF) never manifest intra-tubule crystals or interstitial fibrosis. Patients with brushite (calcium monohydrogen phosphate) stones and those with cystine stones have many fewer IMCD and BD plugged with apatite (or cystine, in cystinuria), and interstitial fibrosis is limited to the regions around plugged ducts. Patients with dRTA often present a radiographic picture of nephrocalcinosis. Our direct surgical observations reveal that these may be surgically removable stones, especially in patients with well preserved renal function. In all, dRTA SF have a more diffuse papillary renal disease than other SF thus studied, and are also unusual for the degree of interstitial fibrosis.

Randall's plaque: Pathogenesis and role in calcium oxalate nephrolithiasis

The purpose of these studies was to test the hypothesis that Randall's plaque develops in unique anatomical sites of the kidney and their formation is conditioned by specific stone-forming pathophysiologies. We performed intraoperative papillary biopsies from kidneys of idiopathic-calcium oxalate (CaOx), intestinal bypass for obesity, brushite (BR) and cystine stone formers (SF) during percutaneous nephrolithotomy. Tissues were examined by infrared analysis and light and electron microscopy. Our analysis revealed a distinct pattern of mineral deposition and papillary pathology for each type of SF. CaOx SF had interstitial apatite crystals beginning at thin loops of Henle. These deposits termed Randall's plaque are thought to serve as sites for stone attachment. No tubular injury was noted. Intestinal bypass patients possessed intraluminal apatite deposits in inner medullary collecting ducts (IMCD) with associated cell injury. BR SF showed the most severe form of cortical and medullary changes with sites of Randall's plaque, and yellowish intraluminal deposits of apatite in IMCD. Cystine SF had plugging of ducts of Bellini with cystine crystals and apatite deposits in IMCD and loops of Henle. Intratubular sites of crystalline deposits were always associated to adjacent regions of interstitial fibrosis. The metabolic, anatomic, and surgical pathologic findings in four distinct groups of SF clearly show that 'the histology of the renal papilla from a stone former, is particular to the clinical setting'. We believe our approach to studying stone disease will provide insights into the pathogenesis of stone formation for each type of SF that will lead to improved clinical treatment.

Periurethral transurethral microwave thermotherapy for the treatment of benign prostatic hyperplasia: an interim 1-year safety and efficacy analysis using the thermatrx TMx-2000

Transurethral microwave thermotherapy (TUMT) represents an accepted minimally invasive approach to the management of patients with benign prostatic hyperplasia (BPH). The TherMatrx TMx-2000 represents a further evolution in TUMT technique. This device uses periurethral transurethral microwave thermotherapy (P-TUMT) technology to directly target the BPH tissue adjacent to the prostatic urethra by using a catheter without a urethral-cooling surface. This article provides a technical review of the device and describes the results of a randomized, controlled multicenter study of P-TUMT for the treatment of symptomatic BPH. A discussion of the physiologic effects of P-TUMT is presented and compared to conventional TUMT. A comparison of P-TUMT to contemporary TUMT series in relation to efficacy and complications is also described. This study concludes that P-TUMT using the TherMatrx TMx-2000 device represents a minimally invasive, efficacious, and well-tolerated treatment for symptomatic BPH.

Divergence between stone composition and urine supersaturation: clinical and laboratory implications

PURPOSE

In general high urine supersaturation with respect to calcium oxalate, calcium phosphate or uric acid is associated with that phase in stones. We explore the exceptions when supersaturation is high and a corresponding solid phase is absent (type 1), and when the solid phase is present but supersaturation is absent or low (type 2).

MATERIALS AND METHODS

Urine supersaturation values for calcium oxalate, calcium phosphate and uric acid, and other accepted stone risk factors were measured in 538 patients at a research clinic and 178 at stone prevention sites in a network served by a single laboratory.

RESULTS

Of the patients 14% lacked high supersaturation for the main stone constituent (type 2 structural divergence) because of high urine volume and low calcium excretion, perhaps from changes in diet and fluid intake prompted by stones. Higher calcium excretion and low urine volume caused type 1 divergences, which posed no clinical concern.

CONCLUSIONS

Type 1 divergence appears to represent a condition of low urine volume which raises supersaturation in general. Almost all of these patients are calcium oxalate stone formers with the expected high supersaturation with calcium oxalate as well as high uric acid and calcium phosphate supersaturations without either phase in stones. Type 2 divergence appears to represent an increase in urine volume and decrease in urine calcium excretion between stone formation and urine testing.

Medical reduction of stone risk in a network of treatment centers compared to a research clinic

PURPOSE

We determined whether a network of 7 comprehensive kidney stone treatment centers supported by specialized stone management software and laboratory resources could achieve reductions in urine supersaturation comparable to those in a single research clinic devoted to metabolic stone prevention.

MATERIALS AND METHODS

Supersaturation values for calcium oxalate, calcium phosphate and uric acid in 24-hour urine samples were calculated from a set of kidney stone risk factor measurements made at a central laboratory site for the network and research laboratory for the clinic. Individual results and group outcomes were presented to each center in time sequential table graphics. The decrease in supersaturation with treatment was compared in the network and clinic using analysis of variance.

RESULTS

Supersaturation was effectively reduced in the network and clinic, and the reduction was proportional to the initial supersaturation value and increase in urine volume. The clinic achieved a greater supersaturation reduction, higher fraction of patient followup and greater increase in urine volume but the treatment effects in the network were, nevertheless, substantial and significant.

CONCLUSIONS

Given proper software and laboratory support, a network of treatment centers can rival but not quite match results in a dedicated metabolic stone research and prevention clinic. Therefore, large scale stone prevention in a network system appears feasible and effective.

Supersaturation and stone composition in a network of dispersed treatment sites

PURPOSE

We determined the validity of urine supersaturation assessed from 2, 24-hour urine collections from outpatients eating uncontrolled diets and receiving care at a network of treatment sites that uses a central laboratory. We compared supersaturation to stone composition to determine whether supersaturation values correlate with composition.

MATERIALS AND METHODS

Two 24-hour urine samples collected from 183 patients at 6 treatment sites were shipped to a single central laboratory. Complexations and crystallizations in vitro from aging during the transport step were interrupted by pH change in acid and alkaline directions. Relevant analytes were measured, and supersaturation was calculated for calcium oxalate, calcium phosphate as brushite and uric acid. Stone analysis was done at various laboratories.

RESULTS

Urine supersaturation values correlated well with stone composition. Higher calcium phosphate and uric acid supersaturation was noted when stones contained higher amounts of calcium phosphate and any uric acid, respectively. In a validation study values of relevant urine materials were unchanged after 48 hours of aging.

CONCLUSIONS

Despite the need for sample transport, resulting in the inevitable aging of samples, and variations in diet and details of sample collection, supersaturation values measured in only 2, 24-hour urine collections accurately reflected stone composition. This finding indicates that supersaturation values are reasonably stable in most patients during the months to years required for stones to form. In addition, samples collected in standard practice settings and sent to a central laboratory may accurately reflect these supersaturation values.

Metabolic urinary correlates of calcium oxalate dihydrate in renal stones

PURPOSE

We determined what metabolic features of the 24-hour urine predict calcium oxalate dihydrate in kidney stones. Prior studies have suggested that low urine magnesium, high urine calcium, high calcium-to-oxalate ratio and high urine supersaturation with respect to calcium oxalate monohydrate predict calcium oxalate dihydrate.

MATERIALS AND METHODS

Stone analyses and results from 2, 24-hour pretreatment urine collections from 96 patients with nephrolithiasis were drawn from 3 kidney stone prevention centers. Standard stone risk measurements were made on the urine, including supersaturation for calcium oxalate monohydrate, brushite and uric acid.

RESULTS

The main differences in metabolic urine findings were between patients with no calcium oxalate dihydrate and those with any calcium oxalate dihydrate in stones. Percent calcium oxalate dihydrate itself did not correlate with urine findings. Patients with no calcium oxalate dihydrate in stones showed a biphasic pattern of urine calcium oxalate monohydrate supersaturation, about half had values below almost any found among patients with calcium oxalate dihydrate in stones (less than 7) and the rest overlapped with the calcium oxalate dihydrate group. Except for higher calcium oxalate monohydrate supersaturation, patients with calcium oxalate dihydrate in stones had higher urine calcium excretion and lower urine citrate concentrations, even after calcium oxalate monohydrate supersaturation was considered.

CONCLUSIONS

Patients with low calcium oxalate monohydrate supersaturation (less than 7) are unlikely to have calcium oxalate dihydrate in renal stones. However, many patients with no calcium oxalate dihydrate have higher calcium oxalate monohydrate supersaturation values, and so prediction of calcium oxalate dihydrate or its absence from urine findings is imperfect. Urine magnesium and the calcium-to-oxalate ratio are unrelated to calcium oxalate dihydrate.

Laparoscopic complications in markedly obese urologic patients (a multi-institutional review)

OBJECTIVES

Significant obesity is considered to be a relative contraindication to laparoscopic surgery. This study reviews the complications encountered in massively obese patients undergoing urologic laparoscopic surgery.

METHODS

Body mass index (BMI) was used as an objective index to indicate massive obesity. Eleven institutions compiled retrospective data on 125 patients having a BMI greater than 30. Procedures performed included 76 pelvic lymph node dissections, 14 nephrectomies, 7 bladder neck suspensions, and 28 miscellaneous procedures.

RESULTS

For the group as a whole, the mean BMI was 35.1 (range 30.1 to 57.2). Mean operative time was 202 minutes (range 60 to 480). Conversion to open surgery occurred in 15 of the 125 patients (12%). Complication rates (minor and major) were 22% (27 occurrences in 125 patients) intraoperatively and 26% (33 occurrences in 125 patients) postoperatively. The major complications included 2 trocar injuries to abdominal wall vessels, 1 bladder injury, 3 peripheral nerve injuries, 1 dysrhythmia, 1 deep vein thrombosis, 1 wound seroma, 1 nephrocutaneous fistula, 1 incisional hernia, and 1 death.

CONCLUSIONS

In this review, complication rates for urologic laparoscopic surgery on massively obese patients were higher than in the general population undergoing laparoscopic surgery (0.3% to 21%).

Extracorporeal shock wave lithotripsy: multicenter study of kidney and upper ureter versus middle and lower ureter treatments

Six institutions throughout the United States participated in this study. Each center used a multifunctional flat table lithotriptor (Dornier MFL-5000) to treat 658 patients with kidney and upper ureteral stones (766 treatments) and 323 with middle and lower ureteral stones (391 treatments), for a total of 925 patients (1,157 treatments). Some patients received more than 1 treatment (that is the kidney and ureter), for a total of 981 patient events. Complete followup was available for 81% of the patients. The overall stone-free rate at followup of approximately 90 days was greater in the middle and lower ureter group (83%) than in the kidney and upper ureter group (67%). The proportion of single stones treated was greater for the former group (89.5%) than for the latter group (72%). A larger proportion (18%) of the middle and lower ureter group required 2 or more treatments to the targeted stone than did the kidney and upper ureter group (13%). Anesthesia was required or selected in only 26.7% of the kidney and upper ureteral stone patients and in 18.5% of those with middle and lower ureteral calculi, usually at the request of the patient or physician, or for performance of an adjunctive procedure. The relative safety of this treatment is demonstrated by a low overall rate of complications reported during and after treatment, including a ureteral obstruction rate of 2.1% for kidney and upper ureteral stones and 2.5% for middle and lower ureteral stones. There were no demonstrated trends in a review of laboratory data to suggest significant treatment side effects. The diastolic blood pressure increased to more than 95 mm. Hg after extracorporeal shock wave lithotripsy (ESWL*) in 6% of the kidney and upper ureteral and 4% of the middle and lower ureteral stone patients, while pretreatment hypertension resolved after ESWL in 11% of both groups. The results of this clinical evaluation indicate somewhat greater effectiveness for the specified indications of ESWL of stones in the ureter below the upper rim of the bony pelvis, as opposed to those in the kidney and upper ureter, with a low incidence of complications and side effects.

National High Blood Pressure Education Program (NHBPEP) review paper on complications of shock wave lithotripsy for urinary calculi

This decade has witnessed dramatic advances in the surgical management of urinary calculi. Today, most stones can be removed by minimally invasive means. In fact, the treatment of choice in 60% to 90% of patients with renal and ureteral calculi that need to be surgically removed is extracorporeal shock wave lithotripsy (ESWL). This article reviews indications for ESWL and discusses deleterious effects of ESWL.

Report of the United States cooperative study of extracorporeal shock wave lithotripsy

Extracorporeal shock wave lithotripsy effectively fragments urinary calculi in the upper urinary tract and upper ureter. These fragments pass completely by 3 months in 77.4 per cent of the patients with single stones. Risk of obstruction, increased postoperative pain, need for additional urological operations and retained fragments are low for stones less than 1 cm. in size. As the number of stones treated or single stone size increases above 1 cm. the risk for these factors increases. Adjunctive urological surgical management is required in 9 per cent of the patients preoperatively and 8 per cent postoperatively. Only 0.6 per cent of the patients require some type of open operation to resolve the stone problems after extracorporeal shock wave lithotripsy. Hemorrhage, obstruction by fragments, severe pain and urinary infection all constitute known complications and require careful urological management of all patients. Hospitalization averages 2 days after treatment and patients usually return to work within a few days after they are discharged from the hospital.