Safety profile of GreenLight XPS laser photoselective vaporisation of the prostate in patients at high risk of bleeding

Abstract

Objective:

This study aimed to assess the utility and safety profile of the GreenLight Xcelerated Performance System (XPS) photoselective vaporisation of the prostate (PVP) to treat benign prostatic hyperplasia (BPH) in high-risk patients.

Patients and methods:

A retrospective study of a prospectively managed database was carried out. The study reviewed a single surgeon’s experience of treating high-risk patients with GreenLight XPS PVP between two sites over a four-year period. Patients considered to be high risk were those who were at an increased risk of bleeding, those who had a prostate size >80 mL, those with preoperative urinary retention and/or those aged >80 years.

Results:

In total, 374 patients were identified as being high risk for GreenLight PVP. Patient age ranged from 44 to 96 years (M_age=71 years). Of the 374 patients, 103 were aged >80 years. All 374 patients were considered to be at an increased risk of bleeding, as they underwent GreenLight PVP while taking antiplatelet agents (not including aspirin), anticoagulant agents or both. Ninety-one patients had preoperative urinary retention and indwelling urinary catheter. Fifty-four patients had a prostate size >80 mL. Length of stay varied from 1 to 14 days. Most patients (n=270) were discharged on postoperative day 1. There were no perioperative blood transfusions. One patient developed acute coronary syndrome on postoperative day 4, requiring percutaneous coronary intervention. Twenty-two patients required readmission: 12 due to urinary retention with or without haematuria, and 10 due to haematuria without associated acute retention. Two patients required cystoscopy and bladder washout. There were two blood transfusions in the ‘readmission due to haematuria’ group. Outcomes for patients aged >80 years were favourable. The average length of stay was 2.7 days (range 1–14 days). This group was responsible for 12 of the 22 readmissions. There were no perioperative cardiovascular events.

Conclusion:

We conclude that GreenLight XPS PVP is a safe procedure in patients with one or more high-risk factors. The ability to proceed without the need to stop antiplatelets or anticoagulant agents also allows for high-risk medical patients to be treated without the additional risks of cardiovascular events.

Level of evidence:

Not applicable for this multicentre audit.

Keywords

Benign prostate disorders endourology core urology education training

Introduction

Benign prostatic hyperplasia (BPH) is a common condition characterised by an increase in size of the prostate. BPH is commonly associated with troublesome lower urinary tract symptoms (LUTs), which can have a profound effect on quality of life.¹ BPH-related symptoms become more common with age, affecting 50% of men aged 51–60 years and >80% of men aged >80 years.²

There are many treatment options available in the management of BPH, both medical and surgical. Surgical treatment techniques for BPH can be grouped into ablative techniques, resection techniques, enucleation techniques or minimally invasive techniques.

The standard surgical treatment option for BPH is transurethral resection of the prostate (TURP). This procedure, while very effective, is not always a safe operation in high-risk medical patients due to risks of bleeding, amongst others. TURP is also not suitable for treating large prostates, with the European Association of Urology (EAU) guidelines recommending TURP in prostates between 30 and 80 mL in size.³

Many new types of procedures have been developed to try and tackle the problems associated with TURP. These include GreenLight Xcelerated Performance System (XPS) photoselective vaporisation of the prostate (PVP), holmium laser enucleation of the prostate (HoLEP), Urolift, Bipolar TURP and Rezum. GreenLight XPS PVP is a minimally invasive treatment for BPH. The main advantage of this is that it produces less bleeding when compared to TURP.⁴

National Institute for Health and Care Excellent (NICE) guidelines from 2016 support the routine adoption of GreenLight XPS PVP for the treatment of BPH in low-risk patients.⁵ However, it comments that there are currently insufficient data to support its routine adoption in high-risk patients. NICE identifies high-risk patients as those who are at an increased risk of bleeding, have a prostate size >100 mL or who have preoperative urinary retention.

Globally, we have an ageing population.⁶ With an ageing population, there will also be an increase in chronic illness. Antiplatelet agents and anticoagulants are widely used in the elderly population. It is estimated that >30% of men needing surgery for BPH are taking some form of anti-thrombotic therapy (warfarin, novel oral anticoagulant).^7,8 Perioperative management of these medications remains a challenge, with much variation in practice.⁹ One must balance the risk of severe haemorrhage versus the potentially devastating risk of thrombotic events.^10–12 With an ageing population there are also increasing co-morbidities. Therefore, it becomes necessary to find methods of treating these high-risk patients in a safe and effective manner.

Our study aimed to assess the utility and safety profile of GreenLight XPS PVP for treating BPH in high-risk patients.

Methods

After Institutional Review Board approval was obtained, we carried out a retrospective study of our prospectively managed database. The study reviewed a single surgeon’s (B.J.J.) experience of treating high-risk patients with GreenLight XPS PVP between two sites (Hermitage Medical Clinic, Dublin, and Aut Even Hospital, Kilkenny) over a four-year period. Patient charts were reviewed, and data relating to each inpatient episode and risk factors were collected. Patients considered to be high risk were those who were at an increased risk of bleeding, those with a prostate size >80 mL (as per EAU guidelines 2015) and/or those with preoperative urinary retention. Age >80 years was also considered to be a high-risk factor for this study.

Results

In total, 374 patients were identified as being high risk for GreenLight PVP. Patient age ranged from 44 to 96 years, with an average age of 71 years. Of the 374 patients, 103 were aged >80 years. Further information on the patient cohort is given in Table 1.

Table 1.

Patient cohort.

N	374
Average age (years)	71 (44–96)
Age >80 years	103 (27.5%)
ASA III	202 (54%)
ASA IV	20 (5.4%)
Preoperative haematuria	40

ASA: American Society of Anaesthesiologists.

Patients were grouped using the American Society of Anaesthesiologists (ASA) physical status clarification system. Just over half (n=202; 54%) of patients were given the grade of ASA III. Twenty (5.3%) patients were graded as ASA IV, mostly due to recent acute coronary syndrome with percutaneous coronary intervention (PCI) and insertion of a drug-eluting stent. One patient was awaiting bilateral lung transplant but was unable to proceed with transplantation due to recurrent urinary tract infections secondary to a long-term urinary catheter.

Figure 1 describes the prevalence of the selected risk factors amongst the patient cohort. All 374 patients were considered to be at an increased risk of bleeding, as they underwent GreenLight PVP while taking antiplatelet agents (not including aspirin), anticoagulant agents or both. Furthermore, 91 (24.3%) patients had preoperative urinary retention and were dependent on a long-term urinary catheter. Prostate size was measured using a Mindray portable ultrasound scanner. Fifty-four (14.4%) patients had a prostate >80 mL in size, and 47 (12.6%) had a prostate >100 mL in size.

Table 2 describes the contributing factors to patients being considered at increased risk of bleeding. Most major antiplatelet and anticoagulant agents are represented in the study. The most common risk factor for bleeding was dual antiplatelet therapy in the form of clopidogrel and aspirin (186/374; 49.7%). Two patients had preoperative thrombocytopaenia and received a platelet transfusion. Patients taking warfarin had their International Normalized Ratio (INR) checked preoperatively to ensure the level was within the therapeutic range (2.0–2.5).

Table 2.

Risk factors for bleeding.

Clopidogrel±aspirin	186
Ticagrelor±aspirin	8
Warfarin (INR <3)±aspirin	95
Warfarin and clopidogrel	1
Warfarin and low molecular weight heparin	2
Dabigatran±aspirin	40
Rivaroxaban±aspirin	34
Dabigatran and clopidogrel	2
Apixaban±aspirin	4
Severe thrombocytopaenia	2

INR: International Normalized Ratio.

Results are shown in Table 3. Length of stay varied from 1 to 14 days. Nearly three-quarters (n=270; 72.2%) of patients were discharged on postoperative day 1. There were no perioperative blood transfusions. Two patients required a delayed conversion to TURP due to urinary retention. One patient developed acute coronary syndrome on postoperative day 4 requiring PCI and a single coronary stent. This occurred while taking antiplatelet agents.

Table 3.

Results (N=374).

Discharged on postoperative day 1	270 (72%)
Perioperative blood transfusion	0
Perioperative platelet transfusion	1 (planned)
Delayed conversion to TURP	2 (urinary retention)
ACS	1 (NSTEMI postoperative day 4)

TURP: transurethral resection of the prostate; NSTEMI: non-ST segment elevation myocardial infarction.

In total, 5.9% (22/374) patients required readmission, as shown in Table 4. Of these, 12 were due to urinary retention, and 10 were due to haematuria. The readmissions due to urinary retention were managed with temporary urethral catheterisation followed by trial without catheter until post-void residual bladder volumes were satisfactory. Five (42%) of these had a prostate size >100 mL.

Table 4.

Readmissions (N=22).

Readmitted with urinary retention (no haematuria)	12
Readmitted with haematuria	10 (6.3%)
Managed with catheter irrigation	8
Cystoscopy and bladder washout	2
Blood transfusions	2

Of the readmissions due to haematuria, nine (90%) had prostates >100 mL. The risk factors for bleeding in this group are described in Table 5. Eight were managed conservatively with urethral catheter and continuous bladder irrigation until urine cleared. However, two patients required cystoscopy and bladder washout. There were two blood transfusions (both two units of red cell concentrate) in the ‘readmission due to haematuria’ group. Both of these patients had a prostate size >100 mL. One patient was taking warfarin (INR 3.7 on readmission), and the other was taking clopidogrel and aspirin.

Table 5.

Risk factors for bleeding in patients readmitted with haematuria (N=10).

Clopidogrel and aspirin (186)	3
Ticagrelor and aspirin (8)	1
Rivaroxaban and aspirin (34)	1
Dabigatran and aspirin (40)	1
Warfarin and aspirin (95)	3
Warfarin and clopidogrel (1)	1

The postoperative urinary drainage method of choice was to use a Bonanno suprapubic catheter (SPC). If appropriate, this slender SPC would be inserted under cystoscopic guidance at the end of the PVP procedure. If haematuria was present at the end of the procedure, a urethral catheter would also be inserted, and continuous bladder irrigation started until the urine was clear. Table 6 demonstrates the results from using the Bonanno catheter. In total, 301 (80.5%) patients were managed with a Bonanno SPC alone. Forty (10.7%) patients required a temporary urethral catheter (for one to two hours) and 25 (6.7%) patients required overnight bladder irrigation. Eight patients were precluded from Bonanno SPC insertion due to previous lower midline incision or laparoscopic inguinal hernia surgery. Only one of the 12 readmissions due to urinary retention had been managed post PVP with Bonanno SPC.

Table 6.

Bonanno SPC.

Bonanno SPC only	301
Bonanno SPC and temporary UC	40
UC and overnight irrigation	25
SPC precluded	8

SPC: suprapubic catheter; UC: urethral catheter.

Outcomes for patients aged >80 years were favourable and are shown in Table 7. Of note, 19.4% (20/103) of patients had previously undergone TURP, and 5.7% (6/103) had undergone PVP. The average length of stay was 2.7 days (range 1–14 days). Ninety-three were managed with Bonanno SPC alone. The readmission rate in this group was higher compared to the main cohort, with 11.7% (12/103) of patients requiring readmission. There were no perioperative cardiovascular events in this group. One patient developed bleeding from the SPC site, requiring removal and suturing for haemostasis.

Table 7.

Outcomes: patients >80 years of age.

N	103
Previous TURP	20
Previous PVP	6
Average length of stay	2.7 (1–14)
Bonanno SPC only	93
Readmission (haematuria/retention)	12
Bleeding from SPC site	1

PVP: photoselective vaporisation of the prostate.

Complication rates were low in this cohort, as shown in Table 8. The overall complication rate was 6.42%. Complications were classified according to the Clavien–Dindo classification of surgical complications. Most of the readmissions were graded as Clavien–Dindo I. Two patients returned to theatre for haemostasis accounting for the Clavien–Dindo III. The only Clavien–Dindo IV was a patient who developed acute coronary syndrome on postoperative day 4.

Table 8.

Clavien–Dindo classification of surgical complications (N=24).

I	21
II	0
III	2
IV	1
V	0

Discussion

This case series has shown that GreenLight XPS PVP for BPH is a safe treatment option in patients with one or more high-risk factors. With 374 patients, it is the largest cohort in the literature to date focusing on patients at high risk of bleeding. The cohort includes patients with each of the high-risk factors according to the NICE guidelines. There are also a number of high-risk patients from an anaesthetic point of view (ASA III or higher) as well as many patients aged >80 years.

One area of difference between our study inclusion criteria and the NICE guidelines is the cut-off prostate volume. The guideline considers a high-risk prostate volume to be >100 mL, whereas in our study we considered a high-risk prostate volume to be >80 mL. While this is different from the NICE guideline, it is in keeping with levels used in other studies.^13–15 It is difficult to say whether the lower limit for prostate size would significantly impact the outcome data. West and Woo published a retrospective study of 137 patients. Patients were divided into groups based on prostate size (<40, 40–79, 80–119 and >120 mL). Operating time was longer for the larger prostates, but there was otherwise no statistically significant difference in outcomes between the groups.¹⁶

The overall complication rate is quite low at 6.42%. However, there were no Clavien–Dindo II complications, which is likely underreported. Only 2.7% of patients developed haematuria/clot retention postoperatively, which is similar to other studies.¹⁷ Monopolar TURP has been found to have complication rates as high as 11% in this study with >10,000 patients.¹⁸ This study did not stratify patients according to the risk of bleeding.

In total, 29.7% (14/47) of patients with a prostate size >100 mL required readmission (nine due to haematuria, and five due to AUR). Most (90%; 9/10) patients admitted with haematuria also had a prostate >100 mL. This indicates that the combination of an enlarged prostate and anticoagulant/antiplatelet medications increases the risk of significant postoperative bleeding. The antiplatelet and anticoagulant agents associated with readmissions due to bleeding are detailed in Table 5. No antiplatelet/anticoagulant agent was associated with a higher rate of readmission compared to the others.

There are few studies directly comparing GreenLight XPS PVP with standard TURP.^19–21 The GOLIATH trial is a European multi-centre randomised controlled trial comparing GreenLight XPS PVP and TURP for the treatment of BPH. Patients were followed for a total of 24 months. This non-inferiority trial found the effectiveness and safety profile of GreenLight XPS PVP to be similar to TURP. The study also found GreenLight XPS PVP to be associated with a shorter duration of catheterisation and hospital stay. Complication rates were similar between the two groups. The GOLIATH study found GreenLight XPS PVP as being at least as effective as TURP for relieving symptoms of BPH. These were measured using the International Prostate Symptom Score and maximum flow rate of urine on uroflowmetry (Qmax). These outcomes were not measured in our study, and this is a consideration for future investigations.

It is worth noting that the GOLIATH study did not include patients considered to be at high-risk, that is, with an increased risk of bleeding, a prostate size >100 mL and/or preoperative urinary retention. There are no randomised controlled trials comparing TURP and GreenLight XPS PVP in high-risk patients. TURP is not usually considered to be a safe treatment option for these patients, and GreenLight PVP offers a safe alternative. The NICE guidelines identified seven studies with data relating to GreenLight XPS PVP in high-risk patients.^{14–17,22–24} Similar to our study, they are all retrospective studies or case series, with the exception of Tao et al.²⁴

The study by Woo et al. 2008 was the largest of these, which looked at 305 patients who underwent GreenLight High Performance System (HPS) for the treatment of BPH.¹⁴ GreenLight HPS is the older version of GreenLight XPS and uses a 120 W system compared to the 180 W system used in XPS. The results compared the outcomes of patients identified as being high risk (i.e. increased risk of bleeding, prostate size >80 mL and/or urinary retention) to non-high-risk patients. There were no differences in outcomes for patients at an increased risk of bleeding. As our study did not include any low-risk patients, we are unable to offer any comparison.

One aspect of our study which is not described in the literature is the use of a Bonanno SPC for postoperative drainage. The catheter is only suitable in the absence of significant haematuria (urine clear or rose coloured). This slender SPC is easily blocked, even by very mild haematuria. This is testament to the low levels of bleeding associated with GreenLight PVP. By clamping the SPC prior to removal, it becomes easy to assess if the patient is voiding satisfactorily postoperatively. It is also easy for the patient to self-manage the SPC in the event the patient is not voiding satisfactorily postoperatively. A urinary catheter often acts as a barrier to discharge, as patients are unable or unhappy to manage it themselves. Use of the Bonanno SPC may facilitate earlier discharge in the event that a patient is not voiding on day 1 postoperatively, and it could even allow GreenLight XPS PVP to be performed as an outpatient procedure in certain patients.

There are only two trials comparing the use of GreenLight PVP and HoLEP for treating BPH. Elshal et al. performed a randomised controlled trial of 103 patients, including patients at higher risk of bleeding, those with larger prostates and/or those with urinary retention.²⁵ Patients were randomised into two groups: HoLEP or GreenLight XPS vapo-enucleation of prostate (as opposed to PVP). The study found no significant difference in outcomes between the two groups, other than Qmax (31.1 vs. 18.5 mL, p=0.01) and percentage of patients whose length of stay was more than one day (6.4% vs. 23.5%, p=0.02). However, GreenLight vapo-enucleation is a different technique compared to PVP.

Knapp et al. published a study comparing adverse events amongst patients undergoing PVP.²⁶ This study contained 59 patients taking anticoagulants and 42 patients taking aspirin while undergoing PVP and compared against a control group of 272 patients. This study also highlighted the low bleeding risk associated with PVP, with only one patient from each of the aspirin and anticoagulant groups requiring readmission due to haematuria/clot retention. This study also had no perioperative blood transfusions.

At present, the evidence supporting the use of PVP in patients while taking antiplatelet agents or oral anticoagulants remains limited to a few retrospective studies. The SOAP trial is currently recruiting patients in France.²⁷ This will be the first multi-centre randomised controlled trial investigating the safety profile of PVP in patients taking oral anticoagulants at the time of surgery versus perioperatively. Recruitment of patients was due to cease in January 2020. Results of this trial are awaited but could provide evidence for new guidelines on the perioperative management of oral anticoagulants in patients undergoing PVP.

This study is limited due to the retrospective nature of the data. Another limitation is that all procedures were performed by a single experienced surgeon who performs a high volume of PVP cases.

In conclusion, GreenLight XPS PVP is a safe procedure in patients with one of more high-risk factors. The ability to proceed without the need to stop antiplatelets or anticoagulant agents allows for high-risk medical patients to be treated safely. However, at present, the evidence supporting the routine adoption of PVP for patients at high risk of bleeding remains limited.

Footnotes

Acknowledgements

None.

Conflicting interests

The authors declare that there is no conflict of interest.

Funding

The authors received no financial support for the research, authorship and/or publication of this article.

Ethical approval

Ethical approval was not sought for this article because of the retrospective nature of the study.

Informed consent

Informed consent was not sought for this article because of the retrospective nature of the study.

Guarantor

B.J.

Contributorship

B.J. and D.W. researched the literature and conceived the study. R.K., F.M. and F.O. were involved in data collection, protocol development, gaining ethical approval, patient recruitment and data analysis. D.W. was involved in data analysis and wrote the first draft of the manuscript. All authors reviewed and edited the manuscript and approved the final version of the manuscript.

ORCID iD

Darragh K Waters

References

Wei

Calhoun

Jacobsen

Urologic Diseases in America project: benign prostatic hyperplasia. J Urol 2005; 173: 1256–1261.

Berry

Coffey

Walsh

, et al. The development of human benign prostatic hyperplasia with age. J Urol 1984; 132: 474–479.

Gratzke

Bachmann

Descazeaud

, et al. EAU guidelines on the assessment of non-neurogenic male lower urinary tract symptoms including benign prostatic obstruction. Eur Urol 2015; 67: 1099–1109.

Whelan

Bowen

Burke

, et al. A prospective trial of GreenLight PVP (HPS120) versus transurethral resection of the prostate in the treatment of lower urinary tract symptoms in Ontario, Canada. Can Urol Assoc J 2013; 7: 335.

GreenLight XPS for treating benign prostatic hyperplasia, https://www.nice.org.uk/guidance/mtg29 (2016, accessed 13 January 2019).

The Department of Economic and Social Affairs of the United Nations. World Population Ageing https://www.un.org/en/development/desa/population/publications/pdf/ageing/WPA2017_Highlights.pdf (2017, accessed 27 August 2019).

Raj

McDonald

Brooks

, et al. Stopping anticoagulation before TURP does not appear to increase perioperative cardiovascular complications. Urology 2011; 78: 1380–1384.

Descazeaud

Robert

Lebdai

, et al. Impact of oral anticoagulation on morbidity of transurethral resection of the prostate. World J Urol 2010; 29: 211–216.

Enver

Hoh

Chinegwundoh

The management of aspirin in transurethral prostatectomy: current practice in the UK. Ann R Coll Surg Engl 2006; 88: 280–283.

10.

Hahn

Farahmand

Hallin

, et al. Incidence of acute myocardial infarction and cause-specific mortality after transurethral treatments of prostatic hypertrophy. Urology 2000; 55: 236–240.

11.

Levine

Bates

Bittl

, et al. 2016 ACC/AHA guideline focused update on duration of dual antiplatelet therapy in patients with coronary artery disease: a report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines: an update of the 2011 ACCF/AHA/SCAI guideline for percutaneous coronary intervention, 2011 ACCF/AHA guideline for coronary artery bypass graft surgery, 2012 ACC/AHA/ACP/AATS/PCNA/SCAI/STS guideline for the diagnosis and management of patients with stable ischemic heart disease, 2013 ACCF/AHA guideline for the management of ST-elevation myocardial infarction, 2014 AHA/ACC guideline for the management of patients with non–ST-elevation acute coronary syndromes, and 2014 ACC/AHA guideline on perioperative cardiovascular evaluation and management of patients undergoing noncardiac surgery. Circulation 2016; 134.

12.

Schulz

Schuster

Mehilli

, et al. Stent thrombosis after drug-eluting stent implantation: incidence, timing, and relation to discontinuation of clopidogrel therapy over a 4-year period. Eur Heart J 2009; 30: 2714–2721.

13.

Woo

Reich

Bachmann

, et al. Outcome of GreenLight HPS 120-W laser therapy in specific patient populations: those in retention, on anticoagulants, and with large prostates (⩾80 mL). Eur Urol Suppl 2008; 7: 378–383.

14.

Chen

Lin

Chiang

Outcome of GreenLight HPS laser therapy in surgically high-risk patients. Lasers Med Sci 2012; 28: 1297–1303.

15.

Hueber

Bienz

Valdivieso

, et al. Photoselective vaporization of the prostate for benign prostatic hyperplasia using the 180 Watt system: multicenter study of the impact of prostate size on safety and outcomes. J Urol 2015; 194: 462–469.

16.

Woo

West

Does prostate size impact upon perioperative outcomes associated with photoselective vaporization of the prostate using the 180W lithium triborate laser?

Urol Ann 2015; 7: 17.

17.

Knapp

Chalasani

Woo

Perioperative adverse events in patients on continued anticoagulation undergoing photoselective vaporisation of the prostate with the 180-W Greenlight lithium triborate laser. BJU Int 2017; 119: 33–38.

18.

Reich

Gratzke

Bachmann

, et al. Morbidity, mortality and early outcome of transurethral resection of the prostate: a prospective multicenter evaluation of 10,654 patients. J Urol 2008; 180: 246–249.

19.

Bachmann

Tubaro

Barber

, et al. 180-W XPS GreenLight laser vaporisation versus transurethral resection of the prostate for the treatment of benign prostatic obstruction: 6-month safety and efficacy results of a European multicentre randomised trial – the GOLIATH Study. Eur Urol 2014; 65: 931–942.

20.

Bachmann

Tubaro

Barber

, et al. A European multicenter randomized noninferiority trial comparing 180 W GreenLight XPS laser vaporization and transurethral resection of the prostate for the treatment of benign prostatic obstruction: 12-month results of the GOLIATH Study. J Urol 2015; 193: 570–578.

21.

Thomas

Tubaro

Barber

, et al. A multicenter randomized noninferiority trial comparing GreenLight-XPS laser vaporization of the prostate and transurethral resection of the prostate for the treatment of benign prostatic obstruction: two-yr outcomes of the GOLIATH Study. Eur Urol 2016; 69: 94–102.

22.

Woo

Hossack

Photoselective vaporization of the prostate with the 120-W lithium triborate laser in men taking coumadin. Urology 2011; 78: 142–145.

23.

Sohn

Choi

Kim

, et al. Effectiveness and safety of photoselective vaporization of the prostate with the 120 W HPS GreenLight laser in benign prostatic hyperplasia patients taking oral anticoagulants. Korean J Urol 2011; 52: 178.

24.

Tao

Xue

Zang

, et al. The application of 120-W high-performance system GreenLight laser vaporization of the prostate in high-risk patients. Lasers Med Sci 2012; 28: 1151–1157.

25.

Elshal

Elkoushy

El-Nahas

, et al. GreenLight™ laser (XPS) photoselective vapo-enucleation versus holmium laser enucleation of the prostate for the treatment of symptomatic benign prostatic hyperplasia: a randomized controlled study. J Urol 2015; 193: 927–934.

26.

Charbonneau

Pasquié

Peyronnet

, et al. Stopping or maintaining Oral Anticoagulation in patients undergoing Photoselective vaporization of the prostate (SOAP) surgery for benign prostate obstruction: study protocol for a multicentre randomized controlled trial. Trials 2018; 19.