Simultaneous Bladder Drainage via Suprapubic and Urethral Catheters: Which Drains More Completely and Why?

Background: Reconstructive urologists often place both a urethral and suprapubic catheter intraoperatively to prevent extravasation of undrained urine across anastomosis sutures. As no consensus exists on which catheter drains the bladder more completely, many surgeons leave one catheter to gravity drainage and cap the other postoperatively. We sought to identify differences in catheter urine outflow during dual bladder drainage with suprapubic and urethral catheters in postoperative urology patients. Methods: Urine output (UOP) from transgender men who underwent Stage II Phalloplasty with urethral lengthening was retrospectively reviewed. Both 16 French urethral and suprapubic catheters were placed to gravity drainage postoperatively. Urine output from each catheter was recorded separately, twice daily. Mixed model regression modeling tested for differences in urine output by time of day (day/night) and activity status (Bedrest: Postop Day 0-2, Ambulatory: Postop Day 3+). Results: The aggregate number of 12-hour shift urine output observations was 250 (125 for urethral and 125 for suprapubic catheters) across 14 inpatients. Suprapubic catheters had a mean 410 ml higher output than urethral catheters per 12-hour shift (p=0.002; 95% CI: 185, 636 ml). During daytime, Suprapubic catheters demonstrated higher UOP than urethral catheters per 12-hour shift (Estimated Difference: 464 ml; p=0.002; 95% CI: 211, 718 ml). During nighttime, a similar phenomenon was observed (Estimated Difference: 356 ml; p=0.009; 95% CI: 104, 606 ml). When comparing mean UOP from each catheter during the Bedrest Phase, suprapubic catheters averaged an estimated 295 ml higher UOP compared to urethral catheters per 12-hour shift with a trend toward statistical significance (p=0.052; 95% CI -3, 594 ml). During the Ambulatory Phase, mean suprapubic catheter UOP was an estimated 472 ml higher than urethral catheters per 12-hour shift (p=0.009; 95% CI 142, 802 ml). Conclusions: Simultaneous bladder drainage with urethral and suprapubic catheters shows greater drainage from the suprapubic catheter (35% vs 65%). When using two catheters, both can be placed to gravity to maximize bladder drainage as the suprapubic catheter can drain residual urine not adequately drained by the urethral catheter.

Robotic bilateral nephrectomy for large polycystic kidney disease.

Objective: This study aims to describe our technique and review our experience with synchronous robotic bilateral nephrectomy for large kidneys in ADPKD with the da Vinci XI and da Vinci Single Port platforms (Intuitive Surgical, Sunnyvale, CA). Materials and Methods: We performed a retrospective review of all robotic bilateral nephrectomy cases from January 2020 to present at a high-volume robotic single centre. Demographic data and perioperative details including preoperative CT scans, indication for nephrectomy and renal function were collected. We also collected post-op course data and final specimen data details. Results: Fourteen cases were included. Patient demographics, indications for surgery and specimen data are outlined in Table 1. The largest kidney removed has a measurement of 32 cm in the largest dimension on preoperative imaging. Median operating time from incision to closure was 299 min (IQR 260, 339). Median estimated blood loss was 75 cc (IQR 50, 187.5). Two patients were transfused intraoperatively. Median pre- and post-operative Hgb was 11.0 and 9.6, respectively. Median length of stay was 3 days (IQR 2, 3.5). There were no intraoperative complications and no open conversions. Post-operative complications included one incisional hematoma and one superficial wound infection. One patient was admitted to the surgical ICU post operatively for ventilatory support. Two patients were readmitted within 30 days of surgery. Conclusion: The robotic approach to bilateral native nephrectomy for ADPKD should be considered when native nephrectomies are indicated. The operative times and outcomes are favourable compared with prior series, and this technique works even for very large kidneys.

Management and Outcomes of Ileal Pouch-Urethral Fistulas.

OBJECTIVE: To describe a single-center experience with the management of ileal pouch-urethral fistulas (IPUF) following restorative proctocolectomy with ileal pouch-anal anastomosis (IPAA). METHODS: We retrospectively identified patients with documented IPUF managed at our institution from a urethral fistula cohort and analyzed their cases. RESULTS: Thirteen patients who underwent surgeries for IPUF management from 2005-2022 were identified. Median age at IPAA was 29 years (range 11-53). Indications for IPAA included familial adenomatous polyposis (n=3) and ulcerative colitis (n=10). Median time from IPAA to fistula diagnosis was 15 years (range 0.5-38.5). Eleven patients were initially diverted with either loop (n=8) or end ileostomy (n=3). Overall, two patients had resolution of IPUF symptoms with a loop ileostomy alone and eight eventually underwent pouch excision with end ileostomy, one of which subsequently underwent redo IPAA. Seven patients were managed with primary closure of the urethral defect at the time of pouch excision, five of which also underwent gracilis muscle interposition. With a median follow-up of 4 years (range 0.3-13 years), all patients had resolution of their fistulae without any recurrences. CONCLUSION: IPUFs are a rare complication after IPAA. In this cohort, all patients had their urinary tract preserved, but most ultimately had permanent fecal diversion. These results can help guide management of this complex issue.

Radium-223 Utilization Patterns and Outcomes in Clinical Practice.

INTRODUCTION: Radium-223 was approved for metastatic castration-resistant prostate cancer based on the ALSYMPCA trial. We characterize radium-223 treatment patterns and overall survival (OS) in a large equal access health system. METHODS: We identified all men within the Veterans Affairs (VA) Healthcare System who received radium-223 between January 2013 and September 2017. Patients were followed until death or last followup. We abstracted all treatments received prior to radium; no treatments after radium were abstracted. Our primary aim was understanding practice patterns, and secondary outcome was the association between treatment pattern and OS measured using Cox models. RESULTS: We identified 318 bone metastatic castration-resistant prostate cancer patients who received radium-223 within the VA Healthcare System. Of these patients 277 (87%) died during followup. The 5 predominant treatment patterns that encompassed 88% of patients (279/318) were 1) androgen receptor-targeted agent (ARTA)-radium, 2) docetaxel-ARTA-radium, 3) ARTA-docetaxel-radium, 4) docetaxel-ARTA-cabazitaxel-radium and 5) radium alone. Median OS was 11 months (95% CI 9.7-12.5). Men who received ARTA-docetaxel-radium had the worst survival. All other treatments had similar outcomes. Only 42% of patients completed the full 6 injections; 25% received only 1 or 2 injections. CONCLUSIONS: We identified the most common radium-223 treatment patterns and their association with OS within the VA population. The better survival in ALSYMPCA (14.9 months) vs our study (11 months) along with 58% of patients not receiving the full radium-223 course suggests radium is being used later in the disease course in the real world in a more heterogeneous population.

Accuracy of Urologic Conditions Portrayed on Grey's Anatomy.

Despite the common prevalence of urologic diseases, studies have demonstrated that the general public often has little knowledge or insight into the field of urology or the role of an urologist. In this study, we investigated the context, frequency, and accuracy of urologic conditions on the television series Grey's Anatomy. We reviewed episodes from the first 15 seasons. Episodes with urologic references were then screened and the urologic conditions, outcomes, and treatments were recorded. We identified a total of only 21 urologic events across 15 seasons and 342 episodes of Grey's Anatomy. A total of 52% (11/21) of the conditions were related to external male genitalia. The portrayal of these conditions and the associated treatments were considered to be medically accurate within reason 62% (13/21) of the time. There is significant room for improvement to increase the portrayal of common urologic conditions and malignancies to improve the public's awareness and perception of our specialty.

Optimal instrument length for transumbilical laparoendoscopic single site (U-LESS) surgery.

The aim of our study was to recommend a novel method for measuring the distance from the umbilicus to intra-abdominal organs, as well as recommend an instrument length that would accommodate transumbilical laparoendoscopic single-site (U-LESS) surgeries to these areas. From CT scans of 50 men and 50 women, we calculated the distance from the umbilicus to 11 intra-abdominal points of interest using two triangles oriented perpendicular to each other. Using known lengths of the triangles, we used the Pythagorean theorem to calculate distances with and without insufflation. Distances were measured from the umbilicus to the xyphoid process, superior most aspect of the spleen, neck of the gallbladder, bifurcation of the descending aorta, adrenal glands, superior pole(s) of the kidneys, inferior most aspect of the inguinal canal, suprapubic margin, and the apex of the prostate (or female bladder neck). We found that an instrument working length of 43 cm would be sufficient to facilitate U-LESS surgery for all of our patients to each of the measured points of interest. The technique described in this paper serves as a useful method by which to measure the distance from the umbilicus to any intra-abdominal point of interest. These measurements would allow surgeons to correctly select instruments with adequate length when planning to perform U-LESS surgery.

Safety of concomitant therapy with radium-223 and abiraterone or enzalutamide in a real-world population.

BACKGROUND: Real-world utilization and outcomes of combination therapy for men with metastatic castrate-resistant prostate cancer (mCRPC) are largely unknown. We evaluated the overall survival (OS) and skeletal-related events (SREs) among men who received radium-223 with or without concomitant abiraterone or enzalutamide in the Veterans Affairs (VA) Health System. METHODS: We reviewed charts of all mCRPC patients who received radium-223 in the VA from January 2013 to September 2017. We used Cox models to test the association between concomitant therapy versus radium-223 alone on OS and SRE. Sensitivity analyses were performed for concomitant use of denosumab/bisphosphonates. RESULTS: Three hundred and eighteen patients treated with radium-223 were identified; 116/318 (37%) received concomitant abiraterone/enzalutamide. Two hundred and seventy-seven (87%) patients died during follow-up. Patients who received concomitant therapy were younger at radium-223 initiation (median age 68 vs. 70, p = .027) and had a longer follow-up (median 29.5 vs. 17.9 months, p = .030). There was no OS benefit for those on concomitant therapy (hazard ratio [HR]: 0.87, 95% confidence interval [CI]: 0.67-1.12, p = .28). There was a trend for an increased SRE risk for patients on concomitant therapy (HR: 1.87, 95% CI: 0.96-3.61, p = .066), but this was not significant. When analyses were limited to men using bone heath agents, similar results were seen for OS (HR: 0.86, 95% CI 0.64-1.15, p = .30) and SRE (HR: 2.36, 95% CI: 0.94-5.94, p = .068). CONCLUSIONS: Despite the common use of concomitant therapy in this real-world study, there was no difference in OS among mCRPC patients. A nonsignificant increased SRE risk was observed. Further work needs to evaluate the optimal sequence, timing, and safety of combination therapies.

Outcomes of Prophylactic Mid-Urethral Sling at the Time of Robotic Sacrocolpopexy.

OBJECTIVE: To compare outcomes of patients who underwent robotic sacrocolpopexy (RSC) with and without concomitant mid-urethral sling (MUS) placement for prophylaxis or treatment of preoperative stress urinary incontinence (SUI) METHODS: We performed a retrospective review of all patients without prior incontinence procedures who underwent RSC with or without MUS placement by 3 surgeons (JA, LA, KE) at a single institution from 2012 to 2017 for treatment of pelvic organ prolapse. Patients had a MUS placed for either documented SUI or prophylaxis of SUI. We compared patient characteristics, operative details, postoperative outcomes, and complications between the groups. RESULTS: A total of 134 patients were identified. 58 (43%) had a MUS placed for documented SUI, 43 (32%) had prophylactic MUS, and 33 (25%) did not have a MUS placed. There were no differences in baseline characteristics between the 3 groups. Patients who did not have a MUS placed had less estimated blood loss (76.4 vs 63.8 vs 36.9 mL, P = .018) but no difference in operative time (P = .408), length of stay (P = .427), or postoperative urinary retention (P = .988). A total of 4 (7%) patients who had a MUS placed for SUI had persistent SUI postoperatively. There were 2 (5%) patients who had a MUS placed prophylactically and 4 (12%) patients who did not have a MUS that developed de novo SUI. CONCLUSION: In this series, we demonstrate the safety and efficacy of prophylactic MUS placement at the time of RSC. Randomized studies evaluating concomitant prophylactic sling at time of robotic sacrocolpopexy could further guide preoperative patient counseling and decision-making.

Uncoiling of a Cook Resonance Metallic Ureteral Stent.

Introduction and Background: The Cook Resonance® metallic ureteral stent's unique configuration allows adequate urine drainage while providing improved resistance to external ureteral compression. We report a case in which a stent broke and subsequently uncoiled during stent removal under cystoscopy. Case Presentation: A 46-year-old woman with a history of cervical carcinoma treated with radiation therapy and chemotherapy and bilateral ureteral strictures presented for cystoscopic removal of bilateral Cook Resonance ureteral stents. During removal of the right ureteral stent, a snap was felt with subsequent uncoiling of the stent. Firm tension to the inner wire and outside curls allowed eventual complete removal of the stent without any retained fragments. Discussion: The all-metal Cook Resonance stent is an attractive alternative to polymeric stents because of reduced frequency of stent exchange and resistance to external compression. However, the metal stent possesses risks such as increased urothelial hyperplasia and stent embedment.

New paradigms in the management of recurrent urinary tract infections.

PURPOSE OF REVIEW: Recurrent urinary tract infections (rUTIs) represent a large burden on the healthcare system. Recent guidelines from the AUA/CUA/SUFU and advancements in the field reflect a paradigm shift for clinician and patients, steering away from empiric antibiotic therapy towards judicious antibiotic use. RECENT FINDINGS: Antibiotic stewardship, including increasing awareness of the collateral damage of antibiotics and the risks of bacterial resistance are a major focus of the new guidelines. Accurate diagnosis of rUTIs is imperative. Urine cultures are necessary to document rUTI and should be obtained prior to any treatment. First line treatment options (trimethoprim-sulfamethoxazole, nitrofurantoin, and fosfomycin) should be used whenever possible. Asymptomatic bacteriuria should not be treated in these patients with rUTI. Although antibiotic prophylaxis methods are effective, nonantibiotic regimens show promise. SUMMARY: The management of rUTIs has evolved significantly with the goal of antibiotic stewardship. It is increasingly important to ensure the accuracy of diagnosis with a positive urine culture in the setting of cystitis symptoms, and standardize treatment with first-line therapies to minimize antibiotic side effects.

Catheter Balloon-trauma: Design, Development, and Ex-vivo Studies Using Intact Human Penis Specimens.

OBJECTIVE: To present a novel urethral catheter design with a pilot balloon to reduce intraurethral retention balloon inflation pressures and to provide a visual alert during catheter placement. METHODS: We manufactured our pilot balloon prototype from both molded and extruded silicone components. Various pilot balloon thicknesses were tested in order to determine the ideal compliance. We studied the filling pressures of the retention balloon of our prototype in a mechanical urethral model. The prototype catheter was then tested in ex-vivo human penis specimens obtained from gender affirming surgery and changes in the size of the retention balloon were measured under fluoroscopy. RESULTS: The thickness of the pilot balloon was directly related to the inflation pressure of the retention balloon in the mechanical urethral model. The thickness chosen for the pilot balloon in our prototype was based on a retention balloon pressure of 70 kPa. In the ex-vivo human penis model, the presence of the pilot balloon resulted in a 40% reduction in the cross-sectional area of the retention balloon compared to a standard urinary catheter. CONCLUSION: The prototype urinary catheter appears to decrease the filling pressure and size of an improperly positioned retention balloon inside a urethra. This can potentially reduce the risk of iatrogenic urethral catheter injuries. In addition, the prototype urinary catheter may act as a visual warning sign for the healthcare practitioner.

Considerations for Bedside Urologic Procedures in Patients With Severe Acute Respiratory Syndrome Coronavirus-2.

OBJECTIVE: To provide guidance when performing bedside urologic procedures on severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) positive patients and offer considerations to maximize the safety of the patients and providers, conserve supplies, and provide optimal management of urologic issues. METHODS: Urologic trainees and attending physicians at our institution, who are familiar with existing safety recommendations and guidelines regarding the care of infected patients, were queried regarding their experiences to determine an expert consensus on best practices for bedside procedures for SARS-CoV-2 positive patients. RESULTS: Our team developed the following general recommendations for urologic interventions on SARS-CoV-2 positive patients: maximize use of telehealth (even for inpatient consults), minimize in-room time, use personal protective equipment appropriately, enlist a colleague to assist, and acquire all supplies that may be needed and maintain them outside the room. Detailed recommendations were also developed for difficult urethral catheterization, bedside cystoscopy, incision and drainage of abscesses, and gross hematuria/clot irrigations. CONCLUSION: As patients hospitalized with SARS-CoV-2 infection are predominantly men over 50 years old, there are significant urologic challenges common in this population that have emerged with this pandemic. While there is tremendous variation in how different regions have been affected, the demographics of SARS-CoV-2 mean that urologists will continue to have a unique role in helping to manage these patients. Here, we summarize recommendations for bedside urologic interventions specific to SARS-CoV-2 positive patients based on experiences from a large metropolitan hospital system. Regulations and requirements may differ on an institutional basis, so these guidelines are intended to augment specific local protocols.

Racial Discrepancies in Overall Survival among Men Treated with 223Radium.

PURPOSE: Several recent studies on metastatic castration resistant prostate cancer demonstrated improved overall survival in black vs white men. 223Radium is Food and Drug Administration approved for metastatic castration resistant prostate cancer based on a survival benefit in the ALSYMPCA (A Phase III Study of Radium-223 Dichloride in Patients with Symptomatic Hormone Refractory Prostate Cancer with Skeletal Metastases) trial, in which 94% of participants were white. We identified a real world population of patients with metastatic castration resistant prostate cancer who received 223radium to compare differences in baseline characteristics and outcomes in black vs nonblack men. MATERIALS AND METHODS: We reviewed the charts of all men who received 223radium in the entire Veterans Affairs system. We compared treatment patterns and baseline characteristics between black and nonblack men. We used Cox models to analyze predictors of time from 223radium start to overall survival and time to skeletal related events. RESULTS: We identified 318 patients treated with 223radium, including 87 (27%) who were black. Median followup after 223radium initiation was 25.3 months (IQR 13.8-37.1). Black men were younger than nonblack men when starting 223radium (median age 67 vs 70 years, p <0.001) and they had higher prostate specific antigen (median 159.9 vs 90.2 ng/ml, p=0.014) and alkaline phosphatase (median 163 vs 135 IU/l, p=0.017). A greater proportion of black men received docetaxel prior to 223radium (77% vs 55%, p <0.001). On multivariable analysis black race was associated with a decreased risk of mortality from the time of 223radium initiation (HR 0.75, 95% CI 0.57-0.99, p=0.045). CONCLUSIONS: Black men had longer overall survival than nonblack men, although they appeared to receive radium later in the disease course. Further studies are required to verify our findings and explore biological differences between black and nonblack men with metastatic castration resistant prostate cancer.

The Complex Relationship Between Lower Urinary Tract Symptoms and Sexual Health.

PURPOSE OF REVIEW: Lower urinary tract symptoms (LUTS) and sexual health have common links. Medical and surgical treatments for LUTS can significantly affect various domains of sexual health including erectile function, ejaculatory function, and libido. This review summarizes recent findings. RECENT FINDINGS: Current literature demonstrates a strong association between LUTS, sexual health, and metabolic syndrome. The role of miRNA is also being investigated. Combination medical therapy with phosphodiesterase 5 inhibitors (PDE5-I) shows promise but needs further investigation. Newer surgical therapies for benign prostatic hyperplasia (BPH) aim to preserve sexual function without sacrificing efficacy and durability. Although we are beginning to acknowledge the link between LUTS and sexual health, a better understanding of the underlying biochemistry is needed. Only then can more effective therapies be developed. Further prospective studies should focus on the long-term durability and safety of treatments for both conditions.

Robotic Urologic Surgery: Trends in Food and Drug Administration-Reported Adverse Events Over the Last Decade.

Background: The da Vinci Surgical System has led to a rapid growth in the volume of robot-assisted surgeries, with 877,000 surgeries performed in 2017. Despite the increasing prevalence of robotic urologic surgeries, few long-term studies exist that examine trends in reported adverse events (RAEs). We analyzed RAEs over the past decade. Materials and Methods: We extrapolated all entries from the Manufacturer and User Facility Device Experience (MAUDE) database with the manufacturer "Intuitive Surgical" from 2007 to 2017. Reports were analyzed for date and type of RAE (death, bodily injury, malfunction, and other). RAEs from urologic surgeries were analyzed further for specific information pertaining to death, bodily injury, and malfunction. Results: A total of 19,783 RAEs were analyzed. Instrument or robot malfunctions comprised the majority of RAEs (84.9%); bodily injuries comprised 8.2%. Death was the least common RAE (1.3%). RAEs for urologic robotic surgeries peaked in 2013 and 2014 and decreased since. A total of 69 (2.3%) deaths, 364 (12.2%) injuries, and 2544 (85.5%) instrument or robot malfunctions occurred. No reported deaths were attributed to system or mechanical malfunction, but rather to medical complications reported to be unrelated to surgery. The most common injuries were bowel (22.3%) and genitourinary (GU) (19.5%). Instrument malfunctions caused 16.8% of bodily injuries. Conclusions: RAEs for robotic urologic surgeries peaked in 2013 to 2014, and have decreased annually since. When malfunctions occurred, they did not result in death and infrequently resulted in bodily injury. Potential quality improvement targets include prevention of bowel and GU injuries through surgical coaching, and improved technology to prevent malfunction of the surgical system and instruments.

Robotic sacrocolpopexy: adverse events reported to the FDA over the last decade.

INTRODUCTION AND HYPOTHESIS: As surgeons increase the volume of robotic abdominal sacrocolpopexies (rASCs) and become more experienced, a subsequent decrease in the number of adverse events is expected over time. Further, as the leading manufacturer of the operative robot (Intuitive Surgical) improves the technology, adverse events should also decrease. We hypothesized that there has been a decrease in adverse event reporting for rASCs and that serious adverse events are rare. METHODS: We performed a search of the FDA Manufacturer and User Facility Device Experience (MAUDE) database. All entries with the manufacturer "Intuitive Surgical" were exported from 2007 to 2017. All entries with "sacrocolpopexy" were then isolated and analyzed. RESULTS: The number of adverse events reported for rASC peaked in 2013 and 2014, at 107 and 124 respectively. In 2015 and 2016, the number dropped to 11 and 7 respectively. There were 334 reported adverse events from 2007 to 2017. Five (1.50%) were categorized as death, 33 (9.88%) as injury, and 296 (88.62%) as malfunction. Analysis of the malfunction reports found that 15 out of 296 (5.07%) were converted to open surgery, 4 out of 296 (1.3%) were converted to laparoscopic surgery, 4 out of 296 (1.3%) cases were aborted, and 6 out of 296 (2.03%) malfunctions resulted in patient injury. CONCLUSIONS: Although the MAUDE database has its limitations, it does indicate that the number of adverse events reported for rASC peaked in 2013 and 2014 and has decreased annually since then. This may be due to improved proficiency of the surgeon and surgical team, in addition to improvements in the robot. When malfunctions do occur, they infrequently cause serious injury or have an impact on surgical approach.

Robotic urologic surgery: trends in litigation over the last decade.

There is a lack of information regarding malpractice claims and indemnity payments associated with robotic cases in surgery. Malpractice claims and indemnity payouts will elucidate and mitigate harms of future adoption of new technology into surgery. We analyzed claims filed against Intuitive Surgical, Inc. from 2000 to 2017. A law librarian identified product liability claims from 2000 to 2017 with the defendant "Intuitive Surgical, Inc." using the Bloomberg Law database. We reviewed all available legal documents pertaining to identified claims, and extracted data points including filing date, surgery date, surgery type, robot type, instrument type, complications, and case outcomes. Since 2000, 123 claims were filed; 108 met criteria for inclusion. Gynecologic surgeries comprised the majority of claims (62%, 67 claims), followed by urologic surgeries (20%, 22 claims). Number of claims filed peaked in 2013 (30%, 32 claims) and then decreased each year, with 6% (7 claims) filed in 2016, and only 1% (1 claim) filed in 2017. Of the 22 claims regarding robotic urologic surgeries, 19 claims (86%) pertained to prostatectomy. Commonly alleged injuries in urologic cases were bowel injury (8 claims), erectile dysfunction (5 claims), bowel fistulas (4 claims), and incontinence (4 claims). Device failure was cited in only 2 claims. Early adopters of robotic surgery were at highest risk of litigation. This risk subsequently decreased despite the wide spread adoption of this technology. Almost all claims were secondary to surgical complications and not device failure, thus demonstrating a need for more systematic training for novel devices and early adopters.

Retroperitoneal hemorrhage after ureteroscopy without laser lithotripsy: an extreme example of an underreported event?

Retroperitoneal hemorrhage and an associated hematoma are uncommon but potentially serious complications following ureteroscopy with laser lithotripsy. However, no reports of serious bleeding complications have been published regarding ureteroscopy without laser lithotripsy in the management of stone disease. We report of such a case here and then review the current literature in order to discuss the incidence, risk factors, and management of such events.