Annual Case Volume Research Articles

Dissemination of Transcatheter Aortic Valve Replacement in the United States

BackgroundSocietal guidelines and payor coverage decisions for transcatheter aortic valve replacement (TAVR) attempt to strike a balance between providing access and maintaining quality. The extent to which dissemination of TAVR has achieved these ideals remains unknown. ObjectivesThis study sought to define patterns of TAVR dissemination in the United States and their influence on outcomes. MethodsUsing data from the TVT (Transcatheter Valvular Therapy) registry, this study identified TAVR sites from 2011 to 2018 and calculated drive-times from existing to new sites. In a contemporary cohort, this study compared site and patient characteristics by annual case volume and density of sites per million Medicare beneficiaries. Using hierarchical regression and Cox methods, this study determined the association between case volumes, site density, and changes in volume and density with patient risk profiles and outcomes. ResultsTAVR sites participating in the TVT registry increased from 198 to 556 from 2011 to 2018. Median drive-time from existing to new sites decreased from 403 minutes (interquartile range: 211-587 minutes) to 26 minutes (interquartile range: 17-48 minutes). In a contemporary cohort, higher site density was associated with lower procedural risk as well as with an increased hazard of 30-day risk-adjusted mortality (P = 0.017). Similarly, longitudinal increases in site density over time were associated with a higher hazard of 30-day (P = 0.011) and 1-year (P = 0.013) mortality. ConclusionsTAVR has expanded significantly over time, but with regional clustering of sites. Although procedural risk is lower at higher density sites, these sites demonstrate an increased hazard of mortality. These findings suggest that the expansion of TAVR services in the United States may have had unintended consequences on procedural quality.

In-house intensivist presence does not affect mortality in select emergency general surgery patients.

This study aimed to assess the relationship between availability of round-the-clock (RTC) in-house intensivists and patient outcomes in people who underwent surgery for a life-threatening emergency general surgery (LT-EGS) disease such as necrotizing soft-tissue infection, ischemic enteritis, perforated viscus, and toxic colitis. Data on hospital-level critical care structures and processes from a 2015 survey of 2,811 US hospitals were linked to patient-level data from 17 State Inpatient Databases. Patients who were admitted with a primary diagnosis code for an LT-EGS disease of interest and underwent surgery on date of admission were included in analyses. We identified 3,620 unique LT-EGS admissions at 368 hospitals. At 66% (n = 243) of hospitals, 83.5% (n = 3,021) of patients were treated at hospitals with RTC intensivist-led care. These facilities were more likely to have in-house respiratory therapists and protocols to ensure availability of blood products or adherence to Surviving Sepsis Guidelines. When accounting for other key factors including overnight surgeon availability, perioperative staffing, and annual emergency general surgery case volume, not having a protocol to ensure adherence to Surviving Sepsis Guidelines (adjusted odds ratio, 2.10; 95% confidence interval, 1.12-3.94) was associated with increased odds of mortality. Our results suggest that focused treatment of sepsis along with surgical source control, rather than RTC intensivist presence, is key feature of optimizing EGS patient outcomes. Therapeutic, level III.

Robotic hysterectomy compared with laparoscopic hysterectomy: is it still more costly to perform?

To establish the economic value of simple robotic hysterectomy vs laparoscopic hysterectomy and assess the impact of surgeon's experience. Retrospective cohort study. University-affiliated US regional healthcare system. Reproductive and post-menopausal women undergoing hysterectomy for benign indications. Robotic or laparoscopic hysterectomy. Between January 2018 and December 2019, a total of 985 simple laparoscopic and robotic hysterectomies were performed by 47 different gynecologists. Overall, the mean payment, direct cost, and profit were comparable (p value > 0.05) among simple robotic and laparoscopic hysterectomy. However, the mean operative time was significantly shorter for robotic hysterectomy compared to laparoscopic hysterectomy (106min vs 127min, respectively, p < 0.05). Operative time decreased as a surgeon's annual robotic case volume increased. Per-minute profitability of robotic hysterectomy increased significantly when a surgeon performed greater than 45 cases annually (p = 0.04). This effect became most pronounced when a surgeon performed 60 or more cases per year (p = 0.01). Simple robotic hysterectomy has shorter operative time compared to laparoscopic hysterectomy, with direct costs being similar. Robotic hysterectomy has higher per-minute profit compared to laparoscopic hysterectomy when a surgeon performs > 45 cases per year.

Prophylaxis for Heterotopic Ossification Following Distal Biceps Tendon Repair.

Heterotopic ossification (HO) is a possible complication of distal biceps tendon repair (DBTR). Several agents can prevent HO formation, although relatively few studies have investigated prophylaxis specifically after DBTR. The purposes of this study were to survey members of the American Shoulder and Elbow Surgeons (ASES) to determine (1) what percentage use HO prophylaxis after DBTR; (2) type, dosage, and duration of prophylaxis used; and (3) use of single-incision or double-incision surgical technique. An anonymous electronic survey was distributed to ASES members to determine the use of HO prophylaxis and DBTR technique. The survey included questions regarding the number of DBTRs performed annually; preferred surgical technique and implants; and type, dosage, and duration of HO prophylaxis used before, during, and after surgery. Descriptive statistics were used to analyze the results. Of 173 respondents, 98 (56.6%) performed 1 to 10 DBTRs per year, 65 (37.6%) performed 11 to 25 DBTRs per year, and 10 (5.8%) performed 26 to 50 DBTRs per year. A total of 131 (75.7%) preferred the single-incision technique, whereas 42 (24.3%) preferred the double-incision technique. A total of 94 (54.3%) performed DBTR using a metal button and interference screw, 35 (20.2%) through drill holes, 25 (14.5%) with suture anchors, and 19 (11.0%) with a metal button alone. A total of 132 (76.3%) respondents did not use HO prophylaxis, and 41 (23.7%) used nonsteroidal anti-inflammatory drugs following surgery. A total of 35 (85.4%) used indomethacin, 18 (51.4%) of whom preferred 75 mg/d for 3 to 4 weeks. Heterotopic ossification is a commonly reported complication following DBTR, especially with the double-incision technique. Prophylaxis with anti-inflammatory medications and suppressive modalities (radiation therapy) appear to reduce the incidence of HO. Despite these data, most surgeons (76.3%) do not use HO prophylaxis. Low annual volume of cases, lack of large-volume studies with outcome data, and the dominant use of the single-incision repair technique may explain this. [Orthopedics. 2021;44(4):e588-e592.].

Association of Annual Intensive Care Unit Sepsis Caseload With Hospital Mortality From Sepsis in the United Kingdom, 2010-2016

Sepsis is associated with a high burden of inpatient mortality. Treatment in intensive care units (ICUs) that have more experience treating patients with sepsis may be associated with lower mortality. To assess the association between the volume of patients with sepsis receiving care in an ICU and hospital mortality from sepsis in the UK. This retrospective cohort study used data from adult patients with sepsis from 231 UK ICUs between 2010 and 2016. Demographic and clinical data were extracted from the Intensive Care National Audit & Research Centre (ICNARC) Case Mix Programme database. Data were analyzed from January 1, 2010, to December 31, 2016. Annual sepsis case volume in an ICU in the year of a patient's admission. Hospital mortality after ICU admission for sepsis assessed using a mixed-effects logistic model in a 3-level hierarchical structure based on the number of individual patients nested in years nested within ICUs. Among 273 001 patients included in the analysis, the median age was 66 years (interquartile range, 53-76 years), 148 149 (54.3%) were male, and 248 275 (91.0%) were White. The mean ICNARC-2018 illness severity score was 21.0 (95% CI, 20.9-21.0). Septic shock accounted for 19.3% of patient admissions, and 54.3% of patients required mechanical ventilation. The median annual sepsis volume per ICU was 242 cases (interquartile range, 177-334 cases). The study identified a significant association between the volume of sepsis cases in the ICU and mortality from sepsis; in the logistic regression model, hospital mortality was significantly lower among patients admitted to ICUs in the highest quartile of sepsis volume compared with the lowest quartile (odds ratio [OR], 0.89; 95% CI, 0.82-0.96; P = .002). With volume modeled as a restricted cubic spline, treatment in a larger ICU was associated with lower hospital mortality. A lower annual volume threshold of 215 patients above which hospital mortality decreased significantly was found; 38.8% of patients were treated in ICUs below this threshold volume. There was no significant interaction between ICU volume and severity of illness as described by the ICNARC-2018 score (β [SE], -0.00014 [0.00024]; P = .57). The findings suggest that patients with sepsis in the UK have higher odds of survival if they are treated in an ICU with a larger sepsis case volume. The benefit of a high sepsis case volume was not associated with the severity of the sepsis episode.

Outcome and Cost of Nurse-Led vs Perfusionist-led Extracorporeal Membrane Oxygenation

BackgroundExtracorporeal membrane oxygenation (ECMO) is a resource-intense modality of care whose use has grown exponentially. We examined volume and utilization trends to identify the financial break-even point that might serve to dichotomize between nurse specialist–led and perfusionist-led ECMO programs. MethodsData pertaining to patients who required ECMO support between 2018 and 2019 were reviewed. ECMO staffing costs were estimated based on national trends and modeled by annual utilization and case volume. A break-even point was derived from a comparison between nurse specialist–led and perfusionist-led models. For each scenario, direct medical costs were calculated based on utilization, which was in turn defined by “low” (4 days), “average” (10 days), and “high” (30 days) duration of time spent on ECMO. ResultsWithin the study time frame, there was a total of 107 ECMO cases with a mean ECMO duration of 11 days. Overall, ECMO nursing personnel costs were less than those for perfusionists ($108,000 vs $175,000). Programmatic costs were higher in the perfusionist-led vs nurse specialist-led model when annual utilization was greater than 10 cases and ECMO duration was longer than a mean of 9.7 days. There was no difference in survival between the 2 models. ConclusionsUse of a perfusionist-led ECMO model may be more cost-conscious in the context of low utilization, smaller case volume and shorter ECMO duration. However, once annual case volume exceeds 10 and mean ECMO duration exceeds 10 days, the nurse specialist–led model may be more cost-conscious.

Proclivity to Explore Locally Advanced Pancreas Cancer Is Not Associated with Surgeon Volume

Background and PurposeThere is limited high-level evidence to guide locally advanced pancreas cancer (LAPC) management. Recent work shows that surgeons’ preferences in LAPC management vary broadly. We sought to examine whether surgeon volume was associated with attitudes regarding LAPC management. MethodsAn electronic survey was distributed by email to an international cohort of pancreas surgeons to evaluate practice patterns regarding LAPC management. Clinical vignette-based questions evaluated surgeons’ attitudes regarding patient eligibility and the proclivity to offer exploration. Surgeons were classified into “low-“ or “high-volume” categories according to thresholds of self-reported annual pancreatectomy volume. Surgeon’s attitudes regarding LAPC management and inclination to consider exploration were compared across annual volume categories. ResultsA total of 153 eligible responses were received from 4 continents, for an estimated response rate of 10.6%. Median duration of practice was 12 years (IQR 6–20). Most respondents reported >25 cases/year (89, 58.2%), of which 34 (22.2%) reported >50. Compared to surgeons with <25 cases/year, surgeons with >25 cases/year practiced longer (median 15 vs. 7.5 years, P<0.001) and were more likely to “always” recommend neoadjuvant chemotherapy (83.2% vs. 56.3%, P=0.001). Surgeons performing >50 cases/year were more likely to offer arterial resection (70.6% vs. 43.7%, P=0.006). The willingness to offer (or defer) exploration did not differ across any categories of surgeons’ annual case volume. ConclusionsIn an international survey of pancreas surgeons, the proclivity to consider exploration for LAPC was not associated with multiple categories of surgeon volume. Better evidence is needed to define the optimal management approach to LAPC.

Fellowship training in endourology: Impact on percutaneous nephrolithotomy access patterns.

Percutaneous nephrolithotomy (PCNL) remains the treatment of choice for kidney stones larger than 2 cm. Few studies have examined the reasons why some urologists obtain their own PCNL access while others prefer to have interventional radiology (IR) obtain access. The objective of this study was to investigate what factors influence this decision. A survey was posted to the American Urological Association's (AUA) Young Urologist Community. Descriptive statistics and exploratory analyses were used to summarize practice trends and motivating factors. All 99 respondents began practicing within the past 11 years. Ninety-two currently perform PCNLs and 47% of them obtain their own access. Endourology fellowship-trained physicians were more likely to currently obtain their own access (75%) compared to urologists who completed non-endourology fellowships (75% vs. 23%, p=0.58) and non-fellowship-trained urologists (75% vs. 45%, p=0.01). Logging >50 cases during training also predicted physicians obtaining their own access and having a larger annual number of PCNL cases. The most common motivator for obtaining one's own access was preference to control their own access point (95%). Urologist-obtained PCNL access was associated with greater training experience (endourology fellowship) and current annual PCNL case volume. Urologist-reported factors that influenced the decision to obtain one's own access include control of access, comfort level, and both physician and patient convenience. By identifying the factors that influence practice patterns, we may better address barriers, improve education to make urologistobtained PCNL access feasible even without fellowship training, and ultimately improve outcomes and quality of care.

Association between case volume of ambulance stations and clinical outcomes of out-of-hospital cardiac arrest: A nationwide multilevel analysis

ObjectivesThe case volume effects of ambulance stations on the survival of out-of-hospital cardiac arrest (OHCA) patients are uncertain. This study was conducted to evaluate the association between the case volume of ambulance stations and clinical outcomes in OHCAs by the number of emergency medical services (EMS) providers at the scene. MethodsAdult cardiac EMS-treated OHCAs between 2015 and 2018 were enrolled. The main exposure was the annual OHCA case volumes of 204 ambulance stations in Korea, which were categorized into three groups; low-volume (<100), moderate-volume (100–159) and high-volume (≥160). The primary and secondary outcomes were good neurological recovery and survival to discharge. Multilevel multivariable logistic regression analysis was conducted to calculate adjusted odds ratios (AORs). Interaction analysis between the number of EMS providers at the scene and the exposure variable was performed. ResultsA total of 92,534 patients were enrolled. OHCAs in the low-volume group tended to be arrest in a public place or a non-metropolitan area, less prehospital administration of an advanced airway and intravenous management. Significant differences were found the main analysis: AORs (95% CIs) compared to the low-volume group were 1.15 (1.03–1.29) and 1.14 (1.03–1.27) in the high-volume and moderate-volume groups for good neurological recovery and 1.19 (1.07–1.33) and 1.14 (1.04–1.25) in the high-volume and moderate-volume groups for survival to discharge. Significant interaction effects between the number of EMS providers at the scene and case volume on clinical outcomes were found. ConclusionOHCA case volumes of ambulance stations are associated with clinical outcomes after cardiac arrest.

Outcomes of Complex Gastrointestinal Cancer Resection at US News & World Report Top-Ranked vs Non-Ranked Hospitals

The US News & World Report (USNWR) annual ranking of the best hospitals for gastroenterology and gastrointestinal surgery offers direction to patients and healthcare providers, especially for recommendations on complex medical and surgical gastrointestinal (GI) conditions. The objective of this study was to examine the outcomes of complex GI cancer resections performed at USNWR top-ranked, compared to non-ranked, hospitals. Using the Vizient database, data for patients who underwent esophagectomy, gastrectomy, and pancreatectomy for malignancy between January and December 2018 were reviewed. Perioperative outcomes were analyzed according to USNWR rank status. Primary outcome was in-hospital mortality. Secondary outcomes include length of stay, mortality index (observed-to-expected mortality ratio), rate of serious complication, and cost. Secondary analysis was performed for outcomes of patients who developed serious complications. There were 3,054 complex GI cancer resections performed at 42 top-ranked hospitals vs 3,608 resections performed at 198 non-ranked hospitals. The mean annual case volume was 73 cases at top-ranked hospitals compared to 18 cases at non-ranked hospitals. Compared with non-ranked hospitals, top-ranked hospitals had lower in-hospital mortality (0.96% vs 2.26%, respectively, p< 0.001) and lower mortality index (0.71 vs 1.53, respectively). There were no significant differences in length of stay, rate of serious complications, or direct cost between groups. In patients who developed serious morbidity, top-ranked hospitals had a lower mortality compared with non-ranked hospitals (8.2% vs 16.8%, respectively, p < 0.01). Within the context of complex GI cancer resection, USNWR top-ranked hospitals performed a 4-fold higher case volume and were associated with improved outcomes. Patients with complex GI-related malignancies may benefit from seeking surgical care at high-volume regional USNWR top-ranked hospitals.

Risk-prediction Model for Patients Undergoing Laparoscopic Hysterectomy

Develop a model for predicting adverse outcomes at the time of laparoscopic hysterectomy (LH) for benign indications. Retrospective cohort study. Large academic center. All patients undergoing LH for benign indications at our institution between 2009 and 2017. LH (including robot-assisted and laparoscopically assisted vaginal hysterectomy) was performed per standard technique. Data about the patient, surgeon, perioperative adverse outcomes (intraoperative complications, readmission, reoperation, operative time >4 hours, and postoperative medical complications or length of stay >2 days), and uterine weight were collected retrospectively. Pathologic uterine weight was used as a surrogate for predicted preoperative uterine weight. The sample was randomly split, using a random sequence generator, into 2 cohorts, one for deriving the model and the other to validate the model. A total of 3441 patients were included. The rate of composite adverse outcomes was 14.1%. The final logistic regression risk-prediction model identified 6 variables predictive of an adverse outcome at the time of LH: race, history of laparotomy, history of laparoscopy, predicted preoperative uterine weight, body mass index, and surgeon annual case volume. Specifically included were race (97% increased odds of an adverse outcome for black women [95% confidence interval (CI), 34%-110%] and 34% increased odds of an adverse outcome for women of other races [95% CI, -11% to 104%] when compared with white women), history of laparotomy (69% increased odds of an adverse outcome [95% CI, 26%-128%]), history of laparoscopy (65% increased odds of an adverse outcome [95% CI, 21%-124%]), and predicted preoperative uterine weight (2.9% increased odds of an adverse outcome for each 100-g increase in predicted weight [95% CI, 2%-4%]). Body mass index and surgeon annual case volume also had a statistically significant nonlinear relationship with the risk of an adverse outcome. Thec-statistic values for the derivation and validation cohorts were 0.74 and 0.72, respectively. The model is best calibrated for patients at lower risk (<20%). The LH risk-prediction model is a potentially powerful tool for predicting adverse outcomes in patients planning hysterectomy.

Abstract P470: Annual Endovascular Treatment Procedural Volume and One Year Mortality in Acute Ischemic Stroke

Background: In-hospital and 30-day mortality, 3-month functional outcome were reported as associated with endovascular treatment (EVT) case volume per hospital, but one-year mortality was unknown. Furthermore, the hospital EVT volume threshold based on one-year mortality was not reported. We aimed to investigate whether there was a correlation between annual EVT case volume per hospital and one-year mortality and suggest volume threshold. Methods: Data from Korean national survey for assessing quality of acute stroke care were used. The survey was conducted since 2005 and the subject was patients with acute stroke who were admitted via emergency rooms within 7 days of onset at hospitals treating 10 or more stroke cases during the three (2013, 2014) or six (2016) month survey period. Ischemic stroke cases treated with EVT during the last available three assessments (2013, 2014, and 2016) were selected for the analysis. Results: A total of 1,746 ischemic stroke cases (age, 69.2 ± 12.4years; male, 56.6%) treated in 120 hospitals with EVT were analyzed. The median annual EVT case volume was 12.0 cases per hospital (interquartile range, 6.0-22.9) and the mortality at one-month, three-month, and one-year were 12.7%, 16.6%, and 23.3%, respectively. When divided into quartiles according to the annual EVT case volume, the lowest quartile group was found to have the highest one-year mortality (odds ratio [95% confidence intervals], 1.49 [1.04-2.13]), adjusted for age, sex, NIHSS, onset to arrival time. Restricted cubic splines performed on the annual EVT case volume per hospital revealed that cut-off value for the probability of one-year mortality was 15 cases per year ( p &lt;0.02) (Figure). Conclusions: There was an association between annual EVT case volume and one-year mortality, and the volume threshold per hospital based on the one-year mortality was found to be 15 EVT cases per year.

Contemporary Practices and Complications of Surgery for Thoracic Outlet Syndrome in the United States

Thoracic outlet syndrome (TOS) surgery is relatively rare and controversial, given the challenges in diagnosis as well as wide variation in symptomatic and functional recovery. Our aims were to measure trends in utilization of TOS surgery, complications, and mortality rates in a nationally representative cohort and compare higher versus lower volume centers. The National Inpatient Sample was queried using International Classification of Diseases, Ninth Revision, codes for rib resection and scalenectomy paired with axillo-subclavian aneurysm (arterial [aTOS]), subclavian deep vein thrombosis (venous [vTOS]), or brachial plexus lesions (neurogenic [nTOS]). Basic descriptive statistics, nonparametric tests for trend, and multivariable hierarchical regression models with random intercept for center were used to compare outcomes for TOS types, trends over time, and higher and lower volume hospitals, respectively. There were 3,547 TOS operations (for an estimated 18,210 TOS operations nationally) performed between 2010 and 2015 (89.2% nTOS, 9.9% vTOS, and 0.9% aTOS) with annual case volume increasing significantly over time (P=0.03). Higher volume centers (≥10 cases per year) represented 5.2% of hospitals and 37.0% of cases, and these centers achieved significantly lower overall major complication (defined as neurologic injury, arterial or venous injury, vascular graft complication, pneumothorax, hemorrhage/hematoma, or lymphatic leak) rates (adjusted odds ratio [OR] 0.71 [95% confidence interval 0.52-0.98]; P=0.04], but no difference in neurologic complications such as brachial plexus injury (aOR 0.69 [0.20-2.43]; P=0.56) or vascular injuries/graft complications (aOR 0.71 [0.0.33-1.54]; P=0.39). Overall mortality was 0.6%, neurologic injury was rare (0.3%), and the proportion of patients experiencing complications decreased over time (P=0.03). However, vTOS and aTOS had >2.5 times the odds of major complication compared with nTOS (OR 2.68 [1.88-3.82] and aOR 4.26 [1.78-10.17]; P<0.001), and ∼10 times the odds of a vascular complication (aOR 10.37 [5.33-20.19] and aOR 12.93 [3.54-47.37]; P<0.001], respectively. As the number of complications decreased, average hospital charges also significantly decreased over time (P<0.001). Total hospital charges were on average higher when surgery was performed in lower volume centers (<10 cases per year) compared with higher volume centers (mean $65,634 [standard deviation 98,796] vs. $45,850 [59,285]; P<0.001). The annual number of TOS operations has increased in the United States from 2010 to 2015, whereas complications and average hospital charges have decreased. Mortality and neurologic injury remain rare. Higher volume centers delivered higher value care: less or similar operative morbidity with lower total hospital charges.

The relationship between cardiac surgeon experience and average patient risk profile: CA and NY statewide analysis.

It is unknown how high and low-risk cases are distributed among cardiac surgeons of different experience levels. The purpose of this study was to determine if high and low-risk coronary artery bypass grafting (CABG) cases are distributed among surgeons in such a way that would optimize outcomes in light of recent studies that show mid-career surgeons may obtain better patient outcomes on more complex cases. We performed a cross-sectional study using aggregated New York (NY) and California (CA) statewide surgeon-level outcome data, including 336 cardiac surgeons who performed 43,604 CABGs. The surgeon observed and expected mortality rates (OMR and EMR) were collected and the number of years-in-practice was determined by searching for surgeon training history on online registries. Loess and linear regression models were used to characterize the relationship between surgeon EMR and surgeon years-in-practice. The median number of surgeon years-in-practice was 20 (interquartile range [IQR] 11-28) with a median annual case volume of 46 (IQR 19, 70.25). The median surgeon observed to expected mortality (O:E) ratio was 0.87 (IQR 0.19-1.4). Median EMR for CA surgeons was 2.42% and 1.44% for NY surgeons. Linear regression models showed EMR was similar across years in practice. Regression models also showed surgeon O:E ratios were similar across years-in-practice. High and low-risk CABG cases are relatively equally distributed among surgeons of differing experience levels. This equal distribution of high and low-risk cases does not reflect a triaging of more complex cases to more experienced surgeons, which prior research shows may optimize patient outcomes.

Vitreoretinal surgeons' experience and time interval from pars-plana vitrectomy to cataract extraction.

To identify the association of the vitreoretinal surgeons' experience with the time interval between pars-plana vitrectomy (PPV) and cataract extraction (CE). Eyes with prior PPV and following CE were included in this retrospective cohort study. The years of practice and the annual case volume were used to describe the surgeons' experience. Multivariable linear regression analysis was used to investigate the relationship between surgeons' experience and the time interval adjusted for the patients age, gender, intraocular tamponade, and case complexity. Of 132 430 eyes, 1445 eyes were included in this study. In multivariable linear regression analysis, cases performed by surgeons with >20 practice years had longer time intervals compared with surgeons with <10 practice years after adjusted for other variables (β=0.329, 95%CI: 0.113 to 0.549, P=0.003). No difference in time interval was detected for comparing the lowest with the highest volume groups (β=0.089, 95%CI: -0.164 to 0.343, P=0.343). The surgeons' practice years were not directly with the volume. For complicated surgery, the higher-practice-year surgeons had longer time interval than lower-practice-year surgeons. The time intervals from PPV to CE is longer in higher-practice-year surgeons. The surgeons' practice years may have a greater effect on the time interval than annual case volume in high-complexity cases. Matching the complexity of vitreoretinal diseases with the surgeons' practice year should be considered.

Effect of institutional case volume on mid-term mortality after coronary artery bypass grafting surgery.

The impact of center case volume on mid-term postoperative outcome after coronary artery bypass grafting surgery (CABG) is still controversial and requires investigation. The aim of this study was to compare mid-term survival after CABG according to the institutional annual CABG case volume. Adult patients (≥ 18years) who underwent CABG from 2009 to 2016 were identified by searching National Health Insurance database of Korea for CABG procedure codes. Hospitals were classified into three groups based on annual case volume; low-volume centers (< 20 cases/year), medium-volume centers (20-50 cases/year), and high-volume centers (> 50 cases/year). A total of 22,575 CABG were performed in 95 centers during the study period, and 14,697 (65.1%) cases performed at 15 high-volume centers, 5,262 (23.3%) cases at 26 medium-volume centers, and 2,616 (11.6%) cases at 54 low-volume centers. The overall 1-year mortality rate was the lowest in high-volume centers (6.5%), followed by medium-volume centers (10.6%) and low-volume centers (15.2%). Logistic regression identified medium-volume centers (adjusted OR 1.30 [95% CI 1.15-1.49], P < 0.01) and low-volume centers (adjusted OR 1.75 [95% CI 1.51-2.03], P < 0.01) as risk factors for 1-year mortality after CABG compared to high-volume centers. In the Cox proportional hazard model, low- and medium-volume centers were significantly risk factors for poor survival (adjusted HR 1.41 [95% CI 1.31-1.54], P < 0.01 and HR 1.26 [95% CI 1.17-1.35], P < 0.01 for low- and medium-volume centers, respectively). Higher institutional case volume of CABG was associated with lower mid-term mortality.

Establishment of an endoscopic retrograde cholangiopancreatography (ERCP) program in rural Kenya: a review of patient and trainee outcomes.

Endoscopic retrograde cholangiopancreatography (ERCP) is a leading modality for treatment of biliary and pancreatic disease but is not widely available in sub-Saharan Africa. We aimed to assess the development and outcomes of an ERCP service in southwestern Kenya, including case volumes, success rates, infrastructure, and training. We conducted a retrospective review of all ERCPs performed at Tenwek Hospital in Bomet, Kenya between January 1, 2011 and March 31, 2020. In total 277 ERCP procedures were attempted during the study period. The commonest indication was obstructive jaundice: 91 patients (32.9%) had malignancy and 85 (30.7%) had choledocholithiasis. Overall clinical success rate was 76.1% and was the highest in patients with biliary stones (81.2%) and lowest in those with tumors (73.5%) (p = 0.094). Procedure-related adverse events occurred in 11.9%, including post-ERCP pancreatitis in 3.6%, with a procedure-related mortality rate of 1.4%. Annual case volumes increased, and mean procedure duration decreased from 162 to 115min (p = 0.0007) over time. A previously- rained endoscopist initially performed all cases; two staff endoscopists were trained in ERCP during the study period, performing 130 and 89 ERCPs during training, with clinical success rates of 84% and 74% during their subsequent independent practice. An ERCP service can be successfully developed at a rural African hospital, with acceptable success and adverse event rates. Biliary obstruction due to stones or tumors are the most common findings. While a previously trained endoscopist should initiate and champion the service, staff endoscopists can be successfully trained despite limited case volumes.

Hospital Case Volume, Health Care Providers, and Mortality in Patients Undergoing Coronary Artery Bypass Grafting: a Nationwide Cohort Study in South Korea.

Surgical quality is evaluated by measuring the annual hospital case volume; a higher case volume is associated with better survival after various surgeries. We aimed to investigate if the annual hospital case volume and the health care providers were associated with a 90-day mortality after coronary artery bypass grafting (CABG). For this population-based cohort study, we used data from a National Health Insurance Service database in South Korea. We included all adult patients diagnosed with ischemic heart disease who underwent isolated CABG between January 2012 and December 2017. Data on the annual surgical volume for CABG in each hospital where the patients received CABG and the total number of health care providers (including physicians [trainees and specialists] from all department of the hospitals, nurses, and pharmacists) were collected. The final analysis included 15,790 adult patients; of these, 1,039 (6.6%) died within 90 days. The annual CABG volume was divided into 4 groups (Q1: ≤33, Q2: 34-86, Q3: 87-223, and Q4: ≥224). Multivariable Cox regression analysis revealed that the 90-day mortality rates in the Q4, Q3, Q2 groups were 75%, 32%, and 31% lower than that in the Q1 group, respectively. Additionally, an increase in the ratio of the total number of specialist physicians to 100 hospital beds was associated with a 4% decrease in the 90-day mortality after CABG. Both, a higher annual hospital case volume and overall specialist physician volume were associated with better 90-day mortality rates after isolated CABG.

M19 Case Volume, Demographics and Surgical Risk Trends of Patients Undergoing Surgical and Transcatheter Aortic Valve Replacement

The indications for transcatheter aortic valve replacement (TAVI) for the treatment of aortic valve disease are expanding and the number of TAVIs performed in Australia is increasing accordingly. Our institution has one of the longest standing TAVI programs in Australia. This study aims to compare the patient demographics, annual case volumes and surgical risk scores of patients undergoing surgical aortic valve replacement (SAVR) and TAVI since the introduction of a TAVI program at our institution.

Google trends as a tool for evaluating public interest in total knee arthroplasty and total hip arthroplasty

There are approximately 1 million total knee arthroplasty (TKA) and total hip arthroplasty (THA) procedures performed annually in the United States. With this number projected to increase, it is vital for orthopedic surgeons and health-care systems to properly anticipate healthcare utilization related to TKA and THA. Google Trends (GT) is a free, open source tool that provides customizable analysis of search terms entered into the Google search engine. We aim to explore the relationship between public interest in TKA and THA as determined by GT data and volume of TKA and THA procedures. GT data were compiled for ten search terms related to TKA and ten search terms related to THA from January 2009 to December 2017. Annual case volumes for TKA/THA procedures were obtained from the Healthcare Cost and Utilization Project National Inpatient Sample from 2009 to 2017. Trend analysis was performed using univariate linear regression of GT data and TKA/THA case volumes. There was a statistically significant positive correlation between GT data and procedure volume for 14 of the 20 search terms studied. Seven TKA-related search terms with a positive correlation to procedure volumes include "total knee replacement," "knee replacement," "knee osteoarthritis," "knee ache," "knee swelling," "knee stiffness," and "chronic knee pain." Seven THA-related search terms with a positive correlation to procedure volumes include "hip arthroplasty," "total hip replacement," "hip replacement," "hip osteoarthritis," "hip ache," "hip swelling," and "chronic hip pain." GT may provide a high utility as a convenient and informative data set for orthopedic surgeons to analyze public interest in TKA and THA procedures. The data provided by GT have the potential to provide real-time, actionable information that may help surgeons and health systems to characterize public interest in TKA and THA and to best identify and address patient needs. The GT tool can be used to measure public interest in TKA/THA, which can inform physician expectations for the patient encounter and lead to the creation of decision aids that better inform the public about the risks and benefits of TKA/THA.