High-volume Group Research Articles

Open approach to the ventral transversus abdominis plane in the dog: evaluation and injectate dispersion in cadavers

ObjectiveTo evaluate a direct intra-abdominal approach to injection of the ventral transversus abdominis plane (TAP) and compare the dispersion of two volumes of injectate. Study designProspective anatomic and feasibility study. AnimalsA total of 10 canine cadavers weighing 9 ± 4 kg. MethodsA ventral incision was made extending through the linea alba, from the umbilicus and extending 5 cm caudally. A single injection of an isovolumic mixture of iopamidol and new methylene blue was performed with a hypodermic needle placed within the TAP of each hemiabdomen, alternating between 0.5 mL kg–1 in low-volume group (LV) and 1 mL kg–1 in high-volume group (HV). Surgical staples marked the incision. Computed tomography and three-dimensional reconstruction of the tomographic images evaluated the dimensions, cranial and caudal spread beyond the incision and the total area of the injectate. Dissection determined the extent of nerve staining within the TAP adjacent to the abdominal incision. Wilcoxon signed rank (stain) or paired t test was used to compare variables between groups. Data are reported as mean ± standard deviation or median (range). ResultsInjectate spread was within the ventral TAP. Length of spread was 2.5 ± 1.6 cm greater in group HV than in group LV. There was a strong positive correlation between the surface area (p = 0.02, r = 0.71) and cranial–caudal spread of injectate (p = 0.041, r = 0.65) with volume.All but two LV injections were associated with staining of all nerves adjacent to the incision. Additional nerves caudal to the incision were stained in group HV (p = 0.02). ConclusionsThis approach to the TAP was easily performed, with volume of injectate positively influencing distribution. Clinical relevanceThis technique is easily applied and future prospective studies are warranted to determine its analgesic efficacy.

Association of surgeon and hospital volume with short-term outcomes after robot-assisted radical prostatectomy: Nationwide, population-based study.

Background and objectiveFew studies have investigated the association between surgical volume and outcome of robot-assisted radical prostatectomy (RARP) in an unselected cohort. We sought to investigate the association between surgical volume with peri-operative and short-term outcomes in a nation-wide, population-based study group.Methods9,810 RARP’s registered in the National Prostate Cancer Register of Sweden (2015–2018) were included. Associations between outcome and volume were analyzed with multivariable logistic regression including age, PSA-density, number of positive biopsy cores, cT stage, Gleason score, and extent of lymph node dissection.ResultsSurgeons and hospitals in the highest volume group compared to lowest group had shorter operative time; surgeon (OR 9.20, 95% CI 7.11–11.91), hospital (OR 2.16, 95% CI 1.53–3.06), less blood loss; surgeon (OR 2.58. 95% CI 2.07–3.21) hospital (no difference), more often nerve sparing intention; surgeon (OR 2.89, 95% CI 2.34–3.57), hospital (OR 2.02, 95% CI 1.66–2.44), negative margins; surgeon (OR 1.90, 95% CI 1.54–2.35), hospital (OR 1.28, 95% CI 1.07–1.53). There was wide range in outcome between hospitals and surgeons with similar volume that remained after adjustment.ConclusionsHigh surgeon and hospital volume were associated with better outcomes. The range in outcome was wide in all volume groups, which indicates that factors besides volume are of importance. Registration of surgical performance is essential for quality control and improvement.

Prognostic impact of bone metastatic volume beyond vertebrae and pelvis in patients with metastatic hormone-sensitive prostate cancer

Although bone metastasis beyond the vertebrae and pelvis has been a key factor in prognostic models of metastatic hormone-sensitive prostate cancer (mHSPC), the clinical significance of it is still unclear. The present study evaluated the prognostic impact of the volume of bone metastasis beyond the vertebrae and pelvis on the outcomes of mHSPC and created an ideal risk classification based on it. We retrospectively reviewed 197 patients with mHSPC who were treated with combined androgen blockade as the initial treatment between June 2003 and October 2019. We calculated the bone scan index (BSI), including the BSI beyond the vertebrae and pelvis (bBSI), using BONENAVI, and investigated the association between the BSI and the overall survival (OS) of mHSPC. According to the CHAARTED criteria, 91 and 106 patients were classified into the low- and high-volume groups, respectively. Of the 79 patients who did not have visceral metastasis in the high-volume group, those with a bBSI ≤ 0.27 (n = 16) showed a favorable OS, as did those in the low-volume group. The modified CHAARTED high-volume group (presence of visceral metastases or 4 bone lesions with a bBSI > 0.27) showed a significantly shorter OS than others, with a hazard ratio (HR) of 4.69 (p < 0.001), which was higher than that observed with the original CHAARTED criteria (HR = 4.33). Our data suggested that considering the volume of bone metastasis beyond the vertebrae and pelvis may help to improve the accuracy of risk classification. Further large-scale prospective studies are needed to validate our findings.

Patients with undetectable PSA 2 years after docetaxel for metastatic castration sensitive prostate cancer (mCSPC).

e17044 Background: Patients with mCPSC have multiple treatment options to combine with androgen deprivation therapy (ADT) including docetaxel, abiraterone, enzalutamide and apalutamide, all of which have demonstrated a survival advantage. While oral anti-androgens are administered daily until progression but are less toxic, docetaxel has more upfront side effects. One of the advantages of using docetaxel is that the 6-cycle regimen (over approximately 4 months) potentially affords patients a respite from daily therapies thereafter. Furthermore, docetaxel may be more cost-effective. In this prospective study, mCSPC patients were treated with docetaxel and Prostvac, a therapeutic cancer vaccine. Since this study was initiated, Prostvac did not demonstrate independent clinical activity in a phase 3 trial in metastatic castration resistant prostate cancer. Nonetheless, this study provides an opportunity to evaluate responses to docetaxel-based therapy in mCSPC. Methods: Eligible patients included those with mCSPC and ECOG of ≤ 2. All patients were treated with docetaxel and were planned to receive 75mg/m2 for 6 cycles within 4 months of starting ADT, as per the CHAARTED regimen. Patients were randomized to receive Prostvac prior to, concurrent with or after docetaxel. Patients were restaged annually with CT and Tc99 bone scan. The study was powered to evaluate immunologic responses, which is ongoing. For the purposes of this analysis, all patients were analyzed as one group and long-term PSA responses were evaluated. Results: The study enrolled 73 patients. Age range was 41-86 with a median of 63 years. Race distribution was 71.6% White, 20.3% Black, 4.1% other, and 4.1% unknown. Gleason scores were 6 (4.1%), 7 (21.6%), and 8-10 (68.9%), with 5.4% being unknown. Median pre-ADT PSA was 34.75 ng/mL. Low-volume disease represented 41.1% of patients and high-volume was 58.9%. After 2 years from the start of ADT, 22% of all patients had PSA values of ≤ 0.2 ng/mL. This included 37% of the low-volume group and 12% of the high-volume group. Three years from the start of ADT, 14% of all patients had PSA values ≤ 0.2 ng/mL (20% of the low-volume group, 9% of the high-volume group). Conclusions: These data highlight long-term outcomes of 6 cycles of docetaxel for men with mCSPC. Although there are concerns about the short-term toxicity of docetaxel, there is potential for prolonged stable disease after ̃4 months of chemotherapy that allows these patients to defer additional oral anti-androgen therapy for years in some patients. The proportions of patients presented here are an underestimate of those who could continue to be monitored for slowly rising, but low PSAs, before starting the next line of therapy. Additional research is required to determine the optimal therapeutic sequence for men diagnosed with mCSPC and long-term implications for quality of life and cost-effectiveness. Clinical trial information: NCT02649855.

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.

Housework is Associated with Better Cognitive, Physical and Sensorimotor Functions in Community-Dwelling Older Adults – the Yishun Study

Background: Regular moderate-to-vigorous intensity recreational physical activity (PA) protects against ill health. The relationship between non-recreational PA with ageing health is less explored, especially in high income countries. We examined the associations between housework and functional health among younger and older Singaporean community-dwelling adults. Methods: Younger (<65yrs,n=249) and older (≥65yrs,n=240) adults were randomly recruited cross-sectionally from a large Singapore residential town. Light (LH) and heavy housework (HH), recreational, occupational and transport-related PA were assessed using PA questionnaires. Participants were dichotomised into low- and high-volume LH and HH groups. Physical, cognitive and sensorimotor functions were measured using Short Physical Performance Battery, repeated-chair-sit-to-stand, gait speed, Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) and Physiological Profile Assessment (PPA). Results were adjusted for level of recreational and other non-recreational PA. Findings: High housework groups had 5–8% higher RBANS score than low housework groups, among older adults only. Specifically, HH was associated with 14% higher attention score, and LH with 8–12% higher immediate/delayed memory scores. In older adults, sit-to-stand-time and PPA scores were 8% and 23% lower in high HH than low HH group. SPPB and gait speed did not differ with age or HH. LH was not associated with physical or sensorimotor function. Interpretation: Among older adults, housework is associated with better cognitive function, specifically in attention and memory. Associations between housework with physical and sensorimotor performance were intensity-dependent. In Singapore, housework PA may improve functional health among community-dwelling older adults, independent of recreation and other non-recreational physical activities. Funding: Geriatric Education and Research Institute, Singapore Declaration of Interest: The authors declare that they have no competing interests. Ethical Approval: Ethics approval was obtained from the National Healthcare Group DSRB (2017/00212), in accordance with the relevant guidelines from the Declaration of Helsinki and the ethical principles in the Belmont Report.

Perioperative blood transfusion decreases long-term survival in pediatric living donor liver transplantation

BACKGROUNDThe impact of perioperative blood transfusion on short- and long-term outcomes in pediatric living donor liver transplantation (PLDLT) must still be ascertained, mainly among young children. Clinical and surgical postoperative complications related to perioperative blood transfusion are well described up to three months after adult liver transplantation.AIMTo determine whether transfusion is associated with early and late postoperative complications and mortality in small patients undergoing PLDLT.METHODSWe evaluated the effects of perioperative transfusion on postoperative complications in recipients up to 20 kg of body weight, submitted to PLDLT. A total of 240 patients were retrospectively allocated into two groups according to postoperative complications: Minor complications (n = 109) and major complications (n = 131). Multiple logistic regression analysis identified the volume of perioperative packed red blood cells (RBC) transfusion as the only independent risk factor for major postoperative complications. The receiver operating characteristic curve was drawn to identify the optimal volume of the perioperative RBC transfusion related to the presence of major postoperative complications, defining a cutoff point of 27.5 mL/kg. Subsequently, patients were reallocated to a low-volume transfusion group (LTr; n = 103, RBC ≤ 27.5 mL/kg) and a high-volume transfusion group (HTr; n = 137, RBC > 27.5 mL/kg) so that the outcome could be analyzed.RESULTSHigh-volume transfusion was associated with an increased number of major complications and mortality during hospitalization up to a 10-year follow-up period. During a short-term period, the HTr showed an increase in major infectious, cardiovascular, respiratory, and bleeding complications, with a decrease in rejection complications compared to the LTr. Over a long-term period, the HTr showed an increase in major infectious, cardiovascular, respiratory, and minor neoplastic complications, with a decrease in rejection complications. Additionally, Cox hazard regression found that high-volume RBC transfusion increased the mortality risk by 3.031-fold compared to low-volume transfusion. The Kaplan-Meier survival curves of the studied groups were compared using log-rank tests and the analysis showed significantly decreased graft survival, but with no impact in patient survival related to major complications. On the other hand, there was a significant decrease in both graft and patient survival, with high-volume RBC transfusion.CONCLUSIONTransfusion of RBC volume higher than 27.5 mL/kg during the perioperative period is associated with a significant increase in short- and long-term postoperative morbidity and mortality after PLDLT.

Impact of Individual Surgeon Volume on Outcomes Following LVAD Implantation

<h3>Purpose</h3> Surgeon volume affects outcomes of complex operations. However, it is not clear if individual surgeon volume in a large volume program affects left ventricular assist device (LVAD) outcomes. <h3>Methods</h3> We reviewed primary LVAD implants at our center between 2013 and 2020. Cases were dichotomized into a high-volume group (surgeons averaging more than 10 LVAD cases per year), and a low-volume group (10 or less cases per year). Propensity score matching was performed. Survival and incidence of major adverse events were compared; predictors of survival were identified with multivariable analysis. <h3>Results</h3> There were 315 patients who met inclusion criteria- 45 implants in the low-volume group, 270 in the high-volume group. In the propensity matched cohort, there was no difference in survival to hospital discharge between the low (91.9%) and high (91.7%) volume groups (p=1). Survival at 1-year was also similar between the groups (85.4% vs 88.6%, p=0.732). There was no difference in the incidence of major adverse events between the groups. Predictors of mortality in the first year included: age (Hazards Ratio [HR] 1.061, p<0.001), prior sternotomy (HR 1.991, p=0.014), elevated INR (HR 4.748, p<0.001), higher AST (HR 1.001, p=0.001), higher bilirubin (HR 1.081, p=0.014), and pre-operative mechanical ventilation (HR 2.662, p=0.005). Individual surgeon volume was not an independent predictor of discharge or one-year survival. <h3>Conclusion</h3> There was no difference in survival or adverse events between high and low volume surgeons suggesting that, in an experienced center, low-volume VAD surgeons can achieve similar outcomes to their high-volume colleagues.

Association Between Anesthesiologist Volume and Short-term Outcomes in Complex Gastrointestinal Cancer Surgery

Intraoperative anesthesiology care is crucial to high-quality surgical care. The clinical expertise and experience of anesthesiologists may decrease the risk of adverse outcomes. To examine the association between anesthesiologist volume and short-term postoperative outcomes for complex gastrointestinal (GI) cancer surgery. This population-based cohort study used administrative health care data sets from various data sources in Ontario, Canada. Adult patients who underwent esophagectomy, pancreatectomy, or hepatectomy for GI cancer from January 1, 2007, to December 31, 2018, were eligible. Patients with an invalid identification number, a duplicate surgery record, and missing primary anesthesiologist information were excluded. Primary anesthesiologist volume was defined as the annual number of procedures of interest (esophagectomy, pancreatectomy, and hepatectomy) supported by that anesthesiologist in the 2 years before the index surgery. Volume was dichotomized into low-volume and high-volume categories, with 75th percentile or 6 or more procedures per year selected as the cutoff point. The primary outcome was a composite of 90-day major morbidity (with a Clavien-Dindo classification grade 3-5) and readmission. Secondary outcomes were individual components of the primary outcome. The association between exposure and outcomes was examined using multivariable logistic regression models, accounting for potential confounders. Of the 8096 patients included, 5369 were men (66.3%) and the median (interquartile range [IQR]) age was 65 (57-72) years. Operations were supported by 842 anesthesiologists and performed by 186 surgeons, and the median (IQR) anesthesiologist volume was 3 (1.5-6) procedures per year. A total of 2166 patients (26.7%) received care from high-volume anesthesiologists. Primary outcome occurred in 36.3% of patients in the high-volume group and 45.7% of patients in the low-volume group. After adjustment, care by high-volume anesthesiologists was independently associated with lower odds of the primary outcome (adjusted odds ratio [aOR], 0.85; 95% CI, 0.76-0.94), major morbidity (aOR, 0.83; 95% CI, 0.75-0.91), unplanned intensive care unit admission (aOR, 0.84; 95% CI, 0.76-0.94), but not readmission (aOR, 0.87; 95% CI, 0.73-1.05) or mortality (aOR, 1.05; 95% CI, 0.84-1.31). E-values analysis indicated that an unmeasured variable would unlikely substantively change the observed risk estimates. This study found that, among adults who underwent complex gastrointestinal cancer surgery, those who received care from high-volume anesthesiologists had a lower risk of adverse postoperative outcomes compared with those who received care from low-volume anesthesiologists. These findings support organizing perioperative care to increase anesthesiologist volume to optimize patient outcomes.

Dose-response effects of aerobic exercise on adiposity markers in postmenopausal women: pooled analyses from two randomized controlled trials.

Exercise may reduce the risk of breast cancer through adiposity changes, but the dose-response effects of exercise volume on adiposity markers are unknown in postmenopausal women. We aimed to compare the dose-response effects of prescribed aerobic exercise volume on adiposity outcomes. Data from the Alberta Physical Activity and Breast Cancer Prevention (ALPHA) and Breast Cancer and Exercise Trial in Alberta (BETA) were pooled for this analysis (N = 720). These were 12-month randomized controlled trials, where participants were randomized to 225 min/week (mid-volume) of aerobic exercise versus usual inactive lifestyle (ALPHA), or 150 min/week (low-volume) versus 300 min/week (high-volume) (BETA). Fat mass and fat-free mass were measured using DXA and intra-abdominal and subcutaneous fat area were assessed with computed tomography. After 12 months of aerobic exercise, increasing exercise volumes from no exercise/control to 300 min/week resulted in statistically significant reductions in BMI, weight, fat mass, fat percentage, intra-abdominal and subcutaneous fat area (P < 0.001). Compared with controls, fat mass loss was -1.13, -1.98 and -2.09 kg in the low-, mid- and high-volume groups, respectively. Similarly, weight loss was -1.47, -1.83, -2.21 kg in the low-, mid- and high-volume groups, respectively, compared to controls, and intra-abdominal fat area loss was -7.44, -15.56 and -8.76 cm2 in the low-, mid- and high-volume groups, respectively, compared to controls. No evidence for a dose-response effect on fat-free mass was noted. A dose-response effect of exercise volume on adiposity markers was noted, however, the differences in adiposity markers were smaller when comparing 225 min/week to 300 min/week of exercise. Given the strong positive associations between obesity and postmenopausal breast cancer risk, this study provides evidence on the importance of exercise volume as part of the exercise prescription to reduce adiposity and, ultimately, postmenopausal breast cancer risk.

Association between hospital surgical volume and complications after total hip arthroplasty in femoral neck fracture: A propensity score-matched cohort study

BackgroundFor displaced femoral neck fractures (FNF), total hip arthroplasty (THA) or hemiarthroplasty (HA) is preferred rather than fracture fixation. THA for patients with FNF requires skilled operators since patient with FNF likely to have osteoporosis and a higher risk of complications. Several reports suggest that higher hospital surgical volume was associated with a lower risk of complications after THA for osteoarthritis. However, little is known concerning this association with THA for FNF. Herein, we investigated the association between THA and complication and the recovery of physical function after THA to optimize the quality of FNF. MethodsA nationwide retrospective cohort study of elderly undergoing THA between April 1, 2011, to March 31, 2018 was performed. The association between hospital surgical volume and complication after THA for FNF was visually described with the restricted cubic spline regression analysis. Then the risk of complications was quantified with propensity score matching analysis based on the cutoff point identified by the restricted cubic spline curve. Primary outcome was secondary revision surgery, and the secondary outcomes included surgical and systemic complications, and the recovery of physical function at hospital discharge. ResultsBy visualization of the spline curve, we identified 20 cases per year as cutoff point of low hospital surgical volume. Following 1,396 patients’ propensity score-match analysis (mean age 75.2 [SD] 8.8, female 80.4%), the risk of secondary revision surgery was significantly higher among the low hospital surgical volume group (absolute risk difference (RD), 2.44%; p = 0.011). Also, the incidence of blood transfusion was higher in the low hospital surgical volume group (RD, 4.01%; p = 0.049). However, there was no significant difference in the recovery of the transferring and walking ability at discharge between high and low hospital surgical volume groups (63.5% vs 62.6%, 58.5% vs 57.5%; p = 0.74, 0.71, respectively). ConclusionOur research demonstrated that an increase in hospital surgical volume significantly reduced the incidence of secondary revision surgery after a certain inflection point, but not significantly improved short-term physical functions.

Overall Complication Rates of DIEP Flap Breast Reconstructions in Germany-A Multi-Center Analysis Based on the DGPRÄC Prospective National Online Registry for Microsurgical Breast Reconstructions.

While autologous breast reconstruction has gained momentum over recent years, there is limited data on the structure and quality of care of microsurgical breast reconstruction in Germany. Using the breast reconstruction database established by the German Society of Plastic, Reconstructive and Aesthetic Surgeons (DGPRÄC), the presented study investigated the overall outcomes of deep inferior epigastric perforator (DIEP) flap reconstructions in Germany. Data of 3926 patients and 4577 DIEP flaps performed by 22 centers were included in this study. Demographics, patient characteristics, perioperative details and postoperative outcomes were accounted for. Centers performing < Ø 40 (low-volume (LV)) vs. ≥ Ø 40 (high-volume (HV)) annual DIEP flaps were analyzed separately. Overall, total and partial flap loss rates were as low as 2.0% and 1.1% respectively, and emergent vascular revision surgery was performed in 4.3% of cases. Revision surgery due to wound complications was conducted in 8.3% of all cases. Mean operative time and length of hospital stay was significantly shorter in the HV group (LV: 385.82 min vs. HV: 287.14 min; LV: 9.04 (18.87) days vs. HV: 8.21 (5.04) days; both p < 0.05). The outcome and complication rates deduced from the national registry underline the high standard of microsurgical breast reconstruction on a national level in Germany.

Redefining High-Volume Gastric Cancer Centers: The Impact of Operative Volume on Surgical Outcomes.

Performance of technically complex surgery at high-volume (HV) centers is associated with improved outcomes. The aim of this study was to assess whether hospital gastrectomy volume is associated with surgical outcomes, and what threshold of case volume meaningfully impacts surgical outcomes. We conducted a retrospective review of adult NCDB patients with gastric adenocarcinoma undergoing gastrectomy between 2004 and 2015. A multivariable Cox proportional hazards model with restricted cubic splines was used to examine the association of annual hospital gastrectomy volume and overall survival. Bootstrap simulation was used to estimate the cut-point corresponding to maximum change in log hazard ratio. Hospitals were divided into HV (≥ 17cases/year) and low-volume (LV; < 17cases/year) groups. We examined the relationship between volume groups and adequate nodal examination, R0 resection, unplanned readmission, and 30- and 90-day mortality. Our cohort consisted of 29,559 patients (7.8% treated at an HV center). Treatment at an HV center was associated with an increased likelihood of adequate nodal examination [odds ratio (OR) 2.12, 95% confidence interval (CI) 1.94-2.32] and R0 resection among patients with cardia tumors (OR 1.42, 95% CI 1.07-1.88). Patients treated at HV centers had decreased 30- and 90-day postoperative mortality, which was more pronounced in those undergoing total gastrectomy. Treatment at an HV gastrectomy center is associated with improved surgical outcomes. Our study identified 17cases/year as a clinically meaningful distinction between HV and LV centers. This definition of an HV center should be considered when evaluating regionalization of gastric cancer care to improve patient outcomes.

Impact of hospital volume on clinical outcomes of hospitalized heart failure patients: analysis of a nationwide database including 447,818 patients with heart failure

BackgroundHospital volume is known to be associated with outcomes of patients requiring complicated medical care. However, the relationship between hospital volume and prognosis of hospitalized patients with heart failure (HF) remains not fully understood. We aimed to clarify the impact of hospital volume on clinical outcomes of hospitalized HF patients using a nationwide inpatient database.Methods and resultsWe studied 447,818 hospitalized HF patients who were admitted from January 2010 and discharged until March 2018 included in the Japanese Diagnosis Procedure Combination database. According to the number of patients, patients were categorized into three groups; those treated in low-, medium-, and high-volume centers. The median age was 81 years and 238,192 patients (53%) were men. Patients who had New York Heart Association class IV symptom and requiring inotropic agent within two days were more common in high volume centers than in low volume centers. Respiratory support, hemodialysis, and intra-aortic balloon pumping were more frequently performed in high volume centers. As a result, length of hospital stay was shorter, and in-hospital mortality was lower in high volume centers. Lower in-hospital mortality was associated with higher hospital volume. Multivariable logistic regression analysis fitted with generalized estimating equation indicated that medium-volume group (Odds ratio 0.91, p = 0.035) and high-volume group (Odds ratio 0.86, p = 0.004) had lower in-hospital mortality compared to the low-volume group. Subgroup analysis showed that this association between hospital volume and in-hospital mortality among overall population was seen in all subgroups according to age, presence of chronic renal failure, and New York Heart Association class.ConclusionHospital volume was independently associated with ameliorated clinical outcomes of hospitalized patients with HF.

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.

Super-activated CNB for CO2 capture: The development of the nitrogen containing porous carbon by chlorination and post KOH-activation

Minimization of carbon dioxide (CO2) emissions into the atmosphere is a prerequisite to solving climate change. Tremendous research has been conducted to capture the CO2 from pre- and post-combustion using nanoporous materials. Nitrogen-doped porous carbon is one of the most promising CO2 adsorbents. Achieving high nitrogen content and high micropore volume is essential to CO2 adsorption properties. In this study, super activated nitrogen and boron co-doped porous carbons (K-CNBs) are successfully synthesized by the chlorination and the subsequent KOH chemical activation. Nitrogen and boron co-doped porous carbons (CNBs) are synthesized by the chlorination of titanium carbonitride and boride mixture. CNBs good thermal and oxidation stability that induces an increase in the nitrogen content as well as an increase in the micropore volume even after the activation. K-CNBs, having both high micropore volume and abundant pyridonic-N functional group, show superior CO2 uptake at ambient temperature at atmospheric pressure with excellent CO2/N2 selectivity. K-CNBs are the best CO2 capturer among the nitrogen-containing carbon materials, reaching the threshold of CO2 uptakes performance.

Abstract 14579: Impact of Hospital MitraClip Volume on Short-term Outcomes of Transcatheter Mitral Valve Replacement

Introduction: Transcatheter mitral valve replacement (TMVR) is an alternative to surgical mitral valve replacement for patients at prohibitive or high surgical risk. Both transseptal TMVR and MitraClip procedures require transseptal puncture and subsequent manipulation of a catheter within the left atrium and ventricle. Hypothesis: Higher MitraClip experience leads to better procedural outcomes of transseptal TMVR. Methods: We retrospectively identified patients who underwent transseptal-TMVR using the Nationwide Readmissions Database 2016-2017. We defined hospital volume as the annual number of MitraClip cases in each hospital and categorized hospitals into high- (≥26 cases/year) and low- (&lt;26 cases/year) volume groups by the median value. We compared the in-hospital and 30-day outcomes between the two groups. Results: A total of 1,023 TMVR patients (median 74 years; female 56.1%) were divided into the high- (n=487) and low- (n=536) volume groups. The high-volume group had a higher prevalence of prior valve implantation (30.8% vs. 24.8%; p=0.036), prior coronary artery bypass grafting (28.7% vs. 22.7%; p=0.031), and heart failure (86.7% vs. 79.5%; p=0.003) than the low-volume group. There was no significant difference in the rates of in-hospital death (9.0% vs. 9.5%; p=0.830), stroke (2.1% vs. 3.2%; p=0.330), and pacemaker implantation (2.5% vs. 4.5%; p=0.091), while surgical bailout was less frequent in the high-volume group (2.5% vs. 6.5%; p=0.002). Multivariable logistic regression analyses showed that high volume was significantly associated with a lower risk of surgical bailout, prolonged hospital stay, cardiovascular-cause readmission, but not with other outcomes including in-hospital death (Figure). Conclusions: Centers with greater MitraClip experience had a lower risk of surgical bailout, prolonged hospital stay, and early readmission after transseptal-TMVR, although mortality was high irrespective of MitraClip experience.

Abstract 15306: Annual Transplant Volume Does Not Affect Center Specific Mortality- A PHTS Database Study

Introduction: Recent studies have suggested a relationship between mortality and center volume in pediatric heart transplantation; however, these studies utilize databases that lack granularity to assess patient risk profiles. Hypothesis: Utilizing the Pediatric Heart Transplant Society (PHTS) database, we hypothesized that there would be a difference in outcomes among centers based on yearly transplant volume, and that the patient’s clinical profiles would differ by center volume. Methods: We performed a retrospective analysis of the PHTS dataset from all pediatric (≤ 18 years of age) cases from 2009-2018. Centers were stratified into 5 groups based on annual volume: ≤ 4, 4-6, 6-9, 9-14, and &gt; 14 transplants. We evaluated specific variables, including those identified as significant risk factors in previous PHTS studies including mechanical ventilation, PRA &gt; 10%, high BUN, gender, and Fontan completion, within each group. We used Kaplan Meier for survival, contingency tables with Pearson Chi-square test for association, and analysis-of-variance to compare means. P&lt; 0.05 was considered statistically significant. Results: There were 6800 cases among 55 centers. Table 1 demonstrates that there was no significant difference in one-year post transplant survival among the groups, and the patient variables showing statistically significant differences followed no specific pattern among the center volume groups. It also demonstrates that there is no clear association between cumulative risk factors within individual patients and center volume. Conclusions: One-year post transplant survival is similar within the PHTS for all centers regardless of case volume. These group differences were different for different variables and did not segregate consistently between lower volume and higher volume groups suggesting there exists a complicated relationship among risk factors and center volume.

Intravenous fluids in acute pancreatitis: a prospective study

Background: Fluid therapy is the mainstay of treatment in the management of acute pancreatitis. Most guidelines recommend aggressive fluid therapy in the initial 48-72 hours. We aimed to compare the occurrence, persistence or worsening of systemic inflammatory response syndrome (SIRS) and occurrence organ failure in patients with acute pancreatitis receiving normal and high volume fluid therapy in the first 24 hours.Methods: This was a prospective observational study. Consecutive adult patients admitted with acute pancreatitis were included in the study. SIRS was defined according to the criteria. Organ failure and local complications were defined according to Atlanta classification. Patients were divided into two groups according to the rate of fluid administered in the initial 24 hours: Normal volume group which received fluids at a rate &lt;150 ml/hour and high volume group &gt;150 ml/hour.Results: A total 60 patients were included in the study with 30 each in the two groups. Persistence or worsening of SIRS at 48 hours was more in normal volume fluid group compared to the high volume fluid group (p=0.076). Organ failure at 48 hours was more in normal volume fluid group compared to the high volume fluid group (p=0.074). Incidence of local complications equal in both group.Conclusions: Our study did not show any statistically significant difference in outcomes in patients with acute pancreatitis receiving normal or high volume fluids in the initial 24 hours. Further multi-centric randomised control trials are required to analyze the outcomes of high and normal volume fluid resuscitation in acute pancreatitis.

The impact of surgeon volume on total thyroidectomy outcomes among otolaryngologists.

To evaluate the impact of surgeon volume on total thyroidectomy complications and outcomes among otolaryngologists. This state-wide, multi-hospital retrospective review identified patients who underwent total thyroidectomy (TT) (ICD9-06.4) through the Statewide Planning and Research Cooperative System (SPARCS) between 1995 and 2015. Surgeons were categorized into high (>100), medium (10-99), and low (<10) volume groups and differences in complication rates were analyzed. Statistical analysis employed Spearman's rank correlation, Kruskal-Wallis testing, and chi-squared testing. 32,133 TT performed by 1032 otolaryngologists were identified. Overall complication rate in our cohort was 9.83% (CI: 9.48-10.18). The most common complication identified overall was hypocalcemia occurring in 3.85% of cases. Surgeons in the high volume group had a complication rate of 9.6%, compared to 10.0% and 11.6% in the medium and low volume groups. This represents a moderate, but statistically significant difference (rho: -0.4, p<0.0001; KW p≤0.0001). When looking at individual complications, temporary tracheostomy rate was higher in the low volume group (5.1%, p=0.001). Other variables such as advanced age, sex, non-white race, or thyroid malignancy were not predictors of increased complication rates for TT. Otolaryngologists who perform a high volume of total thyroidectomy were found to have overall less perioperative complications than those with less volume. In particular, the risk of temporary tracheostomy is higher among low volume surgeons. These findings are consistent with previous studies of the effect of thyroidectomy volume on surgical complications.