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Diagnosis of hand ischemia secondary to an arteriovenous (AV) hemodialysis access is predominantly based on clinical findings. Occasionally, this diagnosis is unclear and more objective diagnostic testing is needed. No validated method of objective testing currently exists. The purpose of this study is to evaluate digital pressure measurements in the diagnosis of AV access-induced hand ischemia. A case-control study of 40 patients with an upper extremity AV access consisted of 15 patients (38%) with clinical AV access-induced hand ischemia and 25 patients (62%) without clinical evidence of ischemia. Arterial pressure in the third finger ipsilateral to the AV access was measured by digital photoplethysmography. Basal digital pressure (BDP), digital to contralateral brachial index (DBI), and change in digital pressure with access compression (CDP) were determined. Logistic regression modeling with gains tables and ROC calculations were used to determine optimal test thresholds and to test model discrimination for predicting AV access-induced hand ischemia. The mean BDP (30 vs 102mmHg; p < 0.001) and mean DBI (0.3 vs 0.8; p < 0.001) were significantly lower in patients with AV access-induced hand ischemia than in those without. The accuracy for determining hand ischemia using a thresholdadjusted BDP of 60 mmHg was 92% (sensitivity 100%, specificity 87%) and using DBI of 0.4 was 94% (sensitivity 92%, specificity 96%). While the mean CDP was significantly higher in patients with hand ischemia (85 vs 40; p < 0.001), the accuracy for predicting ischemia was marginal (78%). In conclusion, a BDP less than 60mmHg or a DBI less than 0.4 in a patient with an AV access were highly associated with hand ischemia. CDP's marginal discrimination ability likely stems from the presence of asymptomatic physiologic steal in the group without clinical steal. Nonetheless, CDP may be useful in identifying patients with ischemia who will not benefit from an intervention that specifically targets the AV access. [ABSTRACT FROM AUTHOR]

Background: Confounding by indication is a serious threat to comparative studies using real world data. We assessed the utility of automated data-adaptive analytic approach for confounding adjustment when both claims and clinical registry data are available. Methods: We used a comparative study example of carotid artery stenting (CAS) vs. carotid endarterectomy (CEA) in 2005–2008 when CAS was only indicated for patients with high surgical risk. We included Medicare beneficiaries linked to the Society for Vascular Surgery's Vascular Registry >65 years old undergoing CAS/CEA. We compared hazard ratios (HRs) for death while adjusting for confounding by combining various 1) Propensity score (PS) modeling strategies (investigator-specified [IS-PS] vs. automated data-adaptive [ada-PS]); 2) data sources (claims-only, registry-only and claims-plus-registry); and 3) PS adjustment approaches (matching vs. quintiles-adjustment with/without trimming). An HR of 1.0 was used as a benchmark effect estimate based on CREST trial. Results: The cohort included 1,999 CAS and 3,255 CEA patients (mean age 76). CAS patients were more likely symptomatic and at high surgical risk, and experienced higher mortality (crude HR = 1.82 for CAS vs. CEA). HRs from PS-quintile adjustment without trimming were 1.48 and 1.52 for claims-only IS-PS and ada-PS, 1.51 and 1.42 for registry-only IS-PS and ada-PS, and 1.34 and 1.23 for claims-plus-registry IS-PS and ada-PS, respectively. Estimates from other PS adjustment approaches showed similar patterns. Conclusions: In a comparative effectiveness study of CAS vs. CEA with strong confounding by indication, ada-PS performed better than IS-PS in general, but both claims and registry data were needed to adequately control for bias. [ABSTRACT FROM AUTHOR]

Occlusion after infra-inguinal bypass surgery for peripheral artery disease is a major complication with potentially devastating consequences. In this descriptive analysis, we sought to describe the natural history and explore factors associated with long-term major amputation-free survival following occlusion of a first-time infra-inguinal bypass. Using a prospective database from a tertiary care vascular center, we conducted a retrospective cohort study of all patients with peripheral artery disease who underwent a first-time infra-inguinal bypass and subsequently suffered a graft occlusion (1997-2021). The primary outcome was longitudinal rate of major amputation-free survival after bypass occlusion. Cox proportional hazard models were used to generate hazard ratios (HRs) and 95% confidence intervals (CIs) to explore predictors of outcomes. Of the 1318 first-time infra-inguinal bypass surgeries performed over the study period, 255 bypasses occluded and were included in our analysis. Mean age was 66.7 (12.6) years, 40.4% were female, and indication for index bypass was chronic limb threatening ischemia (CLTI) in 89.8% (n = 229). 48.2% (n = 123) of index bypass conduits used great saphenous vein, 29.0% (n = 74) prosthetic graft, and 22.8% (n = 58) an alternative conduit. Median (interquartile range) time to bypass occlusion was 6.8 (2.3-19.0) months, and patients were followed for median of 4.3 (1.7-8.1) years after bypass occlusion. Following occlusion, 38.04% underwent no revascularization, 32.94% graft salvage procedure, 25.1% new bypass, and 3.92% native artery recanalization. Major amputation-free survival following occlusion was 56.9% (50.6%-62.8%) at 1 y, 37.1% (31%-43.3%) at 5 y, and 17.2% (11.9%-23.2%) at 10 y. In multivariable analysis, factors associated with lower amputation-free survival were older age, female sex, advanced cardiorenal comorbidities, CLTI at index procedure, CLTI at time of occlusion, and distal index bypass outflow. Initial treatment after occlusion with both a new surgical bypass (HR 0.44, CI: 0.29-0.67) or a graft salvage procedure (HR 0.56, CI: 0.38-0.82) showed improved amputation-free survival. One-year rate of major amputation or death were 59.8% (50.0%-69.6%) for those who underwent no revascularization, 37.9% (28.7%-49.0%) for graft salvage, and 26.7% (17.6%-39.5%) for new bypass. Long-term major amputation-free survival is low after occlusion of a first-time infra-inguinal bypass. While several nonmodifiable risk factors were associated with lower amputation-free survival, treatment after graft occlusion with either a new bypass or a graft salvage procedure may improve longitudinal outcomes. [ABSTRACT FROM AUTHOR]

Background: Surgical patients with limited digital literacy may experience reduced telemedicine access. We investigated racial/ethnic and socioeconomic disparities in telemedicine compared with in-person surgical consultation during the coronavirus disease 2019 (COVID-19) pandemic.Study Design: Retrospective analysis of new visits within the Division of General & Gastrointestinal Surgery at an academic medical center occurring between March 24 through June 23, 2020 (Phase I, Massachusetts Public Health Emergency) and June 24 through December 31, 2020 (Phase II, relaxation of restrictions on healthcare operations) was performed. Visit modality (telemedicine/phone vs in-person) and demographic data were extracted. Bivariate analysis and multivariable logistic regression were performed to evaluate associations between patient characteristics and visit modality.Results: During Phase I, 347 in-person and 638 virtual visits were completed. Multivariable modeling demonstrated no significant differences in virtual compared with in-person visit use across racial/ethnic or insurance groups. Among patients using virtual visits, Latinx patients were less likely to have video compared with audio-only visits than White patients (OR, 0.46; 95% CI 0.22-0.96). Black race and insurance type were not significant predictors of video use. During Phase II, 2,922 in-person and 1,001 virtual visits were completed. Multivariable modeling demonstrated that Black patients (OR, 1.52; 95% CI 1.12-2.06) were more likely to have virtual visits than White patients. No significant differences were observed across insurance types. Among patients using virtual visits, race/ethnicity and insurance type were not significant predictors of video use.Conclusion: Black patients used telemedicine platforms more often than White patients during the second phase of the COVID-19 pandemic. Virtual consultation may help increase access to surgical care among traditionally under-resourced populations. [ABSTRACT FROM AUTHOR]

The author reflects on health-related quality of life (HRQoL) in the U.S. He states that assessing changes in HRQoL allows health personnel to measure a more comprehensive outcome that reflects a patient. He cites that HRQoL has been used as predicator of outcomes, specially survival, in patients with coronary heart disease. He cites that health personnel must incorporate measure of HRQoL to their clinical research designs to analyze composite outcomes relevant to the patient's perspective

Background: Racial disparities in colorectal cancer (CRC) screening are frequently attributed to variations in insurance status. The objective of this study was to ascertain whether universal insurance would lead to more equitable utilization of CRC screening for black patients in comparison with white patients.Methods: Claims data from TRICARE (insurance coverage for active, reserve, and retired members of the US Armed Services and their dependents) for 2007-2010 were queried for adults aged 50 years in 2007, and they were followed forward in time for 4 years (ages, 50-53 years) to identify their first lower endoscopy and/or fecal occult blood test (FOBT). Variations in CRC screening were compared with descriptive statistics and multivariate logistic regression.Results: Among the 24,944 patients studied, 69.2% were white, 20.3% were black, 4.9% were Asian, and 5.6% were other. Overall, 54.0% received any screening: 83.7% received endoscopy, and 16.3% received FOBT alone. Compared with whites, black patients had higher screening rates (56.5%) and had 20% higher risk-adjusted odds of being screened (95% confidence interval [CI], 1.11-1.29). Asian patients had a likelihood of screening similar to that of white patients (odds ratio [OR], 1.06; 95% CI, 0.92-1.23). Females (OR, 1.20; 95% CI, 1.10-1.33), active-duty personnel (OR, 1.15; 95% CI, 1.06-1.25), and officers (OR, 1.28; 95% CI, 1.18-1.37) were also more likely to be screened.Conclusion: Within an equal-access, universal health care system, black patients had higher rates of CRC screening in comparison with prior reports and even in comparison with white patients within the population. These findings highlight the need to understand and develop meaningful approaches for promoting more equitable access to preventative care. Moreover, equal-access, universal health insurance for both the military and civilian populations can be presumed to improve access for underserved minorities. [ABSTRACT FROM AUTHOR]

Background: Conventional economic principles suggest that increases in competition are associated with price decreases. The purpose of this study is to determine whether this association holds true between objective measures of hospital competition and gross charges, by analyzing standardized operations where variations in costs should be minimal. Study Design: Hospital Market Structure file (from Agency for Healthcare Research and Quality, available for years 2000 and 2003) was linked to Nationwide Inpatient Sample database. Appendectomy, carotid endarterectomy, bariatric surgery, radical prostatectomy, and pyloromyotomy were analyzed, after excluding patients with possible complications. Primary outcomes included total hospital charges. Primary independent variable was Herfindahl-Hirschman Index (HHI) calculated by the Agency for Healthcare Research and Quality for each hospital based on its patient-flow market. Higher HHI represents the presence of more dominant hospitals in the market or lower competition. Results: A total of 162,823 patients from 1,492 hospitals (85,791 appendectomies, 38,619 carotid endarterectomies, 18,383 bariatric operations, 16,784 radical prostatectomies, 3,246 pyloromyotomies) were analyzed. Single linear regression analyses demonstrated higher HHI was significantly associated with lower hospital gross charges in all cases. On multivariate analysis, a 1 percentage-point increase on HHI was associated with −$114 for appendectomy, −$163 for carotid endarterectomy, and −$193 for radical prostatectomy (all p ≤ 0.001), and were independent of hospital urbanicity, teaching status, and payer mix. In contrast, no association was found between competition and hospital costs. Conclusions: Higher level of hospital competition is associated with higher hospital gross charges, although competition intensity is not associated with hospital costs. These data are important as health policy makers consider possible cost-control measures. [Copyright &y& Elsevier]

Background: Shared decision making and patient‐centred communication have become part of pre‐procedural decisions and perioperative care across medical specialties. However, gaps exist in patient communication about the implanted device received and the benefits in sharing information about their procedure and device. Objective: To understand the patients' knowledge of identifying information for their implanted devices and perspectives on sharing their implanted device information. Methods: Four focus groups were conducted with patients who had received a cardiac or vascular implanted device from one of the study sites within the previous 6 months. Data were transcribed and thematically analysed. Results: Five themes emerged: lack of awareness of identifying information on implanted devices; value of information on implanted devices; varying trust with sharing device information; perceived risk with sharing device information; and lack of consensus on a systematic process for tracking implanted devices. Discussion: Patients desire post‐procedural information on their implanted device and a designated plan for longitudinal follow‐up, but lack trust and perceive risk with broadly sharing their implanted device information. Conclusion: After receiving an implanted device, post‐procedural patient communication needs to be expanded to include identifying information on the device including the unique device identifier, how long‐term tracking will be supported and the process for notification in case of a problem with the device. This communication should also include education on how sharing device information supports patients' long‐term health care, post‐market safety surveillance and research. Patient or Public Contribution: The research team included members who were also patients with implanted devices. [ABSTRACT FROM AUTHOR]

Index length of stay (LOS) and readmissions are viewed as important quality measures. However, these metrics represent competing demands as an inordinate reduction in LOS may lead to unplanned readmissions. We sought to assess the optimal LOS associated with the lowest 90-d readmission rate following discharge after common surgical procedures. This was a retrospective study relying on Tricare claims. We identified all eligible adult patients (18-64 y) receiving a series of common surgical procedures between 2006 and 2014. We used a generalized additive model with spline regression to determine the optimal LOS associated with the lowest 90-d risk of readmission. Ninety-day readmission rates varied from 6.03% to 34.69%. Most procedures exhibited a logit linear relationship, with the lowest risk of readmission evident on postoperative day-1 and increasing thereafter. Among the more invasive procedures (e.g., esophagectomy and radical cystectomy), a U-shaped relationship was realized, indicating that expedited discharge would increase the potential for readmission as would any extended hospital LOS. For these procedures, the ideal index LOS appeared to be 6-7 d for radical cystectomy and 12-13 d for esophagectomy. Our results support the practice of discharging patients as soon as clinically feasible after hip and knee arthroplasty, lumbar spine surgery, hernia repair, appendectomy, nephrectomy, and colectomy. Among esophagectomy or radical cystectomy, there is a well-defined optimal index admission period and discharge outside this window appears to be detrimental. Our results suggest that invasive procedures appear to possess a unique "signature" when it comes to optimal LOS. [ABSTRACT FROM AUTHOR]

Critical limb ischemia (CLI) is a frequent and major vascular problem and can lead to amputation and death despite surgical revascularization. Women have been shown to have 3 to 4 per cent lower revascularization rates for CLI compared with men as well as inferior outcomes. We hypothesize that this difference is a result of women being more likely admitted to low-volume hospitals, which in turn perform fewer revascularizations. Prospective cohort study. Data from the Nationwide Inpatient Sample 2007 to 2010 were used to identify admissions with primary International Classification of Diseases-9 codes for CLI (International Classification of Diseases-9 codes: 440.22, 440.23, 440.24, 707.1, 707.10-707.15, or 707.19). Hospitals were grouped in quintiles by annual revascularization procedures. Bivariate analyses were performed and multivariable logistic regression was used to analyze the odds of revascularization, amputation, and mortality while controlling for patient and hospital-level factors. Of 113,631 admissions, 54,370 (47.8%) were women, who were more likely admitted to low-volume hospitals (very low: 49.6% vs very high: 47.1%; P < 0.001). Revascularization rates were lower in women (31.6% vs 35.1%, P < 0.001) across all volume quintiles, whereas the difference was greatest in the use of open surgical revascularization (12.5% vs 16.0%, P < 0.001). In multivariable analysis, female gender [odds ratio (OR) 0.87, 95% confidence interval (CI) 0.83-0.92, P < 0.001] and very-low hospital volume (OR 0.21, 95% CI 0.17-0.26, P < 0.001) were both significantly associated with lower rates of revascularization. Women had lower odds of major amputation compared with men (OR 0.75, 95% CI 0.69-0.82, P < 0.001), whereas treatment in a very high-volume hospital was associated with increased odds for amputation (OR 1.37, 95% CI 1.09-1.73, P = 0.008). Neither gender nor hospital volume were independently associated with in-hospital mortality in the multivariable regression model. Women are more likely to be admitted to low-volume hospitals for treatment of CLI. Because of this, they are less likely to undergo revascularization, although they also had lower rates of major amputation. [ABSTRACT FROM AUTHOR]

Medical studies increasingly involve a large sample of independent clusters, where the cluster sizes are also large. Our motivating example from the 2010 Nationwide Inpatient Sample (NIS) has 8,001,068 patients and 1049 clusters, with average cluster size of 7627. Consistent parameter estimates can be obtained naively assuming independence, which are inefficient when the intra-cluster correlation (ICC) is high. Efficient generalized estimating equations (GEE) incorporate the ICC and sum all pairs of observations within a cluster when estimating the ICC. For the 2010 NIS, there are 92.6 billion pairs of observations, making summation of pairs computationally prohibitive. We propose a one-step GEE estimator that (1) matches the asymptotic efficiency of the fully iterated GEE; (2) uses a simpler formula to estimate the ICC that avoids summing over all pairs; and (3) completely avoids matrix multiplications and inversions. These three features make the proposed estimator much less computationally intensive, especially with large cluster sizes. A unique contribution of this article is that it expresses the GEE estimating equations incorporating the ICC as a simple sum of vectors and scalars. [ABSTRACT FROM PUBLISHER]

Background: This study seeks to quantify variation in healthcare utilization and per capita costs using system-defined geographic regions based on enrollee residence within the Military Health System (MHS).Methods: Data for fiscal years 2007 - 2010 were obtained from the Military Health System under a data sharing agreement with the Defense Health Agency (DHA). DHA manages all aspects of the Department of Defense Military Health System, including TRICARE. Adjusted rates were calculated for per capita costs and for two procedures with high interest to the MHS- back surgery and Cesarean sections for TRICARE Prime and Plus enrollees. Coefficients of variation (CoV) and interquartile ranges (IQR) were calculated and analyzed using residence catchment area as the geographic unit. Catchment areas anchored by a Military Treatment Facility (MTF) were compared to catchment areas not anchored by a MTF.Results: Variation, as measured by CoV, was 0.37 for back surgery and 0.13 for C-sections in FY 2010- comparable to rates documented in other healthcare systems. The 2010 CoV (and average cost) for per capita costs was 0.26 ($3,479.51). Procedure rates were generally lower and CoVs higher in regions anchored by a MTF compared with regions not anchored by a MTF, based on both system-wide comparisons and comparisons of neighboring areas.Conclusions: In spite of its centrally managed system and relatively healthy beneficiaries with very robust health benefits, the MHS is not immune to unexplained variation in utilization and cost of healthcare. [ABSTRACT FROM AUTHOR]

Background Liver transplantation centers are unevenly distributed within the Donor Service Areas (DSAs) of the United States. This study assessed how market competition and liver transplantation center density are associated with liver transplantation volume within individual DSAs. Study Design We conducted a retrospective cohort study of 53,156 adult liver transplants in 45 DSAs with 110 transplantation centers identified from the Scientific Registry of Transplant Recipients between 2003 and 2012. The following measures were derived annually for each DSA: market competition using the Herfindahl Hirschman Index, transplantation center density by the Average Nearest Neighbor method, liver quality by the Liver Donor Risk Index, and patient risk by the Model for End-Stage Liver Disease. A hierarchical mixed effects negative binomial regression model of the relationship between liver transplants and market factors was created annually. Patient and graft survival were investigated with a Cox proportional hazards model. Results Transplantation center density was associated with market competition (p < 0.0001), listings for organ transplantation (p < 0.0001), and Model for End-Stage Liver Disease at transplantation (p = 0.0005). More liver transplantation centers (incidence rate ratio [IRR] = 1.03; p = 0.04), greater market competition (IRR = 1.36; p = 0.02), increased listings (IRR = 1.14; p < 0.0001), more donors (IRR = 1.24; p < 0.0001), and higher Liver Donor Risk Index (IRR = 3.35; p < 0.0001) were associated with more transplants. No market variables were associated with increased mortality after transplantation. Conclusions After controlling for demographic and market factors, a greater concentration of centers was associated with more liver transplants without impacting overall survival. These results warrant additional investigation into the relationship between geospatial factors and liver transplantation volume with consideration for the optimization of scarce resources. [ABSTRACT FROM AUTHOR]

Background Failure-to-rescue (FTR or death after postoperative complication) is thought to explain surgical mortality excesses across hospitals, and FTR is an emerging performance measure and target for quality improvement. We compared the FTR population to preoperatively identifiable subpopulations for their potential to close the mortality gap between lowest- and highest-mortality hospitals. Study Design Patients undergoing small bowel resection, pancreatectomy, colorectal resection, open abdominal aortic aneurysm repair, lower extremity arterial bypass, and nephrectomy were identified in the 2007 to 2011 Nationwide Inpatient Sample. Lowest- and highest-mortality hospitals were defined using risk- and reliability-adjusted mortality quintiles. Five target subpopulations were established a priori: the FTR population, predicted high-mortality risk (predicted highest-risk quintile), emergency surgery, elderly (>75 years old), and diabetic patients. Results Across the lowest mortality quintile (n = 282 hospitals, 56,893 patients) and highest-mortality quintile (282 hospitals, 45,784 patients), respectively, the size of target subpopulations varied only for the FTR population (20.2% vs 22.4%, p = 0.002) but not for other subpopulations. Variation in mortality rates across lowest- and highest-mortality hospitals was greatest for the high-mortality risk (7.5% vs 20.2%, p < 0.0001) and FTR subpopulations (7.8% vs 18.9%, p < 0.0001). The FTR and high-risk populations had comparable sensitivity (81% and 75%) and positive predictive value (19% and 20%, respectively) for mortality. In Monte Carlo simulations, the mortality gap between the lowest- and highest-mortality hospitals was reduced by nearly 75% when targeting the FTR population or the high-risk population, 78% for the emergency surgery population, but less for elderly (51%) and diabetic (17%) populations. Conclusions Preoperatively identifiable patients with high estimated mortality risk may be preferable to the FTR population as a target for surgical mortality reduction. [ABSTRACT FROM AUTHOR]

Background Performance measurement has become central to surgical practice. We systematically reviewed all endorsed performance measures from the National Quality Forum, the national clearing house for performance measures in health care, to identify measures relevant to surgical practice and describe measure stewardship, measure types, and identify gaps in measurement. Study Design Performance measures current to June 2014 were categorized by denominator statement as either assessing surgical practice in specific or as part of a mixed medical and surgical population. Measures were further classified by surgical specialty, Donabedian measure type, patients, disease and events targeted, reporting eligibility, and measure stewards. Results Of 637 measures, 123 measures assessed surgical performance in specific and 123 assessed surgical performance in aggregate. Physician societies (51 of 123, 41.5%) were more common than government agencies (32 of 123, 26.0%) among measure stewards for surgical measures, in particular, the Society for Thoracic Surgery (n = 32). Outcomes measures rather than process measures were common among surgical measures (62 of 123, 50.4%) compared with aggregate medical/surgical measures (46 of 123, 37.4%). Among outcomes measures, death alone was the most commonly specified outcome (24 of 62, 38.7%). Only 1 surgical measure addressed patient-centered care and only 1 measure addressed hospital readmission. We found 7 current surgical measures eligible for value-based purchasing. Conclusions Surgical society stewards and outcomes measure types, particularly for cardiac surgery, were well represented in the National Quality Forum. Measures addressing patient-centered outcomes and the value of surgical decision-making were not well represented and may be suitable targets for measure innovation. [ABSTRACT FROM AUTHOR]

Background: Surgical patients and their physicians currently have tools to provide individualized prognostication for morbidity and mortality. For improved shared decision making, formal prediction of patient-centered outcomes is necessary. We derived and validated a simple, interview-based method to predict discharge home after surgery. Study Design: We used the American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) Patient User File for 2011. Derivation in general and vascular surgery patients undergoing inpatient surgery was completed using serial multiple logistic regression. Validation was performed within multiple surgical specialties. Results: The derivation cohort included 88,068 patients, of whom 11,771 (13.4%) were not discharged home. The derived Home Calculator had excellent discrimination (c-statistic = 0.864) using 4 variables: age, American Society of Anesthesiologists' performance status, elective surgery, and preadmission residence. Validation cohorts had varying rates of home discharge as follows: general (63,826 of 71,591, 89.2%), vascular (12,319 of 16,102, 76.5%), gynecologic (16,603 of 17,005, 97.6%), urologic (13,662 of 14,435, 94.6%), orthopaedic (12,000 of 19,514, 61.5%), thoracic (4,467 of 5,092, 87.7%). The Home Calculator provided good to excellent discrimination in validation cohorts: general (c = 0.866), vascular (c = 0.800), gynecologic (c = 0.793), urologic (c = 0.814), orthopaedic (c = 0.876), and thoracic (c = 0.800). Comparable discrimination was demonstrated in sensitivity analyses in surgical patients admitted exclusively from home. Conclusions: We derived and validated a simple Home Calculator that reliably predicts discharge to home after surgery and may be useful when counseling patients about postoperative course. Patient-centered tools such as this may allow physicians to better prepare patients and families for surgery and the recovery process. [Copyright &y& Elsevier]

BACKGROUND: We hypothesized that human perivascular and subcutaneous adipose tissues hold distinct phenotypic signatures. We also evaluated the impact of clinical parameters on the adipose phenotype. Our overall goal is to understand. the determinants of adipose biology so that this tissue can be manipulated therapeutically to lessen peripheral vascular disease. METHODS: Perivascular and subcutaneous adipose tissues were collected from patients undergoing lower-extremity amputation (n = 27) and protein assayed for proinflammatory mediators (ie, interleukin 6, interleukin 8, leptin, tumor necrosis factor α, monocyte chemoattractant protein-1 , and resistin), atheroprotective adiponectin, and the fibrinolysis inhibitor plasminogen activator inhibitor-1. RESULTS: Leptin (2.7-fold, P = .015), TNF-α (2.2-fold, P = .013), MCP-1 (1.5-fold, P = .047), and adiponectin (1.8-fold, P = .004) were more abundant in subcutaneous vs perivascular adipose tissue. Age positively correlated with perivascular adipose tissue PAl-I expression (β = .64, P = .042), and hyperlipidemia negatively correlated with perivascular adiponectin (β = -1.18, P = .039). CONCLUSIONS: Human perivascular and subcutaneous adipose tissues hold distinct phenotypic signatures. In amputation patients, the subcutaneous adipose tissue proinflammatory phenotype was relatively attenuated in perivascular adipose tissue. [ABSTRACT FROM AUTHOR]

The restenosis rates of 5% to 15% have been reported after carotid endarterectomy (CEA). We undertook this investigation to determine whether the routine practice of carotid artery patch closure and intraoperative completion duplex ultrasonography would result in lower rates of carotid restenosis after CEA. All consecutive carotid endarterectomies performed between 2000 and 2004 at a single institution were reviewed retrospectively. Patients underwent CEA using a longitudinal arteriotomy, followed by routine patching and intraoperative completion duplex ultrasonography. Only patients with at least one postoperative duplex scan performed at a minimum of 180 days after CEA were included. During the 5-year study period, 407 consecutive carotid endarterectomies were performed, with a combined 30-day stroke and mortality rate of 2.5%; 217 patients (53%) had one or more duplex ultrasound examinations performed at least 180 days after CEA. The mean follow-up duration was 692 days. Of the patients who underwent intraoperative intervention based on the results of the completion duplex study, none experienced restenosis, stroke, or death. CEA that is performed with routine patching and intraoperative duplex completion ultrasonography is a safe, durable operation with restenosis rates below those commonly reported. [ABSTRACT FROM AUTHOR]

Introduction: Analysis of large complex survey databases is an important research tool for health services researchers in Surgery. Missing data elements are challenging as reasons they are missing are multi-factorial, especially variables with multiple categories such as race. We simulated missing data for race and analyzed the bias from five missing data methods used in predicting major amputation in patients with critical limb ischemia (CLI). Methods: Discharges with fully observed data containing lower extremity revascularization or major amputation and CLI were selected from the 2003-2007 Nationwide Inpatient Sample, a complex survey database (weighted N=684,057). Considering random and non-random missing data schemes, we simulated missing data for race to compare five missing data methods (complete case analysis (CCA), missing indicator variable (MIV), single imputation with mean frequencies, re-weighted estimating equations (RWEEs), and multiple imputation). Bias was determined by comparing mean regression coefficients estimated from 100 simulated datasets (B_miss) to those estimated from the fully observed dataset (B_full), with relative bias calculated as (B_full–B_miss/B_full)*100%. Results: Our results demonstrate that RWEEs produce the least biased and MIV the most biased coefficients. CCA, single imputation, and multiple imputation resulted in moderate bias. Sensitivity analysis demonstrated that optimal method choice depends on quantity and type of missing data encountered. Conclusions: Missing data is an important analytical topic in research with large databases. RWEEs are flexible and provided the least biased coefficients. The commonly used MIV method introduces the most bias and should be used with caution. We present empirical evidence to guide method selection for handling missing data. [ABSTRACT FROM AUTHOR]