Association of Treatment for Critical Limb Ischemia with Gender and Hospital Volume.

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.

The effect of social integration on outcomes after major lower extremity amputation.

OBJECTIVE: Major lower extremity (MLE) amputation is a common procedure that results in a profound change in a patient's life. We sought to determine the association between social support and outcomes after amputation. We hypothesized that patients with greater social support will have better post amputation outcomes. METHODS: From November 2011 to May 2013, we conducted a cross-sectional, observational, multicenter study. Social integration was measured by the social integration subset of the Short Form Craig Handicap Assessment and Reporting Technique. Systemic social support was assessed by comparing a United States and Tanzanian population. Walking function was measured using the 6-minute walk test and quality of life (QoL) was measured using the EuroQol-5D. RESULTS: We recruited 102 MLE amputees. Sixty-three patients were enrolled in the United States with a mean age of 58.0. Forty-two (67%) were male. Patients with low social integration were more likely to be unable to ambulate (no walk 39% vs slow walk 23% vs fast walk 10%; P = .01) and those with high social integration were more likely to be fast walkers (no walk 10% vs slow walk 59% vs fast walk 74%; P = .01). This relationship persisted in a multivariable analysis. Increasing social integration scores were also positively associated with increasing QoL scores in a multivariable analysis (ß, .002; standard error, 0.0008; P = .02). In comparing the United States population with the Tanzanian cohort (39 subjects), there were no differences between functional or QoL outcomes in the systemic social support analysis. CONCLUSIONS: In the United States population, increased social integration is associated with both improved function and QoL outcomes among MLE amputees. Systemic social support, as measured by comparing the United States population with a Tanzanian population, was not associated with improved function or QoL outcomes. In the United States, steps should be taken to identify and aid amputees with poor social integration.

Navigational bronchoscopy at a community hospital: clinical and economic outcomes.

AIM: To evaluate the clinical and financial impact of introducing electromagnetic navigation bronchoscopy (ENB) at a community center. METHODS: This retrospective, single-arm, single-center study evaluated 90 consecutive patients who had undergone ENB in 2012. Radial probe endobronchial ultrasound was used to localize the lesion after initial ENB. ENB-aided diagnoses, follow-up procedures and treatments, and adverse events were collected through 2 years. RESULTS: ENB was conducted for lung biopsy (86 patients), fiducial placement (five), and/or dye marking (two). ENB-aided diagnostic yield was 82.6% (71/86), including 36 malignant and 35 nonmalignant cases. NSCLC was stage I-II in 84.6%. There were four false negatives. Sensitivity and negative predictive value were 90.0 and 88.6%. Pneumothorax occurred in 6/90 (5/6 with chest tube) and minor bleeding in four. The downstream revenue of new ENB cases was US$363,654. CONCLUSION: ENB introduction provided high diagnostic yield, early-stage diagnosis, acceptable safety, and was financially justified.

Craniofacial Measurements of Donors and Recipients Correlate with Aesthetic Outcome in Virtual Face Transplantation.

BACKGROUND: Face transplantation is an increasingly feasible option for patients with severe disfigurement. Donors and recipients are currently matched based on immune compatibility, skin characteristics, age, and gender. Aesthetic outcomes of the match are not always optimal and not possible to study in actual cases due to ethical and logistical challenges. We have used a reproducible and inexpensive three-dimensional virtual face transplantation (VFT) model to study this issue. METHODS: Sixty-one VFTs were performed using reconstructed high-resolution computed tomography angiographs of male and female subjects aged 20-69 years. Twenty independent reviewers evaluated the level of disfigurement of the posttransplant models. Absolute differences in 9 soft-tissue measurements and 16 bony cephalometric measurements from each of the VFT donor and recipient pretransplant model pairs were correlated to the reviewers' evaluation of disfigurement after VFT through a multivariate logistic regression model. RESULTS: Five soft-tissue measurements and 3 bony measurements were predictive of the rating of disfigurement after VFT (odds ratio; 95% confidence interval): trichion-to-nasion facial height (1.106; 1.066-1.148), endocanthal width (1.096; 1.051-1.142), exocanthal width (1.067; 1.036-1.099), mouth/chelion width (1.064; 1.019-1.110), subnasale-to-menton facial height (1.029; 1.003-1.056), inner orbit width (1.039; 1.009-1.069), palatal plane/occlusal plane angle (1.148; 1.047-1.258), and sella-nasion/mandibular plane angle (1.079; 1.013-1.150). CONCLUSIONS: This study provides early evidence for the importance of soft-tissue and bony measurements in planning of facial transplantation. With future improvements to immunosuppressive regimens and increased donor availability, these measurements may be used as an additional criterion to optimize posttransplant outcomes.

Young women with breast cancer in the United States and South Korea: comparison of demographics, pathology and management.

BACKGROUND: Breast cancer diagnosed in young women may be more aggressive, with higher rates of local and distant recurrence compared to the disease in older women. Epidemiologic evidence suggests that Korean women have a lower incidence of breast cancer than women in the United States, but that they present at a younger age than their American counterparts. We sought to compare risk factors and management of young women with breast cancer in Boston, Massachusetts (US) with those in Seoul, South Korea (KR). MATERIALS AND METHODS: A retrospective review was performed of consecutive patients less than 35 years old with a diagnosis of breast cancer at academic cancer centers in the US and KR from 2000-2005. Patient data were obtained by chart review. Demographic, tumor and treatment characteristics were compared utilizing Pearson's chi- square or Wilcoxon rank-sum tests where appropriate. All differences were assessed as significant at the 0.05 level. RESULTS: 205 patients from the US and 309 from KR were analyzed. Patients in US were more likely to have hormone receptor positive breast cancer, while patients in KR had a higher rate of triple negative lesions. Patients in US had a higher mean body mass index and more often reported use of birth control pills, while those in the KR were less likely to have a sentinel node procedure performed or to receive post mastectomy radiation. CONCLUSIONS: Patients under 35 diagnosed with breast cancer in the US and KR differ with respect to demographics, tumor characteristics and management. Although rates of breast conservation and mastectomy were similar, US patients were more likely to receive post mastectomy radiation. The lower use of sentinel node biopsy is explained by the later adoption of the technique in KR. Further evaluation is necessary to evaluate recurrence rates and survival in the setting of differing disease subtypes in these patients.

Racial variation in the use of life-sustaining treatments among patients who die after major elective surgery.

BACKGROUND: Although various studies have documented increased life-sustaining treatments among racial minorities in medical patients, whether similar disparities exist in surgical patients is unknown. METHODS: A retrospective cohort study using the Nationwide Inpatient Sample (2006 to 2011) examining patients older than 39 years who died after elective colectomy was performed. Primary predictor variable was race, and main outcome was the use of life-sustaining treatment. RESULTS: In univariate analysis, significant differences existed in use of cardiopulmonary resuscitation (CPR; black, 35.9%; Hispanic, 29.0%; other, 24.5%; white, 11.7%; P = .002) and reintubation (Hispanic, 75.0%; other, 69.0%; black, 52.3%; white, 45.2%; P = .01). In multivariate analysis, black (odds ratio [OR], 3.67; P = .01) and Hispanic (OR, 4.21; P = .03) patients were more likely to have undergone CPR, and Hispanic patients (OR, 4.24; P = .01) were more likely to have been reintubated (reference: white). CONCLUSIONS: Blacks and Hispanics had increased odds of experiencing CPR, and Hispanics were more likely to have been reintubated before death after a major elective operation. These variations may imply worse quality of death and increased associated costs.

Prospective, randomized, multi-institutional clinical trial of a silver alginate dressing to reduce lower extremity vascular surgery wound complications.

OBJECTIVE: Wound complications negatively affect outcomes of lower extremity arterial reconstruction. By way of an investigator initiated clinical trial, we tested the hypothesis that a silver-eluting alginate topical surgical dressing would lower wound complication rates in patients undergoing open arterial procedures in the lower extremity. METHODS: The study block-randomized 500 patients at three institutions to standard gauze or silver alginate dressings placed over incisions after leg arterial surgery. This original operating room dressing remained until gross soiling, clinical need to remove, or postoperative day 3, whichever was first. Subsequent care was at the provider's discretion. The primary end point was 30-day wound complication incidence generally based on National Surgical Quality Improvement Program guidelines. Demographic, clinical, quality of life, and economic end points were also collected. Wound closure was at the surgeon's discretion. RESULTS: Participants (72% male) were 84% white, 45% were diabetic, 41% had critical limb ischemia, and 32% had claudication (with aneurysm, bypass revision, other). The overall 30-day wound complication incidence was 30%, with superficial surgical site infection as the most common. In intent-to-treat analysis, silver alginate had no effect on wound complications. Multivariable analysis showed that Coumadin (Bristol-Myers Squibb, Princeton, NJ; odds ratio [OR], 1.72; 95% confidence interval [CI], 1.03-2.87; P = .03), higher body mass index (OR, 1.05; 95% CI, 1.01-1.09; P = .01), and the use of no conduit/material (OR, 0.12; 95% CI, 0.82-3.59; P < .001) were independently associated with wound complications. CONCLUSIONS: The incidence of wound complications remains high in contemporary open lower extremity arterial surgery. Under the study conditions, a silver-eluting alginate dressing showed no effect on the incidence of wound complications.

Investigating the "Rule of W," a mnemonic for teaching on postoperative complications.

OBJECTIVE: To identify the timing and relative frequency of common postoperative complications in a contemporary, diverse surgical population and develop a mnemonic for teaching and clinical decision support. PATIENTS AND METHODS: We enrolled a cohort of general and vascular surgical patients undergoing elective, inpatient surgery in the American College of Surgeons National Surgical Quality Improvement Program database between 2005 and 2011. Index complications were noted by postoperative day (POD). Timing and incidence were compared within each day. RESULTS: Among 614,525 patients, 51,173 (9.88%) experienced the following index complications over 30 days: pneumonia (n = 5947), urinary tract infection (n = 9459), superficial surgical site infection (sSSI) (n = 20,460), deep/organ space surgical site infection (dSSI) infection (n = 11,847), venous thromboembolism (n = 4478), kidney injury (n = 2620), and myocardial infarction (n = 1813). Median time to complication differed significantly for index complications (p < 0.0001). On POD 0, the most common complication was myocardial infarction (incidence 4.26/10,000 patient days; 95% CI: 3.75-4.78). On POD 1 and 2, pneumonia was the most common complication, with peak incidence on POD 2 (20.36; 95% CI: 19.22-21.51). On POD 3, pneumonia (16.3; 95% CI: 15.27-17.33) and urinary tract infection (15.5; 95% CI: 14.49-16.51) were significantly more common than other complications. On POD 4, the most common complication was sSSI (16.24; 95% CI: 15.20-17.28). From POD 5 to POD 30, sSSI and dSSI were the 2 most common complications. Risk of venous thromboembolism declined only slightly through POD 30. CONCLUSION: We propose a mnemonic for postoperative complication timing and frequency, independent of fever, as follows: Waves (myocardial infarction), Wind (pneumonia), Water (urinary tract), Wound (sSSI and dSSI), and Walking (venous thromboembolism) in the order of likelihood.

Cost analysis of conventional face reconstruction versus face transplantation for large tissue defects.

BACKGROUND: Large facial tissue defects are traditionally treated with staged conventional reconstruction. Facial allograft transplantation has emerged as a treatment modality. Facial allografts are procured from a dead donor and transplanted to the recipient. Recipients are then subjected to lifelong global immunosuppression to prevent immunologic rejection. This study analyzes the cost of facial allograft transplantation in comparison with conventional reconstruction. METHODS: Hospital billing records from facial allograft transplantation (2009 to 2011) and conventional reconstruction (2000 to 2010) patients were compiled. Comparative 1-year costs were calculated, segregated by physician, hospital, and hospital's department costs. Because most conventional reconstruction patients had smaller facial deficits than their facial allograft transplantation counterparts, regression models were used to estimate costs of conventional reconstruction for full facial defects, mirroring the facial transplantation cohort. All costs were adjusted using the medical consumer price index. RESULTS: One-year costs for facial allograft transplantation were significantly higher than those for conventional reconstruction (mean/median, $337,360/$313,068 versus $70,230/$64,451, respectively). One-year costs for a hypothetical full-face conventional reconstruction were $184,061 (95 percent CI, $89,358 to $278,763). The per-patient cost in a hypothetical cohort of conventional reconstruction patients with deficits identical to four facial allograft transplantation recipients was $155,475 (95 percent CI, $69,021 to $241,929). CONCLUSIONS: Initial cost comparison portrays facial allograft transplantation as significantly more costly than conventional reconstruction. However, after adjustments for case severity, the cost profiles are similar. Gains in efficiency and experience are expected to lower costs. Additional unmeasured benefits may also positively influence the cost-to-benefit ratio of facial allograft transplantation.

The effect of surgeon specialization on outcomes after ruptured abdominal aortic aneurysm repair.

OBJECTIVE: Although mortality after elective abdominal aortic aneurysm (AAA) repair has steadily declined, operative mortality for a ruptured AAA (rAAA) remains high. Repair of rAAA at hospitals with a higher elective aneurysm workload has been associated with lower mortality rates irrespective of the mode of treatment. This study sought to determine the association between surgeon specialization and outcomes after rAAA repair. METHODS: The American College of Surgeons National Surgical Quality Improvement Project database from 2005 to 2010 was used to examine the 30-day mortality and morbidity outcomes of patients undergoing rAAA repair by vascular and general surgeons. Multivariable logistic regression analysis was performed for each death and morbidity, adjusting for all independently predictive preoperative risk factors. Survival curves were compared using the log-rank test. RESULTS: We identified 1893 repairs of rAAAs, of which 1767 (96.1%) were performed by vascular surgeons and 72 (3.9%) were performed by general surgeons. There were no significant differences between patients operated on by general vs vascular surgeons in preoperative risk factors or method of repair. Overall 30-day mortality was 34.3% (649 of 1893). After risk adjustment, mortality was significantly lower in the vascular surgery group compared with the general surgery group (odds ratio [OR], 0.51; 95% confidence interval [CI], 0.30-0.86; P = .011). The risk of returning to the operating room (OR, 0.58; 95% CI, 0.35-0.97; P = .038), renal failure (OR, 0.54; 95% CI, 0.31-0.95; P = .034), and a cardiac complication (OR, 0.53; 95% CI, 0.28-0.99; P = .047) were all significantly less in the vascular surgery group. CONCLUSIONS: Despite similar preoperative risk factors profiles, patients who were operated on by vascular surgeons had lower mortality, less frequent returns to the operating room, and decreased incidences of postoperative renal failure and cardiac events. These data add weight to the case for further centralization of vascular services.

Institutional differences in carotid artery duplex diagnostic criteria result in significant variability in classification of carotid artery stenoses and likely lead to disparities in care.

BACKGROUND: The indications for carotid revascularization are based almost exclusively on the results of carotid duplex ultrasonography. Noninvasive vascular laboratories show large variation in the diagnostic criteria used to classify degree of carotid artery stenosis. We hypothesize that variability of these diagnostic criteria causes significant variation in stenosis classification directly affecting the number of revascularizations and associated costs. METHODS AND RESULTS: The diagnostic criteria to interpret carotid duplex ultrasounds were obtained from 10 New England institutions. All carotid duplex scans performed at our institution were reviewed from 2008 to 2012. Using the diagnostic criteria from each institution, the degree of stenosis that would have been reported was classified as 70% to 99% asymptomatic, 80% to 99% asymptomatic, and 50% to 99% symptomatic. We then calculated the theoretical number of carotid revascularization procedures that this cohort would be offered using each institution's diagnostic criteria and the costs of these procedures based on reimbursement rates. Among 10 614 patients who underwent 15 534 carotid duplex scans, 31 025 arteries were reviewed. Application of the 10 institutions' criteria to the patients from our institution yielded marked variation in the number classified as 70% to 99% asymptomatic (range, 186-2201), 80% to 99% asymptomatic (range, 78-426), and 50% to 99% symptomatic (range, 157-781). If revascularizations were based on these results, costs would range from $2.2 to $26 million, $0.9 to $5.0 million, and $1.9 to $9.2 million, respectively. CONCLUSIONS: Differences in diagnostic criteria to interpret carotid ultrasound result in significant variation in classification of carotid artery stenosis, likely leading to differences in the number and subsequent costs of revascularizations. This theoretical model highlights the need for standardization of carotid duplex criteria.

National variation in the utilization of alternative imaging in peripheral arterial disease.

OBJECTIVE: The value and cost-effectiveness of less invasive alternative imaging (AI) modalities (duplex ultrasound scanning, computed tomography angiography, and magnetic resonance angiography) in the care of peripheral arterial disease (PAD) has been reported; however, there is no consensus on their role. We hypothesized that AI utilization is low compared with angiography in the United States and that patient and hospital characteristics are both associated with AI utilization. METHODS: The Nationwide Inpatient Sample (2007-2010) was used to identify patients with an International Classification of Diseases-Ninth Edition diagnosis of claudication or critical limb ischemia (CLI) as well as PAD treatment (surgical, endovascular, or amputation). Patients with AI and those with angiography or expected angiography (endovascular procedures without imaging codes) were selected and compared. Multivariable logistic regression was performed for receiving AI stratified by claudication and CLI and adjusting for patient and hospital factors. RESULTS: We identified 290,184 PAD patients, of whom 5702 (2.0%) received AI. Patients with AI were more likely to have diagnosis of CLI (78.8% vs 48.6%; P < .0001) and receive open revascularizations (30.4% vs 18.8%; P < .0001). Van Walraven comorbidity scores (mean [standard error] 5.85 ± 0.22 vs 4.10 ± 0.05; P < .0001) reflected a higher comorbidity burden in AI patients. In multivariable analysis for claudicant patients, AI was associated with large bed size (odds ratio [OR], 3.26, 95% confidence interval [CI], 1.16-9.18; P = .025), teaching hospitals (OR, 1.97; 95% CI, 1.10-3.52; P = .023), and renal failure (OR, 1.52; 95% CI, 1.13-2.05; P = .006). For CLI patients, AI was associated with black race (OR, 1.53; 95% CI, 1.13-2.08; P = .006) and chronic heart failure (OR, 1.29; 95% CI, 1.04-1.60; P = .021) and was negatively associated with renal failure (OR, 0.80; 95% CI, 0.67-0.95; P = .012). The Northeast and West regions were associated with higher odds of AI in claudicant patients (OR, 2.41; 95% CI, 1.23-4.75; P = .011; and OR, 2.59; 95% CI, 1.34-5.02; P = .005, respectively) and CLI patients (OR, 4.31; 95% CI, 2.20-8.36; P < .0001; and OR, 2.18; 95% CI, 1.12-4.22; P = .021, respectively). Rates of AI utilization across states were not evenly distributed but showed great variability, with ranges from 0.31% to 9.81%. CONCLUSIONS: National utilization of AI for PAD is low and shows great variation among institutions in the United States. Patient and hospital factors are both associated with receiving AI in PAD care, and AI utilization is subject to significant regional variation. These findings suggest differences in systems of care or practice patterns and call for a clearer understanding and a more unified approach to imaging strategies in PAD care.

Failure to rescue in safety-net hospitals: availability of hospital resources and differences in performance.

IMPORTANCE: Failure to rescue (FTR), the mortality rate among surgical patients with complications, is an emerging quality indicator. Hospitals with a high safety-net burden, defined as the proportion of patients covered by Medicaid or uninsured, provide a disproportionate share of medical care to vulnerable populations. Given the financial strains on hospitals with a high safety-net burden, availability of clinical resources may have a role in outcome disparities. OBJECTIVES: To assess the association between safety-net burden and FTR and to evaluate the effect of clinical resources on this relationship. DESIGN, SETTING, AND PARTICIPANTS: A retrospective cohort of 46,519 patients who underwent high-risk inpatient surgery between January 1, 2007, and December 31, 2010, was assembled using the Nationwide Inpatient Sample. Hospitals were divided into the following 3 safety-net categories: high-burden hospitals (HBHs), moderate-burden hospitals (MBHs), and low-burden hospitals (LBHs). Bivariate and multivariate analyses controlling for patient, procedural, and hospital characteristics, as well as clinical resources, were used to evaluate the relationship between safety-net burden and FTR. MAIN OUTCOMES AND MEASURES: FTR. RESULTS: Patients in HBHs were younger (mean age, 65.2 vs 68.2 years; P = .001), more likely to be of black race (11.3% vs 4.2%, P < .001), and less likely to undergo an elective procedure (39.3% vs 48.6%, P = .002) compared with patients in LBHs. The HBHs were more likely to be large, major teaching facilities and to have high levels of technology (8.6% vs 4.0%, P = .02), sophisticated internal medicine (7.7% vs 4.3%, P = .10), and high ratios of respiratory therapists to beds (39.7% vs 21.1%, P < .001). However, HBHs had lower proportions of registered nurses (27.9% vs 38.8%, P = .02) and were less likely to have a positron emission tomographic scanner (15.4% vs 22.0%, P = .03) and a fully implemented electronic medical record (12.6% vs 17.8%, P = .03). Multivariate analyses showed that HBHs (adjusted odds ratio, 1.35; 95% CI, 1.19-1.53; P < .001) and MBHs (adjusted odds ratio, 1.15; 95% CI, 1.05-1.27; P = .005) were associated with higher odds of FTR compared with LBHs, even after adjustment for clinical resources. CONCLUSIONS AND RELEVANCE: Despite access to resources that can improve patient rescue rates, HBHs had higher odds of FTR, suggesting that availability of hospital clinical resources alone does not explain increased FTR rates.

When to call it a day: incremental risk of amputation and death after multiple revascularization.

BACKGROUND: Patients with critical limb ischemia (CLI) often undergo revascularization before amputation. The exact relationship between multiple procedures and increased risk of amputation is unclear. We sought to determine the increased risk of amputation for each additional revascularization. METHODS: The 2007-2009 California State Inpatient Database (SID) was used to identify a cohort of CLI patients undergoing revascularization and conduct a time-to-event analysis for patients undergoing one or more revascularization procedures. One-year estimates were generated with Kaplan-Meier curves and compared with the log-rank test. The Wei-Lin-Weissfeld (WLW) marginal proportional hazards model was used to assess independent effects of number of revascularization procedures on amputation and death. RESULTS: A total of 11,190 patients with CLI underwent revascularization between July 2007 and December 2009. Their mean age was 71.0 years (interquartile range 62-80 years) and 6255 (55.9%) were male. Over half the subjects (55.2%) were smokers and there was a high burden of comorbidities in the cohort. One-year estimates of amputation by number of revascularizations (1: 23.3%; 2: 27.1%; 3: 30.3%; 4: 26.7%; 5(+): 28.6%; P < 0.001) and death (1: 18.7%; 2: 21.1%; 3: 26.3%; 4: 23.6%; 5+: 32.1%; P = 0.012) increased significantly as procedures increased. In the WLW model for amputation, the hazard increased significantly for patients with 2 revascularization versus 1 (HR = 1.22; 95% CI 1.09-1.37; P = 0.001) and 3 revascularizations versus 2 (HR = 1.33; 95% CI 1.10-1.62; P = 0.004). In the multivariable WLW models for death, the increase in revascularization procedures for 2 compared with 1 (HR = 1.18; 95% CI 1.04-1.34; P = 0.010) was significant. CONCLUSIONS: The risk of amputation increases with each additional revascularization procedure. These findings hold true for both percutaneous transluminal angioplasty only and lower extremity bypass only subsets. In addition, increased revascularization procedures appear to result in an increased risk of death. We advocate for continued communication between clinicians and patients on the true risks and benefits of additional revascularization procedures.

Comparative methods for handling missing data in large databases.

OBJECTIVE: Analysis of complex survey databases is an important tool for health services researchers. Missing data elements are challenging because the reasons for "missingness" are multifactorial, especially categorical variables such as race. We simulated missing data for race and analyzed the bias from five methods used in predicting major amputation in patients with critical limb ischemia (CLI). METHODS: Patient discharges with fully observed data containing lower extremity revascularization or major amputation and CLI were selected from the 2003 to 2007 Nationwide Inpatient Sample, a complex survey database (weighted n = 684,057). Considering several random missing data schemes, we compared five missing data methods: complete case analysis, replacement with observed frequencies, missing indicator variable, multiple imputation, and reweighted estimating equations. We created 100 simulated data sets, with 5%, 15%, or 30% of subjects' race drawn to be missing from the full data set. Bias was estimated by comparing the estimated regression coefficients averaged over 100 simulated data sets (ß(miss)) from each method vs estimates from the fully observed data set (ß(full)), with relative bias calculated as (ß(full) - ß(miss)/ß(full)) × 100%. RESULTS: Our results demonstrate that reweighted estimating equations produce the least biased and the missing indicator variable produces the most biased coefficients. Complete case analysis, replacement with observed frequencies, and multiple imputation resulted in moderate bias. Sensitivity analysis demonstrated the optimal method choice depends on the quantity and type of missing data encountered. CONCLUSIONS: Missing data are an important analytic topic in research with large databases. The commonly used missing indicator variable method introduces severe bias and should be used with caution. We present empiric evidence to guide method selection for handling missing data.

Use of surveillance imaging following treatment of small renal masses.

PURPOSE: With the increasing incidence of small renal masses, there is greater use of ablation, nephron sparing surgery and surveillance compared to radical nephrectomy. However, patterns of care in the use of posttreatment imaging remain uncharacterized. The purpose of this study is to determine the rate of posttreatment imaging after various treatments for small renal mass. MATERIALS AND METHODS: Using SEER (Surveillance, Epidemiology and End Results)-Medicare data during 2005 to 2009, we identified 1,682 subjects diagnosed with small renal mass and treated with open partial nephrectomy (330), minimally invasive partial nephrectomy (160), open radical nephrectomy (404), minimally invasive radical nephrectomy (535), thermal ablation (212) and surveillance (42). Use of imaging was compared within 24 months of treatment and multivariate regression models were constructed to identify factors associated with increased imaging use. RESULTS: On adjusted analyses thermal ablation was associated with almost eightfold greater odds of surveillance imaging compared with open radical nephrectomy (OR 7.7, 95% CI 1.01-59.4). Specifically, thermal ablation was associated with increased computerized tomography (OR 5.28) and magnetic resonance imaging (OR 2.19) use and decreased ultrasound use (OR 0.59). Minimally invasive partial nephrectomy (OR 3.28) and open partial nephrectomy (OR 3.19) were also associated with increased computerized tomography use to a lesser extent. CONCLUSIONS: Subjects undergoing nephron sparing surgery undergo more posttreatment imaging compared to open radical nephrectomy. Although possibly associated with lower morbidity, thermal ablation is associated with significantly greater use of imaging compared to other small renal mass treatments. This may increase costs and radiation exposure, although further study is needed for confirmation.

Facial appearance transfer and persistence after three-dimensional virtual face transplantation.

BACKGROUND: Facial appearance transfer from donor to recipient in face transplantation is a concern. Previous studies of facial appearance transfer and facial appearance persistence (preservation of the recipient's facial likeness) in face transplants simulated using two-dimensional photographic manipulations found low facial appearance transfer (2.6 percent) and high facial appearance persistence (66 percent). Three-dimensional computer simulation of complex facial transplant patterns may improve the accuracy of facial appearance transfer and facial appearance persistence estimations. METHODS: Three-dimensional virtual models of human faces were generated from deidentified computed tomographic angiographs and used as "donors" or "recipients" for virtual face transplantation. Surgical planning software was used to perform 73 virtual face transplantations by creating specific facial defects (mandibular, midface, or large) in the recipient models and restoring them with allografts extracted from the donor models. Twenty independent reviewers evaluated the resemblance of each resulting posttransplant model to the donor (facial appearance transfer) and recipient (facial appearance persistence). The results were analyzed using tests for equal results with one-sample and pairwise Rao-Scott Pearson chi-square testing, correcting for clustering and multiple testing. RESULTS: Overall rates of facial appearance persistence and facial appearance transfer were high (69.2 percent) and low (32.4 percent), respectively. The mandibular pattern had the highest rates of facial appearance persistence and lowest rates of facial appearance transfer. Facial appearance persistence and transfer were similar across sexes. CONCLUSIONS: Facial appearance persistence is high and facial appearance transfer is low after virtual face transplantation. Appearance transfer and persistence after virtual face transplantation are more dependent on the anatomy than on the size of transplanted facial aesthetic units. This information may reassure recipients of partial face transplants and donor families.

Outcomes of lower extremity bypass performed for acute limb ischemia.

OBJECTIVE: Acute limb ischemia remains one of the most challenging emergencies in vascular surgery. Historically, outcomes following interventions for acute limb ischemia have been associated with high rates of morbidity and mortality. The purpose of this study was to determine contemporary outcomes following lower extremity bypass performed for acute limb ischemia. METHODS: All patients undergoing infrainguinal lower extremity bypass between 2003 and 2011 within hospitals comprising the Vascular Study Group of New England were identified. Patients were stratified according to whether or not the indication for lower extremity bypass was acute limb ischemia. Primary end points included bypass graft occlusion, major amputation, and mortality at 1 year postoperatively as determined by Kaplan-Meier life table analysis. Multivariable Cox proportional hazards models were constructed to evaluate independent predictors of mortality and major amputation at 1 year. RESULTS: Of 5712 lower extremity bypass procedures, 323 (5.7%) were performed for acute limb ischemia. Patients undergoing lower extremity bypass for acute limb ischemia were similar in age (66 vs 67; P = .084) and sex (68% male vs 69% male; P = .617) compared with chronic ischemia patients, but were less likely to be on aspirin (63% vs 75%; P < .0001) or a statin (55% vs 68%; P < .0001). Patients with acute limb ischemia were more likely to be current smokers (49% vs 39%; P < .0001), to have had a prior ipsilateral bypass (33% vs 24%; P = .004) or a prior ipsilateral percutaneous intervention (41% vs 29%; P = .001). Bypasses performed for acute limb ischemia were longer in duration (270 vs 244 minutes; P = .007), had greater blood loss (363 vs 272 mL; P < .0001), and more commonly utilized prosthetic conduits (41% vs 33%; P = .003). Acute limb ischemia patients experienced increased in-hospital major adverse events (20% vs 12%; P < .0001) including myocardial infarction, congestive heart failure exacerbation, deterioration in renal function, and respiratory complications. Patients who underwent lower extremity bypass for acute limb ischemia had no difference in rates of graft occlusion (18.1% vs 18.5%; P = .77), but did have significantly higher rates of limb loss (22.4% vs 9.7%; P < .0001) and mortality (20.9% vs 13.1%; P < .0001) at 1 year. On multivariable analysis, acute limb ischemia was an independent predictor of both major amputation (hazard ratio, 2.16; confidence interval, 1.38-3.40; P = .001) and mortality (hazard ratio, 1.41; confidence interval, 1.09-1.83; P = .009) at 1 year. CONCLUSIONS: Patients who present with acute limb ischemia represent a less medically optimized subgroup within the population of patients undergoing lower extremity bypass. These patients may be expected to have more complex operations followed by increased rates of perioperative adverse events. Additionally, despite equivalent graft patency rates, patients undergoing lower extremity bypass for acute ischemia have significantly higher rates of major amputation and mortality at 1 year.

Impact of hospital market competition on endovascular aneurysm repair adoption and outcomes.

OBJECTIVE: The share of total abdominal aortic aneurysm (AAA) repairs performed by endovascular aneurysm repair (EVAR) increased rapidly from 32% in 2001 to 65% in 2006 with considerable variation between states. We hypothesized that hospitals in competitive markets were early EVAR adopters and had improved AAA repair outcomes. METHODS: Nationwide Inpatient Sample and linked Hospital Market Structure (HMS) data was queried for patients who underwent repair for nonruptured AAA in 2003. In HMS, the Herfindahl Hirschman Index (HHI, range 0-1) is a validated and widely accepted economic measure of competition. Hospital markets were defined using a variable geographic radius that encompassed 90% of discharged patients. We conducted bivariate and multivariable linear and logistic regression analyses for the dependent variable of EVAR use. A propensity score-adjusted multivariable logistic regression model was used to control for treatment bias in the assessment of competition on AAA repair outcomes. RESULTS: A weighted total of 21,600 patients was included in our analyses. Patients at more competitive hospitals (lower HHI) were at increased odds of undergoing EVAR vs open repair (odds ratio, 1.127 per 0.1 decrease in HHI; P < .0127) after adjusting for patient demographics, comorbidities, and hospital level factors (bed size, teaching status, AAA repair volume, and ownership). Competition was not associated with differences in in-hospital mortality or vascular, neurologic, or other minor postoperative complications. CONCLUSIONS: Greater hospital competition is significantly associated with increased EVAR adoption at a time when diffusion of this technology passed its tipping point. Hospital competition does not influence post-AAA repair outcomes. These results suggest that adoption of novel vascular technology is not solely driven by clinical indications but may also be influenced by market forces.