Estimating the Effect of Bariatric Surgery on Cardiovascular Events Using Observational Data?

BACKGROUND: Observational studies have reported strongly protective effects of bariatric surgery on cardiovascular disease, but with oversimplified definitions of the intervention, eligibility criteria, and follow-up, which deviate from those in a randomized trial. We describe an attempt to estimate the effect of bariatric surgery on cardiovascular disease without introducing these sources of bias, which may not be entirely possible with existing observational data. METHODS: We propose two target trials among persons with diabetes: (1) bariatric operation (vs. no operation) among individuals who have undergone preoperative preparation (lifestyle modifications and screening) and (2) preoperative preparation and a bariatric operation (vs. neither preoperative nor operative component). We emulated both target trials using observational data of US veterans. RESULTS: Comparing bariatric surgery with no surgery (target trial #1; 8,087 individuals), the 7-year cardiovascular risk was 18.0% (95% CI = 6.9, 32.7) in the surgery group and 18.9% (95% CI = 17.7, 20.1) in the no-surgery group (risk difference -0.9, 95% CI = -12.0, 14.0). Comparing preoperative components plus surgery vs. neither (target trial #2; 10,065 individuals), the 7-year cardiovascular risk was 17.4% (95% CI = 13.6, 22.0) in the surgery group and 18.8% (95% CI = 17.8, 19.9) in the no-surgery group (risk difference -1.4, 95% CI = -5.1, 3.2). Body mass index and hemoglobin A1c were reduced with bariatric interventions in both emulations. CONCLUSIONS: Within limitations of available observational data, our estimates do not provide evidence that bariatric surgery reduces cardiovascular disease and support equipoise for a randomized trial of bariatric surgery for cardiovascular disease prevention.

Symptomatic Diaphragmatic Hernia after Thoracofemoral Bypass.

Despite its relative underutilization in the primary management of aortoiliac occlusive disease, thoracofemoral bypass is an attractive extra-anatomic surgical option in select patients. Thoracofemoral bypass classically entails passing a graft from the left chest into the retroperitoneal space through a small opening created in the diaphragm. While theoretically possible that this maneuver may predispose to a peri-graft diaphragmatic hernia, currently there are no cases of this complication reported in the literature, nor has its surgical repair been described. This case illustrates the rare complication of symptomatic diaphragmatic hernia following a thoracobifemoral bypass.

Toward Best Practices for Surgical Morbidity and Mortality Conferences: A Mixed Methods Study.

OBJECTIVE: To assess formats for surgical morbidity and mortality conferences (M&M) for strengths and challenges. DESIGN: A mixed methods approach with local observations to assess key domains of M&M practice (i.e., goals, structure, and process/content) and surveys to assess participants' expectations and experiences. SETTING: Surgical departments of two teaching hospitals (Boston, USA and Leiden, Netherlands). PARTICIPANTS: Participants of surgical M&M, including attending surgeons, residents, physician assistants, and medical students (total n = 135). RESULTS: Surgical M&M practices at both hospitals had education as its overarching goal, but varied in structure and process/content. Expectations were similar at both sites with ≥80% of participants (n = 90; 67% response) expecting M&M to be focused on education as well as quality improvement (QI), blame-free, mandatory for both residents and attendings, and to lead to changes in clinical practice. However, compared to expectations, significantly fewer participants at both sites experienced: a QI focus (both p < 0.001); mandatory faculty attendance (p = 0.004; p < 0.001) and changes to practice (both p < 0.001). In comparison, at the site where an active moderator and QI committee are present, respondents seemed more positive about experiencing a QI focus (73% vs 30%) and changes to practice (44% vs 16%). CONCLUSION: Despite variation in M&M practice, the same (unmet) expectations existed at both hospitals, indicating that certain challenges may be more universal. M&M was reported to be well-focused on education, and certain aspects (e.g., active moderator and QI committee) seemed beneficial, but expectations were not met for the conference's focus and function for QI. Greater exchange of "best practices" for M&M may enhance the conference's value for improving surgical care.

Provider-Induced Demand in the Treatment of Carotid Artery Stenosis: Variation in Treatment Decisions Between Private Sector Fee-for-Service vs Salary-Based Military Physicians.

Importance: Although many factors influence the management of carotid artery stenosis, it is not well understood whether a preference toward procedural management exists when procedural volume and physician compensation are linked in the fee-for-service environment. Objective: To explore evidence for provider-induced demand in the management of carotid artery stenosis. Design, Setting, and Participants: The Department of Defense Military Health System Data Repository was queried for individuals diagnosed with carotid artery stenosis between October 1, 2006, and September 30, 2010. A hierarchical multivariable model evaluated the association of the treatment system (fee-for-service physicians in the private sector vs salary-based military physicians) with the odds of procedural intervention (carotid endarterectomy or carotid artery stenting) compared with medical management. Subanalysis was performed by symptom status at the time of presentation. The association of treatment system and of management strategy with clinical outcomes, including stroke and death, was also evaluated. Data analysis was conducted from August 15, 2015, to August 2, 2016. Main Outcomes and Measures: The odds of procedural intervention based on treatment system was the primary outcome used to indicate the presence and effect of provider-induced demand. Results: Of 10 579 individuals with a diagnosis of carotid artery stenosis (4615 women and 5964 men; mean [SD] age, 65.6 [11.4] years), 1307 (12.4%) underwent at least 1 procedure. After adjusting for demographic and clinical factors, the odds of undergoing procedural management were significantly higher for patients in the fee-for-service system compared with those in the salary-based setting (odds ratio, 1.629; 95% CI, 1.285-2.063; P < .001). This finding remained true when patients were stratified by symptom status at presentation (symptomatic: odds ratio, 2.074; 95% CI, 1.302-3.303; P = .002; and asymptomatic: odds ratio, 1.534; 95% CI, 1.186-1.984; P = .001). Conclusions and Relevance: Individuals treated in a fee-for-service system were significantly more likely to undergo procedural management for carotid stenosis compared with those in the salary-based setting. These findings remained consistent for individuals with and without symptomatic disease.

Predictors of major amputation despite patent bypass grafts.

OBJECTIVE: Despite patent vein bypass grafts, some patients with critical limb ischemia (CLI) receive major amputations. We analyzed the predictive factors leading to major amputation in the presence of patent lower extremity bypass (LEB) grafts. METHODS: Data from the Project of Ex-Vivo vein graft Engineering via Transfection III (PREVENT III), a large prospective randomized trial of 1404 patients who underwent LEB with vein graft for CLI, were queried for outcomes. The primary outcome was major amputation with patent (PMA) LEB compared with patients with patent LEB who achieved limb salvage (PLS). The population excluded those who received amputation for occluded grafts. A Cox proportional hazard model identified independent predictors. RESULTS: Of 1404 LEB patients, 162 (11.5%) had major amputation: 89 (6.3%) with patent and 73 (5.2%) with occluded LEB. For PMA, 21 of 89 (23.6%) developed critical stenosis and 11 of 21 (52.4%) were revised. For PLS, 460 of 1242 (37.0%) developed critical stenosis and 351 of 460 (76.3%) were revised. Predictive patient factors included having preoperative gangrene (vs rest pain; hazard ratio [HR], 3.504; 95% confidence interval [CI], 1.533-8.007; P = .0029), diabetes (HR, 1.800; 95% CI, 1.006-3.219; P = .0477), black (vs white) race (HR, 1.779; 95% CI, 1.051-3.011; P = .0321), baseline creatinine clearance <25 mL/min (vs >65 mL/min; HR, 1.759; 95% CI, 1.016-3.048; P = .0439), prior history of coronary artery bypass grafting (HR, 1.702; 95% CI, 1.080-2.683; P = .0221), and lower baseline activity quality of life score (HR, 1.401; 95% CI, 1.105-1.778; P = .0054). Postoperative wound factors included gangrenous changes (HR, 5.830; 95% CI, 1.647-20.635; P = .0063), surgical wound necrosis (HR, 5.319; 95% CI, 1.478-19.146; P = .0105), deep (vs superficial) wound infection (HR, 3.815; 95% CI, 1.220-11.927; P = .0213), and wound healing abnormally (HR, 3.754; 95% CI, 1.061-13.278; P = .0402). Associated postoperative consequences leading to PMA included having recurrent CLI symptoms (HR, 2.915; 95% CI, 1.816-4.681; P < .0001), a severe (vs mild) adverse event (HR, 2.751; 95% CI, 1.391-5.443; P = .0036), fewer percutaneous revisions (HR, 2.425; 95% CI, 1.573-3.740; P < .0001), discharge on low-molecular-weight heparin (HR, 2.087; 95% CI, 1.309-3.326; P = .0020), and decreasing days to critical stenosis/occlusion/revision/amputation (HR, 1.010; 95% CI, 1.007-1.012; P < .0001). CONCLUSIONS: Whereas a patent vein graft is important to all vascular surgeons, additional factors should be considered in trying to attain limb salvage for patients with CLI. These factors include intervening surgically before CLI has progressed to a state of gangrene or limited activity and optimizing nutrition, diabetes control, cardiac conditions, and activity level. Revision offers hope for clinical improvement but may be delayed when there is no graft lesion identified. The absence of a graft lesion to revise may also portend amputation despite a patent graft because of nongraft-related factors such as infection. Finally, the experience of a severe (vs mild) adverse event may also result in limb loss despite a patent graft. Systematic efforts to reduce severe adverse events among patients may also lead to increased limb salvage.

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.

Text paging of surgery residents: Efficacy, work intensity, and quality improvement.

BACKGROUND: Text pages can communicate important information but also disrupt workflow, which can affect the safety of patient care. The purpose of this study was to analyze the content, volume, and distribution of text pages received by general surgery residents and physician's assistants (PAs) using natural language processing (NLP). METHODS: We studied text pages received by residents and PAs at a tertiary care teaching hospital from March to May 2012 using NLP. The number and content of pages were stratified by recipient seniority, surgical service, patient census, and patient location. Chi-square tests, t test, and analysis of variance were used to detect statistical significance. RESULTS: We captured 48,202 pages. The average number (mean ± standard deviation) of pages per hour was 3.1 ± 2.2 for postgraduate year (PGY)-1s and 2.8 ± 1.9 for PAs (P < .0001). The greatest number of pages per day by Service was 86.1 ± 37.5 on the acute care surgery service. The most common paging topic was medications (18,444 [38.3%]) and the most common symptom was pain (6,240 pages [12.9%]). On services where patients were located near each other (regionalized), the number of pages per day per recipient per patient on census was almost half that compared with nonregionalized services (1.40 vs 2.43; P < .0001). CONCLUSION: Residents receive a high volume of pages at this tertiary care center, particularly regarding medications and pain. Services with regionalized patients exhibit less paging need per patient. Initiatives to improve pain management and regionalize patients may streamline communication, decrease the number of pages, and increase patient safety.

Concurrent venography during first rib resection and scalenectomy for venous thoracic outlet syndrome is safe and efficient.

OBJECTIVE: Surgical treatment of acute axillosubclavian vein thrombosis from venous thoracic outlet syndrome (VTOS) traditionally involves first rib resection and scalenectomy (FRRS) followed by interval venography and balloon angioplasty. This approach can lead to an extended need for anticoagulation and a separate anesthesia session. We present outcomes for FRRS with concurrent venography. METHODS: Retrospective chart review was performed for consecutive patients undergoing FRRS with concurrent venography for VTOS from February 2007 to April 2014. Venography was performed immediately after FRRS with the arm in neutral and provocative positions. The primary outcomes of this study were primary and primary-assisted patency. Secondary outcomes included whether concurrent venography resulted in modification of the procedure, postoperative anticoagulation use, and postoperative complications. RESULTS: Thirty patients underwent first rib resection with venography with a mean follow-up time of 24.4 months. The mean age was 29.5 years (range, 17-52 years), and 17 (56.7%) were female. All were maintained on anticoagulation before the procedure. Concurrent venography resulted in modification of the procedure in 28 patients (93.3%). Of these, 27 patients (96.4%) underwent balloon angioplasty and two patients (7.1%) underwent further rib resection. Twenty patients (66.7%) were discharged after the procedure with no anticoagulation. For those receiving postoperative anticoagulation for persistent minor thrombus, median time for anticoagulation duration was 5.0 months (range, 0.8 and 16.7 months). Two patients (6.7%) had postoperative bleeding requiring thoracentesis or video-assisted thoracoscopic evacuation of hemothorax. One patient (3.3%) suffered rethrombosis and was successfully lysed open, resulting in a 2-year subclavian vein (SCV) primary patency of 96.7% and primary-assisted patency of 100%. No patients required reoperation for VTOS, and all reported improvements in symptoms. Three patients (10.0%) later underwent prophylactic first rib resection on the contralateral side for symptoms and SCV stenosis. CONCLUSIONS: FRRS with concurrent venography is a safe procedure for VTOS that allows effective intraoperative modification of the surgical plan, resulting in excellent patency of the SCV, early cessation of anticoagulation, and durable relief of symptoms.

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.

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.