Katie E. Shean

Sex differences in mortality and morbidity following repair of intact abdominal aortic aneurysms

Objective: Medicare studies have shown increased perioperative mortality in women compared with men following endovascular and open abdominal aortic aneurysm (AAA) repair. However, a recent regional study of high‐volume centers, adjusting for anatomy but limited in sample size, did not show sex to be predictive of worse outcomes. This study aimed to evaluate sex differences after intact AAA repair in a national clinical registry. Methods: The targeted vascular module of the National Surgical Quality Improvement Program was queried to identify patients undergoing endovascular aneurysm repair (EVAR) or open repair for intact, infrarenal AAA from 2011 to 2014. Univariate analysis was performed using the Fisher exact test and Mann‐Whitney test. Multivariable logistic regression was used to account for differences in comorbidities, aneurysm details, and operative characteristics. Results: We identified 6661 patients (19% women) who underwent intact AAA repair (87% EVAR; 83% women vs 88% men; P < .001). Women were older (median age, 76 vs 73 years; P < .001), had smaller aneurysms (median, 5.4 vs 5.5 cm; P < .001), and had more chronic obstructive pulmonary disease (22% vs 17%; P < .001). Among patients undergoing EVAR, women had longer operative times (median, 138 [interquartile range, 103–170] vs 131 [106–181] minutes; P < .01) and more often underwent renal (6.3% vs 4.1%; P < .01) and lower extremity (6.6% vs 3.8%; P < .01) revascularization. After open repair, women had shorter operative time (215 [177–304] vs 226 [165–264] minutes; P = .02), but women less frequently underwent lower extremity revascularization (3.1% vs 8.2%; P = .03). Thirty‐day mortality was higher in women after EVAR (3.2% vs 1.2%; P < .001) and open repair (8.0% vs 4.0%; P = .04). After adjusting for repair type, age, aneurysm diameter, and comorbidities, female sex was independently associated with mortality (odds ratio [OR], 1.7; 95% confidence interval [CI], 1.1–2.6; P = .02) and major complications (OR, 1.4; CI, 1.1–1.7; P < .01) after intact AAA repair. However, after adjusting for aortic size index rather than for aortic diameter, the association between female sex and mortality (OR, 1.5; CI, 0.98–2.4; P = .06) and major complications (OR, 1.1; CI, 0.9–1.4; P = .24) was reduced. Conclusions: Women were at higher risk for 30‐day death and major complications after intact AAA repair. Some of this disparity may be explained by differences in aortic size index, which should be further evaluated to determine the ideal threshold for repair.

The effect of surgeon and hospital volume on mortality after open and endovascular repair of abdominal aortic aneurysms

Background: Higher hospital and surgeon volumes are independently associated with improved mortality after open repair of abdominal aortic aneurysms (AAAs) in the era before endovascular AAA repair (EVAR). The effects of both surgeon and hospital volume on mortality after EVAR and open repair in the current era are less well defined. Methods: We studied Medicare beneficiaries who underwent elective AAA repair from 2001 to 2008. Volume was measured by procedure type during the 1‐year period preceding each procedure and was further categorized into quintiles of volume for surgeon and hospital. Multilevel logistic regression models were used to evaluate the effect of surgeon volume, accounting for hospital volume, on mortality after adjusting for patient demographic and comorbid conditions as well as the analogous effect of hospital volume adjusting for surgeon volume. The multilevel models included random effects for surgeon and hospital to account for the clustering of multiple patients within the same surgeon and within the same hospital. Results: We studied 122,495 patients who underwent AAA repair (open: 45,451; EVAR: 77,044). After EVAR, perioperative mortality did not differ by surgeon volume (quintile 1 [0–6 EVARs]: 1.8%; quintile 5 [28–151 EVARs]: 1.6%; P = .29), but decreased with greater hospital volume (quintile 1 [0–9 EVARs]: 1.9%; quintile 5 [49–198 EVARs]: 1.4%; P < .01). After open repair, perioperative mortality decreased with both higher surgeon volume (quintile 1 [0–3 open repairs]: 6.4%; quintile 5 [14–62 open repairs]: 3.8%; P < .01) and hospital volume (quintile 1 [0–5 open repairs]: 6.3%; quintile 5 [14–62 open repairs]: 3.8%; P < .01). After adjustment for other predictors, surgeon volume was not associated with perioperative mortality after EVAR (odds ratio [OR], 0.9; 95% confidence interval [CI], 0.7–1.1); however, hospital volume was associated with higher perioperative mortality (quintile 1: OR, 1.5; 95% CI, 1.2–1.9; quintile 2: OR, 1.3; 95% CI, 1.02–1.6; and quintile 3: OR, 1.2; 95% CI, 1.01–1.5, compared with 5). After open repair, higher surgeon volume was also associated with lower mortality (quintile 1: OR, 1.5; 95% CI, 1.3–1.8; quintile 2: OR, 1.3; 95% CI, 1.1–1.6; and quintile 3: OR, 1.2; 95% CI, 1.1–1.4, compared with 5). Risk of mortality also was higher for patients treated at lower‐volume hospitals (quintile 1: OR, 1.3; 95% CI, 1.1–1.5; quintile 2: OR, 1.3; 95% CI, 1.1–1.5; and quintile 3: OR, 1.2; 95% CI, 1.1–1.4, compared with 5). Conclusions: After EVAR, hospital volume is minimally associated with perioperative mortality, with no such association for surgeon volume. After open AAA repair, surgeon and hospital volume are both strongly associated with mortality. These findings suggest that open surgery should be concentrated in hospitals and surgeons with high volume.

Predictors of renal dysfunction after endovascular and open repair of abdominal aortic aneurysms

Objective: Renal complications after repair of abdominal aortic aneurysms (AAAs) have been associated with increased morbidity and mortality. However, limited data have assessed risk factors for renal complications in the endovascular era. This study aimed to identify predictors of renal complications after endovascular AAA repair (EVAR) and open repair. Methods: Patients who underwent EVAR or open repair of a nonruptured infrarenal AAA between 2011 and 2013 were identified in the National Surgical Quality Improvement Project Targeted Vascular module. Patients on hemodialysis preoperatively were excluded. Renal complications were defined as new postoperative dialysis or creatinine increase >2 mg/dL. Patient demographics, comorbidities, glomerular filtration rate (GFR), operative details, and outcomes were compared using univariate analysis between those with and without renal complications. Multivariable logistic regression was used to identify independent predictors of renal complications. Results: We identified 4503 patients who underwent elective repair of an infrarenal AAA (EVAR: 3869, open repair: 634). Renal complication occurred in 1% of patients after EVAR and in 5% of patients after open repair. There were no differences in comorbidities between patients with and without renal complications. A preoperative GFR <60 mL/min/1.73m2 occurred more frequently among patients with renal complications (EVAR: 81% vs 37%, P < .01; open: 60% vs 34%, P < .01). The 30‐day mortality was also significantly increased (EVAR: 55% vs 1%, P < .01; open: 30% vs 4%, P < .01). After adjustment, renal complications were strongly associated with 30‐day mortality (odds ratio [OR], 38.3; 95% confidence interval [CI], 20.4–71.9). Independent predictors of renal complications included GFR <60 mL/min/1.73m2 (OR, 4.6; 95% CI, 2.4–8.7), open repair (OR, 2.6; 95% CI, 1.3–5.3), transfusion (OR, 6.1; 95% CI, 3.0–12.6), and prolonged operative time (OR, 3.0; 95% CI, 1.6–5.6). Conclusions: Predictors of renal complications include elevated baseline GFR, open approach, transfusion, and prolonged operative time. Given the dramatic increase in mortality associated with renal complications, care should be taken to use renal protective strategies, achieve meticulous hemostasis to limit transfusions, and to use an endovascular approach when technically feasible.

Early extubation reduces respiratory complications and hospital length of stay following repair of abdominal aortic aneurysms

Background: Early extubation after cardiac surgery is associated with decreased hospital stay and resource savings with similar mortality and has led to the widespread use of early extubation protocols. In the Vascular Quality Initiative, there is significant regional variation in the frequency of extubation in the operating room (endovascular aneurysm repair [EVAR], 77%‐97%; open repair, 30%‐70%) after repair of intact abdominal aortic aneurysms (AAAs). However, the effects of extubation practices on patient outcomes after repair of AAAs are unclear. Methods: All patients undergoing repair of an intact AAA in the Vascular Study Group of New England from 2003 to 2015 were evaluated. Patients undergoing concomitant procedures or conversions were excluded. Timing of extubation was stratified for EVAR (operating room, <12 hours, >12 hours) and open repair (operating room, <12 hours, 12‐24 hours, >24 hours). Prolonged hospital stay was defined as >2 days after EVAR and >7 days after open repair. Univariate and multivariable analyses were completed, and independent predictors of extubation outside of the operating room were identified. Results: There were 5774 patients evaluated (EVAR, 4453; open repair, 1321). After both EVAR and open repair, respiratory complications, prolonged hospital stay, and discharge to a skilled nursing facility (SNF) increased with intubation time. After adjustment, the odds of complications increased with each 12‐hour delay in extubation: respiratory (EVAR: odds ratio [OR], 4.3 [95% confidence interval (CI), 3.0‐6.1]; open repair: OR, 1.8 [95% CI, 1.5‐2.2]), prolonged hospital stay (EVAR: OR, 2.7 [95% CI, 2.0‐3.8]; open repair: OR, 1.3 [95% CI, 1.1‐1.4]), and discharge to SNF (EVAR: OR, 2.0 [95% CI, 1.5‐2.8]; open repair: OR, 1.4 [95% CI, 1.1‐1.6]). Predictors of extubation outside of the operating room after EVAR included increasing age (OR, 1.5; 95% CI, 1.2‐1.8), congestive heart failure (OR, 1.9; 95% CI, 1.2‐3.0), chronic obstructive pulmonary disease (OR, 2.0; 95% CI, 1.4‐2.9), symptomatic aneurysm (OR, 3.8; 95% CI, 2.3‐5.7), and increasing diameter (OR, 1.01; 95% CI, 1.01‐1.01). After open repair, increasing age (OR, 1.4; 95% CI, 1.1‐1.6), congestive heart failure (OR, 1.8; 95% CI, 1.01‐3.3), dialysis (OR, 2.8; 95% CI, 1.7‐70), symptomatic aneurysm (OR, 2.8; 95% CI, 1.9‐4.3), and hospital practice patterns (OR, 1.01; 95% CI, 1.01‐1.01) were predictive of extubation outside of the operating room. Conclusions: The benefits of early extubation in cardiac patients are also seen after AAA repair. Suitable patients should be extubated in the operating room to decrease respiratory complications, length of stay, and discharge to an SNF. Early extubation protocols should be considered to reduce regional variation in extubation practices and to improve patient outcomes.

Female sex independently predicts mortality after thoracic endovascular aortic repair for intact descending thoracic aortic aneurysms

Objective: Whereas sex differences in the pathogenesis, presentation, and outcomes of repair for abdominal aortic aneurysms are well studied, less is known about sex differences after thoracic endovascular aortic repair (TEVAR). The goal of this study was to evaluate the association between sex and morbidity and mortality after TEVAR. Methods: A retrospective review of all TEVARs in the Society for Vascular Surgery Vascular Quality Initiative (VQI) registry from 2011 to 2015 was conducted, excluding those with dissection, trauma, and rupture. Statistical analysis was performed using the Fisher exact test and the Mann‐Whitney U test for categorical and continuous variables. Multivariable logistic regression and Cox hazards modeling were used to account for differences in demographics, comorbidities, and aneurysm characteristics in 30‐day mortality and long‐term survival. Results: We identified 2574 patients (40% women) who underwent TEVAR. Women were older, were less likely to be white, and had smaller aortic diameters but larger aortic size indices (aortic diameter/body surface area). Women also had more chronic obstructive pulmonary disease but less coronary artery disease and fewer coronary interventions. Women were more likely to be symptomatic at presentation and subsequently to have a nonelective procedure. Women had higher estimated blood loss >500 mL (20% vs 17%; P = .04), were more likely to be transfused (29% vs 21%; P < .001), and more frequently underwent iliac access procedures (4.3% vs 2.1%; P < .01). Operative time and left subclavian intervention were similar. Postoperatively, women had increased median hospital (5 vs 4 days; P < .001) and intensive care unit (2.5 vs 2 days; P < .001) lengths of stay and were less likely to be discharged home (75% vs 86%; P < .001). Mortality was higher for women at 30 days (5.4% vs 3.3%; P < .01) and 1 year (9.8% vs 6.3%; P < .01). After adjusting for age, aortic size index, symptoms, and comorbidities, female sex remained independently predictive of 30‐day mortality (odds ratio, 1.5; 95% confidence interval, 1.1‐2.1, P < .01) and long‐term mortality (hazard ratio, 1.3; 95% confidence interval, 1.03‐1.6; P = .02). Conclusions: Even after adjusting for differences in age and comorbidities, female patients have higher perioperative mortality and lower long‐term survival after TEVAR. These findings, along with the rupture risk by sex, should be considered by clinicians in determining the timing of intervention.

Adherence to lipid management guidelines is associated with lower mortality and major adverse limb events in patients undergoing revascularization for chronic limb-threatening ischemia

Objective: The 2013 American College of Cardiology/American Heart Association lipid management guidelines recommend high‐intensity statins for all patients ≤75 years old with chronic limb‐threatening ischemia (CLTI) and moderate‐intensity statins for CLTI patients >75 years old without contraindications or on dialysis, but these recommendations are based primarily on coronary and stroke data. We aimed to validate these guidelines in patients with CLTI and to assess current adherence to these recommendations. Methods: We identified all patients with CLTI who underwent first‐time revascularization (endovascular or surgical) at Beth Israel Deaconess Medical Center from 2005 to 2014. Patients were classified as taking high‐intensity, moderate‐intensity, low‐intensity, or no statin postoperatively. Outcomes included death and major adverse limb event (MALE). Propensity scores were calculated for the probability of receiving guideline‐recommended intensity of statin therapy to account for nonrandom assignment of treatments. Cox regression models were constructed and adjusted for the propensity scores and further adjusted for strong potential confounders. Results: After excluding patients on hemodialysis (n = 252), we identified 1019 limbs from 931 patients with a median follow‐up of 380 days. Patients discharged on the recommended statin intensity had higher rates of preoperative statin use, coronary artery disease, chronic kidney disease, stroke, atrial fibrillation, congestive heart failure, and coronary artery bypass grafting; they had lower smoking rates and were less likely to be ambulatory preoperatively. Overall, only 35% were taking the recommended statin dosage: 55% of those >75 years old and 20% of those ≤75 years old. In multivariable analysis including propensity scores where appropriate, discharge on any statin was associated with lower mortality (hazard ratio [HR], 0.71; 95% confidence interval [CI], 0.60‐0.90; P < .01). Discharge on the recommended intensity of statin therapy was associated with lower mortality (HR, 0.73; 95% CI, 0.60‐0.99; P < .05) and lower MALE rate (HR, 0.71; 95% CI, 0.51‐0.97; P < .05). Patients >75 years old and ≤75 years old accrued similar benefit. In patients >75 years old, moderate‐intensity statin therapy was associated with lower rates of death and MALE compared with high‐intensity therapy but did not reach statistical significance. Conclusions: Use of the recommended intensity of statin therapy in compliance with 2013 American College of Cardiology/American Heart Association lipid management guidelines is associated with significantly improved survival and lower MALE rate in patients undergoing revascularization for CLTI. Adherence to current guidelines is an appealing target for quality improvement.

Regional variation in patient selection and treatment for carotid artery disease in the Vascular Quality Initiative

Objective: Previous studies involving large administrative data sets have revealed regional variation in the demographics of patients selected for carotid endarterectomy (CEA) and carotid artery stenting (CAS) but lacked clinical granularity. This study aimed to evaluate regional variation in patient selection and operative technique for carotid artery revascularization using a detailed clinical registry. Methods: All patients who underwent CEA or CAS from 2009 to 2015 were identified in the Vascular Quality Initiative (VQI). Deidentified regional groups were used to evaluate variation in patient selection, operative technique, and perioperative management. χ2 analysis was used to identify significant variation across regions. Results: A total of 57,555 carotid artery revascularization procedures were identified. Of these, 49,179 patients underwent CEA (asymptomatic: median, 56%; range, 46%‐69%; P < .01) and 8376 patients underwent CAS (asymptomatic: median, 36%; range, 29%‐51%; P < .01). There was significant regional variation in the proportion of asymptomatic patients being treated for carotid stenosis <70% in CEA (3%‐9%; P < .01) vs CAS (3%‐22%; P < .01). There was also significant variation in the rates of intervention for asymptomatic patients older than 80 years (CEA, 12%‐27% [P < .01]; CAS, 8%‐26% [P < .01]). Preoperative computed tomography angiography or magnetic resonance angiography in the CAS cohort also varied widely (31%‐83%; P < .01), as did preoperative medical management with combined aspirin and statin (CEA, 53%‐77% [P < .01]; CAS, 62%‐80% [P < .01]). In the CEA group, the use of shunt (36%‐83%; P < .01), protamine (32%‐89%; P < .01), and patch (87%‐99%; P < .01) varied widely. Similarly, there was regional variation in frequency of CAS done without a protection device (1%‐8%; P < .01). Conclusions: Despite clinical benchmarks aimed at guiding management of carotid disease, wide variation in clinical practice exists, including the proportion of asymptomatic patients being treated by CAS and preoperative medical management. Additional intraoperative variables, including the use of a patch and protamine during CEA and use of a protection device during CAS, displayed similar variation in spite of clear guidelines. Quality improvement projects could be directed toward improved adherence to benchmarks in these areas.

The impact of endovascular repair on management and outcome of ruptured thoracic aortic aneurysms

Background: Thoracic endovascular aortic repair (TEVAR) has become an alternative to open repair for the treatment of ruptured thoracic aortic aneurysms (rTAAs). The aim of this study was to assess national trends in the use of TEVAR for the treatment of rTAA and to determine its impact on perioperative outcomes. Methods: Patients admitted with an rTAA between 1993 and 2012 were identified from the National Inpatient Sample. Patients were grouped in accordance with their treatment: TEVAR, open repair, or nonoperative treatment. The primary outcomes were treatment trends over time and in‐hospital death. Secondary outcomes included perioperative complications and length of stay. Trend analyses were performed using the Cochran‐Armitage test for trend, and adjusted mortality risks were established using multivariable logistic regression analysis. Results: A total of 12,399 patients were included, with 1622 (13%) undergoing TEVAR, 2808 (23%) undergoing open repair, and 7969 (64%) not undergoing surgical treatment. TEVAR has been increasingly used from 2% of total admissions in 2003‐2004 to 43% in 2011‐2012 (P < .001). Concurrently, there was a decline in the proportion of patients undergoing open repair (29% to 12%; P < .001) and nonoperative treatment (69% to 45%; P < .001). The proportion of patients undergoing surgical repair has increased for all age groups since 1993‐1994 (P < .001 for all) but was most pronounced among those aged 80 years with a 7.5‐fold increase. After TEVAR was introduced, procedural mortality decreased from 36% in 2003‐2004 to 27% in 2011‐2012 (P < .001); mortality among those undergoing nonoperative treatment remained stable between 63% and 60% (P = .167). Overall mortality after rTAA admission decreased from 55% to 42% (P < .001). Since 2005, mortality for open repair was 33% and 22% for TEVAR (P < .001). In adjusted analysis, open repair was associated with a twofold higher mortality than TEVAR (odds ratio, 2.0; 95% confidence interval, 1.7‐2.5). Conclusions: TEVAR has replaced open repair as primary surgical treatment for rTAA. The introduction of endovascular treatment appears to have broadened the eligibility of patients for surgical treatment, particularly among the elderly. Mortality after rTAA admission has declined since the introduction of TEVAR, which is the result of improved operative mortality as well as the increased proportion of patients undergoing surgical repair.

Regional variation in outcomes for lower extremity vascular disease in the Vascular Quality Initiative

Background: Increased focus has been placed on perioperative and long‐term outcomes in the treatment of peripheral artery disease (PAD), both for purposes of quality improvement and for assessment of performance at a surgeon and institutional level. This study evaluates regional variation in outcomes after treatment for PAD within the Vascular Quality Initiative (VQI). By describing the variation in practice patterns and outcomes across regions, we hope that each regionally based quality group can select which areas are most important for them to focus on as they will have access to their regional data to compare. Methods: We identified all patients in the VQI who had infrainguinal bypass or endovascular intervention from 2009 to 2014. We compared variation in perioperative and 1‐year outcomes stratified by symptom status and revascularization type among the 16 regional groups of the VQI. We analyzed variation in perioperative end points using χ2 analysis, and 1‐year end points were analyzed using Kaplan‐Meier and life‐table analysis. Results: We identified 15,338 bypass procedures for symptomatic PAD: 27% for claudication, 59% for chronic limb‐threatening ischemia (CLI; 61% of these for tissue loss), and 14% for acute limb ischemia. We identified 33,925 endovascular procedures for symptomatic PAD: 42% for claudication, 48% for CLI (73% of these for tissue loss), and 10% for acute limb ischemia. Thirty‐day mortality varied significantly after endovascular intervention for CLI (0.5%‐3%; P < .001) but not for claudication (0.0%‐0.5%, P = .77) or for bypass for claudication (0.0%‐2.6%; P = .37) or CLI (0.0%‐5.0%; P = .08). After bypass, rates of >2 units transfused red blood cells (claudication, 0.0%‐13% [P < .001]; CLI, 6.9%‐27% [P < .001]) varied significantly. In‐hospital major amputation was variable after bypass for CLI (0.0%‐4.3%; P = .004) but not for claudication (0.0%‐0.6%; P = .98), as was postoperative myocardial infarction (claudication, 0.0%‐4% [P = .36]; CLI, 0.8%‐6% [P = .001]). One‐year survival varied significantly for endovascular interventions for claudication (92%‐100%; P < .001), bypass for CLI (85%‐94% [P < .001]), and endovascular interventions for CLI (77%‐96%; P < .001) but not after bypass for claudication (95%‐100%; P = .57). Conclusions: In this real‐world comparison among VQI regions, we found significant variation in perioperative and 1‐year end points for patients with PAD undergoing bypass or endovascular intervention. This study highlights opportunities for quality improvement efforts to reduce variation and to improve outcomes.

Treatment outcomes in diabetic patients with chronic limb-threatening ischemia

Objective: There are conflicting reports about outcomes after infrainguinal bypass for chronic limb‐threatening ischemia (CLTI) in patients with diabetes. We compared perioperative outcomes between patients with and patients without diabetes in the current era. Methods: The National Surgical Quality Improvement Program vascular module, 2011 to 2014, was used to identify patients undergoing infrainguinal revascularization for CLTI. Patients with and without diabetes were compared in terms of presentation, comorbidities, operative approach, and 30‐day outcomes. Major adverse limb events (MALEs) included 30‐day major reintervention or amputation, and major adverse cardiovascular events (MACEs) included 30‐day myocardial infarction, cardiac arrest, stroke, or death. Multivariable logistic regression was used to adjust for baseline differences. Results: We identified 8887 patients undergoing open (5744; 50% diabetic) or endovascular (3143; 62% diabetic) treatment for CLTI. Patients with diabetes were younger and more often nonwhite, nonsmokers, and obese. Patients with diabetes presented more often with tissue loss (71% vs 47%; P < .001) and were more likely to be treated with endovascular intervention (41% vs 29%; P < .001). The 30‐day mortality was similar before (open, 3.1% vs 2.8% [P = .53]; endovascular, 2.6% vs 2.1% [P = .37]) and after adjustment for baseline differences (open: odds ratio [OR], 1.1 [95% confidence interval (CI), 0.7‐1.5]; endovascular: OR, 1.2 [95% CI, 0.7‐2.0]). Patients with diabetes had longer lengths of stay (open, 8 vs 6 days [P < .001]; endovascular, 3 vs 2 days [P < .001]) and higher 30‐day readmission rates (open, 21% vs 18% [P < .01]; endovascular, 20% vs 15% [P < .01]); however, these differences were no longer significant after adjustment for baseline differences. Patients with diabetes had a higher rate of MACEs (7.0% vs 5.1%; P < .01) and lower rate of MALEs (8.1% vs 10%; P < .01) after bypass. After adjustment, patients with diabetes still had a lower rate of MALEs (OR, 0.7; 95% CI, 0.6‐0.9) but no longer had a higher rate of MACEs (OR, 1.2; 95% CI, 0.9‐1.6). Conclusions: CLTI patients with diabetes undergoing revascularization have similar 30‐day outcomes compared with those without diabetes, although they appear to be at lower risk for MALEs after bypass. Prolonged length of stay and readmission in patients with diabetes is not due to underlying diabetic disease but likely secondary to other baseline comorbidities, such as higher rates of tissue loss. Concern for worse perioperative outcomes in patients with diabetes after lower extremity bypass is unsubstantiated and should not discourage a physician from performing an open bypass.