Alexander B. Pothof

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.

Risk factors for 30-day unplanned readmission following infrainguinal endovascular interventions

Objective: Unplanned hospital readmissions following surgical interventions are associated with adverse events and contribute to increasing health care costs. Despite numerous studies defining risk factors following lower extremity bypass surgery, evidence regarding readmission after endovascular interventions is limited. This study aimed to identify predictors of 30‐day unplanned readmission following infrainguinal endovascular interventions. Methods: We identified all patients undergoing an infrainguinal endovascular intervention in the targeted vascular module of the American College of Surgeons National Surgical Quality Improvement Program between 2012 and 2014. Perioperative outcomes were stratified by symptom status (chronic limb‐threatening ischemia [CLI] vs claudication). Patients who died during index admission and those who remained in the hospital after 30 days were excluded. Indications for unplanned readmission related to the index procedure were evaluated. Multivariable logistic regression was used to identify preoperative and in‐hospital (during index admission) risk factors of 30‐day unplanned readmission. Results: There were 4449 patients who underwent infrainguinal endovascular intervention, of whom 2802 (63%) had CLI (66% tissue loss) and 1647 (37%) had claudication. The unplanned readmission rates for CLI and claudication patients were 16% (n = 447) and 6.5% (n = 107), respectively. Mortality after index admission was higher for readmitted patients compared with those not readmitted (CLI, 3.4% vs 0.7% [P < .001]; claudication, 2.8% vs 0.1% [P < .01]). Approximately 50% of all unplanned readmissions were related to the index procedure. Among CLI patients, the most common indication for readmission related to the index procedure was wound or infection related (42%), whereas patients with claudication were mainly readmitted for recurrent symptoms of peripheral vascular disease (28%). In patients with CLI, predictors of unplanned readmission included diabetes (odds ratio, 1.3; 95% confidence interval, 1.01‐1.6), congestive heart failure (1.6; 1.1‐2.5), renal insufficiency (1.7; 1.3‐2.2), preoperative dialysis (1.4; 1.02‐1.9), tibial angioplasty/stenting (1.3; 1.04‐1.6), in‐hospital bleeding (1.9; 1.04‐3.5), in‐hospital unplanned return to the operating room (1.9; 1.1‐3.5), and discharge other than to home (1.5; 1.1‐2.0). Risk factors for those with claudication were dependent functional status (3.5; 1.4‐8.7), smoking (1.6; 1.02‐2.5), diabetes (1.5; 1.01‐2.3), preoperative dialysis (3.6; 1.6‐8.3), procedure time exceeding 120 minutes (1.8; 1.1‐2.7), in‐hospital bleeding (2.9; 1.2‐7.4), and in‐hospital unplanned return to the operating room (3.4; 1.2‐9.4). Conclusions: Unplanned readmission after endovascular treatment is relatively common, especially in patients with CLI, and is associated with substantially increased mortality. Awareness of these risk factors will help providers identify patients at high risk who may benefit from early surveillance, and prophylactic measures focused on decreasing postoperative complications may reduce the rate of readmission.

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.

Preoperative anemia associated with adverse outcomes after infrainguinal bypass surgery in patients with chronic limb-threatening ischemia

Objective: Preoperative anemia in elderly patients undergoing surgery is prevalent and associated with adverse events; however, the interaction with other risk factors in patients with chronic limb‐threatening ischemia (CLTI) is not well described. The purpose of this study was to assess the association between lower hematocrit (HCT) levels on admission and postoperative outcomes after infrainguinal bypass surgery. Methods: Patients with CLTI undergoing nonemergent infrainguinal bypass were identified in the targeted vascular module of National Surgical Quality Improvement Program (NSQIP; 2011–2014). The 30‐day outcomes were compared across preoperative HCT levels: severe (≤29%), moderate (29.1%‐34%), mild (34.1%‐39%), or no anemia (>39%), with no anemia serving as the reference group for all analyses. Independent associations between levels of anemia and postoperative outcomes were established using multivariable logistic regression. A sensitivity analysis was performed to assess interactions between preoperative anemia and blood transfusions. Results: We identified 5081 patients undergoing bypass, of which 741 (15%) had severe, 1317 (26%) moderate, 1516 (30%) mild, and 1507 (30%) no anemia. Anemic patients were older and more commonly suffered from tissue loss and comorbidities (eg, hypertension, diabetes, and renal insufficiency; all P < .001). After adjustment for baseline conditions, mortality was higher in those with severe anemia (3.1%; odds ratio [OR], 2.8; 95% confidence interval [CI], 1.3–6.3) and moderate anemia (3.0%; OR, 2.6; 95% CI, 1.2–5.5) compared with those without anemia (0.7%). Severe anemia was independently associated with major amputation (6.9% vs 3.3%; OR, 1.6; 95% CI, 1.01–2.6) compared with no anemia. Anemia on admission was additionally associated with several other adverse outcomes, such as major adverse cardiovascular event (MACE; severe: OR, 1.9; 95% CI, 1.1–3.0; moderate: OR, 1.9; 95% CI, 1.3–2.9; mild: OR, 1.6; 95% CI, 1.1–2.4) and unplanned return to the operating room (severe: OR, 1.6; 95% CI, 1.2–2.1; moderate: OR, 1.5; 95% CI, 1.2–1.8; mild, OR: 1.3; 95% CI, 1.03–1.6). Moreover, mortality associated with preoperative anemia was not different in patients receiving postoperative blood transfusions compared with those who did not, whereas MACE was significantly higher in patients with preoperative anemia and blood transfusions (interaction; P < .001). Conclusions: Mortality and major adverse events in CLTI patients undergoing infrainguinal bypass are inversely associated with preoperative HCT levels, with the highest event rates in the most severely anemic patients. The correlation between anemia and MACE—but not mortality—was stronger in those patients receiving postoperative blood transfusions. Further research is needed to define an appropriate transfusion threshold, and attention should be focused on how to best optimize anemic CLTI patients before intervention.

Patient selection and perioperative outcomes of bypass and endovascular intervention as first revascularization strategy for infrainguinal arterial disease

Objective The optimal initial revascularization strategy remains uncertain for patients with peripheral arterial disease. The purpose of this study was to evaluate current nationwide selection and perioperative outcomes of patients undergoing bypass or endovascular intervention for infrainguinal disease in those with no prior ipsilateral revascularization. Methods Patients undergoing nonemergent first‐time infrainguinal revascularization were identified in the Targeted Vascular module of the National Surgical Quality Improvement Program (NSQIP) for 2011 to 2014 and stratified by symptom status (chronic limb‐threatening ischemia [CLTI] or claudication). Patients treated with endovascular intervention were compared with those who underwent bypass. Multivariable logistic regression was used to evaluate current selection of patients and to establish independent associations between first‐time procedures and postoperative outcomes. Results Of 5998 first‐time infrainguinal revascularizations performed, 3193 were bypass procedures (63% for CLTI) and 2805 were endovascular interventions (64% for CLTI). Current patient characteristics associated with an endovascular‐first approach as opposed to bypass‐first in CLTI patients were age ≥80 years, tissue loss, nonsmoking, functional dependence, diabetes, dialysis, and tibial lesions, whereas age ≥80 years, nonwhite race, nonsmoking, diabetes, and tibial lesions were associated with an endovascular approach for claudication. In comparing first‐time endovascular intervention with bypass, there was no difference in 30‐day mortality in CLTI patients (univariate: 2.1% vs 2.2%; adjusted: odds ratio [OR], 0.7; 95% confidence interval [CI], 0.4‐1.1) or claudication patients (0.3% vs 0.6%). Among CLTI patients, endovascular‐first intervention was associated with lower rates of major adverse cardiovascular event (3.6% vs 4.7%; OR, 0.6; 95% CI, 0.4‐0.9), surgical site infection (0.9% vs 7.7%; OR, 0.1; 95% CI, 0.1‐0.2), bleeding (8.5% vs 17%; OR, 0.4; 95% CI, 0.3‐0.5), unplanned reoperation (13% vs 17%; OR, 0.7; 95% CI, 0.5‐0.8), and unplanned readmission (17% vs 18%; OR, 0.8; 95% CI, 0.7‐0.9). Patients with claudication undergoing endovascular‐first intervention also had lower rates of major adverse cardiovascular event (0.8% vs 1.6%; OR, 0.4; 95% CI, 0.2‐0.95), surgical site infection (0.7% vs 6.6%; OR, 0.1; 95% CI, 0.04‐0.2), bleeding (2.3% vs 6.0%; OR, 0.3; 95% CI, 0.2‐0.5), unplanned reoperation (4.3% vs 6.6%; OR, 0.6; 95% CI, 0.4‐0.9), and unplanned readmission (5.9% vs 9.0%; OR, 0.6; 95% CI, 0.4‐0.8). Conversely, endovascular‐first intervention was associated with a higher rate of secondary revascularizations within 30 days for CLTI (4.3% vs 3.1%; OR, 1.6; 95% CI, 1.04‐2.3) but not for claudication (2.6% vs 1.9%; OR, 1.7; 95% CI, 0.9‐3.4). Conclusions An endovascular‐first approach as a revascularization strategy for infrainguinal disease was associated with substantially lower early morbidity but not mortality, at the cost of higher rates of postoperative secondary revascularizations. As a national representation of first‐time revascularizations, this study highlights the early endovascular perioperative benefit, although more robust long‐term data are needed to adopt either one strategy or the other in select patients with peripheral arterial disease.

Regional variation in patient outcomes in carotid artery disease treatment in the Vascular Quality Initiative

Objective Quality metrics were developed to improve outcomes after carotid artery revascularization; however, few studies have evaluated regional differences in perioperative outcomes. This study aimed to evaluate regional variation in mortality and perioperative outcomes after carotid endarterectomy (CEA) and carotid artery stenting (CAS). Methods We identified all patients who underwent CEA or CAS from 2009 to 2016 in the Vascular Quality Initiative. Patients were analyzed on the basis of their symptom status. We assessed variation in perioperative outcomes using χ2 analysis, Fisher exact test, and t‐test, where appropriate. Results A total of 78,467 carotid interventions were identified; 85% were CEAs, with 69% of those asymptomatic. Within CAS, 39% were asymptomatic. Perioperative stroke/death varied across regions within both CAS groups (asymptomatic, 0%‐5.8% [P = .03]; symptomatic, 2.4%‐8.1% [P = .1]), and several regions did not meet the American Heart Association (AHA) guidelines of 3% for asymptomatic patients and 6% for symptomatic patients, which persisted after risk adjustment. For CEA, the stroke/death rates fell within the standards set by the AHA guidelines in all regions for both the unadjusted and risk‐adjusted models; however, there was significant regional variation in the cohorts (asymptomatic, 0.9%‐3.1% [P < .01]; symptomatic, 1.3%‐4.9% [P < .01]). Variation in 30‐day mortality was significant in symptomatic patients (asymptomatic: CEA, 0%‐1.3% [P = .2], CAS, 0%‐2.4% [P = .2]; symptomatic: CEA, 0%‐1.8% [P < .01], CAS, 0%‐4.6% [P = .01]). Rates of in‐hospital stroke, postoperative myocardial infarction, prolonged length of stay (>2 days), and use of intravenous blood pressure medications all varied significantly across the regions. After CEA, there was significant variation in the rates of cranial nerve injuries (asymptomatic, 0.9%‐4.9% [P < .01]; symptomatic, 1.5%‐7.7% [P < .01]), return to the operating room (asymptomatic, 0.9%‐3.4% [P < .01]; symptomatic, 0.6%‐3.4% [P = .02]), and discharge on antiplatelet and statin (asymptomatic, 75%‐87% [P < .01]; symptomatic, 78%‐91% [P < .01]). After CAS, significant variation was found in the rates of access site complications (asymptomatic, 2.3%‐18.2% [P < .01]; symptomatic, 1.4%‐16.9% [P < .01]) and discharge on dual antiplatelet therapy (asymptomatic, 79%‐94% [P < .01]; symptomatic, 83%‐93% [P < .01]). Conclusions Unwarranted regional variation exists in outcomes after carotid artery revascularization across the regions of the VQI. Significant variation was seen in a number of outcomes for which quality metrics currently exist, such as length of stay and discharge medications. In addition, after CAS, several regions failed to meet the AHA guidelines for stroke and death. Given these results, quality improvement projects should be targeted to improve adherence to current guidelines to promote best practices.

Preoperative anemia is associated with mortality after carotid endarterectomy in symptomatic patients

Objective Preoperative anemia and blood transfusions are associated with worse outcomes after surgery. However, the impact of preoperative anemia and transfusions on outcomes after carotid endarterectomy (CEA) is unknown. Methods CEA patients from 2011 to 2015 in the American College of Surgeons National Surgical Quality Improvement Program Targeted Vascular module were compared by the presence of preoperative anemia (hematocrit <36%) after stratification by symptom status. Multivariable analysis accounted for differences in baseline characteristics. We included an interaction term in our multivariable model to assess whether the effect of anemia differed significantly between patients who received a perioperative transfusion and those who did not, with 30‐day mortality as our primary outcome. Results Of 16,068 patients, 6734 (42%) were symptomatic, of whom 1500 (22%) had anemia. Of the 9334 asymptomatic patients, 1935 (21%) had anemia. Both symptomatic and asymptomatic anemic patients were more likely to be transfused perioperatively compared with nonanemic patients, with 7.0% vs 0.4%, and 5.8% vs 0.7% (both P < .001). Among symptomatic patients, those with anemia compared with those without had a higher rate of 30‐day mortality (2.5% vs 0.7%; P < .001). After adjustment, anemic symptomatic patients had a higher 30‐day mortality risk (odds ratio [OR], 3.1; 95% confidence interval [CI], 1.9‐5.0; P < .001) compared with nonanemic symptomatic patients. In addition, in symptomatic patients, we found a significant interaction between anemia and perioperative transfusion on the outcome of 30‐day mortality (P = .004), with a higher risk in perioperatively transfused symptomatic patients with anemia (OR, 7.8; 95% CI, 3.4‐18.0; P < .001) than in symptomatic patients with anemia who did not receive a perioperative transfusion (OR, 2.3; 95% CI, 1.4‐3.9; P = .002). In asymptomatic patients, anemic and nonanemic patients had comparable 30‐day mortality rates (0.9% vs 0.6%; P = .2). After adjustment, anemia was not associated with 30‐day mortality in asymptomatic patients (OR, 1.0; 95% CI, 0.5‐2.0; P = .9), nor did we identify an interaction between anemia and perioperative transfusion in asymptomatic patients (P = .1). Patients who received a preoperative transfusion had a higher 30‐day mortality rate than anemic patients not receiving preoperative transfusion in both symptomatic (n = 31, 9.7% vs 2.5%; P = .04) and asymptomatic patients (n = 21, 9.5% vs 0.9%; P = .02). Conclusions Preoperative anemia is a risk factor for 30‐day mortality after CEA in symptomatic patients but not in asymptomatic patients. These results should be factored into the selection of symptomatic patients for CEA and dissuade treatment of asymptomatic patients scheduled for CEA who need a preoperative transfusion.

The impact of race on outcomes after carotid endarterectomy in the United States

Objective: Black patients undergoing carotid endarterectomy (CEA) in the United States are more often symptomatic at presentation and have more comorbidities compared with white patients. However, the impact of race on outcomes after CEA is largely unknown. Methods: We identified CEA patients in the Vascular Quality Initiative registry (2012‐2017) and compared them by race (black vs white). All other nonwhite races (891 [1.4%]) and Hispanics (2222 [3.4%]) were excluded. We used multilevel logistic regression to account for differences in demographics and comorbidities. We assessed long‐term survival using multivariable Cox regression. The primary outcome was perioperative stroke/death, with long‐term survival as a secondary outcome. Results: We included 57,622 CEA patients; 2909 (5.0%) were black, of whom 983 (34%) were symptomatic. Of the 54,713 white patients, 16,132 (30%) were symptomatic. Black patients, compared with white patients, had a higher vascular disease burden and were less likely to be operated on in a high‐volume hospital or by a high‐volume surgeon. In addition, black symptomatic patients, compared with white symptomatic patients, were more often operated on <2 weeks after the index neurologic symptom (47% vs 40%; P < .001). Perioperative stroke/death was comparable between black and white patients (symptomatic, 2.8% vs 2.2% [P = .2]; asymptomatic, 1.6% vs 1.3% [P = .2]), as was unadjusted survival at 3 years (93% vs 93%; P = .7). However, after adjustment, black patients did experience better long‐term survival compared with white patients (hazard ratio, 0.8; 95% confidence interval, 0.7‐0.9; P = .01). On multilevel logistic regression, race was not associated with perioperative stroke/death (odds ratio, 1.0; 95% confidence interval, 0.8‐1.3; P = .98). Conclusions: Despite the greater prevalence of vascular risk factors in black patients and racial inequalities in surgical treatment, rates of perioperative stroke/death and unadjusted survival were similar between white and black patients. Moreover, black patients experienced better adjusted long‐term survival after CEA.

Three-dimensional image fusion is associated with lower radiation exposure and shorter time to carotid cannulation during carotid artery stenting

Objective Three‐dimensional (3D) image fusion is associated with lower radiation exposure, contrast agent dose, and operative time during endovascular abdominal aortic aneurysm repair. Therefore, we evaluated the impact of this technology on carotid artery stenting (CAS). Methods We identified consecutive CAS procedures from 2009 to 2017 and compared those performed with and without 3D image fusion. For image fusion, we created a 3D reconstruction of the aortic arch anatomy based on preoperative computed tomography or magnetic resonance angiography that we merged with two‐dimensional fluoroscopy, allowing 3D image overlay. We compared radiation exposure, fluoroscopy time, contrast agent dose, time to common carotid artery (CCA) cannulation, time from CCA cannulation to completion angiography, and total procedure time in procedures with and without image fusion. We also assessed rates of 30‐day stroke/death, in‐hospital and 30‐day stroke, and acute kidney injury. We used multivariable linear regression to adjust for patient and procedural characteristics and used these models to compute the marginal effects of image fusion compared with no image fusion. Results There were 46 patients who underwent CAS with a 3D image fusion system and 70 patients without. Patients undergoing CAS with image fusion experienced 31% lower radiation exposure compared with the control group (207 ± 23 mGy vs 300 ± 26 mGy, respectively; P < .01), shorter fluoroscopy time (21 ± 6 minutes vs 24 ± 8 minutes; P = .02), shorter time to carotid cannulation (21 ± 9 minutes vs 31 ± 8 minutes; P < .001), and shorter total procedure time (47 ± 13 minutes vs 54 ± 18 minutes; P = .03). There was no difference in contrast material volume, time from CCA cannulation to completion angiography, or total in‐room time. After multivariable adjustment, 3D image fusion remained associated with lower radiation dose, shorter fluoroscopy time, and shorter time to carotid cannulation (all P < .05). The rate of 30‐day stroke/death was 2.7% (three strokes and no deaths at 30 days), and the rate of acute kidney injury was 1.8%. Conclusions CAS with 3D image fusion was associated with lower radiation exposure and shorter time to CCA cannulation. These results represent the potential technical advantage gained with image fusion and add to the growing body of evidence demonstrating its impact on radiation exposure and operative times during complex endovascular procedures.

Overtreatment or Undertreatment of Carotid Disease: A Transatlantic Comparison of Carotid Endarterectomy Patient Cohorts

Outcomes after carotid revascularization and medical therapy in randomized controlled trial (RCTs) have improved over time1; however, their generalizability to general practice has been questioned, fueling the debate on the treatment of carotid stenosis. This is most apparent in global differences in the selection of asymptomatic patients for carotid endarterectomy (CEA). For instance, asymptomatic patients comprise a mere 2.8% of all patients undergoing revascularization in the Netherlands2, compared with 66% in the United States.3 However, it is unknown how the difference in the proportion of asymptomatic CEA patients between the United States and the Netherlands impacts the type of patients selected for revascularization or their outcomes. Thus, we compared patient characteristics and outcomes for patients undergoing CEA in the United States and in the Netherlands. We used the Targeted Vascular module of the National Surgical Quality Improvement Program (NSQIP) registry and the Dutch Athero-Express registry. NSQIP collected data from 89 centers, accounting for 5% of all CEAs performed in the United States annually.4 The Athero-Express registry collected data from 2 Dutch centers, which …