Ruby C. Lo

Gender differences in abdominal aortic aneurysm presentation, repair, and mortality in the Vascular Study Group of New England

OBJECTIVE Prior studies of gender differences in abdominal aortic aneurysm (AAA) repair suggest there may be differences in presentation, suitability for endovascular aneurysm repair (EVAR), and outcomes between men and women. METHODS We used the Vascular Study Group of New England database to identify all patients undergoing EVAR or open AAA repair. We analyzed demographics, comorbidities, and procedural, and perioperative data. Results were compared using the Fisher exact test and the Student t-test. Multivariable logistic regression and Cox proportional hazards modeling were performed to identify predictors of mortality. RESULTS We identified 4026 patients (78% men) who underwent AAA repair (54% EVAR). Women were less likely than men to undergo EVAR for intact aneurysms (50% vs 60% of intact AAA repair; P < .001) but not for ruptured aneurysms (26% vs 20%; P = .23). Women were older (median age, 75 vs 72 years for intact; P < .001; 78 vs 73 years for rupture; P < .001) with smaller aortic diameters (57 vs 59 mm for elective; P < .001; 71 vs 79 mm for rupture; P < .001). Arterial injury was more common in women (5.4% vs 2.7%; P = .013) among patients undergoing EVAR for intact aneurysms. Women stayed in the hospital longer (4.3 vs 2.7 days; P = .018) and had lower odds of being discharged home, even after adjusting for age. Among patients undergoing open repair for intact aneurysms, women more frequently experienced leg ischemia/emboli (4% vs 1%; P = .001) and bowel ischemia (5% vs 3%; P = .044). Women had higher 30-day mortality after OAR for intact (4% vs 2%; P = .03) and rupture (48% vs 34%; P = .03) repairs. However, 30-day mortality after EVAR was similar for intact (1% in men vs 1% in women; P = .57) and rupture (29% in men vs 27% in women; P > .99) repairs. Late survival was worse in women than men only for patients undergoing open repair of ruptured aneurysms (hazard ratio, 1.8; 95% confidence interval, 1.0-3.1; P = .04). After controlling for age, type of repair, urgency at presentation (ie, elective/intact vs ruptured), comorbidities, and other relevant risk factors, gender was not predictive of 30-day or 1-year mortality. CONCLUSIONS Women with AAAs are being treated at older ages and smaller AAA diameters and are undergoing rupture repair at smaller diameters than men. Women are more likely to experience perioperative complications as a result of less favorable vascular anatomy. Age >80 years, comorbidity, presentation, and type of repair are more important predictors of mortality than gender.

Relative importance of aneurysm diameter and body size for predicting abdominal aortic aneurysm rupture in men and women

OBJECTIVE Women have been shown to have up to a fourfold higher risk of abdominal aortic aneurysm (AAA) rupture at any given aneurysm diameter compared with men, leading to recommendations to offer repair to women at lower diameter thresholds. Although this higher risk of rupture may simply reflect greater relative aortic dilatation in women who have smaller aortas to begin with, this has never been quantified. Our objective was therefore to quantify the relationship between rupture and aneurysm diameter relative to body size and determine whether a differential association between aneurysm diameter, body size, and rupture risk exists for men and women. METHODS We performed a retrospective review of all patients in the Vascular Study Group of New England (VSGNE) database who underwent endovascular or open AAA repair. Height and weight were used to calculate each patients body mass index and body surface area (BSA). Next, indices of each measure of body size (height, weight, body mass index, BSA) relative to aneurysm diameter were calculated for each patient. To generate these indices, we divided aneurysm diameter (in cm) by the measure of body size; for example, aortic size index (ASI) = aneurysm diameter (cm)/BSA (m(2)). Along with other relevant clinical variables, we used these indices to construct different age-adjusted and multivariable-adjusted logistic regression models to determine predictors of ruptured repair vs elective repair. Models for men and women were developed separately, and different models were compared using the area under the curve. RESULTS We identified 4045 patients (78% male) who underwent AAA repair (53% endovascular aortic aneurysm repairs). Women had significantly smaller diameter aneurysms, lower BSA, and higher BSA indices than men. For men, the variable that increased the odds of rupture the most was aneurysm diameter (area under the curve = 0.82). Men exhibited an increased rupture risk with increasing aneurysm diameter (<5.5 cm: odds ratio [OR], 1.0; 5.5-6.4 cm: OR, 0.9; 95% confidence interval [CI], 0.5-1.7; P = .771; 6.5-7.4 cm: OR, 3.9; 95% CI, 1.9-1.0; P < .001; ≥ 7.5 cm: OR, 11.3; 95% CI, 4.9-25.8; P < .001). In contrast, the variable most predictive of rupture in women was ASI (area under the curve = 0.81), with higher odds of rupture at a higher ASI (ASI >3.5-3.9: OR, 6.4; 95% CI, 1.7-24.1; P = .006; ASI ≥ 4.0: OR, 9.5; 95% CI, 2.3-39.4; P = .002). For women, aneurysm diameter was not a significant predictor of rupture after adjusting for ASI. CONCLUSIONS Aneurysm diameter indexed to body size is the most important determinant of rupture for women, whereas aneurysm diameter alone is most predictive of rupture for men. Women with the largest diameter aneurysms and the smallest body sizes are at the greatest risk of rupture.

Presentation, treatment, and outcome differences between men and women undergoing revascularization or amputation for lower extremity peripheral arterial disease

OBJECTIVE Prior studies have suggested treatment and outcome disparities between men and women for lower extremity peripheral arterial disease after surgical bypass. Given the recent shift toward endovascular therapy, which has increasingly been used to treat claudication, we sought to analyze sex disparities in presentation, revascularization, amputation, and inpatient mortality. METHODS We identified individuals with intermittent claudication and critical limb ischemia (CLI) using International Classification of Diseases, Ninth Revision codes in the Nationwide Inpatient Sample from 1998 to 2009. We compared presentation at time of intervention (intermittent claudication vs CLI), procedure (open surgery vs percutaneous transluminal angioplasty or stenting vs major amputation), and in-hospital mortality for men and women. Regional and ambulatory trends were evaluated by performing a separate analysis of the State Inpatient and Ambulatory Surgery Databases from four geographically diverse states: California, Florida, Maryland, and New Jersey. RESULTS From the Nationwide Inpatient Sample, we identified 1,797,885 patients (56% male) with intermittent claudication (26%) and CLI (74%), who underwent 1,865,999 procedures (41% open surgery, 20% percutaneous transluminal angioplasty or stenting, and 24% amputation). Women were older at the time of intervention by 3.5 years on average and more likely to present with CLI (75.9% vs 72.3%; odds ratio [OR], 1.21; 95% confidence interval [CI], 1.21-1.23; P < .01). Women were more likely to undergo endovascular procedures for both intermittent claudication (47% vs 41%; OR, 1.27; 95% CI, 1.25-1.28; P < .01) and CLI (21% vs 19%; OR, 1.14; 95% CI, 1.13-1.15; P < .01). From 1998 to 2009, major amputations declined from 18 to 11 per 100,000 in men and 16 to 7 per 100,000 in women, predating an increase in total CLI revascularization procedures that was seen starting in 2005 for both men and women. In-hospital mortality was higher in women regardless of disease severity or procedure performed even after adjusting for age and baseline comorbidities (.5% vs .2% after percutaneous transluminal angioplasty or stenting for intermittent claudication; 1.0% vs .7% after open surgery for intermittent claudication; 2.3% vs 1.6% after percutaneous transluminal angioplasty or stenting for CLI; 2.7% vs 2.2% after open surgery for CLI; P < .01 for all comparisons). CONCLUSIONS There appears to be a preference to perform endovascular over surgical revascularization among women, who are older and have more advanced disease at presentation. Percutaneous transluminal angioplasty or stenting continues to be popular and is increasingly being performed in the outpatient setting. Amputation and in-hospital mortality rates have been declining, and women now have lower amputation but higher mortality rates than men. Recent improvements in outcomes are likely the result of a combination of improved medical management and risk factor reduction.

Accuracy of administrative data versus clinical data to evaluate carotid endarterectomy and carotid stenting.

OBJECTIVE Administrative data have been used to compare carotid endarterectomy (CEA) and carotid artery stenting (CAS). However, there are limitations in defining symptom status, Centers for Medicare and Medicaid Services high-risk status, as well as complications. Therefore, we did a direct comparison between administrative data and physician chart review as well as between data collected for the National Surgical Quality Improvement Program (NSQIP) and physician chart review for CEA and CAS. METHODS We performed an outcomes analysis on all CEA and CAS procedures from 2005 to 2011. We obtained International Classification of Diseases, Ninth Revision diagnosis codes from hospital discharge records regarding symptom status, high-risk status, and perioperative stroke. We also obtained data on all CEA patients submitted to NSQIP over the same time period. One of the study authors (R.B.) then performed a chart review of the same patients to determine symptom status, high-risk status, and perioperative strokes and the results were compared. RESULTS We identified 1342 patients who underwent CEA or CAS between 2005 and 2011 and 392 patients who underwent CEA that were submitted to NSQIP. Administrative data identified fewer symptomatic patients (17.0% vs 34.0%), physiologic high-risk patients (9.3% vs 23.0%), and anatomic high-risk patients (0% vs 15.2%). Although administrative data identified a similar proportion of perioperative strokes (1.9% vs 2.0%), this was due to the fact that these data identified eight false positive and nine false negative perioperative strokes. NSQIP data identified more symptomatic patients compared with chart review (44.1% vs 30.3%), fewer physiologic high-risk patients (13.0% vs 18.6%), fewer anatomic high-risk patients (0% vs 6.6%), and a similar proportion of perioperative strokes (1.5% vs 1.8%, only one false negative stroke and no false positives). CONCLUSIONS Administrative data are unreliable for determining symptom status, high-risk status, and perioperative stroke and should not be used to analyze CEA and CAS. NSQIP data do not adequately identify high-risk patients, but do accurately identify perioperative strokes and to a lesser degree, symptom status.

Clinical Relevance of Cranial Nerve Injury following Carotid Endarterectomy

OBJECTIVES The benefit of carotid endarterectomy (CEA) may be diminished by cranial nerve injury (CNI). Using a quality improvement registry, we aimed to identify the nerves affected, duration of symptoms (transient vs. persistent), and clinical predictors of CNI. METHODS We identified all patients undergoing CEA in the Vascular Study Group of New England (VSGNE) between 2003 and 2011. Surgeon-observed CNI rate was determined at discharge (postoperative CNI) and at follow-up to determine persistent CNI (CNIs that persisted at routine follow-up visit). Hierarchical multivariable model controlling for surgeon and hospital was used to assess independent predictors for postoperative CNI. RESULTS A total of 6,878 patients (33.8% symptomatic) were included for analyses. CNI rate at discharge was 5.6% (n = 382). Sixty patients (0.7%) had more than one nerve affected. The hypoglossal nerve was most frequently involved (n = 185, 2.7%), followed by the facial (n = 128, 1.9%), the vagus (n = 49, 0.7%), and the glossopharyngeal (n = 33, 0.5%) nerve. The vast majority of these CNIs were transient; only 47 patients (0.7%) had a persistent CNI at their follow-up visit (median 10.0 months, range 0.3-15.6 months). Patients with perioperative stroke (0.9%, n = 64) had significantly higher risk of CNI (n = 15, CNI risk 23.4%, p < .01). Predictors for CNI were urgent procedures (OR 1.6, 95% CI 1.2-2.1, p < .01), immediate re-exploration after closure under the same anesthetic (OR 2.0, 95% CI 1.3-3.0, p < .01), and return to the operating room for a neurologic event or bleeding (OR 2.3, 95% CI 1.4-3.8, p < .01), but not redo CEA (OR 1.0, 95% CI 0.5-1.9, p = .90) or prior cervical radiation (OR 0.9, 95% CI 0.3-2.5, p = .80). CONCLUSIONS As patients are currently selected in the VSGNE, persistent CNI after CEA is rare. While conditions of urgency and (sub)acute reintervention carried increased risk for postoperative CNI, a history of prior ipsilateral CEA or cervical radiation was not associated with increased CNI rate.

Abdominal aortic aneurysms in women

Abdominal aortic aneurysm (AAA) has long been recognized as a condition predominantly affecting males, with sex-associated differences described for almost every aspect of the disease from pathophysiology and epidemiology to morbidity and mortality. Women are generally spared from AAA formation by the immunomodulating effects of estrogen, but once they develop, the natural history of AAAs in women appears to be more aggressive, with more rapid expansion, a higher tendency to rupture at smaller diameters, and higher mortality following rupture. However, simply repairing AAAs at smaller diameters in women is a debatable solution, as even elective endovascular AAA repair is fraught with higher morbidity and mortality in women compared to men. The goal of this review is to summarize what is currently known about the effect of gender on AAA presentation, treatment, and outcomes. Additionally, we aim to review current controversies over screening recommendations and threshold for repair in women.

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.

Open repair of intact thoracoabdominal aortic aneurysms in the American College of Surgeons National Surgical Quality Improvement Program

OBJECTIVE Open surgical repair of thoracoabdominal aortic aneurysms (TAAAs) is uncommon. Mortality rates of 20% are reported in studies using national data and are 5% to 8% in single-institution studies. Clinical trials are currently evaluating branched and fenestrated endografts. The purpose of this study is to establish a benchmark for future comparisons with endovascular trials using open repair of TAAAs in the National Surgical Quality Improvement Program (NSQIP) database. METHODS We identified all patients undergoing open elective and emergency surgical repair of intact TAAAs in NSQIP (2005 to 2010) using Current Procedural Terminology (American Medical Association, Chicago, Ill) and International Classification of Diseases, 9th Edition codes. We analyzed demographics, comorbidities, 30-day mortality, postoperative complications, and length of stay. Multivariable logistic regression was used to identify predictors of mortality. RESULTS We identified 450 patients who underwent open surgical repair (418 elective, 32 emergent) of an intact TAAA. Mean age was 69.4 years, 60.7% were male, and 85.6% were white. Comorbidities included hypertension (87.1%), chronic obstructive pulmonary disease (27.3%), prior stroke or transient ischemic attack (16.7%), diabetes (11.6%), and peripheral vascular disease (9.6%). Thirty-day mortality was 10.0%. Pulmonary complications were the most common: failure to wean from ventilator (39.1%), pneumonia (23.1%), and reintubation (13.8%). Acute renal failure requiring dialysis occurred in 10.7% of patients. Multivariable analysis (odds ratio [95% confidence interval]) showed predictors of mortality were emergent repair (3.3 [1.03-10.83]; P = .04), age >70 years (3.5 [1.03-7.56], P = .001), preoperative dialysis (8.4 [1.90-37.29], P = .005), cardiac complication (2.9 [1.05-8.21], P = .04), and renal complications (8.4 [3.41-20.56], P < .001). CONCLUSIONS In this study of NSQIP hospitals, the first to analyze open surgical repair of TAAAs, the 30-day mortality rate of 10.0% is similar to single-institution reports. However, morbidity and mortality after open TAAA repair remain high, confirming the need for less invasive procedures.

Routine use of ultrasound-guided access reduces access site-related complications after lower extremity percutaneous revascularization

OBJECTIVE We sought to elucidate the risks for access site-related complications (ASCs) after percutaneous lower extremity revascularization and to evaluate the benefit of routine ultrasound-guided access (RUS) in decreasing ASCs. METHODS We reviewed all consecutive percutaneous revascularizations (percutaneous transluminal angioplasty or stent) performed for lower extremity atherosclerosis at our institution from 2002 to 2012. RUS began in September 2007. Primary outcome was any ASC (bleeding, groin or retroperitoneal hematoma, vessel rupture, or thrombosis). Multivariable logistic regression was used to determine predictors of ASC. RESULTS A total of 1371 punctures were performed on 877 patients (43% women; median age, 69 [interquartile range, 60-78] years) for claudication (29%), critical limb ischemia (59%), or bypass graft stenosis (12%) with 4F to 8F sheaths. There were 72 ASCs (5%): 52 instances of bleeding or groin hematoma, nine pseudoaneurysms, eight retroperitoneal hematomas, two artery lacerations, and one thrombosis. ASCs were less frequent when RUS was used (4% vs 7%; P = .02). Multivariable predictors of ASC were age >75 years (odds ratio [OR], 2.0; 95% confidence interval [CI], 1.1-3.7; P = .03), congestive heart failure (OR, 1.9; 95% CI, 1.1-1.3; P = .02), preoperative warfarin use (OR, 2.0; 95% CI, 1.1-3.5; P = .02), and RUS (OR, 0.4; 95% CI, 0.2-0.7; P < .01). Vascular closure devices (VCDs) were not associated with lower rates of ASCs (OR, 1.1; 95% CI, 0.6-1.9; P = .79). RUS lowered ASCs in those >75 years (5% vs 12%; P < .01) but not in those taking warfarin preoperatively (10% vs 13%; P = .47). RUS did not decrease VCD failure (6% vs 4%; P = .79). CONCLUSIONS We were able to decrease the rate of ASCs during lower extremity revascularization with the implementation of RUS. VCDs did not affect ASCs. Particular care should be taken with patients >75 years old, those with congestive heart failure, and those taking warfarin.

Carotid stenting versus endarterectomy in patients undergoing reintervention after prior carotid endarterectomy

BACKGROUND Outcomes for patients undergoing intervention for restenosis after prior ipsilateral carotid endarterectomy (CEA) in the era of carotid angioplasty and stenting (CAS) are unclear. We compared perioperative results and durability of CAS vs CEA in patients with symptomatic or asymptomatic restenosis after prior CEA and investigated the risk of reintervention compared with primary procedures. METHODS Patients undergoing CAS and CEA for restenosis between January 2003 and March 2012 were identified within the Vascular Study Group of New England (VSGNE) database. End points included any stroke, death or myocardial infarction (MI) within 30 days, cranial nerve injury at discharge, and restenosis ≥ 70% at 1-year follow-up. Multivariable logistic regression was done to identify whether prior ipsilateral CEA was an independent predictor for adverse outcome. RESULTS Out of 9305 CEA procedures, 212 patients (2.3%) underwent redo CEA (36% symptomatic). Of 663 CAS procedures, 220 patients (33%) underwent CAS after prior ipsilateral CEA (31% symptomatic). Demographics of patients undergoing redo CEA were comparable to patients undergoing CAS after prior CEA. Stroke/death/MI rates were statistically similar between redo CEA vs CAS after prior CEA in both asymptomatic (4.4% vs 3.3%; P = .8) and symptomatic patients (6.6% vs 5.8%; P = 1.0). No significant difference in restenosis ≥ 70% was identified between redo CEA and CAS after prior CEA (5.2% vs 3.0%; P = .5). Redo CEA vs primary CEA had increased stroke/death/MI rate in both symptomatic (6.6% vs 2.3%; P = .05) and asymptomatic patients 4.4% vs 1.7%; P = .03). Prior ipsilateral CEA was an independent predictor for stroke/death/MI among all patients undergoing CEA (odds ratio, 2.1; 95% confidence interval, 1.3-3.5). No difference in cranial nerve injury was identified between redo CEA and primary CEA (5.2% vs 4.7%; P = .8). CONCLUSIONS In the VSGNE, CEA and CAS showed statistically equivalent outcomes in asymptomatic and symptomatic patients treated for restenosis after prior ipsilateral CEA. However, regardless of symptom status, the risk of reintervention was increased compared with patients undergoing primary CEA.