Study Group Of New England Research Articles

Comparison of a Vascular Study Group of New England risk prediction model with established risk prediction models of in-hospital mortality after elective abdominal aortic aneurysm repair

A certain number of deaths may result from elective abdominal aortic aneurysm (AAA) repair due to inherent risks of operation; however, no agreement exists about which predictive model for in-hospital mortality is most accurate in predicting these events. This study developed a risk prediction model using Vascular Study Group of New England (VSGNE) data and compared it with established models. VSGNE data (2003-2013) were queried for patients undergoing elective AAA repair by open or endovascular techniques. Clinical variables and known predictors of mortality were included in a full prediction model. Backward elimination with α= .2 was used to construct a parsimonious model. This VSGNE model was compared with established models-Medicare, Glasgow Aneurysm Score (GAS), and Vascular Governance North West (VGNW)-based on the scope of VSGNE data collection. Model fit was compared with the Vuong test. Model discrimination was compared in equally sized risk-group VSGNE terciles. The overall mortality rate for 4431 elective AAA patients was 1.4%. The discriminating ability of the VSGNE model was high (C statistic= 0.822) and corrected slightly to 0.779 after internal validation. Vuong tests yielded significant overall fit difference favoring the VSGNE model over the Medicare (C statistic= 0.769), VGNW (C statistic= 0.767), and GAS (C statistic= 0.685) models. The VGNW and Medicare models performed better than GAS in predicting mortality among risk-group terciles. The VSGNE risk prediction model is best at forecasting mortality among this patient population. The Medicare and VGNW models showed good discrimination.

Characteristics that define high risk in carotid endarterectomy from the Vascular Study Group of New England

The Stenting with Angioplasty and Protection in Patients at High Risk for Endarterectomy (SAPPHIRE) trial compared carotid endarterectomy (CEA) to carotid artery stenting (CAS) among high-risk patients using a model of risk that has not been validated by previous publications. The objective of our study was to determine the accuracy of this high-risk model and to determine the true risk factors that result in patients being at high risk for CEA. Prospectively collected data for 3098 CEAs between 2003 and 2011 at 20 Vascular Surgery Group of New England (VSGNE) centers were used. SAPPHIRE general inclusion criteria and primary outcomes were assessed. Factors that were associated with the primary outcome by analysis of variance (P < .10) and not linearly dependent, as determined by a Pearson correlation analysis, were further assessed for an independent association by multivariate logistic regression. A risk index model was developed for these significant predictors to accurately define high-risk CEA. The average patient age was 69.9 ± 9.5 years, 60% were male, and 45.7% were asymptomatic. The 1-year composite outcome event rate, defined as postoperative myocardial infarction and stroke or death, was 14.2%. Multivariate analysis (P < .05) found the following independently significant risk factors: age in years (95% confidence interval [CI], 1.0-1.1; P < .001), preadmission living in a nursing home (95% CI, 1.2-6.6; P = .020), congestive heart failure (95% CI, 1.4-2.8; P < .001), diabetes mellitus (DM; 95% CI, 1.1-1.3; P < .001), chronic obstructive pulmonary disease (95% CI, 1.2-1.5; P < .001), any previous cerebrovascular disease (95% CI, 1.1-1.9; P = .003), and contralateral internal carotid artery stenosis (95% CI, 1.0-1.2; P = .001). Three of the SAPPHIRE high-risk criteria-abnormal stress test, recurrent stenosis after CEA, and previous radiotherapy to the neck-were not independently associated with an adverse outcome. Independently significant risk factors not included in the SAPPHIRE criteria are inclusion of ages <80 years, preadmission living in a nursing home, DM, contralateral carotid stenosis, and any previous cerebrovascular accident. The risk index predictors are age in years (40-49: 0 points; 50-59: 2 points; 60-69: 4 points; 70-79: 6 points; 80-89: 8 points), living in a nursing home (4 points), any cardiovascular disease (2 points), congestive heart failure (5 points), chronic obstructive pulmonary disease (3 points), DM (2 points), degree of contralateral stenosis (<50%: 0 points; 50%-69%: 1 point; 70%-near occlusion: 2 points; occlusion: 3 points). High-risk CEA is defined as >13 points, representing adverse outcome rate of 22.5%. SAPPHIRE and other previously reported high-risk CAS inclusion criteria do not include all of the factors found to be independently associated with outcomes. Further studies are required to determine whether CAS is inferior to CEA in high-risk patients using a validated model of risk. In addition, this preoperative assessment includes novel criteria that can be used to stratify risks.

The Society for Vascular Surgery's objective performance goals for lower extremity revascularization are not generalizable to many open surgical bypass patients encountered in contemporary surgical practice

In 2009, the Society for Vascular Surgery (SVS) established objective performance goals (OPG) for lower extremity bypass (LEB) in patients with critical limb ischemia (CLI) based on pooled data from previously performed prospective studies in an effort to provide a benchmark and historical control for future trials. However, patients with a prosthetic conduit and end-stage renal disease were excluded from this cohort. In contemporary practice, many patients do not meet the criteria for SVS OPG inclusion, making generalization of the SVS OPG difficult. The goal of this study was to establish safety and efficacy measures for patients who were excluded from the original SVS OPG analysis. All patients who underwent LEB for CLI in the Vascular Study Group of New England (VSGNE) from 2003 to 2013 were identified. Patients were stratified into OPG-eligible and non-OPG-eligible cohorts. Outcomes included 30-day major adverse limb events, 30-day major adverse cardiovascular events, 1-year survival, and 1-year freedom from amputation. The SVS OPG methodology was used to create new performance goals for the non-OPG-eligible patients. We identified 3609 patients: 2360 OPG (65%) vs 1249 non-OPG (35%), and overall results were stratified as a function of OPG status. The 30-day major adverse limb event rate was 5.0% (5.5% non-OPG vs 4.4% OPG; P = .34), and the 30-day major adverse cardiovascular event rate was 7.3% (9.2% non-OPG vs 6.2% OPG; P = .001). At 1 year, survival was 84% (75.9% non-OPG vs 88.3% OPG; P < .001), and freedom from amputation was 86.9% (80.9% non-OPG vs 90.1% OPG; P < .001). The SVS OPG were attainable in New England for the population of patients who would have met SVS OPG study cohort inclusion criteria. However, 35% of the patients who underwent LEB for CLI in the last 10 years fell outside of these criteria by having end-stage renal disease or requiring a prosthetic conduit. We therefore suggest new benchmarks for these high-risk populations.

The Increased Use of Computed Tomography Angiography and Magnetic Resonance Angiography as the Sole Imaging Modalities Prior to Infrainguinal Bypass Has Had No Effect on Outcomes

Angiography remains the gold standard imaging modality before infrainguinal bypass. Computed tomography angiography (CTA) and magnetic resonance angiography (MRA) have emerged as noninvasive alternatives for preoperative imaging. We sought to examine contemporary trends in the utilization of CTA and MRA as isolated imaging modalities before infrainguinal bypass and to compare outcomes following infrainguinal bypass in patients who underwent CTA or MRA versus those who underwent conventional arteriography. Patients undergoing infrainguinal bypass within the Vascular Study Group of New England were identified (2003-2012). Patients were stratified by preoperative imaging modality: CTA/MRA alone or conventional angiography. Trends in utilization of these modalities were examined and demographics of these groups were compared. Primary end points included primary patency, secondary patency, and major adverse limb events (MALE) at 1 year as determined by Kaplan-Meier analysis. Multivariable Cox proportional hazards models were constructed to evaluate the effect of imaging modality on primary patency, secondary patency, and MALE after adjusting for confounders. In 3123 infrainguinal bypasses, CTA/MRA alone was used in 462 cases (15%) and angiography was used in 2661 cases (85%). Use of CTA/MRA alone increased over time, with 52 (11%) bypasses performed between 2003 and 2005, 189 (41%) bypasses performed between 2006 and 2009, and 221 (48%) bypasses performed between 2010 and 2012 (P < 0.001). Patients with CTA/MRA alone, compared with patients with angiography, more frequently underwent bypass for claudication (33% vs. 26%, P = 0.001) or acute limb ischemia (13% vs. 5%, P < 0.0001), more frequently had prosthetic conduits (39% vs. 30%, P = 0.001), and less frequently had tibial/pedal targets (32% vs. 40%, P = 0.002). After adjusting for these and other confounders, multivariable analysis demonstrated that the use of CTA/MRA alone was not associated with a significant difference in 1 year primary patency (hazard ratio [HR] 0.95, 95% confidence interval [CI] 0.78-1.16), secondary patency (HR 1.30, 95% CI 0.99-1.72), or MALE (HR 1.08, 95% CI 0.89-1.32). CTA and MRA are being increasingly used as the sole preoperative imaging modality before infrainguinal bypass. This shift in practice patterns appears to have no measurable effect on outcomes at 1 year.

PC136. Determinants of Follow-Up Failure in Patients Enrolled in the Vascular Study Group of New England (VSGNE)

PC136. Determinants of Follow-Up Failure in Patients Enrolled in the Vascular Study Group of New England (VSGNE)

Outcomes of infrainguinal bypass determined by age in the Vascular Study Group of New England

Many believe extremes of age correlate with poorer outcomes in treatment for lower extremity peripheral arterial disease (PAD). We hypothesized that the youngest patients would have significantly poorer outcomes compared with older cohorts due to the precocious nature of their PAD. We studied all patients in the Vascular Study Group of New England database undergoing infrainguinal bypass for PAD between 2003 and 2013. Age was grouped by <50 years, 50 to 79 years, and ≥80 years. Our primary outcomes were 1-year freedom from a major adverse limb event (MALE), defined as ipsilateral amputation or need for secondary intervention, and amputation-free survival. A second analysis was performed to analyze the subgroup of patients aged <50 years with critical limb ischemia (CLI), which included a Cox regression model to determine risk factors for MALE or death at 1 year. Of 5265 patients who were treated with infrainguinal bypass for PAD, 324 (6.2%) were aged <50 years. The mean age was 44.6 years, and 66.4% were male. The proportion of African Americans was significantly higher in the youngest age group (<50 years: 6.8% vs 50-79 years: 3.5%, P = .002; vs ≥80 years: 3.5%, P = .013). More bypasses were done for claudication than acute limb ischemia in patients aged <50 years (33.3% vs 11.4%). More vein grafts were used vs prosthetic (<50 years: 72.1% vs 50-79 years: 65.9%, P = .024; vs ≥80 years: 62.6%, P = .002). Fewer concomitant proximal procedures were performed compared with the older groups (<50 years: 37.7% vs 50-79 years: 51.1%, P < .001; vs ≥80 years: 39.5%, P = .045). More young patients returned to the operating room within their initial hospitalization for early graft thrombosis (<50 years: 5.6% vs 50-79 years: 2.9%, P = .001; vs ≥80 years: 2.4%, P = .009) and revision (<50 years: 4.7% vs 50-79 years: 2.2%, P = .012; vs ≥80 years: 1.4%, P = .002) compared with the older patients. Overall, MALE-free survival was similar across age groups (P = .323), as were patency and amputation rates. When considering only patients with CLI, MALE-free survival in the youngest patients was again similar (P = .171) but with significantly more major amputations at 1 year (P = .022). For patients aged <50 undergoing infrainguinal bypass surgery, this large series demonstrates similar overall medium-term graft-related outcomes compared with older cohorts. Further, although the youngest patients with CLI have similar MALEs, their amputation rates are higher than in older cohorts.

The influence of gender on functional outcomes of lower extremity bypass

Our aim was to evaluate the effect of gender on early and late procedural and functional outcomes of lower extremity bypass (LEB). We reviewed the records of 2576 patients (828 women; 32%) who underwent LEB for claudication or critical limb ischemia (CLI) in the Vascular Study Group of New England from 2003 to 2010. Logistic regression and proportional hazards models were used to adjust for potential confounding differences between genders. Morbidity, mortality, graft patency, freedom from major amputation, ambulation, and living status were analyzed postoperatively and over 1 year. Women were older (70 vs 68 years; P < .001), had more hypertension (89% vs 85%; P = .006), less coronary artery disease (35% vs 39%; P = .03), smoking (73% vs 88%; P < .001), and preoperative statin use (60% vs 64%; P = .04). Women were more likely to have CLI (76% vs 71%; P = .003), and ambulate with assistance at presentation (19% vs 16%; P = .02). Morbidity was similar except women had higher rates of reoperation for thrombosis (4% vs 2%; P < .001) without differences in major amputation (2% vs 1%; P = .13) or in-hospital mortality (1.7% vs 1.7%; P = .96). Women and men with claudication had similar 1-year graft patency rates. Women with CLI had lower rates of primary (hazard ratio [HR], 1.24; 95% confidence interval [CI], 1.03-1.48; P = .02), assisted primary (HR, 1.42; 95% CI, 1.15-1.76; P = .001) and secondary patency (HR, 1.40; 95% CI, 1.10-1.77; P = .006) during the first year compared with men. Freedom from amputation was similar for men and women with CLI (HR, 1.17; 95% CI, 0.84-1.63; P = .36). There were no differences in late survival between women and men with claudication (HR, 0.89; 95% CI, 0.60-1.31; P = .36) or CLI (HR, 0.94; 95% CI, 0.81-1.09; P = .39). More female claudicants were not independently ambulatory at discharge (30% vs 19%; P = .002) and were discharged to a nursing home (15% vs 5%; P < .001) but these differences did not persist at 1 year. Women with CLI were more likely to be nonambulatory at discharge (13% vs 9%; P = .006) and at 1 year (13% vs 8%; P < .001). More women with CLI were discharged to a nursing home (44% vs 35%; P = .01) and resided there at 1 year (11% vs 7%; P = .02). Women have complication rates similar to men with inferior early and late functional outcomes after LEB. The reduced patency rates in women with CLI did not translate into differences in limb salvage. These findings might help define physician and patient expectations for women before revascularization.

Outcomes of carotid endarterectomy versus stenting in comparable medical risk patients

In medically high-risk patients the choice between carotid artery stenting (CAS) and carotid endarterectomy (CEA) can be difficult. The purpose of this study was to compare risk-stratified outcomes of CAS and CEA. Patients who underwent isolated primary CEA (n= 11,336) or primary CAS (n= 544) at 29 centers in the Vascular Study Group of New England were analyzed (2003-2013); patients with previous ipsilateral CEA or CAS, or concomitant coronary artery bypass graft were excluded. A medical risk score based on predicted 5-year mortality was developed for each patient using a Cox proportional hazards model. Patients in the highest risk score quartile were termed high-risk (vs normal-risk for the other three quartiles). Medically high-risk patients had a 5-year survival of 65% and comprised 23% of CEA and 25% of CAS patients. Risk-stratified outcomes were compared within neurologically symptomatic and asymptomatic patients. Among asymptomatic patients, rates of in-hospital stroke and/or death were not different between CAS and CEA in normal and high-risk cohorts, ranging from 0.7% in normal-risk CEA patients to 1.6% in high-risk CAS patients. In symptomatic patients, significantly worse outcomes were seen with CAS compared with CEA in normal-risk and high-risk patients. Normal-risk symptomatic patients had a stroke or death rate of 1.3% with CEA, but 5.2% with CAS (P< .01). In high-risk symptomatic patients, the stroke or death rate was 1.5% with CEA and 9.3% with CAS (P< .01). No significant differences were seen between asymptomatic CEA and CAS within risk strata across secondary outcome measures of stroke, death, or myocardial infarction, and ipsilateral stroke, major stroke, or death. However, symptomatic high-risk CAS patients had significantly greater rates of all secondary outcomes compared with CEA except death, and symptomatic normal-risk CAS patients had only significantly greater rates of death and stroke, death, or myocardial infarction. In the Vascular Study Group of New England, asymptomatic normal- and high-risk patients do equally well after CEA or CAS. However, normal- and high-risk symptomatic patients have substantially worse outcomes with CAS compared with CEA. High medical risk alone might be an insufficient indication for CAS in symptomatic patients.

RR6. High-Risk Carotid Endarterectomy (CEA) Beyond the SAPPHIRE Trial and Development of a Risk Index to Define Patients At Risk for Adverse Outcomes After CEA, From the Vascular Study Group of New England (VSGNE)

Recently we defined several independent high-risk criteria that were inclusive and exclusive of the SAPPHIRE (Stenting with Angioplasty and Protection in Patients at High Risk for Endarterectomy) trial. The objective of this study was to create a risk index that may predict patients at high risk for carotid endarterectomy (CEA). Data on 3,098 CEAs between 2003 and 2011 at 20 Vascular Study Group of New England (VSGNE) centers were used for this study. SAPPHIRE general inclusion criteria and primary outcomes of death, stroke, or myocardial infarction were used, as were other previously reported high-risk criteria. Factors that were associated with the primary outcome by analysis of variance (P < .10) and not linearly dependent, as determined by a Pearson's correlation analysis, were further assessed for an independent association by multivariate logistic regression. A risk index model was developed for these significant predictors using an integer score as a reliable formula. Multivariate analysis (P < .05) found the following independently significant risk factors (95% confidence interval): age in years (1.0-1.1; P < .001), preadmission nursing home (1.2-6.6; P = .020), congestive heart failure (CHF; 1.4-2.8; P < .001), diabetes (1.1-1.3; P < .001), chronic obstructive pulmonary disease (COPD; 1.2-1.5; P < .001), any previous cerebrovascular disease (CVD; 1.1-1.9; P = .003), and contralateral internal carotid artery stenosis (1.0-1.2; P = .001). The predictors are age in years (40-49: 0 points; 50-59: 2 points; 60-69: 4 points; 70-79: 6 points; 80-89: 8 points), living in a nursing home (4 points), any CVD (2 points), CHF (5 points), COPD (3 points), diabetes (2 points), degree of contralateral stenosis (<50%: 0 points; 50-69%: 1 point; 70-near occlusion: 2 points; occlusion: 3 points). Lowest-risk CEA was defined as 0 points with an estimated risk of 2.7%, highest-risk CEA was defined as >13 points, representing adverse outcome rate of 22.5%. The SAPPHIRE high-risk CEA definition is not accurate. We propose a new, evidence-based definition of high-risk CEA. The CEA risk index model may assist clinicians in appropriate patient selection. Future studies should aim at validation of this risk index model.

PS4 Reintervention after abdominal aortic aneurysm repair in the Vascular Study Group of New England

PS4 Reintervention after abdominal aortic aneurysm repair in the Vascular Study Group of New England

Factors that determine the length of stay after carotid endarterectomy represent opportunities to avoid financial losses

A postoperative length of stay (LOS) >1day after elective surgery incurs financial losses for hospitals, given fixed diagnosis-related group-based reimbursement. We sought to identify factors leading to a prolonged LOS (>1 postoperative day) after carotid endarterectomy (CEA). Patients undergoing CEA in 23 centers of the Vascular Study Group of New England between 2003 and 2011 (n= 8860) were analyzed. Only elective, primary CEAs were analyzed, leaving a study cohort of 7108 procedures. Hierarchical multivariable logistic regression analysis was performed to identify predictors of a postoperative LOS >1day. A Knaus-Wagner chi-pie analysis was performed to determine the relative contributions of each significant covariate to a postoperative LOS >1day. A postoperative LOS >1day occurred in 17.5% of the sample (n= 1244). The average LOS was 1.4days (range, 1-91days; median, 1). There was significant variation in rates of postoperative LOS >1day across centers (range, 5%-100%; P< .001). Factors independently associated with a postoperative LOS >1day and their percentage contribution to the prediction model included the need for postoperative intravenous medications for hypertension or hypotension (26%), any major adverse event (MAE) postoperatively (21%), low-volume (<15 CEAs per year) surgeons (28%), increasing age (7%), female gender (4%), positive result on a preoperative stress test (3%), preoperative major stroke ≤30days (2%), medication-dependent diabetes (1%), severe chronic obstructive pulmonary disease (1%), history of congestive heart failure (1%), and CEA performed on Friday (2%). Certain patient characteristics predispose to a postoperative LOS >1day after elective CEA. However, patient characteristics play only a modest (17%) role in determining LOS. The need for postoperative blood pressure control and MAEs are the biggest drivers of postoperative LOS >1day, but system factors, such as low operative volume, contribute substantially to postoperative LOS >1day, independent of MAEs. These findings can be used to guide quality improvement efforts designed to reduce LOS after elective CEA.

Comparison of a Vascular Study Group of New England (VSGNE) Risk Prediction Model With the Established Risk Prediction Models of In-Hospital Mortality After Elective Abdominal Aortic Aneurysm (AAA) Repair

Comparison of a Vascular Study Group of New England (VSGNE) Risk Prediction Model With the Established Risk Prediction Models of In-Hospital Mortality After Elective Abdominal Aortic Aneurysm (AAA) Repair

Perioperative management with antiplatelet and statin medication is associated with reduced mortality following vascular surgery

Many patients undergoing vascular surgical procedures are not on appropriate medical therapy. This study sought to examine the variation and impact of antiplatelet (AP) and statin therapy on early and late mortality in patients undergoing vascular surgery in our region. We studied all patients (n = 14,489) undergoing elective carotid endarterectomy (n = 6978), carotid stenting (n = 524), and suprainguinal (n = 763) and infrainguinal bypass (n = 3053), as well as patients with known coronary risk factors undergoing open (n = 1044) and endovascular (n = 2127) abdominal aortic aneurysm repair from 2005 to 2012 in the Vascular Study Group of New England. Optimal medical management was defined as treatment with both AP and statin agents, preoperatively and at discharge. We analyzed temporal, procedural, and center variation of medication use. Multivariable analyses were used to determine the adjusted impact of AP and statin therapy on 30-day mortality and 5-year survival. Optimal medical management improved over the study interval (55% in 2005 to 68% in 2012; P trend < .01) with carotid interventions having the highest rates of optimal medications use (carotid artery stenting, 78%; carotid endarterectomy, 74%) and abdominal aortic aneurysm repair in patients with known cardiac risk factors having the lowest (open, 57%; endovascular aneurysm repair, 56%). Optimal medication use varied by center as well (range, 40%-86%). Preoperative AP and statin use was associated with reduced 30-day mortality (odds ratio, 0.76; 95% confidence interval [CI], 0.5-1.05; P = .09). AP and statin prescription at discharge was additive in survival benefit with improved 5-year survival (hazard ratio, 0.5; 95% CI, 0.4-0.7; P < .01) that was consistent across procedure types. Patients prescribed AP and statin at discharge had 5-year survival of 79% (95% CI, 77%-81%) compared with only 61% (95% CI, 52%-68%; P < .001) for patients on neither medication. AP and statin therapy preoperatively and at discharge was associated with reduced 30-day mortality and an absolute 18% improved 5-year survival after vascular surgery. However, one-third of patients are suboptimally managed in real world practice. This demonstrates an opportunity for quality improvement that can substantially improve survival after vascular surgery.

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

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. 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 patient's 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. 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. 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.

Clinical Relevance of Cranial Nerve Injury following Carotid Endarterectomy

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. 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. 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). 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.

Shared quality data are associated with increased protamine use and reduced bleeding complications after carotid endarterectomy in the Vascular Study Group of New England

The goal of this study was to evaluate whether protamine usage after carotid endarterectomy (CEA) increased within the Vascular Study Group of New England (VSGNE) in response to studies indicating that protamine reduces bleeding complications associated with CEA without increasing the risk of stroke. We reviewed 10,059 CEAs, excluding concomitant coronary bypass, performed within the VSGNE from January 2003 to July 2012. Protamine use and reoperation for bleeding were evaluated monthly using statistical process control. Twelve centers and 77 surgeons entering the VSGNE between 2003 and 2008 were classified as original participants, and 14 centers and 60 surgeons joining after May 2009 were considered new. Protamine use for surgeons was categorized as rare (<10%), selective (10%-80%), or routine (>80%). Outcome measures were in-hospital reoperation for bleeding, postoperative myocardial infarction (POMI), and stroke or death. Two significant increases occurred in protamine use for all VSGNE centers over time. From 2003 to 2007, the protamine rate remained stable at 43%. In 2008, protamine usage increased to 52% (P< .01), coincident with new centers joining the VSGNE. Protamine usage then increased to 62% in 2010 (P< .01), shortly after the presentations of the data showing a benefit of protamine. This effect was due to 10 surgeons in the original VSGNE centers who increased their usage of protamine: six surgeons from rare use to selective use and four surgeons to routine use. Reoperation for bleeding was reduced by 0.84% (relative risk reduction, 57.2%) in patients who received protamine (0.6% vs 1.44%; P< .001). There were no differences in POMI (1.1% vs 1.09%) or stroke or death (1.1% vs 1.03%) between protamine treated and untreated patients, respectively. Reoperation for bleeding was decreased for surgeons who used protamine routinely (0.5%; P< .001) compared with selective (1.4%) and rare users (1.5%) of protamine. There were no differences in POMI (0.9%, 1.2%, 1.1%; P= .720) and stroke or death rates (1.0%, 1.2%, 1.0%; P= .656) for rare, selective, and routine users of protamine. Protamine use increased over time by VSGNE surgeons, most significantly after the presentations of VSGNE-derived data showing the benefit of protamine, and was associated with a decrease in reoperation for bleeding. Improvements in processes of care and outcomes can be achieved in regional quality groups by sharing safety and efficacy data.

Comparison of Graft Patency, Limb Salvage, and Antithrombotic Therapy Between Prosthetic and Autogenous Below-Knee Bypass for Critical Limb Ischemia

The autogenous vein is the preferred conduit in below-knee vascular reconstructions. However, many argue that prosthetic grafts can perform well in crural bypass with adjunctive antithrombotic therapy. We therefore compared outcomes of below-knee prosthetic versus autologous vein bypass grafts for critical limb ischemia and the use of adjunctive antithrombotic therapy in both settings. Utilizing the registry of the Vascular Study Group of New England (2003-2009), we studied 1227 patients who underwent below-knee bypass for critical limb ischemia, 223 of whom received a prosthetic graft to the below-knee popliteal artery (70%) or more distal target (30%). We used propensity matching to identify a patient cohort receiving single-segment saphenous vein yet had remained similar to the prosthetic cohort in terms of characteristics, graft origin/target, and antithrombotic regimen. Main outcome measures were graft patency and major limb amputation within 1 year. Secondary outcomes were bleeding complications (reoperation or transfusion) and mortality. We performed comparisons by conduit type and by antithrombotic therapy. Patients receiving prosthetic conduit were more likely to be treated with warfarin than those with greater saphenous vein (57% vs. 24%, P<0.001). After propensity score matching, we found no significant difference in primary graft patency (72% vs. 73%, P=0.81) or major amputation rates (17% vs. 13%, P=0.31) between prosthetic and single-segment saphenous vein grafts. In a subanalysis of grafts to tibial versus popliteal targets, we noted equivalent primary patency and amputation rates between prosthetic and venous conduits. Whereas overall 1-year prosthetic graft patency rates varied from 51% (aspirin+clopidogrel) to 78% (aspirin+warfarin), no significant differences were seen in primary patency or major amputation rates by antithrombotic therapy (P=0.32 and 0.17, respectively). Further, the incidence of bleeding complications and 1-year mortality did not differ by conduit type or antithrombotic regimen in the propensity-matched analysis. Although limited in size, our study demonstrates that, with appropriate patient selection and antithrombotic therapy, 1-year outcomes for below-knee prosthetic bypass grafting can be comparable to those for greater saphenous vein conduit.

Designation as "Unfit for Open Repair" Is Associated With Poor Outcomes After Endovascular Aortic Aneurysm Repair

Endovascular aortic aneurysm repair (EVAR) is often offered to patients with abdominal aortic aneurysms (AAAs) considered preoperatively to be unfit for open AAA repair (oAAA). This study describes the short- and long-term outcomes of patients undergoing EVAR with AAAs <6.5 cm who are considered unfit for oAAA. We analyzed elective EVARs for AAAs <6.5 cm diameter in the Vascular Study Group of New England (2003-2011). Patients were designated as fit or unfit for oAAA by the treating surgeon. End points included in-hospital major adverse events and long-term mortality. We identified patient characteristics associated with being unfit for open repair and predictors of survival using multivariable analyses. Of 1653 EVARs, 309 (18.7%) patients were deemed unfit for oAAA. These patients were more likely to have advanced age, cardiac disease, chronic obstructive pulmonary disease, and larger aneurysms at the time of repair (54 versus 56 mm, P=0.001). Patients unfit for oAAA had higher rates of cardiac (7.8% versus 3.1%, P<0.01) and pulmonary (3.6 versus 1.6, P<0.01) complications and worse survival rates at 5 years (61% versus 80%; log rank P<0.01) compared with those deemed fit for oAAA. Finally, patients designated as unfit for oAAA had worse survival, even adjusting for patient characteristics and aneurysm size (hazard ratio, 1.6; 95% confidence interval, 1.2-2.2; P<0.01). In patients with AAAs <6.5 cm, designation by the operating surgeon as unfit for oAAA provides insight into both short- and long-term efficacy of EVAR. Patients unable to tolerate oAAA may not benefit from EVAR unless their risk of AAA rupture is very high.

Designation as “Unfit for Open Repair” Is Associated With Poor Outcomes After Endovascular Aortic Aneurysm Repair

Background— Endovascular aortic aneurysm repair (EVAR) is often offered to patients with abdominal aortic aneurysms (AAAs) considered preoperatively to be unfit for open AAA repair (oAAA). This study describes the short- and long-term outcomes of patients undergoing EVAR with AAAs &lt;6.5 cm who are considered unfit for oAAA. Methods and Results— We analyzed elective EVARs for AAAs &lt;6.5 cm diameter in the Vascular Study Group of New England (2003–2011). Patients were designated as fit or unfit for oAAA by the treating surgeon. End points included in-hospital major adverse events and long-term mortality. We identified patient characteristics associated with being unfit for open repair and predictors of survival using multivariable analyses. Of 1653 EVARs, 309 (18.7%) patients were deemed unfit for oAAA. These patients were more likely to have advanced age, cardiac disease, chronic obstructive pulmonary disease, and larger aneurysms at the time of repair (54 versus 56 mm, P =0.001). Patients unfit for oAAA had higher rates of cardiac (7.8% versus 3.1%, P &lt;0.01) and pulmonary (3.6 versus 1.6, P &lt;0.01) complications and worse survival rates at 5 years (61% versus 80%; log rank P &lt;0.01) compared with those deemed fit for oAAA. Finally, patients designated as unfit for oAAA had worse survival, even adjusting for patient characteristics and aneurysm size (hazard ratio, 1.6; 95% confidence interval, 1.2–2.2; P &lt;0.01). Conclusions— In patients with AAAs &lt;6.5 cm, designation by the operating surgeon as unfit for oAAA provides insight into both short- and long-term efficacy of EVAR. Patients unable to tolerate oAAA may not benefit from EVAR unless their risk of AAA rupture is very high.

The need for treatment of hemodynamic instability following carotid endarterectomy is associated with increased perioperative and 1-year morbidity and mortality

The objective of this study was to evaluate the outcomes of patients after carotid endarterectomy (CEA) who developed postoperative hypertension or hypotension requiring the administration of intravenous vasoactive medication (IVMED). We examined consecutive, primary elective CEA performed by 128 surgeons within the Vascular Study Group of New England (VSGNE) database (2003-2010) and compared outcomes of patients who required postoperative IVMED to treat hyper- or hypotension with those who did not. Outcomes included perioperative death, stroke, myocardial infarction (MI), congestive heart failure (CHF), hospital length of stay, and 1-year stroke or death. Propensity score matching was performed to facilitate risk-adjusted comparisons. Multivariable regression models were used to compare the association between IVMED and outcomes in unmatched and matched samples. Factors associated with use of IVMED in postoperative hypertension and hypotension were evaluated, and predictive performance of multivariable models was examined using receiver operating characteristic (ROC) curves. Of 7677 elective CEAs identified, 23% received IVMED for treatment of either postoperative hypertension (11%) or hypotension (12%). Preoperative neurological symptomatic status (20%) was similar across cohorts. In the crude sample, the use of IVMED to treat postoperative hypertension was associated with increased 30-day mortality (0.7% vs 0.1%; P < .001), stroke (1.9% vs 1%; P = .018), MI (2.4% vs 0.5%; P < .001), and CHF (1.9% vs 0.5%; P < .001). The use of IVMED to treat postoperative hypotension was also associated with increased perioperative mortality (0.8% vs 0.1%; P < .001), stroke (3.2% vs 1.0%; P < .001), MI (2.7% vs 0.5%; P < .001), and CHF (1.7% vs 0.5%; P < .001), as well as 1-year death (5.1% vs 2.9%; P < .001) or stroke (4.2% vs 2.1%; P < .001). Hospital length of stay was significantly longer among patients who needed IVMED for postoperative hypertension (2.8 ± 4.7 days vs 1.7 ± 5.5 days; P < .001) and hypotension (2.8 ± 5.9 days vs 1.7 ± 5.5 days; P < .001). In multivariable analysis, IVMED for postoperative hypertension was associated with increased MI, stroke, or death (odds ratio, 2.6; 95% confidence interval [CI], 1.6-4.1; P < .001). Similarly, IVMED for postoperative hypotension was associated with increased MI, stroke, or death (odds ratio, 3.2; 95% CI, 2.1-5.0; P < .001), as well as increased 1-year stroke or death (hazard ratio, 1.6; 95% CI, 1.2-2.2; P = .003). Smoking, coronary artery disease, and clopidogrel (ROC, 0.59) were associated with postoperative hypertension requiring IVMED, whereas conventional endarterectomy and general anesthesia were associated with postoperative hypotension requiring IVMED (ROC, 0.58). The unitization of IVMED varied between 11% and 38% across VSGNE, and center effect did not affect outcomes. Postoperative hypertension requiring IVMED after CEA is associated with increased perioperative mortality, stroke, and cardiac complications, whereas significant postoperative hypotension is associated with increased perioperative mortality, cardiac, or stroke complications, as well as increased 1-year death or stroke following CEA. The utilization of IVMED varied across centers and, as such, further investigation into this practice needs to occur in order to improve outcomes of these at-risk patients.