Study Group Of New England Research Articles

The Modified Harborview Risk Score Successfully Predicts Mortality after Ruptured Abdominal Aortic Aneurysm Repair

The traditional Harborview Risk Score (tHRS) uses four criteria to predict mortality after surgical repair of ruptured abdominal aortic aneurysms (rAAA): preoperative minimum systolic blood pressure (SBP <70mm Hg), creatinine (>2.0 mg/dL), age (>76 years) and preoperative arterial pH (<7.2). Difficulties obtaining arterial pH values limit the clinical utility of this score. International normalized ratio (INR >1.8) has been proposed as an acceptable substitution when arterial blood gases are not available preoperatively. Preliminary studies have shown that the accuracy of the score is not compromised when using this modified criterion. The objective of this study is to validate the modified Harborview Risk Score (mHRS). We conducted a retrospective analysis of all patients presenting with rAAA at a single tertiary-care center from 2011 to 2022. The Vascular Study Group of New England (VSGNE) score was used for comparison. The primary outcome was 30-day mortality. Logistic regression and receiver operating characteristic (ROC) curves were used to evaluate the predictability of each score. Categorical and continuous data were compared using Chi-squared and Student's t-tests, respectively. Of the 91 patients identified during the study period, 69 patients met inclusion criteria. 50 patients underwent endovascular repairs (rEVAR) and 19 patients received open repairs (rOR). All 69 patient records had documented INR values, and 62 patients (89.8%) had documented arterial pH values. The 30-day mortality rate was 38% overall (30% for rEVAR vs. 58% for rOR, p=0.030). There was a stronger linear relationship between the mHRS and 30-day mortality (R2=0.97) than the VSGNE score (R2=0.94). There was no significant difference in the areas under the ROC curves between the mHRS and VSGNE scores (0.70 [0.56-0.83], p=0.007 vs. 0.69 [0.56-0.82], p=0.01, respectively). Logistic regression analysis showed a significant correlation between creatinine (4.0 [1.2-13.8], p=0.03), SBP (3.8 [1.3-11.1], p=0.02), and age (1.7 [1.1-7.4], p=0.04) and 30-day mortality. The mHRS accurately predicted 30-day mortality after rAAA repair using INR >1.8. By using easily obtainable preoperative variables, the mHRS has broader clinical utility, making it a superior scoring system to the tHRS and VSGNE scores.

Association of Anticoagulation and Major Adverse Limb Events After Index Peripheral Endovascular Intervention

Dual-antiplatelet therapy is commonly prescribed after endovascular intervention for peripheral artery disease. However, it is not known whether therapeutic anticoagulation affects outcomes after peripheral endovascular intervention. We sought to investigate whether therapeutic anticoagulation after peripheral endovascular intervention is associated with lower risk of major adverse limb events (MALEs) and all-cause mortality. We studied patients who underwent index endovascular intervention for peripheral artery disease in the Vascular Study Group of New England (2010 to 2018). The main exposure was anticoagulation at the time of discharge. Outcomes included patency loss (occlusion or target lesion reintervention), MALE (any major amputation or reintervention), and all-cause mortality. We compared outcomes between patients who received anticoagulation on discharge versus those who did not receive anticoagulation using Kaplan-Meier survival analysis and Cox regression. In the cohort of 6,809 patients, 15% were discharged on an anticoagulant (mostly warfarin). These patients had a higher prevalence of acute or chronic limb ischemia than those not receiving an anticoagulant (74% vs 47%, p < 0.001) and were less likely to receive any antiplatelet agent after peripheral endovascular intervention (5% vs 14%, p < 0.001). After risk adjustment, compared with patients not on an anticoagulant, patients receiving therapeutic anticoagulation had a higher risk of 2-year patency loss (hazard ratio [HR] 1.41, 95% confidence interval [CI] 1.05 to 1.89), MALE (HR 1.39, 95% CI 1.09 to 1.76), and all-cause mortality (HR 1.24, 95% CI 1.05 to 1.47). In conclusion, anticoagulation after peripheral endovascular intervention was associated with higher risk of adverse events, including patency loss, MALE, and all-cause mortality.

The Use of Multiple Carotid Stents is Associated With Increased Incidence of Developing In-stent Stenosis on Long-term Follow-up

Carotid artery stenting (CAS) has emerged as a feasible and safe option for patients that carry a high anatomic and/or physiologic surgical risk for conventional carotid endarterectomy. The pathophysiology behind the development of in-stent stenosis remains a complex process with multiple factors contributing to it. We sought to identify factors that contribute to developing in-stent stenosis following carotid stenting utilizing the Vascular Quality Initiative (VQI) of the Vascular Study Group of New England.

Preoperative and ICU Scoring Models for Predicting the In-Hospital Mortality of Patients With Ruptured Abdominal Aortic Aneurysms

ObjectivesThis study’s objective was to compare several preoperative and intensive care unit (ICU) prognostic scoring systems for predicting the in-hospital mortality of ruptured abdominal aortic aneurysms (RAAAs). DesignRetrospective cohort study. SettingSingle tertiary university center. ParticipantsThe study comprised 157 patients. InterventionsNone. Measurements and Main ResultsA total of 157 patients (82% male) presented with RAAA at Charité University Hospital from January 2011 to December 2020. The mean age was 74 years (standard deviation ten years). In-hospital mortality was 29% (n = 45), of whom nine patients (6%) died en route to the operating room, 13 (8%) on the operating table, and 23 (15%) in the ICU. A total of 135 patients (86%) were admitted to the ICU. All six models demonstrated good discriminating performance between survivors and nonsurvivors. Overall, the area under the curve (AUC) for RAAA preoperative scores was greater than those for ICU scores. The largest AUC was achieved with the Vascular Study Group of New England (VSGNE) RAAA risk score (AUC = 0.87 for all patients, AUC = 0.84 for patients admitted to the ICU), followed by Hardman Index (AUC = 0.83 for all patients, AUC = 0.81 for patients admitted to the ICU), and Glasgow Aneurysm Score (AUC = 0.74 for all patients, AUC = 0.83 for patients admitted to the ICU). The largest AUC for ICU scores (only patients admitted to the ICU) was achieved with Simplified Acute Physiology Score II (0.75), followed by Sepsis-related Organ Failure Assessment (0.73), and Acute Physiology and Chronic Health Evaluation II (0.71). ConclusionsPreoperative and ICU scores can predict the mortality of patients presenting with RAAA. In addition, the discriminatory ability of preoperative scores between survivors and nonsurvivors was larger than that for ICU scores.

Not all risk scores are created equal: A comparison of risk scores for abdominal aortic aneurysm repair in administrative data and quality improvement registries

ObjectiveAccurate and contemporary prognostic risk prediction is essential to inform clinical decision-making surrounding abdominal aortic aneurysm (AAA) care. Therefore, we validated and compared three different in-hospital mortality risk scores in one administrative and two quality improvement registries. MethodsWe included patients who had undergone elective AAA repair from 2012 to 2015 in the National Inpatient Sample (NIS), Vascular Quality Initiative (VQI; excluding the New England region), and the National Surgical Quality Improvement Program (NSQIP) datasets to validate three risk scores: Medicare, the Vascular Study Group of New England (VSGNE), and Glasgow Aneurysm Score (GAS). The receiver operating characteristic area under the curve (AUC) of all risk scores was calculated, and their discrimination was compared within a dataset using the Delong test and between datasets using a Z test. We constructed graphic calibration curves for the Medicare and VSGNE risk scores and compared the calibration using an integrated calibration index, which indicates the weighted average of the absolute difference between the calibration curve and the diagonal line of perfect calibration. ResultsWe identified a total of 25,461 NIS, 18,588 VQI, and 8051 NSQIP patients who had undergone elective open or endovascular AAA repair. Overall, the Medicare risk score was more likely to overestimate mortality in the quality improvement registries and the VSGNE risk score underestimated mortality in all the databases. After endovascular AAA repair, the Medicare risk score had a higher AUC in the NIS than in the GAS (P < .001) but not compared with the VSGNE risk score (P = .54). The VSGNE risk score was associated with a significantly higher receiver operating characteristic AUC compared with the Medicare (P < .001) and GAS (P < .001) risk scores in the VQI registry. Also, the VSGNE risk score showed improved calibration compared with the Medicare risk score across all three databases (P < .001 for all). After open repair, the Medicare risk score showed improved calibration compared with the VSGNE risk score in the NIS (P < .001). However, in the VQI registry, the VSGNE risk score compared with the Medicare risk score had significantly better discrimination (P = .008) and calibration (P < .001). ConclusionsOverall, the VSGNE risk score performed best in the quality improvement registries but underestimated mortality. However, the Medicare risk score demonstrated better calibration in the administrative dataset after open repair. Although the VSGNE risk score appeared to perform better in the quality improvement registries, its overly optimistic mortality estimates and its reliance on detailed anatomic and clinical variables reduces its broader applicability to other databases.

Frailty is a Poor Predictor of Postoperative Morbidity and Mortality After Ruptured Abdominal Aortic Aneurysm

Frailty has gained prominence as a predictor of postoperative outcomes across a number of surgical specialties, vascular surgery included. The role of frailty is less defined in the acute surgical setting. We assessed the prognostic value of frailty for patients undergoing surgery for a ruptured abdominal aortic aneurysm (rAAA). A single-institution retrospective chart review of all patients undergoing surgical intervention for rAAA between January 1, 2011 and November 27, 2019 was performed. Frailty was assessed for each patient using the modified frailty index (mFI), a validated frailty metric based on the Canadian Study of Health and Aging. Frailty was defined as an mFI ≥0.27. The performance of the mFI was compared to that of the Vascular Study Group of New England (VSGNE) rAAA mortality risk score. Chi square, Fisher's exact, and t tests, were used to evaluate for associations between frailty and in-hospital outcomes. Univariate and multivariate logistic regression were used to obtain odds ratios for in-hospital mortality. A receiver operating characteristic (ROC) curve was generated to compare the predictive value of the mFI and VSGNE score for in-hospital mortality. Sixty patients were identified during the study period with an in-hospital mortality rate of 37%. Twenty-one patients were deemed frail by mFI metric and included all patients with known myocardial infarction, stroke with a neurologic deficit or dependent functional status, however the mortality rate did not differ significantly based on frailty status (33% nonfrail vs. 43% frail, P= 0.47). Frailty status was not significantly different for patients with acute kidney injury (10% nonfrail vs. 10% frail), prolonged intubation (13% vs. 5%), abdominal compartment syndrome (8% vs. 10%), and Type I or Type III endoleak (8% vs. 19%). On multivariate analysis controlling for systolic blood pressure <70 mm Hg, suprarenal aortic control, and creatinine >2.0 mg/dl, the mFI produced an adjusted odds ratio (aOR) of 0.7 (95% confidence interval [CI]: 0.2-3.0). The ROC curve for the mFI produced an area under the curve (AUC) of 0.55 (P= 0.55) for in-hospital mortality while that of the VSGNE score produced an AUC of 0.69 (P= 0.02). The mFI did not significantly predict in-hospital outcomes after rAAA in this cohort. This suggests that the baseline health status of a patient with rAAA may play a less significant role in their postoperative prognosis than their acuity on presentation.

Predictors of Operative Mortality of 928 Intact Aortoiliac Aneurysms

The aim of this study is to identify preoperative and intraoperative factors associated with in-hospital mortality of intact abdominal aortoiliac aneurysm repair. In this observational study, prospectively collected information included demographics, risk factors, comorbidities, aneurysm characteristics (including special aneurysm presentation, i.e., inflammatory, mycotic/infected, aortocaval fistula), investigations, and operative variables. Receiver operating characteristic) curve analysis of the Glasgow aneurysm score (GAS) and the Vascular Study Group of New England (VSGNE) score was performed in the subgroup of bland aneurysms undergoing isolated elective repair. A total of 928 cases with intact aortoiliac aneurysms had an elective (n=882) or urgent (n=46) repair, associated with an in-hospital mortality of 1.7% and 8.7%, respectively (P=0.01). Open repair (n=514) was a predictor of higher mortality (3.3% vs. 0.5% for endovascular aneurysm repair [EVAR], n=414, odds ratio [OR] 7.1, P=0.003), and so was the pre-EVAR era (4.8% vs. 1.3% in the EVAR era, OR 4.0, P=0.004). Other significant predictors included the presence of abdominal/back pain (7.5% vs. 1.3%, OR=6.0, P=0.001), preoperative angiography (7% vs. 1.6%, OR=4.5, P=0.01), special aneurysm presentation (10.9% vs. 1.5%, OR=8.1, P<0.001), concomitant major procedures (19% vs. 1.7%, OR=14.0, P<0.001), serious intraoperative complications (9.1% vs. 1.5%, OR=6.6, P=0.001), median number of transfused units of blood intraoperatively (2 and 0 for cases with and without mortality, respectively, P<0.001), and procedure duration (270 and 150min for cases with and without mortality, respectively, P<0.001). Open repair (OR=4.5, P=0.05), special aneurysm presentation (OR=6.58, P=0.001), and concomitant major procedures (OR=14.3, P<0.001) were independent predictors of higher mortality. ROC curve analysis for the GAS (P=0.87) and VSGNE score (P=0.10) failed to demonstrate statistical significance in the subgroup of bland aneurysms undergoing isolated elective repair. Our study has demonstrated independent risk factors for mortality, which should be considered when contemplating aortoiliac aneurysm repair. We failed to externally validate the GAS and VSGNE score.

Increasing disparity between Society for Vascular Surgery guidelines for infrarenal abdominal aortic aneurysm repair and real-world practice

ObjectiveThe current Society for Vascular Surgery (SVS) guidelines, based on randomized controlled trials published more than a decade ago, recommend a minimum threshold diameter of 5.5 cm for infrarenal abdominal aortic aneurysm (iAAA) repair. It is unknown whether practice patterns with respect to size of repair have changed since the publication of these guidelines. We aimed to evaluate the real-world practice of vascular surgeons in our region with respect to iAAA size at the time of repair, whether this has changed over the past 12 years and if any changes were associated with the repair type, open vs endovascular. MethodsThe Vascular Study Group of New England (VSGNE) database was used to identify all patients who received iAAA repair between 2003 and 2015. The primary end point was to quantify the annual percentage of iAAAs repaired in different size categories (≥5.5 cm; <5.5 cm but ≥5.0 cm; <5.0 cm) over the study time period and by type of repair. The secondary end points were morbidity and mortality in these groups. We excluded nonelective cases (ruptured or symptomatic), patients with coexisting iliac artery aneurysms, and those missing critical data. ResultsA total of 5314 patients with iAAA repairs (1538 open, 3776 endovascular) were identified in the VSGNE database during the study period. In 40% (2110 of 5314) of patients, repair was performed for aneurysms <5.5 cm, with endovascular aneurysm repair (EVAR) comprising 75% (1581 of 2110) and open 25% (529 of 2110). More EVARs were performed for <5.5 cm in 2015 (46%) compared with 2003 (33%) (P < .05, n − 1 χ2) with an average increase of 1.1%/y. There was also a non-statistically significant increase in open repair of small aneurysms (0.7%/y; P = .759). Overall, 30-day mortality was 1.11% in the EVAR group (0.54% in <5.0 cm, 0.91% in ≥5.0 but <5.5 cm, and 1.55% in ≥5.5 cm), compared with 3% in the open group (2.88%, 1.79%, and 3.77%, respectively) with no significant change in mortality in either group over time. ConclusionsDespite the SVS guidelines suggesting surveillance rather than repair of iAAA <5.5 cm, an increasing proportion of repairs in the VSGNE database were performed below that threshold. The reasons for this are likely multifactorial and might include a lesser complexity and lower operative mortality for smaller aneurysms and markedly improved third- and fourth-generation stent graft technology with possibly better long-term survival. As such, it may be time to re-examine the current guidelines for iAAA repair.

Modern mortality risk stratification scores accurately and equally predict real-world postoperative mortality after ruptured abdominal aortic aneurysm

ObjectiveIt is often unclear which patients presenting with a ruptured abdominal aortic aneurysm (rAAA) are likely to survive after surgery. The Harborview Medical Center (HMC), Dutch Aneurysm Score (DAS), and Vascular Study Group of New England (VSGNE) risk scores have been recent attempts at predicting mortality in this setting. We compared the prognostic value of these scoring systems for patients at our institution with rAAA. MethodsA retrospective chart review was performed for all patients who received surgery at our institution for rAAA between January 1, 2011, and November 27, 2019. The χ2, Fisher's exact, and t-tests were used to screen preoperative variables against in-hospital mortality. HMC, DAS, and VSGNE scores were calculated for each patient and tested against in-hospital mortality. Logistic regression and receiver operating characteristic curves were used to assess performance of each scoring system. ResultsSixty-four patients were identified during the study period. Fifteen patients were excluded because 4 patients chose comfort care and an additional 11 patients were missing key variables. The final cohort for analysis included 49 patients who underwent surgery, including 33 patients receiving endovascular repair and 16 patients receiving open repair. The in-hospital mortality was 37% (24% for endovascular repair vs 63% for open repair). Individual variables associated with in-hospital mortality were lowest preoperative systolic blood pressure (P = .036), creatinine greater than 2.0 mg/dL (P = .020), first recorded intraoperative pH (P = .007), and use of suprarenal aortic control (P = .025), and preoperative cardiac arrest approached significance (P = .051). Plots of the HMC and VSGNE scores vs in-hospital mortality rate produced linear relationships (R2 = 0.97 and R2 = 0.93, respectively), in which a higher score was associated with a greater likelihood of mortality. On logistic regression analysis using HMC score components, creatinine greater than 2.0 mg/dL produced a significant association with in-hospital mortality (odds ratio, 12.3; 95% confidence interval [CI], 1.1-131.7). Similar analysis using VSGNE components produced a significant association between suprarenal aortic control and in-hospital mortality (odds ratio, 5.5; 95% CI, 1.2-25.5). receiver operating characteristic curves produced an area under the curve of 0.74 (95% CI, 0.60-0.88), 0.73 (95% CI, 0.58-0.87), and 0.67 (95% CI, 0.51-0.83) for the HMC, VSGNE, and DAS, respectively. ConclusionsThe HMC, VSGNE, and DAS scores performed similarly and adequately predicted in-hospital mortality after rAAA. The HMC score holds the added benefit of using preoperative variables, setting it apart as a valid prognostic indicator in the preoperative setting.

Frailty Index Is a Poor Predictor of Postoperative Morbidity and Mortality After Ruptured Abdominal Aortic Aneurysm

Abstract Objectives : Frailty has gained prominence as a predictor of postoperative outcomes across a number of surgical specialties, vascular surgery included. The role of frailty is less defined in the acute surgical setting. We assessed the prognostic value of frailty for patients undergoing surgery for a ruptured abdominal aortic aneurysm (rAAA). Methods : A single-institution retrospective chart review of all patients undergoing surgical intervention for rAAA between January 1, 2011 and November 27, 2019 was performed. Frailty was assessed for each patient using the modified frailty index (mFI), a validated frailty metric based on the Canadian Study of Health and Aging. Frailty was defined as an mFI ≥ 0.27. The performance of the mFI was compared to that of the Vascular Study Group of New England (VSGNE) rAAA mortality risk score. Chi square, Fisher's exact, and t tests, were used to evaluate for associations between frailty and in-hospital outcomes. Univariate and multivariate logistic regression were used to obtain odds ratios for in-hospital mortality. A receiver operating characteristic (ROC) curve was generated to compare the predictive value of the mFI and VSGNE score for in-hospital mortality. Results : Sixty patients were identified during the study period with an in-hospital mortality rate of 37%. Twenty-one patients were deemed frail by mFI metric and included all patients with known myocardial infarction, stroke with a neurologic deficit or dependent functional status, however the mortality rate did not differ significantly based on frailty status (33% non-frail vs. 43% frail, p=0.47). Frailty status was not significantly different for patients with acute kidney injury (10% non-frail vs. 10% frail), prolonged intubation (13% vs. 5%), abdominal compartment syndrome (8% vs. 10%), and Type I or Type III endoleak (8% vs. 19%). On multivariate analysis controlling for systolic blood pressure 2.0 mg/dl, the mFI produced an adjusted odds ratio (aOR) of 0.7 (95% confidence interval [CI]: 0.2-3.0). The ROC curve for the mFI produced an area under the curve (AUC) of 0.55 (p=0.55) for in-hospital mortality while that of the VSGNE score produced an AUC of 0.69 (p=0.02). Conclusions : The mFI did not significantly predict in-hospital outcomes after rAAA in this cohort. This suggests that the baseline health status of a patient with rAAA may play a less significant role in their postoperative prognosis than their acuity on presentation. Funding : This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

The Use of Embolic Protection Devices during Lower Extremity Peripheral Vascular Interventions

The use of embolic protection device (EPD) during lower extremity peripheral vascular interventions (PVI) has been reported, but its impact on outcomes is unclear. The goal of this study was to assess the use and outcomes of EPDs during PVI. All PVI between 2010 and 2014 in the Vascular Study Group of New England (VSGNE) database were reviewed. The characteristics of patients and lesions treated with EPD were identified. A propensity-matched control group without EPD was selected. The outcomes of both groups were compared, and a multivariable analysis was performed. There were a total of 10,875 procedures. EPD was used in 2% of the procedures. From 2010 to 2014, EPD use significantly increased from 1.1 to 3.5% (P<0.001). Patients undergoing PVI with EPD were less likely to be white but more likely to have diabetes, chronic obstructive pulmonary disease, coronary artery disease, and history of prior PVI. After propensity matching, there were 182 procedures with EPD and 604 controls with no significant difference in risk factors. There was no difference in indication or anatomic level treated, with claudication (52.7% vs. 49.8%) being most common indication and the superficial femoral artery (65.4% vs. 62.1%), the most commonly treated artery. Patients undergoing PVI with EPD were more likely to be treated with excisional atherectomy (26.4% vs. 12.6%), whereas patients without EPD were more likely to be treated with orbital atherectomy (31.9% vs. 41.6%, P=0.017). There was no significant difference in the incidence of minor distal embolization (DE) (1.1% vs. 1.5%) or DE requiring endovascular treatment (2.8% vs. 2.6%) between the two groups, but EPD use was significantly associated with increased fluoroscopy time (P<0.001). There was no difference in technical success, patency, amputation, or mortality between the two groups. On multivariable analysis, there was no significant association between the use of EPD and patency (incidence relative risk (IRR) [95% CI]=1.1 [0.9-1.3]), amputation (IRR=0.7 [0.2-2.1]), or mortality (IRR=0.8 [0.6-1.2]). However, there was a significant difference in fluoroscopy time (mean ratio [95% CI]=1.2 [1.1-1.3]). The analysis was repeated after eliminating all procedures with DE in the EPD group (assuming that EPD use is 100% effective in preventing DE), and the results were no different. EPD use during PVI has significantly increased. Despite EPDs increasing procedural complexity and time, they do not seem to have any impact on PVI outcomes. Additional studies are needed to characterize which patients would benefit from EPDs.

Adverse cardiac events after vascular surgery are prevalent despite negative results of preoperative stress testing

ObjectiveCardiac risk assessment is a critical component of vascular disease management before surgical intervention. The predictive risk reduction of a negative cardiac stress test result remains poorly defined. The objective of this study was to compare the incidence of postoperative cardiac events among patients with negative stress test results vs those who did not undergo testing. MethodsWe reviewed all patients who underwent elective open abdominal aortic aneurysm repair, suprainguinal bypass, endovascular aneurysm repair (EVAR), carotid endarterectomy (CEA), and infrainguinal bypass within the Vascular Study Group of New England from 2003 to 2017. We excluded patients with positive stress test results (n = 3312) and studied two mutually exclusive groups: elective surgery patients with a negative stress test result and elective surgery patients with no stress test (total n = 26,910). The primary outcome was a composite of in-hospital postoperative cardiac events (dysrhythmia, heart attack, heart failure) or death. ResultsA preoperative stress test was obtained in 66.3% of open repairs, 42.8% of suprainguinal bypasses, 37.1% of EVARs, 36.0% of CEAs, and 31.2% of infrainguinal bypasses. The proportion of patients receiving a preoperative stress test varied widely across centers, from 37.1% to 80.0%. The crude odds ratio of in-hospital postoperative cardiac event or death was 1.37 (95% confidence interval [CI], 1.07-1.76) for open repair and 1.52 (CI, 1.13-2.03) for suprainguinal bypass, indicating that patients with negative stress test results before these procedures were 37% and 52% more likely to suffer a postoperative event or die compared with patients selected to proceed directly to surgery without testing. Conversely, the crude odds ratio was 0.92 (CI, 0.66-1.29) for EVAR, 0.92 (CI, 0.70-1.21) for CEA, and 1.13 (CI, 0.90-1.40) for infrainguinal bypass, indicating that patients undergoing these procedures had a similar likelihood of sustaining an event whether they had a negative stress test result or proceeded directly to surgery without a stress test. ConclusionsThe use of cardiac stress testing before vascular surgery varies widely throughout New England. Whereas patients are often appropriately selected to proceed directly to surgery, a negative preoperative stress test result should not assuage the concern for an adverse outcome as these patients retain a substantial likelihood of cardiac events, especially after large-magnitude procedures.

Novel Predictors of Peri-Operative Mortality in a Series Of 931 Consecutive Patients with Intact Aortoiliac Aneurysms Managed at a Single Centre

Introduction - The aim of our study was to identify preoperative and intraoperative factors associated with in-hospital mortality after repair of intact abdominal aortic or iliac aneurysms. Methods - This was a retrospective analysis of prospectively collected information on patients undergoing repair of intact aortoiliac aneurysms during a 28-year period. Recorded information included preoperative demographics, risk factors and co-morbidities, aneurysm characteristics, investigations and operative variables including special aneurysm presentation (inflammatory, mycotic/infected, aortocaval fistula) and procedure type (open vs. endovascular repair). Univariate and multivariate logistic regression analyses (with odds ratios, OR) were performed, the latter performed to develop a predictive model using the generated output. The area under the curve of the receiver operating characteristics (ROC) curve of our score, the Glasgow aneurysm score (GAS),1 and the Vascular Study Group of New England (VSGNE) score,2 was calculated. Results - During the study period we operated on 931 patients with intact aortoiliac aneurysms, on an elective (n=882) or urgent (n=49) basis, and an in-hospital mortality of 1.7% and 8.2%, respectively (p=0.015). Endovascular aneurysm repair (EVAR, n=414) was a predictor of lower mortality (0.5% vs. 3.3% for open repair, n=517, p=0.003). Other significant predictors included the presence of abdominal or back pain (7.5% vs 1.3% for no pain, p<0.001), preoperative angiography (6.9% vs 1.6% for no angiography, p=0.01), special aneurysm presentation (10.7% vs 1.5% for 875 ordinary atherosclerotic aneurysms, p<0.001), concomitant major procedures (19% vs 1.6% for the rest, p<0.001), serious intraoperative complications (9.1% vs 1.5% for no such complications, p<0.001), median number of transfused units of blood intraoperatively (2 and 0 for cases with and without mortality, respectively, p<0.001) and duration of the procedure (300min and 150min for cases with and without mortality, respectively, p<0.001). On multivariate analysis, EVAR was an independent predictor of lower mortality (OR=0.22, p=0.05) and special aneurysm presentation (OR=6.45, p=0.001) and concomitant major procedures (OR=14.3, p<0.001) were independent predictors of higher mortality. The area under the ROC curve, and p values for the GAS, VSGNE score and our score was 0.46, 0.62 and 0.81, and 0.59, 0.084 and 0.00003, respectively (Figure). The difference between the VSGNE and our score was significant (p=0.029). Repeat analysis for electively operated cases demonstrated an area under the ROC curve of 0.66 (p=0.029) and 0.80 (p=0.000069), respectively, for the VSGNE and our score, with the difference becoming non-significant. Conclusion - Our study in patients undergoing aortoiliac aneurysm repair has demonstrated novel risk factors for mortality and externally validated VSGNE in different healthcare settings.

External validation of the Vascular Study Group of New England carotid endarterectomy risk predictive model using an independent U.S. national surgical database

ObjectivePreviously, we described a Vascular Study Group of New England (VSGNE) risk predictive model to predict composite adverse outcomes (postoperative death, stroke, myocardial infarction, or discharge to extended care facilities) after carotid endarterectomy (CEA). The goal of this study was to externally validate this model using an independent database. MethodsThe American College of Surgeons National Surgical Quality Improvement Program (NSQIP) CEA-targeted database (2010-2014) was used to externally validate the risk predictor model of adverse outcomes after CEA previously created using the VSGNE carotid database. Emergent cases and those in which CEA was combined with another operation were excluded. Cases in which a discharge destination cannot be determined were also excluded. To assess the predictive power of our VSGNE prediction score within this sample, a receiver operating characteristic curve was constructed. Risk scores for each NSQIP patient were also computed using beta weights from the VSGNE CEA model. To further assess the construct validity of our VSGNE prediction score, the observed proportion of adverse outcomes was examined at each level of our prediction scale and within five roughly equally sized risk groups formed on the basis of our VSGNE prediction scores. ResultsIn this database, 10,889 cases met our inclusion criteria and were used in this analysis. The overall rate of adverse outcomes in this cohort was 8.5%. External validation of the VSGNE model on this sample showed moderately good predictive ability (area under the curve = 0.745). Patients in progressively higher risk groups, based on their VSGNE model scores, exhibited progressively higher rates of observed adverse outcomes, as predicted. ConclusionsThe VSGNE CEA risk predictive model was externally validated on an NSQIP CEA-targeted sample and showed a fairly accurate global predictive ability for adverse outcomes after CEA. Although this model has a good population concordance, the lack of cut point indicates that individual risk prediction requires more evaluation. Further studies should be geared toward identification of variables that make this risk predictive model more robust.

Interventions for Claudication Offer Low Morbidity, Yet Patients May Still Experience Limb Loss and Worsening Functional Status

Interventional approaches to management of claudication vary widely. Per the Society for Vascular Surgery guidelines, any invasive treatment of claudication must offer long-term benefit at low risk of complications. Our aim was to elucidate contemporary claudication intervention patterns and functional outcomes. The Vascular Study Group of New England (2003-2018) was queried for peripheral vascular interventions (PVIs), infrainguinal bypasses, and suprainguinal bypasses for claudication. Perioperative and 1-year outcomes were evaluated. There were 7051 PVIs, 2527 infrainguinal bypasses, and 849 suprainguinal bypasses performed for claudication. PVI techniques included stenting in 64.4% and atherectomy in 10.6%. Treatment levels were femoral-popliteal (54%), iliac (52.2%), and tibial (5.7%). Isolated tibial interventions were performed in 1.7%. Access site hematomas occurred in 4.9%. Mean hospital length of stay (LOS) was 1 day, and 30-day mortality was 0.4%. After 1 year, among patients initially ambulating independently, 3.6% required assistance and 1% were nonambulatory. One-year freedom from reintervention, amputation, and death was 91.5%, 97.1%, and 97%, respectively. Infrainguinal bypasses were often to the popliteal artery (81.2%); however, 18.8% were to tibial targets. The majority used great saphenous vein (63%). Perioperative complications were commonly cardiac (3.7%) and wound (3.4%). Mean LOS was 4 days, and 30-day mortality was 0.4%. After 1 year, among patients initially ambulating independently, 3.4% required assistance and 1.3% were nonambulatory. One-year freedom from reintervention, amputation, and death was 86.8%, 97.1%, and 96.2%, respectively. Suprainguinal bypasses originated from the abdominal aorta (88.6%), axillary artery (10.6%), and thoracic aorta (0.8%). Perioperative complications were commonly cardiac (11.3%) and wound related (3.9%). Mean LOS was 7 days, and 30-day mortality was 2%. After 1 year, among patients initially ambulating independently, 2.4% required assistance and 0.3% were nonambulatory. One-year freedom from reintervention, amputation, and death was 97.4%, 98.6%, and 95.3%, respectively. Multisegment PVI was the most commonly performed intervention for claudication; however, a subset of patients received nontraditional treatments, including isolated tibial PVI and bypasses with axillary inflow and tibial outflow. Overall, interventions had low morbidity, yet patients were still at risk for limb loss and worsening functional status at 1 year, emphasizing the importance of patient selection, medical optimization, and informed consent.

Comparison of Early and Late Post-operative Outcomes after Supra-inguinal Bypass for Aortoiliac Occlusive Disease

The choice for surgical revascularisation for aortoiliac occlusive disease is often tempered by patient comorbidities. This study compares peri-operative outcomes and the association between choice of operation and one year major adverse limb event (MALE) free survival and five year mortality. The Vascular Study Group of New England (VSGNE) dataset for supra-inguinal bypass operations from 2009 to 2015 was queried. This study excluded cases with bypass other than aortofemoral (AFB), axillofemoral (AXB), and femorofemoral (FFB), and those with endovascular interventions or femoral endarterectomy. Cases combined with other procedures, indications other than occlusive disease, and missing pathology were also excluded. Patients were divided into three groups: AFB, AXB, and FFB. Thirty day post-operative death (POD) and adverse events were compared using univariable and multivariable analyses. One year MALE free survival was compared between groups with log rank test and Kaplan-Meier plot. Proportional hazard Cox regression was used for adjusted comparison of MALE free and five year survival. In total, 1,602 cases were included: 207 (12.9%) AXB; 872 (54.4%) AFB; 523 (32.6%) FFB. AXB patients were older with more comorbidities. Post-operative complications and POD rates were significantly higher for AXB (p<.05). On adjusted analyses, AXB increased the hazard of one year MALE (hazard ratio [HR] 1.76, 95% confidence interval [CI] 1.12-2.78; p=.014) and five year mortality (HR 1.54; 95% CI 1.11-2.41; p=.009). Both FFB and AFB had similar one year MALE free survival but significantly better one year MALE free survival than AXB. After adjusting for confounding variables, and while acknowledging limitations related to the VSGNE data set, FFB led to significantly lower rates of post-operative complications than AXB. FFB may serve as the extra-anatomical operation of choice in high risk patients with extensive disease, who cannot undergo AFB, provided that anatomy permits. AFB should be performed preferentially in low risk patients with appropriate anatomy. Owing to its higher complications rates, the study suggests that AXB should be limited to patients with no other option for revascularisation.

Analysis of Thirty-Day Readmission after Infrainguinal Bypass

The Vascular Study Group of New England (VSGNE) conducted a pilot study evaluating the feasibility of 30-day data collection in patients undergoing infrainguinal bypass (INFRA) which was subsequently expanded to include a limited number of additional sites within the Vascular Quality Initiative (VQI). The purpose of our study was to use these data to evaluate the incidence of 30-day readmission after infrainguinal bypass. A secondary goal of the study was to perform a critical appraisal of the data elements and definitions in the 30-day dataset. All infrainguinal bypass procedures performed during the pilot study period (7/2008 and 4/2016) were identified and merged with a dataset containing the 30-day data. Incidence and types of readmission were assessed. The primary endpoint was 30-day readmission, defined as any hospital readmission within 30days of index operation; unplanned 30-day readmission was the secondary endpoint. Covariates tested for association with the primary and secondary endpoints included patient demographics, comorbidities, procedural, and postoperative characteristics. Variables significant on univariate screen (P<0.2) were evaluated with logistic regression to identify independent determinants. Of 9,847 infrainguinal bypass patients, 5,842 (59%) patients were identified with 30-day data, and 907 (16%) were readmitted within 30 days. Of readmissions, 675 (85%) were unplanned. Potentially modifiable independent determinants of any 30-day readmission included 30-day surgical site infection (SSI) (odds ratio [OR]: 10, 95% confidence interval [CI]: 8.2-12, P<0.0001), postoperative acute kidney injury (OR: 1.7, 95% CI: 1.2-2.5, P=0.002), and discharge anticoagulation (OR: 1.2, 95% CI: 1.04-1.5; P=0.02). Predictors of unplanned 30-day readmission were very similar but identified in-hospital major amputation as an additional independent predictor (OR: 2.8, 95% CI: 1.6-4.9, P=0.0002). This study demonstrates the interest in, and value of, 30-day data collection in VSGNE/VQI and documents the frequency of readmission after infrainguinal bypass. Readmission within 30 days is strongly associated with SSI, stressing the importance of efforts to decrease this complication. Given that many other predictors are unmodifiable, 30-day readmission is only appropriate as a quality metric if it is risk adjusted using large, real-world datasets such as VQI. Lessons learned from this analysis can be used to select optimal 30-day data elements.

Long-term impact of the Vascular Study Group of New England carotid patch quality initiative

ObjectivePatch angioplasty has been shown to decrease rates of restenosis after carotid endarterectomy (CEA). In 2003, the Vascular Study Group of New England (VSGNE) implemented its first quality initiative aimed at increasing the rates of patch closure after CEA. This study reports the effects of that initiative on the rate of patch closure in the VSGNE and also postoperative and 1-year CEA outcomes. MethodsPatients undergoing CEA (N = 14,636) within the VSGNE between 2003 and 2014 were studied. Rates of in-hospital postoperative events (death, ipsilateral stroke or transient ischemic attack [TIA], and return to the operating room for bleeding) and events during 1 year of follow-up (stroke or TIA and restenosis >70% or occlusion) were compared by repair type—patch closure, primary closure, or eversion. One-year follow-up events were also compared over time and by annualized surgeon volume. ResultsDuring the 12 years studied, patch use increased from 71% to 91% (P < .001). There was no difference in postoperative death or ipsilateral stroke or TIA between the repair types. However, there was a statistically lower rate of return to the operating room for bleeding (P < .001), 1-year stroke or TIA (P < .003), and 1-year restenosis or occlusion (P < .001) with patch closure. Overall, the rates of 1-year stroke or TIA and restenosis decreased over time in the VSGNE. The initiative affected patch closure rates and outcomes of high-volume surgeons (>47 CEAs/y) the most. High-volume surgeons increased patch use from 50% to 90% and decreased their restenosis rates from 9.0% to 1.2% and 1-year stroke or TIA from 4.9% to 1.9% (P < .001). ConclusionsThe VSGNE carotid patch quality initiative successfully increased the rates of CEA patch closure. During the same time, there has been a decrease in postoperative bleeding requiring reoperation and 1-year ipsilateral neurologic events and restenosis or occlusion.

IP191. Contemporary Treatment of Intermittent Claudication in the Vascular Study Group of New England

IP191. Contemporary Treatment of Intermittent Claudication in the Vascular Study Group of New England

Major Cardiac Events in Patients Admitted to Intensive Care After Vascular Noncardiac Surgery: A Retrospective Cohort.

Introduction. Patients proposed to vascular noncardiac surgery (VS) have several comorbidities associated with major adverse cardiac events (MACE). We evaluated incidence, predictors, and outcomes, and compared different scores to predict MACE after VS. Methods. We included all patients admitted from 2006 to 2013. Perioperative MACE included cardiac arrhythmias, myocardial infarction (MI), cardiogenic pulmonary edema (CPE), acute heart failure (AHF), and cardiac arrest (CA). Lee Revised Cardiac Risk Index (RCRI), Vascular Quality Initiative (VQI-CRI), Vascular Study Group of New England (VSG-CRI), and South African Vascular Surgical (SAVS-CRI) Cardiac Risk Indexes were calculated and analyzed. We performed multivariate logistic regression to assess independent predictors with calculation of odds ratio (OR) and 95% confidence interval (CI). To reduce overfitting, we used leave-one-out cross-validation approach. The Predictive ability of scores was tested using area under receiver operating characteristic curve (AUROC). Results. A total of 928 patients were included. We observed 81 MACE (28 MI, 22 arrhythmias, 10 CPE, 9 AHF, 12 CA) in 60 patients (6.5%): 3.3% in intermediate-risk surgery and 9.8% in high-risk surgery. Previous history of coronary artery disease (OR = 3.2, CI = 1.8-5.7), atrial fibrillation (OR = 5.1, CI = 2.4-11.0), insulin-treated diabetes mellitus (OR = 3.26, CI = 1.51-7.06), mechanical ventilation (OR = 2.75, CI = 1.41-4.63), and heart rate (OR = 1.02, CI = 1.01-1.03) at admission were considered independent risk factors in multivariate analysis. The AUROC of our model was 0.79, compared with RCRI (0.66), VSG-CRI (0.69), VQI-CRI (0.71), and SAVS-CRI (0.73). Conclusions. Observed MACE were within predicted range (1% to 5% after intermediate-risk surgery and >5% after high-risk surgery). SAVS-CRI and VQI-CRI had slightly better predictive capacity than VSG-CRI or RCRI.