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Objective: Prediction of outcomes following open abdominal aortic aneurysm (AAA) repair remains challenging with a lack of widely used tools to guide perioperative management. We developed machine learning (ML) algorithms that predict outcomes following open AAA repair., Methods: The Vascular Quality Initiative (VQI) database was used to identify patients who underwent elective open AAA repair between 2003 and 2023. Input features included 52 preoperative demographic/clinical variables. All available preoperative variables from VQI were used to maximize predictive performance. The primary outcome was in-hospital major adverse cardiovascular event (MACE; composite of myocardial infarction, stroke, or death). Secondary outcomes were individual components of the primary outcome, other in-hospital complications, and 1-year mortality and any reintervention. We split our data into training (70%) and test (30%) sets. Using 10-fold cross-validation, six ML models were trained using preoperative features (Extreme Gradient Boosting [XGBoost], random forest, Naïve Bayes classifier, support vector machine, artificial neural network, and logistic regression). The primary model evaluation metric was area under the receiver operating characteristic curve (AUROC). Model robustness was evaluated with calibration plot and Brier score. The top 10 predictive features in our final model were determined based on variable importance scores. Performance was assessed on subgroups based on age, sex, race, ethnicity, rurality, median area deprivation index, proximal clamp site, prior aortic surgery, and concomitant procedures., Results: Overall, 12,027 patients were included. The primary outcome of in-hospital MACE occurred in 630 patients (5.2%). Compared with patients without a primary outcome, those who developed in-hospital MACE were older with more comorbidities, demonstrated poorer functional status, had more complex aneurysms, and were more likely to require concomitant procedures. Our best performing prediction model for in-hospital MACE was XGBoost, achieving an AUROC of 0.93 (95% confidence interval, 0.92-0.94). Comparatively, logistic regression had an AUROC of 0.71 (95% confidence interval, 0.70-0.73). For secondary outcomes, XGBoost achieved AUROCs between 0.84 and 0.94. The calibration plot showed good agreement between predicted and observed event probabilities with a Brier score of 0.05. These findings highlight the excellent predictive performance of the XGBoost model. The top three predictive features in our algorithm for in-hospital MACE following open AAA repair were: (1) coronary artery disease; (2) American Society of Anesthesiologists classification; and (3) proximal clamp site. Model performance remained robust on all subgroup analyses., Conclusions: Open AAA repair outcomes can be accurately predicted using preoperative data with our ML models, which perform better than logistic regression. Our automated algorithms can help guide risk-mitigation strategies for patients being considered for open AAA repair to improve outcomes., (Copyright © 2023 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.)

Background: Endovascular aneurysm repair (EVAR) for abdominal aortic aneurysm (AAA) carries important perioperative risks; however, there are no widely used outcome prediction tools. The aim of this study was to apply machine learning (ML) to develop automated algorithms that predict 1-year mortality following EVAR., Methods: The Vascular Quality Initiative database was used to identify patients who underwent elective EVAR for infrarenal AAA between 2003 and 2023. Input features included 47 preoperative demographic/clinical variables. The primary outcome was 1-year all-cause mortality. Data were split into training (70 per cent) and test (30 per cent) sets. Using 10-fold cross-validation, 6 ML models were trained using preoperative features with logistic regression as the baseline comparator. The primary model evaluation metric was area under the receiver operating characteristic curve (AUROC). Model robustness was evaluated with calibration plot and Brier score., Results: Some 63 655 patients were included. One-year mortality occurred in 3122 (4.9 per cent) patients. The best performing prediction model for 1-year mortality was XGBoost, achieving an AUROC (95 per cent c.i.) of 0.96 (0.95-0.97). Comparatively, logistic regression had an AUROC (95 per cent c.i.) of 0.69 (0.68-0.71). The calibration plot showed good agreement between predicted and observed event probabilities with a Brier score of 0.04. The top 3 predictive features in the algorithm were 1) unfit for open AAA repair, 2) functional status, and 3) preoperative dialysis., Conclusions: In this data set, machine learning was able to predict 1-year mortality following EVAR using preoperative data and outperformed standard logistic regression models., (© The Author(s) 2023. Published by Oxford University Press on behalf of BJS Society Ltd. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Background: Systemic administration of heparin is widely used in patients undergoing open elective abdominal aortic aneurysm (AAA) repair. However, no clear consensus exists in the use of intraoperative heparin during open ruptured AAA (rAAA) repair. In this study, we assessed the safety of intravenous heparin administration in patients undergoing open rAAA repair., Methods: A retrospective cohort study comparing patients who received and did not receive heparin during open rAAA repair in the Vascular Quality Initiative database between 2003 and 2020 was conducted. The primary outcomes were 30-day and 10-year mortality. The secondary outcomes included estimated blood loss, number of packed red blood cells transfused, early postoperative transfusions, and postsurgical complications. Propensity score matching was used to adjust for potentially confounding variables. The outcomes were compared between the 2 groups using relative risk for binary outcomes and paired t-test and the Wilcoxon rank-sum test for normally and non-normally distributed continuous variables, respectively. Survival was examined using Kaplan-Meier curves and compared using a Cox proportional hazards model., Results: A total of 2,410 patients who underwent open rAAA repair between 2003 and 2020 were studied. Of the 2,410 patients, 1,853 patients received intraoperative heparin and 557 did not. Propensity score matching on 25 variables yielded 519 pairs for the heparin to no heparin comparison. Thirty-day mortality was lower in the heparin group (risk ratio: 0.74; 95% confidence interval [CI]: 0.66-0.84) and in-hospital was also lower in the heparin group (risk ratio: 0.68; 95% CI: 0.60-0.77). Furthermore, estimated blood loss was 910 mL (95% CI: 230 mL to 1,590 mL) lower in the heparin group and the mean number of packed red blood cells transfused intraoperatively and postoperatively were 17 units lower in the heparin group (95% CI: 8-42). Ten-year survival was higher for patients who received heparin, and their rate of survival was approximately 40% higher than those who did not receive heparin (hazard ratio: 0.62; 95% CI, 0.53-0.72; P < 0.0001)., Conclusions: In patients who received systemic heparin administration at the time of open rAAA repair, there were significant short-term and long-term survival benefits within 30 days and at 10 years. Heparin administration may have afforded a mortality benefit or been a surrogate for healthier and less moribund patients at the time of the procedure., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Objectives: Racial differences in elective abdominal aortic aneurysm (AAA) repair outcomes have been previously reported; however, data on racial differences in ruptured AAA (rAAA) repair outcomes remain limited. This study assessed in-hospital and long-term mortality after rAAA repair in Black versus White patients., Methods: The Vascular Quality Initiative database was queried to identify all Black and White patients who underwent open or endovascular rAAA repair between 2003 and 2019. Baseline demographic and clinical characteristics were recorded, and independent t test and χ 2 test were performed to assess differences between groups. In-hospital and 8-year mortality rates were the primary outcomes. Univariate and multivariate logistic regression and Cox proportional hazards analyses were conducted to analyze associations between race and outcomes., Results: Overall, 310 Black patients and 4679 White patients underwent rAAA repair. A greater proportion of Black patients underwent endovascular repair (73.2% vs 56.1%). Black patients had a lower mean age and were more likely to be female, with a greater proportion being Medicaid insured (9.7% vs 2.1%) or uninsured (4.8% vs 3.3%). Although Black patients were more likely to be current smokers and have hypertension, diabetes, and congestive heart failure, they were not more likely to receive risk reduction medications. The time from symptom onset to incision or access was higher for Black patients (median, 12.0 hours vs 7.0 hours). Similarly, the time from hospital admission to intervention was higher for Black patients (median, 2.8 hours vs 1.3 hours). In-hospital mortality was lower in Black patients (20.0% vs 28.6%; odds ratio [OR], 0.63; 95% confidence interval [CI], 0.47-0.83); however, this did not persist after adjusting for baseline characteristics (adjusted OR, 0.58; 95% CI, 0.30-1.07; P = .09). Furthermore, the 8-year survival was not different between groups (50.4% vs 46.6%; hazard ratio, 0.85; 95% CI, 0.57-1.26; P = .42), even when stratified by repair type., Conclusions: This study identified racial differences in demographic, clinical, and procedural characteristics for patients undergoing rAAA repair. In particular, the door-to-intervention time for Black patients of 2.8 hours does not meet the Society for Vascular Surgery recommendation of 90 minutes. Despite these differences, the 8-year mortality is similar for Black and White patients. These differences should be investigated further, and there are opportunities to improve rAAA care for Black patients., (Copyright © 2023 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.)

Importance: Sex differences in aortic surgery outcomes are commonly reported. However, data on ruptured abdominal aortic aneurysm (rAAA) repair outcomes in women vs men are limited., Objective: To assess differences in perioperative and long-term mortality following rAAA repair in women vs men., Design, Setting, and Participants: A multicenter, retrospective cohort study was conducted using the Vascular Quality Initiative database, which prospectively captures information on patients who undergo vascular surgery across 796 academic and community hospitals in North America. All patients who underwent endovascular or open rAAA repair between January 1, 2003, and December 31, 2019, were included. Outcomes were assessed up to January 1, 2020., Exposures: Patient sex., Main Outcomes and Measures: Demographic, clinical, and procedural characteristics were recorded, and differences between women vs men were assessed using independent t test and χ2 test. The primary outcomes were in-hospital and 8-year mortality. Associations between sex and outcomes were analyzed using univariable and multivariable logistic regression and Cox proportional hazards regression analysis., Results: A total of 1160 (21.9%) women and 4148 (78.1%) men underwent rAAA repair during the study period. There was a similar proportion of endovascular repairs in women and men (654 [56.4%] vs 2386 [57.5%]). Women were older (mean [SD] age, 75.8 [9.3] vs 71.7 [9.6] years), more likely to have chronic kidney disease (718 [61.9%] vs 2184 [52.7%]), and presented with ruptured aneurysms of smaller diameters (mean [SD] 68 [18.2] vs 78 [30.2] mm). In-hospital mortality was higher in women (34.4% vs 26.6%; odds ratio, 1.44; 95% CI, 1.25-1.66), which persisted after adjusting for demographic, clinical, and procedural characteristics (adjusted odds ratio, 1.36; 95% CI, 1.12-1.66; P = .002). Eight-year survival was lower in women (36.7% vs 49.5%; hazard ratio, 1.25; 95% CI, 1.04-1.50; P = .02), which persisted when stratified by endovascular and open repair. This survival difference existed in both the US and Canada. Variables associated with long-term mortality in women included older age and chronic kidney disease., Conclusions and Relevance: Women who underwent rAAA repair had higher perioperative and 8-year mortality rates following both endovascular and open repair compared with men. Older age and higher rates of chronic kidney disease in women were associated with higher mortality rates. These findings suggest that future studies should assess the reasons for these disparities and whether opportunities exist to improve AAA care for women.

Objective: Aortic neck angulation (ANA) prior to endovascular aneurysm repair (EVAR) and its changes after EVAR are considered important predictors of postoperative complications. We sought to assess the effects of vertebral body height loss on ANA in patients post-EVAR., Methods: All patients who had undergone EVAR for infrarenal aortic aneurysms in our institution between August 2010 and December 2018 were assessed. Anterior and posterior vertebral body heights were measured in all patients on preoperative, early postoperative, and follow-up computed tomography scans (T12-L5 vertebral bodies). Patients who had significant height loss in their follow-up period were designated as the Study group. These were matched to a Control group of the same size using propensity-score matching based on age, gender, and duration between follow-up scans. Aortic neck morphology indices including ANA and its changes were measured, and information related to postoperative endoleaks and aneurysm sac size were extracted in the Study and Control groups., Results: During the follow-up period, 10 of 185 patients had a radiologically significant vertebral body compression fracture. There was no significant difference between the Study (n = 10) and Control groups in age (77.6 ± 6.9 vs 77.2 ± 7.5 years; P = .64), gender (seven males and three females in each group; P = 1.0), duration between postoperative scans (1830 ± 665 vs 1800 ± 670 days; P = .25), preoperative ANA (36.0° ± 15.6° vs 42.4° ± 18.6°; P = .41), and early postoperative ANA (21.9° ± 11.7° vs 20.9° ± 16.3°; P = .72). Changes in ANA in the postoperative period (7.2° ± 11.1° vs -4.7° ± 6.7°; P = .009; power = .838) were significantly higher in the Study group., Conclusions: Post-EVAR vertebral body compression fractures exacerbate ANA. Awareness of this can guide both preoperative assessment and postoperative management and follow-up., (Copyright © 2021 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.)

Background: Previous studies have demonstrated significant geographic variations in the management of abdominal aortic aneurysms (AAA) despite standard guidelines. Differences in patient selection, operative technique, and outcomes for AAA repair in Canada versus United States were assessed., Methods: The Vascular Quality Initiative was used to identify all patients who underwent elective endovascular or open AAA repair between 2010 and 2019 in Canada and the United States. Demographic, clinical, and procedural characteristics were recorded and differences between countries were assessed using independent t test and χ 2 test. The primary outcome was the percentage of AAA repaired below recommended diameter thresholds (men, <5.5 cm; women, <5.0 cm). The secondary outcomes were in-hospital and 1-year mortality rates. Associations between region and outcomes were assessed using univariate/multivariate logistic regression and Cox proportional hazards analysis., Results: There were 51,455 U.S. patients and 1451 Canadian patients who underwent AAA repair in Vascular Quality Initiative sites during the study period. There was a higher proportion of endovascular repairs in the United States (83.7% vs 68.4%; odds ratio [OR], 2.38; 95% confidence interval [CI], 2.13-2.63; P < .001). U.S. patients had more comorbidities, including hypertension, congestive heart failure, chronic kidney disease, and prior revascularization. The percentage of AAA repaired below recommended thresholds was significantly higher in the United States (38.8% vs 15.2%; OR, 3.57; 95% CI, 3.03-4.17; P < .001). This difference persisted after controlling for demographic, clinical, and procedural characteristics (adjusted OR, 3.57; 95% CI, 2.63-4.17; P < .001). Factors that predicted AAA repair below recommended thresholds were U.S. region (adjusted OR, 3.57; 95% CI, 3.03-4.17), male sex (adjusted OR, 2.89; 95% CI, 2.72-3.07), and endovascular repair (adjusted OR, 2.08; 95% CI, 1.95-2.21). The in-hospital mortality rate was low (1.0% vs 0.8%) and the 1-year rate mortality was similar between countries (hazard ratio, 0.96; 95% CI, 0.70-1.31; P = .79)., Conclusions: There are significant variations in AAA management between Canada and the United States. A greater proportion of U.S. patients underwent AAA repair below the recommended diameter thresholds. This finding is partly driven by a higher percentage of endovascular repairs. Despite these differences, the perioperative and 1-year mortality rates are similar. Future studies should investigate reasons for these variations and quality improvement projects are needed to standardize care., (Copyright © 2021 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.)

Background: Most studies describing the outcomes after endovascular abdominal aortic aneurysm repair (EVAR) explantation have been from single, high-volume, centers. We performed a multicenter cross-Canadian study of outcomes after EVAR stent graft explantation. Our objectives were to describe the outcomes after late open conversion and EVAR graft explantation at various Canadian centers and the techniques and outcomes stratified by the indication for explant., Methods: The Canadian Vascular Surgery Research Group performed a retrospective multicenter study of all cases of EVAR graft explantation at participating centers from 2003 to 2018. Data were collected using a standardized, secure, online platform (RedCap [Research Electronic Data Capture]). Univariate statistical analysis was used to compare the techniques and outcomes stratified the indication for graft explantation., Results: Patient data from 111 EVAR explants collected from 13 participating centers were analyzed. The mean age at explantation was 74 years, the average aneurysm size was 7.5 cm, and 28% had had at least one instructions for use violation at EVAR. The average time between EVAR and explantation was 42.5 months. The most common indication for explantation was endoleak (n = 66; type Ia, 46; type Ib, 2; type II, 9; type III, 2; type V, 7), followed by infection in 20 patients; rupture in 18 patients (due to type Ia endoleak in 10 patients, type Ib in 1, type II in 1, type III in 2, and type V in 1), and graft thrombosis in 7 patients. The overall 30-day mortality was 11%, and 45% of the patients had experienced at least one major perioperative complication. Mortality was significantly greater for patients with rupture (33.3%) and those with infection (15%) compared with patients undergoing elective explantation for endoleak (4.5%; P = .003). The average center volume during the previous 15 years was 8 cases with a wide range (2-19 cases). A trend was seen toward greater mortality for patients treated at centers with fewer than eight cases compared with those with eight or more cases (19% vs 9%). However, the difference did not reach statistical significance (P = .23). Overall, 41% of patients had undergone at least one attempt at endovascular salvage before explantation, with the highest proportion among patients who had undergone EVAR explantation for endoleak (51%). Only 22% of patients with rupture had undergone an attempt at endovascular salvage before explantation., Conclusions: The performance of EVAR graft explantation has increasing in Canada. Patients who had undergone elective explantation for endoleak had lower mortality than those treated for either infection or rupture. Thus, patients with an indication for explanation should be offered surgery before symptoms or rupture has occurred. A trend was seen toward greater mortality for patients treated at centers with lower volumes., (Copyright © 2021 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.)

An 85-year-old man with a known history of abdominal aortic aneurysm (AAA) presented to a vascular surgery clinic with a severely swollen, tender and erythematous left leg. An urgent CT angiogram demonstrated a left-sided, proximal deep vein thrombosis, and a permanent, Bird's Nest inferior vena cava (IVC) filter (Cook, Inc., Bloomington, Ind.) penetrating his AAA. The patient was treated with a course of apixaban 5 mg two times per day and the decision was made to closely observe his IVC filter and AAA, given his numerous comorbidities and age. This case highlights the unique considerations associated with an approach to permanent IVC filter complications among patients with AAAs., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2021. No commercial re-use. See rights and permissions. Published by BMJ.)

Purpose: To determine whether low total psoas muscle area (tPMA), as a surrogate for sarcopaenia, is a predictor of adverse outcomes in patients undergoing advanced EVAR., Materials and Methods: A retrospective review of medical records was performed for 257 patients who underwent advanced EVAR (fenestrated or branched technique) in a single tertiary centre from 1 January 2008 to 1 September 2019. The study cohort was divided into tertiles based on tPMA measurement performed independently by two observers from a peri-procedural CT scan at the level of mid-L3 vertebral body. The low tertile was considered sarcopaenic. Logistic regression analysis was used to assess the association of tPMA with 30-day mortality and post-procedural complications. Univariable analysis and adjusted multivariable Cox regression were used to assess the association of tPMA with all-cause mortality., Results: A total of 257 patients comprised 193 males and 64 females with the mean age of 75.4 years (± 6.8) were included. Adjusted multivariable Cox regression revealed an 8% reduction in all-cause mortality for every 1 cm 2 increase in tPMA, P < 0.05. TPMA was associated with 30-day mortality (OR 0.85, 95% CI 0.75-0.96, P < 0.05) and spinal cord ischaemia (SCI) (OR 0.89, 95% CI 0.82-0.97, P < 0.05). For remaining post-procedural complications, tPMA was not a useful predictive tool. TPMA correlated negatively with hospital stay length (r s -0.26, P < 0.001). Patients with lower tPMA were more likely to be discharged to a rehabilitation center (OR 0.93, 95% CI 0.87-0.98 , P < 0.05)., Conclusion: Measurement of tPMA can be a useful predictive tool for adverse outcomes after advanced EVAR., Level of Evidence: Level 3, Retrospective cohort study.

Horseshoe kidney, representing abnormal fusion of the inferior renal poles, is a rare anatomic anomaly posing challenges in the setting of surgical abdominal aortic aneurysm repair. Historically, open repair has been the favoured surgical approach. However, due to the location of the renal isthmus and wide-ranging variation in anomalous renal vasculature, endovascular aneurysm repair (EVAR) has emerged as a popular, less invasive alternative. We describe one of the first published cases of two-fenestration EVAR in a patient with concomitant horseshoe kidney, followed by a discussion of current trends in surgical management. With the increasing availability to customise fenestrated grafts to patients' unique anatomy, this advanced EVAR technique may emerge as the preferred approach in certain cases., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2020. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Endovascular aneurysm repair (EVAR) is associated with decreased perioperative morbidity and mortaliy in comparison with open repair, and thus octagenarians are traditionally offered EVAR given their age and medical comorbidities. The aim of this study was to investigate outcomes and predictors of complications associated with EVAR in octogenarians., Methods: We conducted a retrospective chart review of consecutive patients aged 80 years and older who received an EVAR between August 2010 and January 2017 at a single centre in Toronto, Ontario. We conducted univariate comparisons and then completed logistic regression to determine predictors of complications. We used Kaplan-Meier analysis to explore survival times., Results: A total of 154 octogenarians underwent an EVAR during the study period for an infrarenal aneurysm with a mean size of 64.8 (standard deviation [SD] 12.7) mm. The mean age of the patients was 84.1 (SD 3.7) years, and most patients (81%) were men. Eighteen patients presented with a ruptured abdominal aortic aneurysm (AAA). Ninety-five (62%) patients sustained a complication. Fifty percent of patients experienced an intraoperative complication. A majority of these (77%) resulted in an endoleak, with type II endoleaks requiring no further intervenion being the most common (58%, n = 45). The remaining complications (n = 70) occurred postoperatively, with myocardial ischemia (n = 24) and dysrhythmias (n = 10) being the most common. Past aortic surgery (χ2 = 8.62, p = 0.014, Cramer V = 0.27) was found to be a multivariate predictor of complications. Most patients (88%) continued follow-up to an average of 20.9 months. Twenty-one patients (13%) died. Nine of these deaths (43%) occurred during the index admission and involved a ruptured AAA. Past aortic surgery was the only predictor of vascular complications. The mean survival time after EVAR was 57.63 months for patients without events., Conclusion: Endovascular aneurysm repair in octogenarians is a suitable form of therapy with acceptable short- and long-term results in the elective setting. Past aortic surgery was a predictor of complications in this population., Competing Interests: G. Roche-Nagle is a clinical proctor for Cook Medical. No other competing interests were declared., (© 2020 Joule Inc. or its licensors.)

Background: The Society for Vascular Surgery Vascular Quality Initiative (SVS-SVQI) is a database that provides insight into standards of care and highlights opportunities for quality improvement by benchmarking institutional data against local, regional and national trends. Endovascular aneurysm repair (EVAR) is a frequently performed vascular operation. Postoperative length of stay in hospital (LOS) varies among institutions. We reviewed the morbidity and mortality of patients who underwent EVAR at our institution and the financial impact of increased LOS for these patients. In addition, we sought to identify modifiable factors associated with prolonged LOS., Methods: We identified all patients who underwent elective EVAR between Jan. 1, 2011, and Dec. 31, 2014. Preoperative patient characteristics, intraoperative details, postoperative factors, long-term (1 yr) outcomes and cost data were reviewed. Univariate analysis was used to determine statistical differences between patients with LOS less than or equal to 2 days and greater than 2 days. Interventions were implemented to modify factors identified as having a negative impact on EVAR LOS., Results: Identified factors that negatively affected EVAR LOS included social, neurologic, cardiovascular, urologic and renal issues. Following targeted interventions, LOS after EVAR decreased from an average of 3.8 to 3.0 days (p < 0.05). Logistic regression (n = 124) identified cardiovascular issues as the most significant predictor of LOS greater than 2 days (p = 0.001, odds ratio 14.24, 95% confidence interval 2.8–71.4). Reduction in LOS was associated with the additional benefit of 6.6% adjusted cost savings., Conclusion: By leveraging SVS-VQI data, we were able to reduce EVAR LOS by identifying modifiable factors and instituting focused interventions. The reduction in LOS was associated with cost savings to the hospital., Competing Interests: None declared., (© 2020 Joule Inc. or its licensors)

Background: The impact of aneurysm thrombus characteristics on type 2 endoleak rate following endovascular aneurysm repair (EVAR) for abdominal aortic aneurysm (AAA) is unclear. The purpose of this study is to determine the impact of pre-operative aneurysm thrombus volume and density on the incidence of type 2 endoleak following EVAR for infrarenal AAA., Methods: A retrospective analysis was completed on all patients who underwent standard EVAR at an academic medical institution between May 1, 2010 and June 1, 2016 with a minimum follow-up period of 12 months. The final analysis included 170 patients. Thrombus volume and density were determined by analyzing pre-operative computed tomography angiography (CTA) scans using the TeraRecon plaque analysis module. The number and diameter of patent infrarenal aortic branch vessels were also identified. Type 2 endoleak was diagnosed by post-operative CTA, duplex ultrasound, or angiography., Results: Over a median follow-up period of 29 months, 88 (51.8%) of 170 patients had a type 2 endoleak. The thrombus volume as a proportion of the infrarenal aorta volume was significantly lower in patients with type 2 endoleak (odds ratio [OR] 0.034, 95% confidence interval [CI] 0.005-0.291, P = 0.002). The number of patent lumbar arteries was significantly greater in patients with type 2 endoleak (OR 1.45, 95% CI 1.16-1.56, P < 0.0005). Both variables independently predicted the incidence of type 2 endoleak in a multivariate analysis. Thrombus density was not related to the incidence of type 2 endoleak., Conclusions: A lower ratio of thrombus volume/infrarenal aorta volume and a higher number of patent lumbar arteries were associated with an increased incidence of type 2 endoleak. A multivariate logistic regression model was generated to pre-operatively predict the risk of type 2 endoleak. This model can guide the stratification of patients for intensity of endoleak surveillance following EVAR and consideration of pre-operative treatment., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Objectives: The percutaneous endovascular abdominal aortic repair (PEVAR) approach is a minimally invasive technique that has demonstrated clinical benefit over traditional surgical cut down associated with standard endovascular abdominal aortic aneurysm (AAA) repair (EVAR). The objective of our study was to evaluate the budget impact to a Canadian hospital of changing the technique for AAA repair from the EVAR approach to the PEVAR approach., Methods: We examined the budget impact of replacing the EVAR approach with the PEVAR approach in a Canadian hospital that performs 100 endovascular AAA repairs annually. The model incorporates the costs associated with surgery, length of stay, and postoperative complications occurring within 30 days., Results: The use of PEVAR in AAA repair is associated with increased access device costs when compared with the EVAR approach (CAD$1000 vs CAD$400). However, AAA repair completed with the PEVAR approach demonstrates reduced operating time (101 minutes vs 133 minutes), length of stay (2.2 days vs 3.5 days), time in the recovery room (174 minutes vs 193 minutes), and postoperative complications (6% vs 30%), which offset the increased device costs. The model establishes that switching to the PEVAR approach in a Canadian hospital performing 100 AAA repairs annually would result in a potential cost avoidance of CAD$245,120., Conclusions: A change in AAA repair technique from EVAR to PEVAR can be a cost-effective solution for Canadian hospitals., (Copyright © 2017 Canadian Association of Radiologists. Published by Elsevier Inc. All rights reserved.)

Background: Endovascular aneurysm repair is a minimally-invasive method for the treatment of abdominal aortic aneurysms. For aneurysms that involve the visceral arteries, a custom-made stent graft with fenestrations for the branch arteries is required. The purpose of the current study is to evaluate the structural impact of misaligned fenestrations with respect to luminal patency and proximal aortic neck apposition in an in vitro model., Methods: A custom apparatus was used to evaluate seven Anaconda and three Zenith fenestrated stent grafts. All stent grafts were evaluated at 10° increments of stent/fenestration misalignment up to 80°. Images were captured at each interval and the luminal cross-sectional area and wall apposition were measured., Results: The Anaconda stent graft, which has an unsupported main body, demonstrated a linear reduction in luminal patency at increasing angles of misalignment (P < 0.0001). Stent/fenestration misalignments of 20° and 80° resulted in decreases in mean luminal patency of 14% and 54% respectively. The Zenith stent graft demonstrated a similar decrease in luminal patency, starting at misalignments of ≥40° (P < 0.0001). However, with stent/fenestration misalignments of ≥30°, apposition between the Zenith stent graft and the simulated aortic neck was compromised suggesting the creation of a type Ia endoleak., Conclusions: Both the Anaconda and Zenith devices behave adversely at extreme angles of misalignment with luminal narrowing in the Anaconda device and loss of wall apposition in the Zenith device; however, both stent grafts appear to be equivalent at low angles of misalignment., (Copyright © 2016 Royal College of Surgeons of Edinburgh (Scottish charity number SC005317) and Royal College of Surgeons in Ireland. Published by Elsevier Ltd. All rights reserved.)

Objective: Compliance with regular imaging follow-up after endovascular aortic aneurysm repair (EVAR) is inconsistent, and evidence of benefit from scheduled long-term surveillance is limited. This study sought to characterize the association between post-EVAR imaging frequency and long-term survival., Methods: Using administrative health databases for the province of Ontario, Canada, a cohort of patients was identified who underwent EVAR between 2004 and 2014. Minimum appropriate imaging follow-up (MAIFU) was defined as a CT scan or ultrasound of the abdomen within 90 days of EVAR as well as every 15 months thereafter. Multivariate time to event analyses characterized the association between compliance with MAIFU over time and all-cause mortality., Results: 4988 patients treated by EVAR were identified. Median follow-up was 3.4 years (IQR 2.0-5.3 years) and 90 day mortality was 1.6%. Among those who survived over 90 days, 87% (N = 4251 of 4902) underwent at least one CT scan or ultrasound of the abdomen within 90 days, but only 58% (N = 2859 of 4902) went on to meet MAIFU criteria. Infrequent imaging correlated with lower follow-up by a vascular surgeon, but not with infrequent primary care or specialist consultations. Consistently meeting MAIFU criteria was associated with a lower risk of death when compared with missing the first imaging follow-up within 90 days (HR 0.82, 95% CI 0.69-0.96, p = .014), or when compared with having first imaging follow-up within 90 days but subsequently not meeting MAIFU criteria (HR 0.78, 95% CI 0.68-0.91, p = .001). A larger proportion of the follow-up period meeting MAIFU criteria was associated with a lower risk of death., Conclusions: These data support efforts to improve compliance with imaging surveillance after EVAR., (Copyright © 2017 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.)

Endovascular aneurysm repair (EVAR) is a minimally invasive method for the treatment of abdominal aortic aneurysms; however, the implementation of this technique is often limited by the aortic pathology, especially in the urgent or emergent setting. An 82-year-old male with a 7.3 cm symptomatic juxtarenal aneurysm presented at our centre for assessment. He was diagnosed as a high-risk candidate for open repair and therefore, not suitable for a conventional EVAR. Fortunately, a custom two-vessel fenestrated stent graft, which was originally constructed for another patient, was available. This device was implanted with no complications and all branches remain unobstructed; clear of aneurysms at 1 year. We present the use of 'in-stock' fenestrated grafts as a potential option to be considered in the urgent or emergent repair of abdominal aortic aneurysms., (2016 BMJ Publishing Group Ltd.)

Objective: This study determined the 30-day morbidity and mortality and in-hospital costs of elective fenestrated (fEVAR) and branched (bEVAR) endovascular aneurysm repairs at a single academic institution and determined factors that influence them., Methods: All elective fEVAR or bEVAR patients treated between November 2007 and March 2014 in a Canadian academic hospital were included. Procedural details, 30-day morbidity and mortality rates, and cost of hospitalization were analyzed. Nonparametric bootstrap analysis was used to compare means between groups and calculate confidence intervals (CIs)., Results: There were 84 consecutive fEVAR (n = 61) and bEVAR (n = 23) procedures. The 30-day mortality was 3.3% for fEVAR and 4.3% for bEVAR. Mean hospital stay was 7.2 ± 0.8 days for fEVAR and 12.6 ± 2.2 days for bEVAR. The mean cost of the index hospitalization was $57,000 for fEVAR and $91,000 for bEVAR. Device-related costs accounted for 55% of the total costs. The occurrence of intraoperative or postoperative events were used to further divide each of the fEVAR and bEVAR groups into "complicated hospitalization" (fEVAR, n = 10; bEVAR, n = 13) and "uncomplicated hospitalization" (fEVAR, n = 51; bEVAR, n = 10) groups. Device-related costs were not significantly different between the complicated and uncomplicated hospitalization groups (mean difference [95% CI] fEVAR: $3383 [-$3405 to $9809], P = .3; and bEVAR: $1930 [-$7892 to $11,288], P = .68). However, there were significant differences between the complicated and uncomplicated hospitalization groups in hospital length of stay (mean difference [95% CI] fEVAR: 8.1 [3.0-13.2] days, P = .001; and bEVAR: 10.8 [5.9-19.9] days, P = .002) and nondevice-related costs (mean difference [95% CI,] fEVAR: $25,843 [$11,689-$43,247], P = .001; and bEVAR; $20,326 [$9362-$36,615], P = .002)., Conclusions: bEVAR and fEVAR are expensive interventions. Intraoperative adverse events and postoperative systemic complications dramatically increase costs and length of stay. Measures to minimize complications will reduce hospitalization costs and improve patient outcomes., (Copyright © 2015 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.)

Objective: Endovascular repair (EVAR) of abdominal aortic aneurysms is a safe alternative to open aneurysm repair (OAR) in selected patients. The aim of this study was to compare the health-related quality-of-life (HR-QoL) outcomes of patients following EVAR and OAR., Methods: A literature search of PubMed, EMBASE, and the Cochrane Library identified five randomized trials that reported on HR-QoL in EVAR and OAR for elective management of infrarenal abdominal aortic aneurysms. No consistent HR-QOL instrument was used among the studies. A meta-analysis was performed on the 36-Item Short Form (SF-36) and the EuroQol-5D (EQ-5D) HR-QoL results., Results: SF-36 general health scores were higher for EVAR at 3, 6, and 12 months postoperatively. SF-36 physical functioning scores were higher for EVAR at 6 months but this advantage was lost at 12 months. In addition, SF-36 social functioning scores were higher for EVAR at 12 months. SF-36 component summary scores were not significantly different. EVAR was associated with a better EQ-5D score at 3, 6, and 12 months, but not at 24 months of follow-up., Conclusions: EVAR was associated with better HR-QoL in some domains up to 12 months postoperatively. There is insufficient data to demonstrate a HR-QoL advantage beyond 12 months. More studies are required to examine any long-term HR-QoL advantages for either intervention., (Copyright © 2015 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.)

Acute aortic occlusion is an uncommon vascular emergency that can present with predominantly neurologic symptoms owing to spinal cord ischemia. We describe a 62-year-old woman who experienced acute thrombosis of an abdominal aortic aneurysm that initially presented as cauda equina syndrome. She was treated operatively with an axillary bifemoral bypass. Our case report is followed by a discussion of acute aortic occlusion., (Copyright © 2013 Society for Vascular Surgery. Published by Mosby, Inc. All rights reserved.)

In recent years, major improvements have been made, making elective repair of abdominal aortic aneurysm (AAA) a safe procedure. In selected series, mortality rates are less than 5%. Many of the patients with AAA, however, remain asymptomatic until they present with rupture. Once rupture has occurred, the overall mortality approaches 90%. Despite many advances in the management of ruptured AAA, the mortality rate of conventional open surgery has not improved significantly during the last 15 years. Over the last decade, endovascular techniques have been used increasingly to repair AAA, and there is increasing evidence that endovascular aneurysm repair (EVAR) is technically feasible and safe for ruptured AAA. This review studies the evidence and aids the clinician in setting up a practice to manage rAAAs utilizing an endovascular approach.

Aortoduodenal syndrome is a rare complication of an abdominal aortic aneurysm wherein the aneurysm sac obstructs the patient's duodenum. It presents with the symptoms of an upper gastrointestinal tract obstruction and requires surgical intervention to relieve it. Previously, gastric bypass surgery was advocated, but now aortic replacement is the mainstay of treatment. We report a case of a 67-year-old woman whose aortoduodenal syndrome was successfully managed and review the literature on this topic.

A woman aged 75 years developed chylous ascites day 5 after emergency abdominal aortic aneurysm repair. She was still on artificial ventilation at the time of diagnosis. The first symptoms were high ventilation pressure, an elevated diaphragm, and abdominal distention. The patient was treated conservatively with drainage and total parenteral nutrition and given tube feeding without long-chain triglycerides. Unfortunately, the patient died of sepsis on day 25. Chylous ascites is an unusual complication of retroperitoneal surgery. Abdominal paracentesis is a simple means to confirm the diagnosis. Initial treatment consists of draining the chylus and a medium-chain triglyceride diet or total parenteral nutrition. When this fails, more invasive treatment is required, consisting of direct lymphatic repair or peritoneovenous shunting. In mechanically ventilated patients, gradually progressive symptoms of abdominal hypertension after surgery in the retroperitoneal space should arouse suspicion of this complication.