Using Machine Learning (XGBoost) to Predict Outcomes After Infrainguinal Bypass for Peripheral Artery Disease.

OBJECTIVE: To develop machine learning (ML) algorithms that predict outcomes after infrainguinal bypass. BACKGROUND: Infrainguinal bypass for peripheral artery disease carries significant surgical risks; however, outcome prediction tools remain limited. METHODS: The Vascular Quality Initiative database was used to identify patients who underwent infrainguinal bypass for peripheral artery disease between 2003 and 2023. We identified 97 potential predictor variables from the index hospitalization [68 preoperative (demographic/clinical), 13 intraoperative (procedural), and 16 postoperative (in-hospital course/complications)]. The primary outcome was 1-year major adverse limb event (composite of surgical revision, thrombectomy/thrombolysis, or major amputation) or death. Our data were split into training (70%) and test (30%) sets. Using 10-fold cross-validation, we trained 6 ML models using preoperative features. The primary model evaluation metric was the area under the receiver operating characteristic curve (AUROC). The top-performing algorithm was further trained using intraoperative and postoperative features. Model robustness was evaluated using calibration plots and Brier scores. RESULTS: Overall, 59,784 patients underwent infrainguinal bypass, and 15,942 (26.7%) developed 1-year major adverse limb event/death. The best preoperative prediction model was XGBoost, achieving an AUROC (95% CI) of 0.94 (0.93-0.95). In comparison, logistic regression had an AUROC (95% CI) of 0.61 (0.59-0.63). Our XGBoost model maintained excellent performance at the intraoperative and postoperative stages, with AUROCs (95% CI's) of 0.94 (0.93-0.95) and 0.96 (0.95-0.97), respectively. Calibration plots showed good agreement between predicted and observed event probabilities with Brier scores of 0.08 (preoperative), 0.07 (intraoperative), and 0.05 (postoperative). CONCLUSIONS: ML models can accurately predict outcomes after infrainguinal bypass, outperforming logistic regression.

Age is not a sole predictor of outcomes in octogenarians undergoing complex endovascular aortic repair.

OBJECTIVE: To examine the perioperative, postoperative, and long-term outcomes of fenestrated/branched endovascular aneurysm repair (F/BEVAR) in octogenarians compared with nonoctogenarians. METHODS: A multicenter, retrospective cohort study was conducted using the Vascular Quality Improvement database, which prospectively captures information on patients who undergo vascular surgery across 1021 academic and community hospitals in North America. All patients who underwent F/BEVAR endovascular aortic repair from 2012 to 2022 were included. Patients were stratified into two groups: those aged <80 years and those aged ≥80 years at the time of the procedure. The preoperative, intraoperative, and postoperative factors were compared between the two groups. The primary outcome was long-term all-cause mortality; secondary outcomes included aortic-specific mortality and aortic-specific reintervention. RESULTS: A total of 6007 patients (aged <80 years, n = 4860; aged ≥80 years, n = 1147) who had undergone F/BEVAR procedures were included. No significant difference was found in technical success, postoperative length of stay, length of intensive care unit stay, postoperative bowel ischemia, and spinal cord ischemia. After adjustment for baseline covariates, octogenarians were more likely to suffer from a postoperative complication (odds ratio [OR]: 1.16; [95% confidence interval (CI): 0.98-1.37], P < .001) and be discharged to a rehabilitation center (OR: 1.60; [95% CI: 1.27-2.00], P < .001) or nursing home (OR: 2.23; [95% CI: 1.64-3.01], P < .001). Five-year survival was lower in octogenarians (83% vs 71%, hazard ratio [HR]: 1.70; [95% CI: 1.46-2.0], P < .0001). Multivariate Cox proportional hazard analysis demonstrated that age was associated with increased all-cause mortality (HR: 1.72, [95% CI: 1.39-2.12], P < .001) and aortic-specific mortality (HR: 1.92, [95% CI: 1.04-3.68], P = .038). Crawford extent II aortic disease was associated with an increase in all-cause mortality (HR 1.49; [95% CI: 1.01-2.19], P < .001), aortic-specific mortality (HR: 5.05; [95% CI: 1.35-18.9], P = .016), and aortic-specific reintervention (HR: 1.91; [95% CI: 1.24-2.93], P = .003). Functional dependence was associated with increased all-cause mortality (HR: 2.90; [95% CI: 1.87-4.51], P < .001) and aortic-specific mortality (HR: 4.93; [95% CI: 1.69-14.4], P = .004). CONCLUSIONS: Our findings suggest that octogenarians do have a mildly increased mortality rate and rate of adverse events after F/BEVAR procedures. Despite this, when adjusted for other risk factors, age is on par with other medical comorbidities and therefore should not be a strict exclusion criterion for F/BEVAR procedures, rather considered in the global context of patient's aortic anatomy, health, and functional status.

Using machine learning to predict outcomes following suprainguinal bypass.

OBJECTIVE: Suprainguinal bypass for peripheral artery disease (PAD) carries important surgical risks; however, outcome prediction tools remain limited. We developed machine learning (ML) algorithms that predict outcomes following suprainguinal bypass. METHODS: The Vascular Quality Initiative database was used to identify patients who underwent suprainguinal bypass for PAD between 2003 and 2023. We identified 100 potential predictor variables from the index hospitalization (68 preoperative [demographic/clinical], 13 intraoperative [procedural], and 19 postoperative [in-hospital course/complications]). The primary outcomes were major adverse limb events (MALE; composite of untreated loss of patency, thrombectomy/thrombolysis, surgical revision, or major amputation) or death at 1 year following suprainguinal bypass. Our data were split into training (70%) and test (30%) sets. Using 10-fold cross-validation, we trained six ML models 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). The best performing algorithm was further trained using intra- and postoperative data. Model robustness was evaluated using calibration plots and Brier scores. Performance was assessed on subgroups based on age, sex, race, ethnicity, rurality, median Area Deprivation Index, symptom status, procedure type, prior intervention for PAD, concurrent interventions, and urgency. RESULTS: Overall, 16,832 patients underwent suprainguinal bypass, and 3136 (18.6%) developed 1-year MALE or death. Patients with 1-year MALE or death were older (mean age, 64.9 vs 63.5 years; P < .001) with more comorbidities, had poorer functional status (65.7% vs 80.9% independent at baseline; P < .001), and were more likely to have chronic limb-threatening ischemia (67.4% vs 47.6%; P < .001) than those without an outcome. Despite being at higher cardiovascular risk, they were less likely to receive acetylsalicylic acid or statins preoperatively and at discharge. Our best performing prediction model at the preoperative stage was XGBoost, achieving an AUROC of 0.92 (95% confidence interval [CI], 0.91-0.93). In comparison, logistic regression had an AUROC of 0.67 (95% CI, 0.65-0.69). Our XGBoost model maintained excellent performance at the intra- and postoperative stages, with AUROCs of 0.93 (95% CI, 0.92-0.94) and 0.98 (95% CI, 0.97-0.99), respectively. Calibration plots showed good agreement between predicted and observed event probabilities with Brier scores of 0.12 (preoperative), 0.11 (intraoperative), and 0.10 (postoperative). Of the top 10 predictors, nine were preoperative features including chronic limb-threatening ischemia, previous procedures, comorbidities, and functional status. Model performance remained robust on all subgroup analyses. CONCLUSIONS: We developed ML models that accurately predict outcomes following suprainguinal bypass, performing better than logistic regression. Our algorithms have potential for important utility in guiding perioperative risk mitigation strategies to prevent adverse outcomes following suprainguinal bypass.

Following the COMPASS: Antithrombotic Prescription Trends in Patients with Symptomatic Peripheral Arterial Disease following Revascularization.

BACKGROUND: The Vascular Outcomes Study of aspirin (ASA) Along with Rivaroxaban in Endovascular or Surgical Limb Revascularization for peripheral artery disease (PAD) trial demonstrated the superiority of ASA and low-dose rivaroxaban (Cardiovascular Outcomes for People Using Anticoagulation Strategies (COMPASS) trial dosing) compared with ASA alone in reducing major adverse cardiovascular events and major adverse limb events. We studied the COMPASS discharge prescription patterns in patients with symptomatic PAD who have undergone revascularization in our institution, since the time of publication of the Vascular Outcomes Study of ASA Along with Rivaroxaban in Endovascular or Surgical Limb Revascularization for PAD trial. METHODS: All patients included in this study had documented lower-extremity atherosclerotic PAD and were eligible for COMPASS dosing. Revascularization strategies included endovascular (n = 299), suprainguinal bypass (n = 18), and infrainguinal bypass (n = 36). RESULTS: COMPASS prescription patterns for the composite of endovascular and surgical strategies demonstrated a consistently low rate over time, without a trend toward increasing use. COMPASS dosing was prescribed as often as antiplatelet monotherapy (33.4% COMPASS vs. 34.6% antiplatelet monotherapy). This low COMPASS prescription rate was driven by significantly lower COMPASS prescriptions following endovascular therapy compared to surgical bypass (28.8% endovascular vs. 59.3% surgical bypass). COMPASS prescriptions following surgical bypass showed better trends; half of suprainguinal bypass patients (50.0%) and two-thirds of infrainguinal bypass patients (63.9%) were discharged on COMPASS. Despite patients with chronic limb-threatening ischemia (CLTI) representing a high-risk limb presentation, COMPASS prescriptions were low (29.8%), as opposed to patients without CLTI, and did not show a trend toward increasing use. In patients who underwent reinterventions throughout the observation period, there was a low conversion rate from ASA alone to COMPASS (3/26, 11.5%). CONCLUSIONS: In this observational study, one-third of patients were undertreated by prescription of antiplatelet monotherapy, indicating that there is significant room for medical optimization. This is especially true of patients undergoing endovascular treatment, including the high-risk subgroup of patients with CLTI. We highlight the importance of dual pathway antithrombotic therapy in patients eligible for COMPASS dosing to optimize best current evidence medical therapy.

The impact of race on outcomes following ruptured abdominal aortic aneurysm repair.

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 χ2 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.

Using machine learning to predict outcomes following carotid endarterectomy.

OBJECTIVE: Prediction of outcomes following carotid endarterectomy (CEA) remains challenging, with a lack of standardized tools to guide perioperative management. We used machine learning (ML) to develop automated algorithms that predict outcomes following CEA. METHODS: The Vascular Quality Initiative (VQI) database was used to identify patients who underwent CEA between 2003 and 2022. We identified 71 potential predictor variables (features) from the index hospitalization (43 preoperative [demographic/clinical], 21 intraoperative [procedural], and 7 postoperative [in-hospital complications]). The primary outcome was stroke or death at 1 year following CEA. Our data were split into training (70%) and test (30%) sets. Using 10-fold cross-validation, we trained six ML models 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). After selecting the best performing algorithm, additional models were built using intra- and postoperative data. Model robustness was evaluated using calibration plots and Brier scores. Performance was assessed on subgroups based on age, sex, race, ethnicity, insurance status, symptom status, and urgency of surgery. RESULTS: Overall, 166,369 patients underwent CEA during the study period. In total, 7749 patients (4.7%) had the primary outcome of stroke or death at 1 year. Patients with an outcome were older with more comorbidities, had poorer functional status, and demonstrated higher risk anatomic features. They were also more likely to undergo intraoperative surgical re-exploration and have in-hospital complications. Our best performing prediction model at the preoperative stage was XGBoost, achieving an AUROC of 0.90 (95% confidence interval [CI], 0.89-0.91). In comparison, logistic regression had an AUROC of 0.65 (95% CI, 0.63-0.67), and existing tools in the literature demonstrate AUROCs ranging from 0.58 to 0.74. Our XGBoost models maintained excellent performance at the intra- and postoperative stages, with AUROCs of 0.90 (95% CI, 0.89-0.91) and 0.94 (95% CI, 0.93-0.95), respectively. Calibration plots showed good agreement between predicted and observed event probabilities with Brier scores of 0.15 (preoperative), 0.14 (intraoperative), and 0.11 (postoperative). Of the top 10 predictors, eight were preoperative features, including comorbidities, functional status, and previous procedures. Model performance remained robust on all subgroup analyses. CONCLUSIONS: We developed ML models that accurately predict outcomes following CEA. Our algorithms perform better than logistic regression and existing tools, and therefore, have potential for important utility in guiding perioperative risk mitigation strategies to prevent adverse outcomes.

Using machine learning to predict outcomes following open abdominal aortic aneurysm repair.

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.

Machine learning to predict outcomes following endovascular abdominal aortic aneurysm repair.

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 Impact of Sex on Outcomes following Carotid Endarterectomy.

BACKGROUND: Previous studies have demonstrated significant sex differences in vascular surgery outcomes. We assessed stroke or death rates following carotid endarterectomy (CEA) in women versus men. METHODS: The Vascular Quality Initiative was used to identify all patients who underwent CEA between 2010 and 2019. Demographic, clinical, and procedural characteristics were recorded and differences between women and men were assessed using independent t-test and chi-squared test. The primary outcomes were 30-day and 1-year stroke or death. Associations between sex and outcomes were assessed using univariate/multivariate logistic regression and Cox proportional hazards analysis. RESULTS: Overall, 52,137 women and 79,974 men underwent CEA in Vascular Quality Initiative sites during the study period. Women were younger (70.3 vs. 70.5 years, P < 0.001) and more likely to have hypertension (89.2% vs. 88.9%, P < 0.05) and diabetes (36.2% vs. 35.8%, P < 0.001) but less likely to be diagnosed with coronary artery disease (23.2% vs. 31.0%, P < 0.001). A greater proportion of men were receiving cardiovascular risk reduction medications and had symptomatic carotid stenosis (28.5% vs. 26.7%, P < 0.001). Women had shorter procedure times (113 vs. 122 min, P < 0.001) and were less likely to receive electroencephalography neuromonitoring (27.9% vs. 28.8%, P < 0.001), drain (35.9% vs. 37.3%, P < 0.001), and protamine (67.4% vs. 68.0%, P < 0.01). Stroke or death at 30 days (1.9% vs. 1.8%, P = 0.60) and 1 year (hazard ratio [HR] 0.98, 95% confidence interval [CI] 0.94-1.01, P = 0.20) were similar between groups, which persisted in asymptomatic patients (HR 0.97, 95% CI 0.93-1.01, P = 0.17) and symptomatic patients (HR 0.99, 95% CI 0.93-1.05, P = 0.71). The similarities in 1-year stroke or death rates existed in both the United States (HR 0.96, 95% CI 0.92-1.01, P = 0.09) and Canada (HR 1.21, 95% CI 0.47-3.11, P = 0.70). CONCLUSIONS: Despite sex differences in clinical and procedural characteristics, women and men have similar 30-day and 1-year outcomes following CEA.

The Impact of Heparin on Mortality Following Open Ruptured Abdominal Aortic Aneurysm Repair.

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.

Vascular surgical management of profunda femoris artery aneurysms: A single center experience.

OBJECTIVE: Profunda femoris artery aneurysms (PFAAs), which comprise true profunda femoris artery aneurysms (TPFAAs) and profunda femoris artery pseudoaneuryms (PFA PSAs), are rare but clinically significant diseases of the peripheral arterial vasculature. Our aim is to describe our institution's 15-year experience with PFAAs (TPFAAs and PFA PSAs) to provide insight into patient characteristics, diagnostic imaging modalities, and surgical interventions that contribute to clinically important outcomes in patients with PFAAs. METHODS: We conducted a retrospective study at our institution using our radiology database. RESULTS: We identified six patients with PFA PSAs and four patients with TPFAAs. The clinical presentation of PFA PSAs included a triad of thigh pain, bleeding, and unexplained anemia. There was variety in the aetiologies of PFA PSAs, arising from catheterizations, upper thigh fractures, anastomotic complications, or unknown causes. Most patients with PFA PSAs had hypertension and coronary artery disease, and half of our cohort had peripheral vascular disease. All patients were imaged with duplex ultrasonography (DUS) or computed tomography (CT), the latter being more accurate. All patients with PFA PSAs underwent endovascular treatment, including glue, thrombin, or coil embolization as well as stent-graft insertions. All TPFAAs presented to our center were small and incidentally discovered, explaining the conservative management of our TPFAAs. Two of the four TPFAAs were idiopathic in nature, while one was attributed to post-stenotic dilatation, and another was found in a patient with Ehlers Danlos Syndrome. There was an association between TPFAAs and multiple synchronous or asynchronous aneurysms. CONCLUSION: Pseudoaneurysms of the PFA are mostly iatrogenic in nature and can present with the triad of thigh swelling, bleeding, and unexplained anemia. If the clinical picture is suggestive of a PFA PSA but DUS does not detect a pseudoaneurysm, CT may be added as a more accurate imaging modality. Endovascular embolization is used in smaller pseudoaneurysms and in poor surgical candidates. Multiple glue, coil, or thrombin injections may be required to fully thrombose the pseudoaneurysm sac. True aneurysms of the PFA are associated with synchronous/asynchronous aneurysms and small TPFAAs should be carefully monitored, as there is a risk of enlargement and rupture.

Thresholds for abdominal aortic aneurysm repair in Canada and United States.

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 χ2 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.

Assessment of open surgical and endovascular management of true hepatic artery aneurysms over 20 years highlights increased rupture risk in females.

BACKGROUND: True hepatic artery aneurysms (HAAs) are rare but have been associated with a significant risk of rupture and associated mortality. The 2020 release of HAA-specific clinical practice guidelines represented an important step toward management standardization. However, it remains essential to build on the body of evidence to further refine these recommendations. METHODS: The HAA management and outcomes from a single academic center during a 20-year period were retrospectively reviewed. We identified 72 patients from the institutional radiology database (November 24, 1999 to 2019). Pseudoaneurysms were excluded, and 48 patients were found to have had true HAAs. Forty-three HAA patients had sufficient medical records for inclusion in the analysis. RESULTS: Of the 43 patients with HAA included, 65% were male. The mean age was 63 years (range, 22-89 years). Of the HAAs, 72% presented asymptomatically, 16% had ruptured, and 12% were symptomatic at presentation. Most HAAs were of atherosclerotic origin (74%). In addition, 16% of the patients had other visceral aneurysms and 12% had nonvisceral aneurysms on presentation. The mean HAA size overall was 3.3 cm (range, 0.8-10.8 cm), with most being solitary (72%) and involving the common hepatic artery (65%). Rupture was more common in females (40%) and those with vasculitis (67%), with females representing 86% of all patients with rupture. The mean size at intervention was 4.8 cm (21 patients [49%]). Ten patients (23%) had undergone open surgical repair (seven elective and three emergent because of rupture). Eleven patients (26%) had undergone endovascular intervention (64% elective and 36% emergent). Nonoperative management was selected for 22 patients (51%). These patients had a mean HAA diameter of 2.1 cm, and 59% had a life-limiting illness. Of the 18 patients who had been initially monitored for a mean of 3.9 ± 4.1 years, 3 had undergone elective repair and 2 had minimal growth. None of these patients had a subsequently documented rupture. CONCLUSIONS: True HAAs are a rare but important clinical phenomenon, with 16% of patients presenting with rupture in this study. Endovascular intervention is a promising alternative to open surgical repair, with no 30-day mortality, and is suitable for ruptured HAAs. Importantly, for the first time, our findings have demonstrated an increased risk of rupture for females, highlighting the need for additional data and ultimately, sex-specific guidelines.

Effect of vertebral compression fractures on aortic neck angulation after endovascular aneurysm repair.

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.

Rates of Intervention for Claudication versus Chronic Limb-Threatening Ischemia in Canada and United States.

BACKGROUND: Previous studies have demonstrated important geographic variations in peripheral artery disease (PAD) management despite existing guidelines. We assessed differences in patient characteristics, procedural technique, and outcomes for PAD interventions in Canada versus United States. METHODS: The Vascular Quality Initiative (VQI) was used to identify all patients who underwent endovascular intervention or surgical bypass for PAD between 2010 and 2019 in Canada and United States. Independent t-test and chi-square test were performed to assess differences between countries in terms of demographic, clinical, and procedural characteristics. The primary outcome was the percentage of interventions performed for claudication versus chronic limb-threatening ischemia (CLTI). Perioperative outcomes were in-hospital mortality and index limb amputation. The long-term outcome was 1-year amputation-free survival. Univariate/multivariate logistic regression and Cox proportional hazards analysis were performed to investigate associations between region and outcomes. RESULTS: A total of 246,770 US patients and 3,467 Canadian patients underwent revascularization for PAD during the study period. There was a higher proportion of endovascular interventions in the US (75.9% vs. 69.2%, OR 1.41 [95% CI 1.31-1.51], P< 0.001). American patients were younger with more comorbidities, including hypertension, diabetes, and coronary artery disease. The percentage of interventions performed for claudication was significantly higher in the US (42.3% vs. 35.7%, OR 1.31 [95% CI 1.22-1.44], P< 0.001). This persisted after controlling for demographic, clinical, and procedural characteristics (adjusted OR 1.05 [95% CI 1.01-1.10], P = 0.02). Perioperative outcomes were similar between countries after adjustment for baseline differences: in-hospital mortality (adjusted OR 1.07 [95% CI 0.69-1.62], P= 0.75) and index limb amputation (adjusted OR 0.67 [95% CI 0.43-1.07], P= 0.09). However, 1-year amputation-free survival was higher in the US (84.1% vs. 71.0%, HR 1.61 [95% CI 1.47-1.76], P< 0.001). Multivariable Cox proportional hazards analysis demonstrated that the factor most strongly associated with index limb amputation or death at 1-year was intervention for CLTI (HR 1.56 [95% CI 1.54-1.58], P< 0.001). CONCLUSIONS: There are significant variations in PAD management between US and Canada. In particular, a higher proportion of interventions are performed for claudication rather than CLTI in the US compared to Canada. This is an important contributor to the higher 1-year amputation-free survival rate in US patients. Reasons for these differences should be assessed by future studies and evidence-based care may be standardized by targeted quality improvement projects.

Symptom Status of Patients Undergoing Carotid Endarterectomy in Canada and United States.

BACKGROUND: Previous studies have demonstrated significant geographic variations in the management of carotid artery stenosis despite standard guidelines. To further characterize these practice variations, we assessed differences in patient selection, operative technique, and outcomes for carotid endarterectomy (CEA) in Canada vs. United States. METHODS: The Vascular Quality Initiative (VQI) was used to identify all patients who underwent CEA between 2010 and 2019 in Canada and United States. Demographic, clinical, and procedural characteristics were recorded and differences between countries were assessed using independent t-test and chi-square test. The primary outcome was the percentage of CEA performed for asymptomatic versus symptomatic disease. The secondary outcomes were 30-day and long-term stroke or death. Associations between country and outcomes were assessed using univariate/multivariate logistic regression and Cox proportional hazards analysis. RESULTS: During the study period, 131,411 US patients and 701 Canadian patients underwent CEA in VQI sites. Patients from the US were older with more comorbidities including hypertension, diabetes, congestive heart failure, and chronic kidney disease. The use of a shunt, patch, drain, or protamine was less common in the US. Most patients had 70 - 99% stenosis, with no difference between regions. The percentage of CEA performed for asymptomatic disease was significantly higher in the US even after adjusting for demographic, clinical, and procedural characteristics (72.4% vs. 30.7%, adjusted OR 3.91 [95% CI 3.21 - 4.78], p < 0.001). Thirty-day stroke/death was low (1.8% vs. 1.9%) and 1-year stroke/death was similar between groups (HR 0.98 [95% CI 0.69 - 1.39], P = 0.89). The similarities in 1-year stroke/death persisted in asymptomatic patients (HR 0.70 [95% CI 0.37 - 1.30], P = 0.26) and symptomatic patients (HR 1.14 [95% CI 0.74 - 1.73], P = 0.56). CONCLUSIONS: There are significant variations in CEA practice between Canada and US. In particular, most US patients are treated for asymptomatic disease, whereas most Canadian patients are treated for symptomatic disease. Furthermore, adjunctive procedures including shunting, patch use, and protamine administration are performed less commonly in the US. Despite these differences, perioperative and 1-year stroke/death rates are similar between countries. Future studies should investigate reasons for these variations and quality improvement projects are needed to standardize care.

Endovascular community response to mortality data in use of paclitaxel devices for peripheral vascular disease.

OBJECTIVE: We examined the endovascular community response to data demonstrating increased mortality in paclitaxel devices for the treatment of peripheral arterial disease in femoropopliteal lesions. METHODS: A retrospective observational study using the Vascular Quality Initiative Peripheral Vascular Intervention registry dataset was performed to examine paclitaxel device use for peripheral arterial disease in femoropopliteal arteries treated from 2017 to 2019. A total of 41,707 patients and 52,208 procedures were analyzed during the study period. A post hoc analysis was performed to examine paclitaxel device use during selected periods in 2019. RESULTS: The total number of femoropopliteal procedures in 2017, 2018, and 2019 were 17,458, 21,140, and 21,322, respectively. Paclitaxel devices were used for 8852 arteries in 2017, 10,691 in 2018, and 6732 in 2019, which was significantly reduced in 2019 compared with 2017 or 2018 (P < .0001) and 2019 compared with the 2018 and 2017 volumes combined (P < .0001). Post hoc analysis of selected periods in 2019 demonstrated variable use throughout 2019. CONCLUSIONS: After the report of data with concerns of mortality associated with paclitaxel device use in 2018, a rapid reduction in overall paclitaxel device use was observed in 2019.

A Canadian multicenter experience describing outcomes after endovascular abdominal aortic aneurysm repair stent graft explantation.

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.

Ten-year trends in iliofemoral deep vein thrombosis treatment and referral pathways.

OBJECTIVES: Iliofemoral deep venous thrombosis is associated with an increased risk of developing post-thrombotic syndrome resulting in reduced quality of life. As there is debate about best management practices, this study aimed to examine the referral and treatment pathways for patients presenting with iliofemoral deep venous thrombosis over an 11-year period at our institution. METHODS: We conducted a retrospective review of patients diagnosed with lower limb deep vein thrombosis between 2010 and 2020. Ultrasound report findings were reviewed for the presence of iliofemoral deep venous thrombosis with acute, occlusive, or proximal clot. Multiple factors were extracted, including patient demographics, risk factors, diagnostic methods, interventions, referrals, and details of follow-up. The CaVenT and ATTRACT trials studied the benefit of thrombolysis in the early phase of iliofemoral deep venous thrombosis management as compared to anticoagulation alone. An analysis was conducted of patients requiring thrombolysis to determine whether these trials impacted physician practice patterns for thrombolysis. Data were organized and examined by year for trends in treatment and referral pathways. RESULTS: The review yielded 2792 patients assessed for lower limb deep venous thrombosis by ultrasound. Four hundred and sixty-seven (16.7%) patients were confirmed to have an occlusive iliofemoral deep venous thrombosis. The average age was 62.7 years (18-101 years). Half (50.4%) of the patients were male. The most common etiology for clot was malignancy-induced hypercoagulable state (39.0%). There was no difference in incidence of iliofemoral deep venous thrombosis diagnosed by ultrasound per year, with an average of 42.5 per year and a peak of 61. There was a trend towards increased rates of computed tomography imaging, ranging between 9.1% and 52.9%. The rate thrombolysis per year ranged between 1.8% and 8.9%, with a range of 4.3% (n = 20) to 8.9% (n = 5) in 2018. The use of pharmacomechanical thrombolysis increased, from 25% (n = 1) in 2010-2012 to 87.5% (n = 7) in 2018-2020. The rate of inferior vena cava filter insertion alone decreased from 18.2% in 2010 (n = 4) to 5.9% (n = 1) in 2020. The length of thrombolysis treatment also decreased, from 100% of patients (n = 4) receiving treatment duration greater than 24 h in 2010-2012 to 0% (n = 0) in 2018-2020. About 45% of patients receiving thrombolysis (n = 9) had venous stenting. No difference in treatment outcomes were observed, with greater than 87.5% of patients reaching intermediate to full resolution of clot burden. No patients experienced intracranial hemorrhage. CONCLUSIONS: The results of this analysis highlight the change in practice in our institution over time. The low rate of intervention likely reflects the current lack of consensus in published guidelines. It is important for future work to elicit the most appropriate management pathways for patients with iliofemoral deep venous thrombosis.

A survey of Canadian surgeons on the indications for home care nursing following vascular surgery.

Background: Recent evidence suggests that home care nursing is variably prescribed after vascular surgery, and may reduce emergency department visits and hospital readmissions. We therefore sought to characterize the indications for home care nursing following vascular surgery from the surgeon's perspective. Methods: An online survey was distributed to the 141 members of the Canadian Society for Vascular Surgery with questions related to home care nursing after carotid endarterectomy (CEA), endovascular aortic aneurysm repair (EVAR), open abdominal aortic aneurysm (AAA) repair and open or hybrid revascularization for peripheral arterial disease (PAD). We included all questionnaires in our analysis; the frequency denominator changes according to the number of respondents who completed each survey item. Results: There were 46 survey respondents (33% of 141) from across the country. A total of 28 (62% of 45) worked in a teaching hospital. Home care nursing was routinely prescribed by 5%, 10%, 31% and 41% of respondents following CEA, EVAR, open AAA repair and open or hybrid revascularization for PAD, respectively. Across all procedure types, the same procedure-related criteria were most often deemed to warrant a prescription for home care nursing: surgical site infection, wound complications (e.g., open wound, lymphatic leak) and use of negative-pressure wound therapy. Across all procedure types, lack of social support, physical frailty and cognitive impairment were most frequently identified as patient-specific considerations for prescribing home care nursing. Few respondents reported restrictions or standards that informed their prescribing practice. Conclusion: Most surgeon respondents agreed on the indications for home care nursing after vascular surgery. However, evidence-based standards to guide patient selection for home care nursing after vascular surgery are needed.

Contexte: Selon des données récentes, les soins infirmiers à domicile sont prescrits aléatoirement après la chirurgie vasculaire, et pourraient réduire les consultations aux urgences et les réhospitalisations. Nous avons donc voulu caractériser les indications des soins infirmiers à domicile après la chirurgie vasculaire, du point de vue des chirurgiens. Méthodes: Nous avons transmis un sondage en ligne aux 141 membres de la Société canadienne de chirurgie vasculaire (SCCV); les questions portaient sur les soins infirmiers à domicile après l'endartériectomie carotidienne, la réparation endovasculaire de l'anévrisme de l'aorte, la réparation chirurgicale de l'anévrisme de l'aorte abdominale (AAA) et la revascularisation chirurgicale ou hybride de la maladie artérielle périphérique (MAP). Nous avons inclus tous les questionnaires dans notre analyse; le dénominateur de fréquence change en fonction du nombre de répondants qui ont répondu à chaque élément du sondage. Résultats: Quarante-six chirurgiens des quatre coins du pays ont répondu (33 % des 141 membres de la SCCV). En tout, 28 (62 % des of 45) travaillaient dans un établissement universitaire. Les soins infirmiers à domicile étaient prescrits d'emblée par 5 %, 10 %, 31 % et 41 % des répondants suite à l'endartériectomie carotidienne, la réparation endovasculaire de l'anévrisme de l'aorte, la chirurgie pour AAA et la revascularisation chirurgicale ou hybride de la MPA, respectivement. Pour tous les types d'interventions, les mêmes critères liés aux interventions ont semblé justifier la prescription de soins infirmiers à domicile : infection de plaie, complications au niveau de la plaie (p. ex., plaie ouverte, plaie exsudative) et traitement de plaie par pression négative. Pour tous les types d'intervention, l'absence de soutien social, la fragilité physique et le déclin cognitif ont le plus souvent été identifiés parmi les critères spécifiques aux patients pour la prescription de soins infirmiers à domicile. Peu de répondants ont mentionné de possibles restrictions ou normes sur lesquelles fonder leurs habitudes de prescription à ce chapitre. Conclusion: La plupart des chirurgiens participants se sont entendus sur les indications des soins infirmiers à domicile après la chirurgie vasculaire. Il faudrait toutefois établir des normes fondées sur des données probantes pour guider la sélection des patients candidats aux soins infirmiers à domicile après la chirurgie vasculaire.