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.

Predicting the need for subclavian artery revascularization in thoracic endovascular aortic repair: A systematic review and meta-analysis.

OBJECTIVE: This systematic review and meta-analysis aims to investigate the effectiveness of left subclavian artery revascularization compared with non-revascularization in thoracic endovascular aortic repair, and to summarize the current evidence on its indications. METHODS: A computerized search was conducted across multiple databases, including MEDLINE, SCOPUS, Cochrane Library, and Web of Science, for studies published up to November 2023. Study selection, data abstraction, and quality assessment (using the Newcastle-Ottawa Scale) were independently conducted by two reviewers, with a third author resolving discrepancies. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were calculated using random-effects models and publication bias was assessed using funnel plots. RESULTS: In the 76 included studies, left subclavian artery revascularization was associated with reduced risks of stroke (OR, 0.67; 95% CI, 0.45-0.98; n = 15,331), spinal cord ischemia (OR, 0.75; 95% CI, 0.56-0.99; n = 11,995), and arm ischemia (OR, 0.09; 95% CI, 0.01-0.59; n = 8438). No significant reduction in paraplegia (OR, 0.56; 95% CI, 0.21-1.47; n = 1802) or mortality (OR, 0.77; 95% CI, 0.53-1.12; n = 11,831) was observed. Moreover, the risk of endoleak was comparable in both groups (OR, 1.25; 95% CI, 0.55-2.84; P = .60; n = 793), whereas the risk of reintervention was significantly higher in the revascularization group (OR, 1.98; 95% CI, 1.03-3.83; P = .04; n = 272). Both groups had similar risks of major (OR, 0.45; 95% CI, 0.19-1.09; P = .08; n = 1113), minor (OR, 0.21; 95% CI, 0.01-3.45; P = .27; n = 183), renal (OR, 0.61; 95% CI, 0.12-3.06; P = .55; n = 310), and pulmonary (OR, 0.59; 95% CI, 0.16-2.15; P = .42; n = 8083) complications. The most frequent indications for left subclavian artery revascularization were primary prevention of spinal cord ischemia, augmentation of the landing zone, and primary stroke prevention. CONCLUSIONS: Left subclavian artery revascularization in thoracic endovascular aortic repair was associated with reduced neurological complications but was not found to impact mortality. The study highlights important indications for revascularization as well as significant predictors of complications, providing a basis for clinical decision-making and future research.

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.

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.

Percutaneous versus Cutdown Access for Endovascular Aortic Repair.

BACKGROUND: This study aimed to compare the outcomes of the percutaneous femoral access and open surgical cutdown access approaches in patients undergoing thoracic/abdominal endovascular aortic repair. METHODS: We retrospectively reviewed the medical records of 59 patients who underwent a thoracic/abdominal endovascular aortic repair at a single tertiary care hospital between 2015 and 2022. Based on their femoral access type, the patients were categorized into the "percutaneous" or "cutdown" groups. Using a computerized sheet, relevant patient data (including demographic information and patient risk factors) were collected. The operative duration, complication rates, mortality rates, intensive care unit admission and stay durations, and total hospital stay were compared between the two groups. The primary outcomes were differences in the postoperative morbidity and mortality associated with the two approaches. RESULTS: The cutdown and percutaneous groups comprised 24 (41%) and 35 (59%) patients, respectively. The two groups displayed comparable demographic and clinical characteristics (p > 0.05). However, the vascular anatomy differed with the common femoral artery diameter being larger in the percutaneous group compared to the cutdown group (9.63 ± 1.81 mm vs. 8.49 ± 1.54 mm, p = 0.028). The ratio of the sheath diameter to the common femoral artery diameter was significantly lower in the percutaneous group than in the cutdown group (0.73 ± 0.16 vs. 0.85 ± 0.20, p = 0.027). A ratio of ≥0.74 was associated with a higher risk of complications (odds ratio, 12.0; 95% confidence interval, 1.4-102.2; p = 0.023) and mortality (odds ratio, 5.79; 95% confidence interval, 1.13-29.6; p = 0.035). Additionally, the operative duration was significantly shorter in the percutaneous group than in the cutdown group (141.43 ± 97.05 min vs. 218.46 ± 126.31 min, p = 0.001). Compared to the cutdown group, the percutaneous group experienced a shorter total hospital stay (21.54 ± 21.49 days vs. 11.60 ± 12.09 days, p = 0.022) and lower intensive care unit-admission rates (66.7% vs. 40%, p = 0.044). CONCLUSION: The percutaneous approach is a viable and more time-efficient alternative to the traditional cutdown method for delivering vascular endografts. It is associated with a significantly shorter operative duration and briefer hospital stays. Additionally, the ratio of the sheath diameter to the common femoral artery diameter can help surgeons preoperatively predict and anticipate the risks of complications and mortality. Future in-depth research is necessary to better understand the association between this ratio and postoperative outcomes and complications.

Outcomes of abdominal aortic aneurysm repair among patients with rheumatoid arthritis.

OBJECTIVE: In the present study, we compared the outcomes of elective abdominal aortic aneurysm (AAA) repair in patients with and without rheumatoid arthritis (RA) stratified by the type of surgery. METHODS: A retrospective population-based cohort study was conducted from 2003 to 2016. Linked administrative health data from Ontario, Canada were used to identify all patients aged ≥65 years who had undergone elective open or endovascular AAA repair during the study period. Patients were identified using validated procedure and billing codes and matching using propensity scores. The primary outcome was survival. The secondary outcomes were major adverse cardiovascular events (MACE)-free survival (defined as freedom from death, myocardial infarction, and stroke), reintervention, and secondary rupture. RESULTS: Of 14,816 patients undergoing elective AAA repair, a diagnosis of RA was present for 309 (2.0%). The propensity-matched cohort included 234 pairs of RA and control patients. The matched cohort was followed up for a mean ± standard deviation of 4.93 ± 3.35 years, and the median survival was 6.76 and 7.31 years for the RA and control groups, respectively. Cox regression analysis demonstrated no statistically significant differences in the hazards for death, MACE, reintervention, or secondary rupture. Analysis of the differences in outcomes stratified by repair approach also showed no statistically significant differences in the hazards for death, MACE, reintervention, or secondary rupture. CONCLUSIONS: We found no statistically significant differences in survival, MACE, reintervention, or secondary rupture among patients with RA undergoing elective AAA repair compared with controls. Further studies are required to evaluate the impact of comorbidities and antirheumatic medications on the outcomes of elective AAA repair.

A systematic review and meta-analysis of plain versus drug-eluting balloon angioplasty in the treatment of juxta-anastomotic hemodialysis arteriovenous fistula stenosis.

OBJECTIVE: Owing to the lack of comparative evidence between the endovascular technologies for arteriovenous fistula (AVF) stenosis treatments, we sought to summarize the reported data comparing the effectiveness of different endovascular approaches for the treatment of AVF stenoses at the juxta-anastomotic site. METHODS: We performed a systematic review in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The MEDLINE, Embase, and Cochrane Central Register of Controlled Trials databases were searched from inception to June 12, 2018 for observational and randomized studies that had examined the effectiveness of AVF stenosis treatment using plain percutaneous balloon angioplasty (PTA), cutting balloon angioplasty, drug-eluting balloon (DEB) angioplasty, high-pressure balloon angioplasty, and stenting. Bias was assessed using the Newcastle-Ottawa scale for observational studies and the Cochrane Collaboration tool for randomized studies. Article screening, full-text review, assessment of bias, and data collection were conducted in duplicate, with a third reviewer to reconcile any discrepancies. We conducted a qualitative synthesis of the available evidence and a quantitative meta-analysis for the primary assisted patency outcome. The meta-analysis was conducted using Review Manager, version 5.3, using random effects models, with the I2 statistic used to assess heterogeneity. Statistical significance was set at P < .05. RESULTS: Our search yielded 3683 reports. Of these, three randomized trials and three observational studies were included. Three studies with 342 patients had described the effectiveness of high-pressure balloon angioplasty, conventional PTA, and stenting and had analyzed the data qualitatively. Three studies with 141 patients had investigated native AVF patency after DEB angioplasty and conventional PTA and were included in the meta-analysis. DEB angioplasty showed significantly greater primary assisted patency rates at 12 months after treatment compared with PTA (odds ratio, 3.66; 95% confidence interval, 1.32-10.14; I2 = 49%). No statistically significant differences were found in 6-month primary assisted patency among the treatment groups (odds ratio, 2.03; 95% confidence interval, 0.64-6.45; I2 = 50%). A total of 58 of 72 AVFs remained patent 6 months after DEB angioplasty compared with 45 of 69 at 6 months after PTA. At 12 months after treatment, 48 of 72 AVFs remained patent after DEB angioplasty compared with 23 of 69 AVFs after PTA. CONCLUSIONS: Our findings suggest DEB angioplasty is a more effective treatment option for AVF stenosis at the juxta-anastomotic site compared with PTA. Although DEB angioplasty might provide longer term patency than other endovascular treatments, further high-quality data are needed to confirm this finding.

Population-based long-term outcomes of open versus endovascular aortic repair of ruptured abdominal aortic aneurysms.

OBJECTIVE: Existing data regarding endovascular aortic repair (EVAR) of ruptured abdominal aortic aneurysm (rAAA) are conflicting in their findings. The purpose of this paper was to determine the long-term outcomes of EVAR vs open surgical repair (OSR) for treatment of rAAA. METHODS: A population-based retrospective cohort study of all patients 40 years or more that underwent OSR or EVAR of rAAA in Ontario, Canada, from 2003 to 2016 was conducted. Administrative data from the province of Ontario was used as the data source. The propensity for repair approach was calculated using a logistic regression model including all covariates and used for inverse probability of treatment weighting. Cox proportional hazards regression was conducted using the weighted cohort to determine the survival and major adverse cardiovascular event (MACE)-free survival of EVAR relative to OSR for rAAA up to 10 years after repair. RESULTS: A total of 2692 rAAA (261 EVAR [10%] and 2431 OSR [90%]) repairs were recorded from April 1, 2003, to March 31, 2016. Mean follow-up for the entire cohort was 3.4 years (standard deviation [SD], 3.9 years), with a maximum follow-up of 14.0 years. OSR patients were followed for a mean of 3.5 years (SD, 4.0 years) and maximum of 14.0 years, and EVAR patients were followed for a mean of 2.7 years (SD, 2.7 years) and a maximum of 11.4 years. Median survival was 2.7 years overall, and 2.5 and 3.7 years for OSR and EVAR patients, respectively. There were no significant baseline differences between EVAR and OSR patients after inverse probability of treatment weighting. EVAR patients were at lower hazard for all-cause mortality (hazard ratio, 0.49; 95% confidence interval, 0.37-0.65; P < .01), and MACE (hazard ratio, 0.51, 95% confidence interval, 0.40-0.66; P < .01) within 30 days of repair. There were no statistically significant differences between EVAR and OSR in the hazard for all-cause mortality or MACE from 30 days to 5 years, and 5 to 10 years. Despite this, the upfront mortality and MACE benefits of EVAR persisted for more than 4.5 years after repair. CONCLUSIONS: This population-based cohort study using administrative data from Ontario, Canada, demonstrated lower hazards for all-cause mortality and MACE within 30 days of operation in favor of EVAR, but no differences in the mid- or longer-term results. More work is needed to understand and improve the long-term outcomes of ruptured endovascular aortic aneurysm repair and ruptured open surgical repair.

Short-term outcomes of combined neuraxial and general anaesthesia versus general anaesthesia alone for elective open abdominal aortic aneurysm repair: retrospective population-based cohort study†.

BACKGROUND: Use of neuraxial anaesthesia for open abdominal aortic aneurysm repair is postulated to reduce mortality and morbidity. This study aimed to determine the 90-day outcomes after elective open abdominal aortic aneurysm repair in patients receiving combined general and neuraxial anaesthesia vs general anaesthesia alone. METHODS: A retrospective population-based cohort study was conducted from 2003 to 2016. All patients ≥40 yr old undergoing open abdominal aortic aneurysm repair were included. The propensity score was used to construct inverse probability of treatment weighted regression models to assess differences in 90-day outcomes. RESULTS: A total of 10 447 elective open abdominal aortic aneurysm repairs were identified; 9003 (86%) patients received combined general and neuraxial anaesthesia and 1444 (14%) received general anaesthesia alone. Combined anaesthesia was associated with significantly lower hazards for all-cause mortality (hazard ratio [HR]=0.47; 95% confidence interval [CI], 0.37-0.61) and major adverse cardiovascular events (HR=0.72; 95% CI, 0.60-0.86). Combined patients were at lower odds for acute kidney injury (odds ratio [OR]=0.66; 95% CI, 0.49-0.89), respiratory failure (OR=0.41; 95% CI, 0.36-0.47), and limb complications (OR=0.30; 95% CI, 0.25-0.37), with higher odds of being discharged home (OR=1.32; 95% CI, 1.15-1.51). Combined anaesthesia was also associated with significant mechanical ventilation and ICU and hospital length of stay benefits. CONCLUSIONS: Combined general and neuraxial anaesthesia in elective open abdominal aortic aneurysm repair is associated with reduced 90-day mortality and morbidity. Neuraxial anaesthesia should be considered as a routine adjunct to general anaesthesia for elective open abdominal aortic aneurysm repair.

The economic burden of inpatient diabetic foot ulcers in Toronto, Canada.

OBJECTIVE: Diabetic foot ulcer, which often leads to lower limb amputation, is a devastating complication of diabetes that is a major burden on patients and the healthcare system. The main objective of this study is to determine the economic burden of diabetic foot ulcer-related care. METHODS: We conducted a multicenter study of all diabetic foot ulcer patients admitted to general internal medicine wards at seven hospitals in the Greater Toronto Area, Canada from 2010 to 2015, using the GEMINI database. We compared the mean costs of care per patient for diabetic foot ulcer-related admissions, admissions for other diabetes-related complications, and admissions for the top five most costly general internal medicine conditions, using the Ontario Case Costing Initiative. Regression models were used to determine adjusted estimates of cost per patient. Propensity-score matched analyses were performed as sensitivity analyses. RESULTS: Our study cohort comprised of 557 diabetic foot ulcer patients; 2939 non-diabetic foot ulcer diabetes patients; and 23,656 patients with the top 5 most costly general internal medicine conditions. Diabetic foot ulcer admissions incurred the highest mean cost per patient ($22,754) when compared to admissions with non-diabetic foot ulcer diabetes ($8,350) and the top five most costly conditions ($10,169). Using adjusted linear regression, diabetic foot ulcer admissions demonstrated a 49.6% greater mean cost of care than non-diabetic foot ulcer-related diabetes admissions (95% CI 1.14-1.58), and a 25.6% greater mean cost than the top five most costly conditions (95% CI 1.17-1.34). Propensity-scored matched analyses confirmed these results. CONCLUSION: Diabetic foot ulcer patients incur significantly higher costs of care when compared to admissions with non-diabetic foot ulcer-related diabetes patients, and the top five most costly general internal medicine conditions.

A systematic review and meta-analysis of the long-term outcomes of endovascular versus open repair of abdominal aortic aneurysm.

OBJECTIVE: This study synthesized the literature comparing the long-term (5-9 years) and very long-term (≥10 years) all-cause mortality, reintervention, and secondary rupture rates between endovascular aneurysm repair (EVAR) and open surgical repair (OSR) of abdominal aortic aneurysm (AAA). METHODS: MEDLINE, Embase, and CENTRAL databases were searched from inception to May 2018 for studies comparing EVAR to OSR with a minimum follow-up period of 5 years. Study selection, data abstraction, and quality assessment were conducted by two independent reviewers, with a third author resolving discrepancies. Study quality was assessed using the Cochrane and Newcastle-Ottawa scales. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were calculated using random-effects models. Heterogeneity was quantified using the I2 statistic, and publication bias was assessed using funnel plots. RESULTS: Our search yielded 3431 unique articles. Three randomized controlled trials and 68 observational studies comparing 151,092 EVAR to 148,692 OSR patients were included. Inter-rater agreement was excellent at the screening (κ = 0.78) and full-text review (κ = 0.89) stages. Overall, the risk of bias was low to moderate. For long-term outcomes, 54 studies reported all-cause mortality (n = 203,246), 23 reported reintervention (n = 157,151), and 4 reported secondary rupture (n = 150,135). EVAR was associated with higher long-term all-cause mortality (OR, 1.19; 95% CI, 1.06-1.33; P = .003, I2 = 91%), reintervention (OR, 2.12; 95% CI, 1.67-2.69; P < .00001, I2 = 96%), and secondary rupture rates (OR, 4.84; 95% CI, 2.63-8.89; P < .00001, I2 = 92%). For very long-term outcomes, 15 studies reported all-cause mortality (n = 48,721), 9 reported reintervention (n = 7511), and 1 reported secondary rupture (n = 1116). There was no mortality difference between groups, but EVAR was associated with higher reintervention (OR, 2.47; 95% CI, 1.71-3.57; P < .00001, I2 = 84%) and secondary rupture rates (OR, 8.10; 95% CI, 1.01-64.99; P = .05). Subanalysis of more recent studies, with last year of patient recruitment 2010 or after, demonstrated no long-term mortality differences between EVAR and OSR. CONCLUSIONS: EVAR is associated with higher long-term all-cause mortality, reintervention, and secondary rupture rates compared with OSR. In the very long-term, EVAR is also associated with higher reintervention and secondary rupture rates. Notably, EVAR mortality has improved over time. Vigilant long-term surveillance of EVAR patients is recommended.

Population-based secular trends in lower-extremity amputation for diabetes and peripheral artery disease.

BACKGROUND: The evolving clinical burden of limb loss secondary to diabetes and peripheral artery disease remains poorly characterized. We sought to examine secular trends in the rate of lower-extremity amputations related to diabetes, peripheral artery disease or both. METHODS: We included all individuals aged 40 years and older who underwent lower-extremity amputations related to diabetes or peripheral artery disease in Ontario, Canada (2005-2016). We identified patients and amputations through deterministic linkage of administrative health databases. Quarterly rates (per 100 000 individuals aged ≥ 40 yr) of any (major or minor) amputation and of major amputations alone were calculated. We used time-series analyses with exponential smoothing models to characterize secular trends and forecast 2 years forward in time. RESULTS: A total of 20 062 patients underwent any lower-extremity amputation, of which 12 786 (63.7%) underwent a major (above ankle) amputation. Diabetes was present in 81.8%, peripheral artery disease in 93.8%, and both diabetes and peripheral artery disease in 75.6%. The rate of any amputation initially declined from 9.88 to 8.62 per 100 000 between Q2 of 2005 and Q4 of 2010, but increased again by Q1 of 2016 to 10.0 per 100 000 (p = 0.003). We observed a significant increase in the rate of any amputation among patients with diabetes, peripheral artery disease, and both diabetes and peripheral artery disease. Major amputations did not significantly change among patients with diabetes, peripheral artery disease or both. INTERPRETATION: Lower-extremity amputations related to diabetes, peripheral artery disease or both have increased over the last decade. These data support renewed efforts to prevent and decrease the burden of limb loss.

Perceptions of Canadian Vascular Surgeons Toward Pharmacologic Risk Reduction in Patients with Peripheral Artery Disease: 2018 Update.

BACKGROUND: Vascular surgeons have a central role in managing peripheral artery disease (PAD). This study assessed their knowledge, attitudes, and behaviors regarding pharmacologic risk reduction in PAD and results were compared to a similar 2004 survey conducted by our group. METHODS: An online questionnaire was administered to 161 active members of the Canadian Society for Vascular Surgery. RESULTS: Forty-eight participants (30%) completed the survey. Recommended targets for low-density lipoprotein cholesterol, blood pressure, and glucose were known by 52%, 38%, and 50% of vascular surgeons, respectively. Almost all participants recognized antiplatelet dosages and statin indications, but less than half could identify indications (29%) and precautions (44%) for angiotensin converting enzyme (ACE) inhibitor therapy. A majority (58%) routinely evaluate risk factors in <50% of their patients. Most vascular surgeons regularly provide risk reduction counseling, but less than 10% initiate or modify antihypertensive or ACE inhibitor therapy. Compared to 2004, knowledge of targets and indications/precautions for common cardiovascular medications and frequency of risk factor assessment have not changed. Rates of counseling for diabetes control and statin prescription have improved, but remain suboptimal. Regarding newer medications with cardiovascular benefit, less than 10% would prescribe proprotein convertase subtilisin/kexin type 9 and sodium-glucose cotransporter 2 inhibitors if they were available. The majority of vascular surgeons rate their PAD risk reduction knowledge as average and support an up-to-date Canadian PAD guideline. Most participants believe that risk reduction therapy is best provided by family physicians and internists, but also acknowledge that vascular surgeons should be well-versed in assessing and managing risk factors in PAD. CONCLUSIONS: Significant knowledge and action gaps exist among Canadian vascular surgeons with regards to pharmacologic cardiovascular risk reduction in PAD. Although there is recognition that vascular surgeons are central to the medical management of patients with PAD, few routinely evaluate risk factors and prescribe medications. There is little evidence of sufficient improvement since 2004. New educational and clinical strategies are needed to improve PAD risk reduction pharmacotherapy among Canadian vascular surgeons.

The Current Status of Lithoplasty in Vascular Calcifications: A Systematic Review.

Background. Lithoplasty is a method of alleviating vessel stenosis by using localized high-speed pressure waves to disrupt calcium deposits. A systematic review of the literature was performed to summarize the early outcomes of lithoplasty in peripheral and coronary artery disease. Methods. We searched EMBASE, MEDLINE, and the Cochrane Central Register of Controlled Trials from database inception to July 2018 for original studies describing the use of lithoplasty. Study selection and data extraction were performed in duplicate, with a third author resolving discrepancies. Results. A total of 9 records were included from the 201 studies eligible for screening. In total, 211 patients with vascular calcification lesions underwent lithoplasty. The patients on average had an age of 73.2 years and had a maximum follow-up period of 5.5 months. Most lesions (72%, 152/212) were in peripheral artery beds, with the remainder occurring in coronary vessels. Lesioned vessels typically had severe calcium burden 62.6% (131/210), with an average initial stenosis of 76.6% (range, 68.1%-77.8%). After treatment, the average residual stenosis was 21.0% (range, 13.3%-26.2%), with a mean acute gain of vessel diameter of 2.5 mm. A limited number of type D dissections occurred, with a total of 2.4% (5/211) of patients requiring stent implantation. Conclusions. Recent studies suggest that lithoplasty is a promising intervention to decrease vessel stenosis in both peripheral artery disease and coronary artery disease, with minimal occurrence of major adverse events. Further research studies, with more rigorous study designs, are needed to determine the effectiveness of lithoplasty in vascular calcifications.

Long-term Outcomes of Carotid Endarterectomy Versus Stenting in a Multicenter Population-based Canadian Study.

OBJECTIVE: To compare the long-term outcomes of patients treated with carotid endarterectomy and carotid-artery stenting. BACKGROUND: Evidence for the long-term safety and efficacy of carotid-artery stenting compared with endarterectomy is accumulating from randomized trials. However, comparative data on the long-term outcomes of carotid revascularization strategies in real world practice are lacking. METHODS: We conducted a population-based, multicenter, observational cohort study using validated linked databases from Ontario, Canada. We identified all individuals treated with carotid endarterectomy and stenting (2002-2014), and followed them up to 2015. We compared long-term (up to 13 years) and 30-day outcomes of each strategy using multilevel multivariable Cox proportional-hazards models, and conducted confirmatory analyses using propensity-score matching methods. RESULTS: In all, 15,525 patients received carotid-artery revascularization. Rate of the primary composite outcome of 30-day death, stroke, or myocardial infarction plus any stroke during 13-year follow-up was higher with stenting (16.3%) compared with endarterectomy (9.7%) [adjusted hazard ratio (HR) 1.57, 95% confidence interval (CI) 1.43-1.73, P < 0.001). The increased risk with stenting was observed regardless of age, sex, intervention year, carotid-artery symptoms, or diabetes. The primary outcome was driven by higher rates of 30-day stroke (adjusted HR 1.59, 95% CI 1.29-1.95), 30-day death (adjusted HR 2.62, 95% CI 2.20-3.13), and long-term stroke >30 days after the procedure (adjusted HR 1.47, 95% CI 1.36-1.59) with stenting; 30-day myocardial infarction was lower with stenting (adjusted HR 0.70, 95% CI 0.57-0.86). These results were confirmed with 1:2 propensity-score matching (HR for primary composite outcome with stenting 1.55, 95% CI 1.31-1.83, P < 0.001). CONCLUSIONS: Compared with carotid endarterectomy, stenting was associated with an early and sustained approximately 55% increased hazard for major adverse events over long-term follow-up. Although nonrandomized, these results raise potential concerns about the interchangeability of carotid endarterectomy and stenting in the context of actual clinical practice.

Impact of Clinical Trial Results on the Temporal Trends of Carotid Endarterectomy and Stenting From 2002 to 2014.

BACKGROUND AND PURPOSE: Randomized trials provide conflicting data for the efficacy of carotid-artery stenting compared with endarterectomy. The purpose of this study was to examine the impact of conflicting clinical trial publications on the utilization rates of carotid revascularization procedures. METHODS: We conducted a population-level time-series analysis of all individuals who underwent carotid endarterectomy and stenting in Ontario, Canada (2002-2014). The primary analysis examined temporal changes in the rates of carotid revascularization procedures after publications of major randomized trials. Secondary analyses examined changes in overall and age, sex, carotid-artery symptom, and operator specialty-specific procedure rates. RESULTS: A total of 16 772 patients were studied (14 394 endarterectomy [86%]; 2378 stenting [14%]). The overall rate of carotid revascularization decreased from 6.0 procedures per 100 000 individuals ≥40 years old in April 2002 to 4.3 procedures in the first quarter of 2014 (29% decrease; P<0.001). The rate of endarterectomy decreased by 36% (P<0.001), whereas the rate of carotid-artery stenting increased by 72% (P=0.006). We observed a marked increase (P=0.01) in stenting after publication of the SAPPHIRE trial (Stenting and Angioplasty With Protection in Patients at High Risk for Endarterectomy) in 2004, whereas stenting remained relatively unchanged after subsequent randomized trials published in 2006 (P=0.11) and 2010 (P=0.34). In contrast, endarterectomy decreased after trials published in 2006 (P=0.04) and 2010 (P=0.005). CONCLUSIONS: Although the overall rates of carotid revascularization and endarterectomy have fallen since 2002, the rate of carotid-artery stenting has risen since the publication of stenting-favorable SAPPHIRE trial. Subsequent conflicting randomized trials were associated with a decreasing rate of carotid endarterectomy.

Aneurysms of the foot arteries.

Aneurysms of the foot arteries are uncommon but can lead to devastating complications such as acute foot ischemia or arterial rupture if left untreated. In this case series, we present four cases of aneurysms of the foot: one true dorsalis pedis artery aneurysm and three cases of post-traumatic plantar artery pseudoaneurysms with arteriovenous fistulas. All four patients were successfully managed with surgical excision of the aneurysm with or without arteriovenous fistulas ligation. Our case series is followed by discussion on the etiology, clinical presentation and management strategy of patients with aneurysms of the foot arteries.

Predicting Outcomes Following Lower Extremity Endovascular Revascularization Using Machine Learning.

BACKGROUND: Lower extremity endovascular revascularization for peripheral artery disease carries nonnegligible perioperative risks; however, outcome prediction tools remain limited. Using machine learning, we developed automated algorithms that predict 30-day outcomes following lower extremity endovascular revascularization. METHODS AND RESULTS: The National Surgical Quality Improvement Program targeted vascular database was used to identify patients who underwent lower extremity endovascular revascularization (angioplasty, stent, or atherectomy) for peripheral artery disease between 2011 and 2021. Input features included 38 preoperative demographic/clinical variables. The primary outcome was 30-day postprocedural major adverse limb event (composite of major reintervention, untreated loss of patency, or major amputation) or death. Data were split into training (70%) and test (30%) sets. Using 10-fold cross-validation, 6 machine learning models were trained using preoperative features. The primary model evaluation metric was area under the receiver operating characteristic curve. Overall, 21 886 patients were included, and 30-day major adverse limb event/death occurred in 1964 (9.0%) individuals. The best performing model for predicting 30-day major adverse limb event/death was extreme gradient boosting, achieving an area under the receiver operating characteristic curve of 0.93 (95% CI, 0.92-0.94). In comparison, logistic regression had an area under the receiver operating characteristic curve of 0.72 (95% CI, 0.70-0.74). The calibration plot showed good agreement between predicted and observed event probabilities with a Brier score of 0.09. The top 3 predictive features in our algorithm were (1) chronic limb-threatening ischemia, (2) tibial intervention, and (3) congestive heart failure. CONCLUSIONS: Our machine learning models accurately predict 30-day outcomes following lower extremity endovascular revascularization using preoperative data with good discrimination and calibration. Prospective validation is warranted to assess for generalizability and external validity.

Outcomes of carotid endarterectomy: Insights from a single-center retrospective cohort study.

OBJECTIVES: To analyze the outcomes of carotid endarterectomy in individuals with carotid artery stenosis in the context of a tertiary care center. METHODS: We carried out a retrospective cohort investigation between 2015-2022. Patient data includes demographics, risk factors, preoperative medications, and operative details. The primary outcomes were 30-day postoperative stroke and mortality rates, while the secondary outcome of the study was to assess the morbidity of the procedure. RESULTS: The mean age of the 54 patients was 66.9±9.88 years, and 57.4% were men. The 30-day stroke rate was 3.7%, and the mortality rate was 1.9%. Most patients did not develop postoperative complications; however, surgical site hematoma was the most common complication encountered (12.9%). Long-term follow-up showed disease regression in 68.5% of patients, with a minority of patients developing ipsilateral restenosis. Admission to an intensive care monitoring unit was the only independent predictor of postoperative complications. CONCLUSION: This study provided insights into the outcomes of carotid endarterectomy in patients with carotid artery stenosis, emphasizing the importance of careful patient selection and postoperative monitoring. Perioperative risks, including stroke and mortality, were within acceptable limits. Further research incorporating structured and non-structured data for predictive analyses, should explore refining patient profiling and optimizing treatment approaches for different carotid artery stenosis clinical and morphological presentations.