Vascular Quality Initiative Database Research Articles

Developing machine learning algorithms to predict outcomes following vascular surgery using the Vascular Quality Initiative database

Developing machine learning algorithms to predict outcomes following vascular surgery using the Vascular Quality Initiative database

Association between aortic pathology, surgeon experience, and regional variability on use of intravascular ultrasonography during thoracic endovascular aortic repair

ObjectiveIntravascular ultrasound (IVUS) is a useful adjunct to obtain precise intraluminal measurements during thoracic endovascular aortic repair (TEVAR), but IVUS examination is not routinely used by all surgeons or centers during TEVAR. We sought to identify patient- and system-related factors that influence the decision to use IVUS examination during TEVAR. MethodsA retrospective review of the Vascular Quality Initiative (VQI) database was performed to identify all patients undergoing TEVAR from 2015 to 2019. Multivariable logistic regression modeling with three-fold repeated cross-validation was performed to identify predictors of IVUS use during TEVAR. Association of IVUS use with contrast volume and radiation exposure was also assessed. ResultsA total of 12,414 patients undergoing TEVAR met the inclusion criteria. Of these, IVUS examination was used in 41.3% of cases (n = 5121). IVUS use was more common in younger patients with fewer comorbidities; however, IVUS examination was also more commonly deployed in symptomatic patients and those with a higher preoperative American Society of Anesthesiology classification. IVUS examination was use in 80% (n = 3385/4213) TEVAR procedures performed for type B aortic dissection, which accounted for 50% of total IVUS use and only 11% of cases during which IVUS examination was not used (n = 822/7293) (P < .01). In multivariable analysis, the strongest independent predictor of IVUS use was aortic dissection (odds ratio, 13.7; 95% confidence interval, 11.7-16.3; P < .001, with aortic aneurysm as the reference). Surgeon years of independent practice experience was not associated with IVUS use, but when accounting for clustering on physicians and geographic regions, these variables explained 15% of the variance observed in the final risk-adjusted model. After adjustment for confounding factors, IVUS use was associated with a significant decrease in fluoroscopy time and contrast volume (both P < .001). ConclusionsThe decision to use IVUS examination during TEVAR is most heavily influenced by aortic pathology. Although surgeon experience was not associated with the decision to use IVUS examination, there was substantial variation in IVUS examination use among individual surgeons and VQI regions. IVUS use was associated with decreased contrast administration and fluoroscopy use but did not appear to have an impact on survival or re-intervention. Although aortic dissection was strongly associated with IVUS use, a significant number of TEVAR for dissection were performed without IVUS examination. Further research is warranted to identify the barriers to IVUS use as well as the risks and benefits of IVUS use during TEVAR so that quality benchmarks can be established and resource use is improved.

Octogenarians fare better under local anesthesia for elective endovascular aortic aneurysm repair

ObjectiveWith an aging patient population, an increasing number of octogenarians are undergoing elective endovascular abdominal aortic aneurysm repair (EVAR) in the United States. Multiple studies have shown that, for the general population, use of local anesthetic (LA) for EVAR is associated with improved short-term and long-term outcomes as compared with performing these operations under general anesthesia (GA). Therefore, this study aimed to study the association of LA for elective EVARs with perioperative outcomes, among octogenarians. MethodsThe Vascular Quality Initiative database (2003-2021) was used to conduct this study. Octogenarians (Aged ≥80 years) were selected and sorted into two study groups: LA (Group I) and GA (Group II). Our primary outcomes were length of stay and mortality. Secondary outcomes included operative time, estimated blood loss, return to operating room, cardiopulmonary complications, and discharge location. ResultsOf the 16,398 selected patients, 1197 patients (7.3%) were included in Group I, and 15,201 patients (92.7%) were in Group II. Procedural time was significantly shorter for the LA group (114.6 vs 134.6; P < .001), as was estimated blood loss (152 vs 222 cc; P < .001). Length of stay was significantly shorter (1.8 vs 2.6 days; P < .001), and patients were more likely to be discharged home (LA 88.8% vs GA 86.9%; P = .036) in the LA group. Group I also experienced fewer pulmonary complications; only 0.17% experienced pneumonia and 0.42% required ventilator support compared with 0.64% and 1.02% in Group II, respectively. This finding corresponded to fewer days in the intensive care unit for Group I (0.41 vs 0.69 days; P < .001). No significant difference was seen in 30-day mortality cardiac, renal, or access site-related complications. Return to operating room was also equivocal between the two groups. Multivariate regression analysis confirmed GA was associated with a significantly longer length of stay and significantly higher rates of non-home discharge (adjusted odds ratio [AOR], 1.59; P < .001 and AOR, 1.40; P = .025, respectively). When stratified by the New York Heart Association classification system, classes I, II, III, and IV (1.55; P < .001; 1.26; P = .029; 2.03; P < .001; 4.07; P < .001, respectively) were associated with significantly longer hospital stays. ConclusionsThe use of LA for EVARs in octogenarians is associated with shorter lengths of stay, fewer respiratory complications, and home discharge. These patients also experienced shorter procedure times and less blood loss. There was no statistically significant difference in 30-day mortality, return to operating room, or access-related complications. LA for octogenarians undergoing EVAR should be considered more frequently to shorten hospital stays and decrease complication rates.

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

To develop machine learning (ML) algorithms that predict outcomes after infrainguinal bypass. Infrainguinal bypass for peripheral artery disease carries significant surgical risks; however, outcome prediction tools remain limited. 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. 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). ML models can accurately predict outcomes after infrainguinal bypass, outperforming logistic regression.

Abstract 17625: Comparative Analysis of Mortality and Amputation Rates in Patients Undergoing Atherectomy for Infra-Popliteal Peripheral Arterial Disease: Insight From the VQI

Introduction: Infra-popliteal peripheral arterial disease (IPPAD) poses challenges due to complex vasculature. The BASIL-2 trial demonstrated superiority in endovascular treatment compared with surgical bypass in patients with IPPAD. However, the choice of endovascular modality has not been conclusive. Hypothesis: Combining plain balloon angioplasty (POBA)+atherectomy is associated with improved clinical outcomes compared to POBA. Methods: Patients that underwent POBA vs POBA+Atherectomy for IPPAD from the Vascular Quality Initiative database were identified. Propensity score matching (PSM) was employed to balance the distribution of confounding variables for mortality identified on multivariable logistic regression. Patient characteristics and long-term outcomes between the two treatment groups were compared. Results: A total of 10,494 individuals (74.6%) were treated with POBA, while 3,569 (25.4%) were treated with POBA+atherectomy. PSM ensured minimal differences in baseline characteristics, such as indication for procedure and prior revascularization. The atherectomy group was associated with higher technical success and lower perioperative complications, such as renal complications and hematoma, at the expense of higher rates of distal embolization. During long term follow up, patients who underwent atherectomy had lower rates of major amputation but lower freedom from reintervention. There were no differences in major adverse limb events and mortality. Conclusion: Combining POBA with atherectomy appears to be a safe approach in IPPAD, with lower rates of long-term amputation at the cost of higher risk for future re-intervention.

Abstract 14618: Comparative Outcomes of Elective Endovascular Abdominal Aortic Aneurysm Repair in Patients With Preoperative Cardiac Stress Testing

Introduction: The use of cardiac stress testing (CST) before endovascular abdominal aortic aneurysm (EVAR) repair is controversial. While prior research has explored the utility of CST before EVAR, EVAR outcomes in patients with different CST results have not been studied. The objective of this study is to evaluate EVAR outcomes in patients with abnormal CST. Hypothesis: Patients with abnormal CST before EVAR have inferior outcomes compared to patients with normal CST. Methods: The Vascular Quality Initiative (VQI) database for EVAR was reviewed. Patients who underwent CST prior to elective EVAR were included. In VQI, abnormal CST is defined as having ischemia, infarction, or both ischemia and infarction (BII). Outcomes of patients with normal and abnormal CST were compared, including a subgroup analysis of CST abnormalities. Results: A total of 19,964 patients were included and 23.7% (4,723) had abnormal CST. Patients with abnormal CST were more commonly males with comorbidities. Patients with abnormal CST had significantly more perioperative complications including MACE and one-year mortality compared to patients with normal CST. ( Table ) Regression analysis revealed that abnormal CST was independently associated with increased perioperative MACE (OR=1.59 [1.28-1.97]) and one-year mortality (HR=1.11 [1.00-1.23]). Subgroup analysis of patients with abnormal CST showed that patients with BII had significantly more perioperative MACE (6.8% vs 4.1%, P =0.002) and mortality (1.1% vs 0.4%, P =0.040) compared to patients with either ischemia or infarction. BII was independently associated with MACE (OR=1.62 [1.06-2.41]) and 30-day mortality (OR=3.28 [1.21-8.16]) compared to either abnormality. Conclusions: Patients with abnormal CST have worse outcomes after elective EVAR compared to patients with normal CST, particularly patients with BII. CST is a useful tool for perioperative and long-term risk stratification in patients undergoing elective EVAR.

Abstract 16935: Distressed Community Index in Patients Undergoing Carotid Artery Stenting in Medicare-Linked Vascular Quality Initiative Registry

Introduction: Patients with high community-level socioeconomic distress have worse cardiovascular outcomes, yet its impact on carotid artery stenting (CAS) outcomes is unknown. We assessed the association between the Distressed Community Index (DCI), a zip-code level measure of community distress, with post-CAS mortality and stroke. Methods: We used the Vascular Quality Initiative database linked with Medicare claims outcomes data to identify patients undergoing CAS between 2015 and 2019. From a time-dependent ROC curve and using Youden index, we classified patients as high community distress if DCI≥65. Thirty-six-month cumulative mortality incidence using Kaplan-Meier by DCI groups, and hierarchical Cox regression with random intercept for site for linear DCI were used. For stroke, we used 36-month cumulative incidence function by DCI groups, and Fine and Gray models accounting for competing risk of death for linear DCI. Models were later adjusted for patient and procedural characteristics. Results: The final complete-case cohort included 8,595 patients (2,580/30% DCI≥65), had a mean age of 74.7 (±7.8) years, was 92.7% white and 97.6% non-Hispanic/Latino. The 36-month cumulative mortality incidence was similar in both groups (26.0% vs 22.5%, P=0.236). A 10-point increase in DCI did not increase mortality risk (unadjusted HR 1.00; 95% CI 0.98-1.03 and adjusted HR 1.01; 95% CI 0.87-1.17). At 36 months the high community distress group experienced higher stroke risk (29.8% vs 22.9%, P=0.008). However, a 10-point increase in DCI did not increase stroke risk (unadjusted sub-HR: 1.01; 95% CI 0.99-1.03, adjusted sub-HR: 1.00; 95% CI 0.98-1.02). Conclusions: In this selective set of patients with underrepresentation of demographic groups, for those who get prioritized to CAS, higher community distress was associated with an increased unadjusted 36-month stroke risk by DCI group. However, a 10-point increase in DCI was nonsignificant regardless of adjustment.

Comparative Analysis of Mortality and Amputation Rates in Patients Undergoing Atherectomy for Infra-Popliteal Peripheral Arterial Disease: Insight From the VQI.

Infra-popliteal peripheral arterial disease (IPPAD) poses challenges due to high restenosis and occlusion rates. The BASIL-2 trial demonstrated the superiority of endovascular treatment compared with surgical bypass in patients with IPPAD. However, the association between different endovascular modalities and clinical outcomes has not been conclusive. Combining plain old balloon angioplasty (POBA) with atherectomy is associated with improved clinical outcomes compared with POBA alone. Patients who underwent POBA vs POBA+atherectomy for IPPAD from the Vascular Quality Initiative database were identified. To mitigate potential selection bias, we employed propensity score matching (PSM) to balance the distribution of confounding variables for mortality identified on multivariable logistic regression. Subsequently, we compared patient characteristics and long-term outcomes between the 2 treatment groups. Among patients who underwent endovascular intervention for IPPAD, 19 979 individuals (80.8%) were treated with POBA alone, while 4747 (19.2%) were treated with both POBA+atherectomy after PSM. Propensity score matching ensured minimal differences in baseline characteristics, such as indication for lower extremity revascularization (LER) and history of LER. After PSM, patients receiving POBA+atherectomy experienced higher rates of technical success and lower perioperative complications, such as renal complications and hematoma, compared with POBA alone. During long-term follow-up, patients who underwent atherectomy had lower rates of major amputation and major adverse limb events (MALE) but slightly lower freedom from reintervention. Nonetheless, there were no differences in mortality. Combining POBA with atherectomy appears to be a safe approach in patients with IPPAD, with lower rates of long-term amputation and MALE at the cost of a higher risk of reintervention. The use of adjunctive atherectomy is associated with improved long-term outcomes in patients with infra-popliteal disease.

Arterial dissection during peripheral vascular interventions

ObjectiveArterial dissection (AD) is a known complication of peripheral vascular interventions (PVIs), but its incidence and significance have not been well-characterized. This study examines AD in the Vascular Quality Initiative database for patients treated for peripheral arterial disease. Our hypothesis is that AD is associated with decreased patency and worse limb outcomes. MethodsThe Vascular Quality Initiative PVI registry (2016-2021) was reviewed. Patients were divided based on the presence or absence of reported AD during the procedure. Trend of incidence and management of AD was derived. The characteristics and outcomes of patients with and without AD were compared. The primary endpoint was primary patency. ResultsThere was a total of 177,790 cases, and 3% had AD. The incidence of AD significantly increased over the study period from 2.4% to 3.6% (P = .007). Endovascular therapy was used to treat AD in 83.7% of cases, 14.5% were treated medically, and only 1.8% required open surgery. Patients with AD were significantly more likely to be female (47.4% vs 39.7%; P < .001). Patient with AD were more likely to have a history of smoking (79.7% vs 77.2%; P < .001), but were significantly less likely to be on dialysis (8.2% vs 9.3%; P < .001) compared with patients without AD. Patients with AD were more likely to have femoropopliteal disease (45.2% vs 38.0%; P < .001) and undergo treatment of more complex disease as denoted by higher mean number of lesions treated (1.95 ± 1.01 vs 1.71 ± 0.89; P < .001), longer occlusion length (8 ± 16 vs 7 ± 15 cm; P < .001), and more severe TransAtlantic Inter-Society Consensus grade (Grade D: 36.2% vs 29.1%; P < .001). The proportion of stenting as a treatment modality was higher in the dissection group (55.4% vs 41.1%; P < .001). After a mean follow-up of 828 days, patients with AD had significantly lower primary patency than patients without AD. Kaplan-Meier curves demonstrated that the AD group had lower primary patency (86.9% vs 91%; P < .001) and reintervention-free survival (79.5 % vs 84.1%; P < .001) at 1 year with difference in amputation-free survival. Cox proportional hazard regression confirmed the independent association of AD with primary patency and reintervention-free survival. ConclusionsAD is more common in women and is more likely to occur during treatment of the femoropopliteal segment. AD is associated with decreased primary patency and reintervention-free survival after PVI for peripheral arterial disease.

Using machine learning to predict outcomes following suprainguinal bypass

ObjectiveSuprainguinal 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. MethodsThe 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. ResultsOverall, 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. ConclusionsWe 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.

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

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. 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. 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. In this data set, machine learning was able to predict 1-year mortality following EVAR using preoperative data and outperformed standard logistic regression models.

Intraoperative fusion imaging during transcarotid artery revascularization.

Transcarotid artery revascularization (TCAR) with reverse-flow neuroprotection has emerged as an alternative to transfemoral carotid artery stenting and carotid endarterectomy. However, it requires fluoroscopic guidance, exposing the patient and surgeon to radiation. Although fusion-guided endovascular aneurysm repair has been demonstrated to significantly decrease this radiation risk, not much is known about similar outcomes for TCAR. The purpose of this study is to evaluate the outcomes at a single institution using fusion-guided imaging during TCAR compared with regional TCAR cases in the Vascular Quality Initiative (VQI) registry without fusion imaging. A retrospective analysis was conducted of data collected from all patients undergoing TCAR with fusion-guided imaging (TCAR-F) at our hospital and patients undergoing TCAR alone within the VQI database. The primary outcomes included the total operative time, dose area product, fluoroscopy time, contrast usage, and flow-reversal time. The demographics and preoperative risk factors were also assessed in both groups. Continuous outcomes were compared using the Welch t test. Categorical outcomes were compared using the Fisher exact test. A total of 30 TCAR-F cases (January 2019 to May 2022) at our institution were compared against the regional VQI dataset (n= 2535). The TCAR-F cases had a lower dose area product (5.67 vs 93.1Gycm2; P< .0001), shorter fluoroscopy time (8.07 vs 16.4minutes; P< .0001), and less contrast usage (13.49 vs 76.7mL; P< .0001) compared with the regional averages of the same. The TCAR-F cases had a longer total operative time (117.3 vs 80.9minutes; P< .0001) and flow-reversal time (14.4 vs 11.7minutes; P= .025) compared with the regional cases. The results from this pilot study comparing TCAR-F patients at a single institution with VQI regional TCAR patients suggest that TCAR-F cases use less radiation and contrast compared with TCAR without fusion imaging. Fusion-guided imaging might provide radiation protection to both patients and surgeons and decrease contrast usage for the patient.

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

ObjectivePrediction 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. MethodsThe 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. ResultsOverall, 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. ConclusionsOpen 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.

Gender disparities in patients with aortoiliac disease requiring open operative intervention

ObjectivePeripheral artery disease is known to affect males and females in different proportions. Disparate surgical outcomes have been quantified after endovascular aortic aneurysm repair, arteriovenous fistula creation, and treatment of critical limb ischemia. The aim of this study is to objectively quantify the sex differences in outcomes in patients undergoing open surgical intervention for aortoiliac occlusive disease. MethodsPatients were identified in the aortoiliac occlusive disease Vascular Quality Initiative database who underwent aorto-bifemoral bypass or aortic thromboendarterectomy as determined by Current Procedural Terminology codes between 2012 and 2019. Patients with a minimum of 1-year follow-up were included. Risk differences (RDs) by sex were calculated using a binomial regression model in 30-day and 1-year incidence of mortality and limb salvage. Additionally, incidence of surgical complications including prolonged length of stay (>10 days), reoperation, and change in renal function (>0.5 mg/dl rise from baseline), were recorded. Inverse probability weighting was used to standardize demographic and medical history characteristics. Multivariate logistic regression models were employed to conduct analyses of the before mentioned clinical outcomes, controlling for known confounders. ResultsOf 16,218 eligible patients from the VQI data during the study period, 6538 (40.3%) were female. The mean age, body mass index, and race were not statistically different between sexes. Although there was no statistically significant difference detected in mortality between males and females at 30 days postoperatively, females had an increased crude 1-year mortality with an RD of 0.014 (95% confidence interval, 0.01-0.02; P value < .001. Males had a higher rate of a postoperative change in renal function with an RD of −0.02 (95% confidence interval, −0.03 to −0.01; P < .001). ConclusionsAlthough there was no sex-based mortality difference at 30 days, there was a statistically significant increase in mortality in females after open aortoiliac intervention at 1 year based on our weighted model. Male patients are statistically significantly more likely to have a decline in renal function after their procedures when compared with females. Postoperative complications including prolonged hospital stay, reoperation, and wound disruption were similar among the sexes, as was limb preservation rates at 1 year. Further studies should focus on elucidating the underlying factors contributing to sex-based differences in clinical outcomes following aortoiliac interventions.

Use of Glycoprotein IIb-IIIa Inhibitors in Patients Undergoing Carotid Artery Stenting in the Vascular Quality Initiative

Antiplatelet therapies with thromboxane inhibitors and adenosine 5'-diphosphate antagonists have been widely used following carotid artery stenting (CAS). However, these therapies may not apply to patients who are intolerant or present acutely. Glycoprotein IIb/IIIa inhibitors (GPI) are a proposed alternative therapy in these patients; however, their use has been limited due to concerns of increased risk for intracranial bleeding. Thus, this study aims to assess the safety profile of GPI in patients undergoing CAS. All patients undergoing CAS in the Society of Vascular Surgery - Vascular Quality Initiative database from 2012 to 2021 was included and grouped into GPI versus non-GPI therapy (control). The primary outcome was in-hospital stroke or death, and secondary outcomes included in-hospital stroke/transient ischemic attack (TIA), death, myocardial infarction, and intracranial hemorrhage (ICH)/seizure. Patients were stratified by surgical approach (Transcarotid artery revascularization using flow reversal (TCAR) and transfemoral carotid artery stenting), and stepwise backward logistic regression analysis was conducted to evaluate major primary and secondary outcomes. A total of 50,628 patients underwent carotid revascularization. Of these, 4.4% of the patients received GPI. Mean age was similar between control versus GPI (71.35(9.67) vs. 71.36(10.20) years). Compared to the control group, patients who receive GPI are less likely to be on optimal medical therapy, including aspirin (83.0% vs. 88.1%), P2Y12 inhibitor (73.0% vs. 82.7%), and statin (82.3% vs. 86.0%) (All P<0.05). In addition, patients in the GPI group were more likely to undergo TCAR for carotid revascularization (52.2% vs. 48.4%) for emergent/urgent (29.4% vs. 16.8%) and symptomatic indications (55.5% vs. 49.7%) (All P<0.001). After stratifying by surgical approach, if patients underwent TFCAS and received a GPI, they were at increased odds of developing stroke/death (1.77(1.25-2.51)), death (odds ratio (OR) (95% CI): 1.67(1.07-2.61)), stroke/TIA (OR (95% confidence interval (CI)): 1.65(1.09-2.51)), and ICH/seizure (OR (95% CI): 2.13(1.23-3.68)) (All P<0.05). No difference was seen in outcomes between the 2 groups if undergoing TCAR. Patients who receive GPI were more likely to be symptomatic at presentation and less likely to be medically optimized before their carotid revascularization. Transfemoral access in patients receiving GPI was associated with increased odds of morbidity and mortality. However, this was not observed if undergoing TCAR. TCAR can be considered for its overall favorable results in high-risk patients who are not medically optimized.

Depressed Ejection Fraction Does Not Affect Perioperative Mortality After Thoracic Endovascular Aortic Repair for Type B Aortic Dissection

Despite the expanded application of thoracic endovascular aortic repair (TEVAR) in patients with significant cardiac comorbidities, the effect of decreased left ventricular ejection fraction (EF) on outcomes remains unknown. The aim of this study was to compare outcomes in patients with normal and abnormal EFs undergoing TEVAR for type B aortic dissection (TBAD). The Vascular Quality Initiative database was reviewed from 2012-2020. Patients were categorized into severely reduced (EF≤30%), reduced (EF 30-50%) and normal EF (EF>50%). Baseline characteristics, procedural details and 18-month outcomes were compared. Multivariable logistic regression identified factors associated with mortality, major adverse cardiac events (MACE), and aortic-related re-intervention. Of 1,993 patients, 38 (2%) and 208 (10%) patients had SREF and REF. Patients with abnormal EF were more likely to have cardiac comorbidities and be prescribed angiotensin-converting enzyme inhibitors and anticoagulants. Perioperatively, patients with SREF were more likely to experience mortality (13.2% vs 6.7% vs 4.4%, p = .018), MACE (26.3% vs 11.5% vs 8%, p <.001), hemodialysis (13.5% vs 5% vs 2.9%, p = .001) and aortic related reintervention (21.1% vs 13% vs 10%, p= .041), compared to REF and NEF patients. However, these associations were not present on multivariable analysis. At 18 months, mortality was significantly higher in patients with SREF, which was confirmed on multivariable analysis, but depressed EF was not associated with increased aortic reintervention compared to NEF. SREF was not independently associated with peri-operative mortality or MACE compared to NEF. REF had similar risk of morbidity and mortality compared to NEF in both the peri- and early post-operative periods. TEVAR-related complications were similar among the cohorts. As such, TEVAR may be offered to appropriately selected patients regardless of EF.

The Use and Impact of Cilostazol on Patients Undergoing Peripheral Vascular Interventions

Cilostazol is used for the treatment of intermittent claudication. The impact of cilostazol on the outcomes of peripheral vascular interventions (PVIs) remains controversial. This study assesses the use and impact of cilostazol on patients undergoing PVI for peripheral arterial disease (PAD). The Vascular Quality Initiative (VQI) database files for PVI were reviewed. Patients who underwent PVI for PAD were included and divided based on the use of cilostazol preoperatively. After propensity matching for patient demographics and comorbidities, the short-term and long-term outcomes of the two groups were compared. A total of 183,661 patients underwent PVI procedures, and 6.5% (n = 12,014) of them were on cilostazol preoperatively. PVI was performed for claudication in 62% (n = 6174) on cilostazol. Patients that received cilostazol were more likely to be White (77% vs 75%; P < .001) and smokers (84% vs 77%; P < .001). They were more likely to undergo balloon angioplasty (39% vs 31%; P < .001) and less likely to have diabetes mellitus (50% vs 56%; P < .001), congestive heart failure (14% vs 22%; P < .001), and prior amputation (10% vs 19%; P < .001) compared with patients who did not receive cilostazol. After 3:1 propensity matching, there were 37,304 patients included in the analysis. Patients receiving cilostazol had significantly higher incidence of dissection (3.3% vs 2.6%; P = .007) with but were more likely to be discharged home (95% vs 94%; P < .001). Patients on cilostazol had lower rates of long-term mortality (10% vs 12%; P = .003). There were no significant differences in rates of major amputation, reintervention, major adverse limb events, or patency rates after PVI (Table). Amputation-free survival rates were significantly higher for patients on cilostazol, after 4 years of follow-up (90% vs 88%; P = .03) (Fig). Cilostazol is underutilized in the VQI database and seems to be associated with improved amputation-free survival. Cilostazol therapy should be considered in all patients with PAD who can tolerate it prior to PVI.TableCharacteristics and outcomes of patients treated with PVI with and without cilostazol after propensity matchingCharacteristicsNo cilostazol, n = 27,978Cilostazol, n = 9326P-valueaSMDDemographics Age, years68 ± 1068 ± 100.015 Female sex10,108 (36)3446 (37)0.017 Race0.059White21,857 (78)7054 (76)African American4231 (15)1581 (17)Other1890 (6.8)691 (7.4) Hispanic1611 (5.8)675 (7.2) Body mass index, kg/m228.2 ± 6.128.1 ± 6 Living status0.016Nursing home/homeless492 (1.8)184 (2.0) Function0.043Independent21,987 (79)7165 (77)Assisted5248 (19)1885 (20)Non-ambulatory743 (2.7)276 (3.0)Comorbidities Hypertension25,127 (90)8433 (90)0.03 Diabetes14,279 (51)4856 (52)0.021 Smoking23,136 (83)7623 (82)0.025 Chronic obstructive pulmonary disease7489 (27)2595 (28)0.024 Congestive heart failure3764 (13)1321 (14)0.021 Cardiovascular disease4000 (14)1132 (12) Coronary artery disease9792 (35)3396 (36)0.03 Coronary artery bypass graft5464 (20)1979 (21)<.001 Percutaneous coronary intervention7195 (26)2475 (27).11 Renal status0.034Chronic kidney disease21,203 (76)6937 (74)End-stage renal disease1210 (4.3)411 (4.4) Prior lower-extremity revascularization15,927 (57)5408 (58)0.021 Prior amputation2926 (10)1054 (11).022 Prior coronary artery stenting/carotid endarterectomy2465 (8.8)852 (9.1).3 Prior aneurysm894 (3.2)190 (2.0)<.001Medications Angiotensin-converting enzyme inhibitor15,563 (56)5481 (59)<.001 Aspirin20,786 (74)7387 (79)<.001 Statin21,593 (77)7837 (84)<.001 P2Y12 inhibitors13,409 (48)4964 (53)<.001 Anticoagulation5163 (18)1441 (15)<.001Procedural characteristics Indication0.008Claudication17,384 (62)5833 (63)Chronic limb-threatening ischemia10,594 (38)3493 (37) Urgency0.055Elective25,485 (91)8344 (89)Urgent/emergent2493 (8.9)982 (11) Fluoroscopy time, minutes14 (8-22)15 (9-24)<.001OutcomesNo cilostazol, n = 16,619bCilostazol, n = 5435b Periprocedural outcomesTechnical success15,461 (95)5105 (95).9Thrombosis99 (0.6)28 (0.5).5Dissection428 (2.6)177 (3.3).007Hematoma349 (2.1)121 (2.2).6 Surgical length of stay, days2.2 ± 15.41.6 ± 7.1.052 Systemic complicationsCardiac169 (1.0)48 (0.9).4Myocardial infarction54 (0.3)13 (0.2).3Pulmonary48 (0.3)16 (0.3)>.9Renal85 (0.5)23 (0.4).4Infection13 (<0.1)3 (<0.1).8 30-day mortality122 (0.7)28 (0.5).088 Discharge status<.001Home15,537 (94)5165 (95)Rehab unit447 (2.7)104 (1.9)Others609 (3.7)157 (2.9)Long-term outcomes Follow-up time, days393 ± 183396 ± 174.2 Reintervention1971 (16)641 (15).3 Secondary patency8675 (90)3042 (91).4 Major amputation571 (4.5)166 (3.8).059 Major adverse limb events2415 (19)780 (18).13 Mortality1928 (12)550 (10).003SMD, Standardized mean differences for variables used in propensity-matching.Data are expressed as median (interquartile range), number (%), or mean ± standard deviation.Boldface P values indicates statistically significant difference for P < .05 and SMD >0.1.aWilcoxon rank sum test; Pearson χ- test.bSample numbers changed due to loss to follow-up. 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One-year Outcomes Among Patients Undergoing Tibial Endovascular Reinterventions for Recurrent Critical Limb Ischemia

Angioplasty, stenting, and atherectomy for tibial occlusive disease are commonly performed among critical limb ischemia patients, but restenosis and occlusion significantly hinder long-term durability. For patients requiring reintervention for recurrent tibial occlusive disease, the impact on clinical benefit and patency equivalence is unclear. We compared 1-year outcomes following repeat tibial endovascular intervention(s) to the first (primary) tibial endovascular intervention. Procedural and long-term data from the Vascular Quality Initiative database were queried for patients with critical limb ischemia (Rutherford Class 4-6) undergoing endovascular intervention for isolated tibial occlusive disease (2010-2020). Outcomes included 1-year change from baseline in ambulatory status, functional status (Eastern Cooperative Oncology Group), disposition, minor amputation, and major adverse outcomes (death, below-knee amputation, above-knee amputation). Statistically significant and clinically relevant variables were included in multivariate logistic regression. We included 1871 patients underwent primary isolated tibial endovascular intervention for critical limb ischemia. Of those, 433 (23.1%) patients underwent tibial endovascular reintervention for recurrent disease (tissue loss 35.0%). 81.6% and 14.5% of patients underwent angioplasty and atherectomy, respectively, for primary intervention. Patients requiring repeat intervention(s) had significantly decreased clinical improvement after primary intervention (67.4% vs 77.9%; P < .001) and repeat intervention (67.8% vs 77.9%; P < .001) compared to patients with no reintervention (Table). Among the three groups, a minority of patients achieved improvement in functional status (22.2% vs 20.7% vs 21.9%; P = .84) and ambulatory status at 1-year (20.0% vs 18.6% vs 17.1%; P = .54). Approximately 50% of patients were fully ambulatory at 1 year (Table). After multivariate adjustment, patients with reintervention were 50% less likely to have a patent target vessel at 1-year after primary endovascular treatment vs patients having no reintervention (odds ratio [OR], 0.50; 95% CI, 0.31-0.79; P = .03). Patients with reintervention were also found to have increased risk for minor amputation compared to patients without reintervention (OR, 1.64; 95% CI, 1.20-2.23; P = .002). Repeat interventions significantly increased risk of minor amputation at 1-year compared to primary intervention (OR, 2.41; 95% CI, 1.53-3.80; P < .001). There was no significant difference in death or major amputation (below or above knee) (Table). Atherectomy was associated with significant reduction in high-grade stenosis at 1 year (>50%) after primary treatment compared to angioplasty (OR, 0.097; 95% CI, 0.018-0.52; P = .006). Major adverse outcomes after repeat endovascular tibial intervention for recurrent tibial occlusive disease were similar to those after primary tibial endovascular intervention. However, patients with recurrent tibial occlusive disease requiring reintervention had decreased symptom improvement after primary and repeat treatment, decreased target lesion patency, and increased risk of minor amputation.TableOne-year outcomes following tibial endovascular intervention for critical limb ischemiaPrimary endovascular intervention (no future intervention), n = 1438Primary endovascular intervention (future reintervention), n = 433Repeat endovascular intervention (2+ interventions), n = 143P valueDeath335 (23.3)86 (19.9)39 (27.3).14Symptom improvementn = 1094n = 380n = 115 Regression72 (6.6)35 (9.2)13 (11.3)<.001 No change170 (15.5)89 (23.4)24 (20.9) Improvement852 (77.9)256 (67.4)78 (67.8)Patency (patent)755/827 (91.3)259/298 (86.9)77/89 (86.5).05>50% Stenosis27/160 (16.9)14/75 (18.7)2/20 (10.0).66Functional status changen = 517n = 198n = 64.87 Regression173 (33.5)72 (36.4)25 (39.1) No change229 (44.3)85 (42.9)25 (39.1) Improvement115 (22.2)41 (20.7)14 (21.9)Ambulation status (ambulatory)565/1075 (52.6)200/377 (53.1)60/112 (53.6).69Ambulatory status changen = 1072n = 377n = 111.54 Regression303 (28.3)113 (30.0)26 (23.4) No change555 (51.8)194 (51.5)66 (59.5) Improvement214 (20.0)70 (18.6)19 (17.1)Disposition changen = 358n = 137n = 40.28 Needs advanced care206 (57.5)68 (49.6)23 (57.5) No change152 (42.5)69 (50.4)17 (42.5)Postoperative ABI1.15 ± 0.501.12 ± 0.541.09 ± 0.62.63Amputationn = 1168n = 396n = 118 All cause370 (31.7)152 (38.4)56 (47.5)<.001 Below knee173 (14.8)58 (14.6)15 (12.7).83 Above knee44 (3.8)16 (4.0)8 (6.8).29 Minor amputation (toe/ray/transmetatarsal)153 (16.1)78 (24.2)33 (34.7)<.001Values are number (%) or mean ± standard deviation. Open table in a new tab

Machine Learning Model Predicts Open Bypass Outcomes in VQI Claudicants

Peripheral artery disease (PAD) studies have largely focused on patients with acute or critical limb ischemia, although one in five patients with PAD are claudicants. New endovascular technology has fallen into favor for use in patients with claudication. However, there is debate surrounding the longevity of these interventions that may ultimately still result in a patient requiring an open bypass that could possible last a patient's lifetime. The aim of this prospective study was to leverage existing data in the Vascular Quality Initiative (VQI) database and preoperatively risk stratify patients with lifestyle-limiting claudication who may be eligible for an open bypass. The VQI was queried for all patients who underwent infrainguinal lower extremity bypass between December 2004 and December 2017. Of the 71,561 procedures, 15,633 of these procedures were initial open procedures performed for patients with lifestyle-limiting claudication. Our outcomes of interest included 30-day survival, major adverse limb events (MALE), and major cardiac events (MCE). The machine learning algorithm Random Forrest was used to identify univariate significant predictors after multiple testing correction. Generalized liner models with all significant predictors were then trained on 80% of the existing data set and tested on 20% of the dataset for accuracy of predicting outcomes. Eleven percent of patients survived after 30 days, 3.2% had an MALE, and 14% had an MCE. The best performing prediction model created was for 30-day survival, where we included the following predictors identified on univariate analysis in addition to age, race, and gender: utilizing a conduit other than great saphenous vein (GSV) (odds ratio [OR], 0.79; 95% confidence interval [CI], 0.72-0.88; P corrected = .05), uncontrolled hypertension (OR, 0.50; 95% CI, 0.42-0.60; P corrected = 8.96 × 10−11), preoperative ambulation with assistance (OR, 1.75; 95% CI, 1.53-2.01; P corrected = 8.39 × 10−12), quitting smoking before the surgery (OR, 0.72; 95% CI, 0.61-0.85; P corrected = .05), and having a preoperative computed tomography angiography available (OR, 1.28; 95% CI, 1.16-1.43; P corrected = .02). Model characteristics for each of the three outcome are listed in Table I. The model for 30-day readmission had an area under the curve of 0.79 (95% CI, 0.74-0.82) (Fig). We developed a model to predict 30-day survival in claudicants undergoing infrainguenal bypass using clinical characteristics commonly available to physicians. This computational machine learning model was developed using real world VQI data and can possibly be used in a general clinic setting for preoperative risk stratification.TableModel characteristics used to predict 30-day survival, major adverse limb event (MALE) created from a composite of any limb amputation and any return to the operating room for revision, and major cardiac event (MCE) created from a composite of stroke, myocardial infarction, or death30-day survivalMALEMCEAUC (95% CI)0.79 (0.74-0.82)0.68 (0.57-0.72)0.71 (0.69-0.74)TPR (IQR)0.79 (0.66-0.91)0.55 (0.27-0.83)0.76 (0.50-0.90)FPR (IQR)0.46 (0.20-0.73)0.39 (0.10-0.69)0.47 (0.22-0.73)Cutoff0.10.030.1Sensitivity0.810.680.65Specificity0.640.510.65AUC, Area under the curve; CI, confidence interval; FPR, false positive rate; IQR, interquartile range; TPR, true positive rate. Open table in a new tab

Medicare Patients with Symptomatic Carotid Disease Requiring Carotid Revascularization Are Likely to Have Delayed Access: An Analysis of a Multicenter Surgical Data

The Society for Vascular Surgery clinical practice guidelines for management of extracranial cerebrovascular disease recommends carotid revascularization as soon as the patient is neurologically stable after 48 hours and before 14 days of symptom onset in patients with recent stroke. In the United States, insurance status has been demonstrated to play a role in wait times for surgical care. There are no large-scale studies that assess the effect of patient primary insurance status on time to surgery in patients with symptomatic carotid disease. We utilized the Vascular Quality Initiative (VQI) database to evaluate our hypothesis that insurance status is associated with waiting times before surgery in patients with symptomatic carotid disease. All patients who underwent carotid revascularization in the VQI dataset from 2010 to 2022 were included. Patients with incomplete or missing outcomes data, Modified Rankin score of >2 and asymptomatic were excluded. Primary outcome was time between onset of symptomatic carotid disease and intervention. Categorical variables were compared using χ2 test and one-way analysis of variance for continuous variables. Multivariable logistic regression was used to assess the association between insurance status and waiting time to surgery while adjusting for potential confounders. The study consisted of 11,973 patients who had carotid revascularization within 14 days of symptoms (early cohort) and 21,253 patients in the late cohort (after 14 days). Patients in the late cohort were older (70.1 ± 9.8 vs 69.8 ± 10.5; P = .02), less likely to undergo carotid endarterectomy (85.9% vs 88.4%; P < .01), and more likely to have an elective procedure (90.3% vs 44.3%; P < .01). Fig 1 shows the distribution of insurance coverage among the study cohort. After adjusting for potential confounders, compared to Medicare, recipients of other insurer types had lower odds of experiencing delayed surgery: Medicare Advantage (adjusted odds ratio [aOR], 0.89; 95% confidence interval [CI], 0.80-0.99; P = .03), commercial (aOR, 0.84; 95% CI, 0.78-0.90; P < .001), military/Department of Veterans Affairs (aOR, 0.67; 95% CI, 0.54-0.84; P < .001), and self-pay (aOR, 0.54; 95% CI, 0.45-0.65; P < .001). Medicaid patients had similar delay (aOR, 0.90; 95% CI, 0.78-1.03; P = .14) and non-US insurance had longer delay to surgery (aOR, 1.48; 95% CI, 1.13-1.95; P = .005), in comparison to Medicare patients (Fig 2). Symptomatic carotid patients on Medicare and Medicaid are more likely to receive delayed revascularization procedures compared to patient with commercial insurance. Future studies are needed to investigate and potentially mitigate the underlying causes for the delay and the overall health implications of such a delay on the long-term outcomes of these patients.Fig 2Adjusted odds of receiving late carotid revascularization in symptomatic patients requiring surgery: comparing other major insurance providers with Medicare. *Model adjusted for urgency of procedure, prior coronary artery disease, prior carotid endarterectomy/coronary artery stenting, preoperative beta-blocker use, prior congestive heart failure, type of procedure (carotid endarterectomy, transcarotid artery revascularization, transfemoral carotid artery stenting), age, race, body mass index, preoperative creatinine levels, preoperative hemoglobin concentration, preoperative dysrhythmia, previous major amputation, preoperative functional status, American Society of Anesthesiologists class, chronic obstructive pulmonary disease, and degree of stenosis.View Large Image Figure ViewerDownload Hi-res image Download (PPT)