Leveraging Artificial Intelligence to Optimize the Care of Peripheral Artery Disease Patients.

Peripheral artery disease is a major atherosclerotic disease that is associated with poor outcomes such as limb loss, cardiovascular morbidity, and death. Artificial intelligence has seen increasing integration in medicine, and its various applications can optimize the care of peripheral artery disease patients in diagnosis, predicting patient outcomes, and imaging interpretation. In this review, we introduce various artificial intelligence applications such as natural language processing, supervised machine learning, and deep learning, and we analyze the current literature in which these algorithms have been applied to peripheral artery disease.

The Order of Operative Repair Does Not Influence Outcomes in Patients with Concomitant Popliteal Artery and Orthopedic Injuries.

BACKGROUND: The most challenging lower extremity traumatic injuries involve concomitant vascular and orthopedic injuries with amputation rates approaching 50%. Controversy exists as to how to prioritize the vascular and orthopedic repairs. We reviewed patients with popliteal artery and lower extremity orthopedic injuries to analyze the sequence of the vascular and orthopedic repairs on outcomes. METHODS: All adult patients with a diagnosis of concomitant popliteal artery and lower extremity fracture or dislocation were identified through a review of an institutional trauma registry performed at a level 1 trauma center from 2014 to 2019. Patient demographics, timing of presentation, injury severity score (ISS), surgical interventions, and limb outcome data were collected and examined. The sequence of operative repairs and factors influencing the operative order were analyzed. RESULTS: Twenty-nine patients were treated for popliteal artery injuries. Twelve of these 29 patients had concomitant popliteal artery and orthopedic fractures requiring surgical repair. Injury mechanisms included both blunt (50%, 6/12) and penetrating trauma (50%, 6/12); the majority involved femur fractures (58%, 7/12). Vascular repair included arterial bypass (75%, 9/12) or interposition grafts (25%, 3/12). Orthopedic repair included external fixation (83%, 10/12) and open reduction internal fixation (17%, 2/12). Vascular repair was performed first in 7/12 limbs (58%). Patients having vascular repair first had a trend toward lower blood pressure on arrival (P = 0.068). There was no significant difference in emergency department to operating room (OR) time, OR time, ISS, mangled extremity severity score, estimated blood loss, or blood transfusion for the sequence of operative repair. Fasciotomy was nearly ubiquitous, present in 11/12 patients (92%). There were no graft complications related to orthopedic manipulation, and there were no reported limb-length to graft-length discrepancies. Early limb salvage trended lower in the cohort with revascularization first (71% vs. 100%, P = 0.19). Of the remaining limbs available for follow-up, limb salvage at 4.25 years is 100%. CONCLUSIONS: In this small study of patients with concomitant lower extremity popliteal artery and orthopedic injuries, the order of operative repair does not appear to influence the success of revascularization.

Analysis of Extracranial Cerebrovascular Injuries: Clinical Predictors of Management and Outcomes.

BACKGROUND: Optimal management of traumatic extracranial cerebrovascular injuries (ECVIs) remains undefined. We sought to evaluate the factors that influence management and neurologic outcomes (stroke and brain death) following traumatic ECVI. METHODS: A retrospective review of a single level 1 trauma center's prospectively maintained data registry of patients older than 18 years of age with a diagnosis of ECVI was performed from 2013 to 2019. Injuries limited to the external carotid artery were excluded. Patient demographics, type of injury, timing of presentation, Biffl Classification of Cerebrovascular Injury Grade, Injury Severity Score (ISS), and Abbreviated Injury Scale were documented. Ultimate treatments (medical management and procedural interventions) and brain-related outcomes (stroke and brain death) were recorded. RESULTS: ECVIs were identified in 96 patients. The primary mechanism of injury was blunt trauma (89.5% vs. 10.5%, blunt versus penetrating), with 70 cases (66%) of vertebral artery injury and 37 cases of carotid artery injury. Treatments included vascular intervention (6.5%) and medical management (93.5%). Overall outcomes included ipsilateral ischemic stroke (29%) and brain death (6.5%). In the carotid group, vascular intervention was associated with higher Biffl grades (mean Biffl 3.17 vs. 2.23; P = 0.087) and decreased incidence of brain death (0% vs. 19%, P = 0.006), with no difference seen in ISS scores. Brain death was associated with higher ISS scores (40.29 vs. 24.17, P = 0.01), lower glascow coma score on arrival (3.57 vs. 10.63, P < 0.001), and increased rates of ischemic stroke (71% vs. 30%, P = 0.025). In the vertebral group, neither Biffl grade nor ISS were associated with treatment or outcomes. Regarding the timing of stroke in ECVI, there was no significant difference in the time from presentation to cerebral infarction between the carotid and vertebral artery groups (24.7 hr vs. 21.20 hr, P = 0.739). After this window, 98% of the ECVI cases demonstrated no further aneurysmal degeneration or new neurological deficits beyond the early time period (mean follow-up 9.7 months). CONCLUSIONS: Blunt cerebrovascular injuries should be viewed distinctly in the carotid and vertebral territories. In cases of injury to the carotid artery, Biffl grade and ISS score are associated with surgical intervention and neurologic events, respectively; vertebral artery injuries did not share this association. Neurologic deficits were detected in a similar time frame between the carotid artery and the vertebral artery injury groups and both groups had rare late neurologic events.

Medical Management of Traumatic Vertebral Artery Injury Is Safe Regardless of the Severity of Injury.

BACKGROUND: Management of traumatic vertebral artery injury (VAI) remains under debate. Current consensus reserves surgical or endovascular management for high-grade injury in order to prevent stroke. We sought to evaluate the factors that influence posterior fossa stroke outcomes following traumatic VAI. METHODS: A search of the prospectively maintained PROOVIT trauma registry of patients older than 18 years of age with a diagnosis of VAI was performed at a level 1 trauma center from 2013 to 2019. Patient demographics, type of injury, the timing of presentation, Biffl Classification of Cerebrovascular Injury Grade score, medical management, procedural interventions, and stroke outcomes were analyzed. RESULTS: VAIs were identified in 66 trauma patients were identified out of 14,323 patients entered into the PROOVIT registry. The dominant mechanism was blunt injury (91.5% vs. 8.5%, blunt versus penetrating). Nine patients presented with symptomatic ipsilateral posterior circulation strokes visible on imaging. The average Biffl classification grade was similar between the stroke and nonstroke groups (2.0 vs. 1.5; P = 0.39). The average injury severity score (ISS) between stroke and nonstroke groups was also similar (9.0 vs. 14.0; P = 0.35). All 9 patients in the stroke group had magnetic resonance imaging verification of their infarct within an average of 21.2 hr from presentation. In the stroke group, 1 patient underwent diagnostic angiography but had no intervention. In the nonstroke group, all were treated with medical management alone and none underwent vertebral artery intervention. During a mean follow-up of 14.5 months, no patients experienced a new neurological deficit. CONCLUSIONS: The severity of VAI by Biffl grading and ISS are not associated with ischemic stroke at presentation following VAI. Medical management of VAI appears safe regardless of Biffl and ISS staging in this trauma population. Neurological changes related to embolic stroke were generally appreciated on presentation. Conservative medical management was sufficient to protect from secondary neurological deficit regardless of index vertebral injury.

Presentation and outcomes of thoracic and thoracoabdominal aortic aneurysms in females, existing gaps, and future directions: A descriptive review.

Thoracic and thoracoabdominal aortic aneurysms are more common in men. Yet, females often have worse outcomes, fewer interventions, and lower treatment rates. Females have also benefited less from the research and treatment of those diseases than men. Understanding sex- and sex-specific differences in thoracic and thoracoabdominal aortic aneurysms can improve care delivery, reduce disparities, and optimize outcomes for females with thoracic aortic aneurysms and thoracoabdominal aortic aneurysms. The authors reviewed the literature on the presentation and outcomes of thoracic and thoracoabdominal aortic aneurysms in females, discussing the existing gaps and future directions to address them.

Machine learning and image analysis in vascular surgery.

Deep learning, a subset of machine learning within artificial intelligence, has been successful in medical image analysis in vascular surgery. Unlike traditional computer-based segmentation methods that manually extract features from input images, deep learning methods learn image features and classify data without making prior assumptions. Convolutional neural networks, the main type of deep learning for computer vision processing, are neural networks with multilevel architecture and weighted connections between nodes that can "auto-learn" through repeated exposure to training data without manual input or supervision. These networks have numerous applications in vascular surgery imaging analysis, particularly in disease classification, object identification, semantic segmentation, and instance segmentation. The purpose of this review article was to review the relevant concepts of machine learning image analysis and its application to the field of vascular surgery.

Bias in artificial intelligence in vascular surgery.

Application of artificial intelligence (AI) has revolutionized the utilization of big data, especially in patient care. The potential of deep learning models to learn without a priori assumption, or without prior learning, to connect seemingly unrelated information mixes excitement alongside hesitation to fully understand AI's limitations. Bias, ranging from data collection and input to algorithm development to finally human review of algorithm output affects AI's application to clinical patient presents unique challenges that differ significantly from biases in traditional analyses. Algorithm fairness, a new field of research within AI, aims to mitigate bias by evaluating the data at the preprocessing stage, optimizing during algorithm development, and evaluating algorithm output at the postprocessing stage. As the field continues to develop, being cognizant of the inherent biases and limitations related to black box decision making, biased data sets agnostic to patient-level disparities, wide variation of present methodologies, and lack of common reporting standards will require ongoing research to provide transparency to AI and its applications.

Five Year Survival in Medicare Patients Undergoing Interventions for Peripheral Arterial Disease: a Retrospective Cohort Analysis of Linked Registry Claims Data.

OBJECTIVE: To justify the up front risks of offering elective interventions for intermittent claudication (IC), patients should have reasonable life expectancy to derive durable clinical benefits. Open surgery for chronic limb threatening ischaemia (CLTI) is maximally beneficial in patients surviving ≥ 2 years. The aim was to assess long term survival after IC and CLTI interventions. METHODS: In a retrospective cohort analysis, the Vascular Quality Initiative (VQI) registry from 1 January 2010 to 31 May 2021 was queried for peripheral vascular intervention (PVI), infra-inguinal bypasses (IIB), and supra-inguinal bypasses (SIB) for IC and CLTI across 286 US centres. VQI linkage to Medicare insurance claims provided five year survival data. Multivariable analysis identified factors associated with five year mortality. RESULTS: There were 31 457 PVIs (44.7% IC, 55.3% CLTI), 7 978 IIBs (26.9% IC, 73.1% CLTI), and 2 149 SIBs (50.1% IC, 49.9% CLTI) recorded in the VQI. Among the PVI, IIB, and SIB cohorts, average ages were 75, 73, and 72 years, respectively. Respective five year mortality after PVI for IC and CLTI was 37.2% and 71.1%; after IIB for IC and CLTI it was 37.8% and 60%; and after SIB for IC and CLTI it was 33.8% and 53.8%. On multivariable analysis, across all procedures, end stage renal disease, CLTI, congestive heart failure, anaemia, chronic obstructive pulmonary disease, and prior amputation were independently associated with increased mortality. Pre-admission home living and pre-operative aspirin use were independently associated with decreased mortality. CONCLUSION: Long term survival in Medicare patients undergoing interventions in VQI centres for peripheral arterial disease is poor. Two thirds of CLTI patients and over one third of IC patients were not alive at five years. Intervening for IC in patients with high mortality risk should be avoided. For CLTI patients identified with decreased survival likelihood, intervention durability may be less important than invasiveness. Pre-operative medical optimisation should always be undertaken.

Machine learning analysis of confounding variables of a convolutional neural network specific for abdominal aortic aneurysms.

Objective: To identify confounding variables influencing the accuracy of a convolutional neural network (CNN) specific for infrarenal abdominal aortic aneurysms (AAAs) on computed tomography angiograms (CTAs). Methods: A Health Insurance Portability and Accountability Act-compliant, institutional review board-approved, retrospective study analyzed abdominopelvic CTA scans from 200 patients with infrarenal AAAs and 200 propensity-matched control patients. An AAA-specific trained CNN was developed by the application of transfer learning to the VGG-16 base model using model training, validation, and testing techniques. Model accuracy and area under the curve were analyzed based on data sets (selected, balanced, or unbalanced), aneurysm size, extra-abdominal extension, dissections, and mural thrombus. Misjudgments were analyzed by review of heatmaps, via gradient weighted class activation, overlaid on CTA images. Results: The trained custom CNN model reported high test group accuracies of 94.1%, 99.1%, and 99.6% and area under the curve of 0.9900, 0.9998, and 0.9993 in selected (n = 120), balanced (n = 3704), and unbalanced image sets (n = 31,899), respectively. Despite an eightfold difference between balanced and unbalanced image sets, the CNN model demonstrated high test group sensitivities (98.7% vs 98.9%) and specificities (99.7% vs 99.3%) in unbalanced and balanced image sets, respectively. For aneurysm size, the CNN model demonstrates decreasing misjudgments as aneurysm size increases: 47% (16/34) for aneurysms <3.3 cm, 32% (11/34) for aneurysms 3.3 to 5 cm, and 20% (7/34) for aneurysms >5 cm. Aneurysms containing measurable mural thrombus were over-represented within type II (false-negative) misjudgments compared with type I (false-positive) misjudgments (71% vs 15%, P < .05). Inclusion of extra-abdominal aneurysm extension (thoracic or iliac artery) or dissection flaps in these imaging sets did not decrease the model's overall accuracy, indicating that the model performance was excellent without the need to clean the data set of confounding or comorbid diagnoses. Conclusions: Analysis of an AAA-specific CNN model can accurately screen and identify infrarenal AAAs on CTA despite varying pathology and quantitative data sets. The highest anatomic misjudgments were with small aneurysms (<3.3 cm) or the presence of mural thrombus. Accuracy of the CNN model is maintained despite the inclusion of extra-abdominal pathology and imbalanced data sets.

Perioperative complications following open or endovascular revascularization for chronic limb-threatening ischemia in the BEST-CLI Trial.

OBJECTIVE: Anticipated perioperative morbidity is an important factor for choosing a revascularization method for chronic limb-threatening ischemia (CLTI). Our goal was to assess systemic perioperative complications of patients treated with surgical and endovascular revascularization in the Best Endovascular vs Best Surgical Therapy in Patients with CLTI (BEST-CLI) trial. METHODS: BEST-CLI was a prospective randomized trial comparing open (OPEN) and endovascular (ENDO) revascularization strategies for patients with CLTI. Two parallel cohorts were studied: Cohort 1 included patients with adequate single-segment great saphenous vein (SSGSV), whereas Cohort 2 included those without SSGSV. Data were queried for major adverse cardiovascular events (MACE-composite myocardial infarction, stroke, death), non-serious (non-SAEs) and serious adverse events (SAEs) (criteria-death/life-threatening/requiring hospitalization or prolongation of hospitalization/significant disability/incapacitation/affecting subject safety in trial) 30 days after the procedure. Per protocol analysis was used (intervention received without crossover), and risk-adjusted analysis was performed. RESULTS: There were 1367 patients (662 OPEN, 705 ENDO) in Cohort 1 and 379 patients (188 OPEN, 191 ENDO) in Cohort 2. Thirty-day mortality in Cohort 1 was 1.5% (OPEN 1.8%; ENDO 1.3%) and in Cohort 2 was 1.3% (2.7% OPEN; 0% ENDO). MACE in Cohort 1 was 4.7% for OPEN vs 3.13% for ENDO (P = .14), and in Cohort 2, was 4.28% for OPEN and 1.05% for ENDO (P = .15). On risk-adjusted analysis, there was no difference in 30-day MACE for OPEN vs ENDO for Cohort 1 (hazard ratio [HR] 1.5; 95% confidence interval [CI], 0.85-2.64; P = .16) or Cohort 2 (HR, 2.17; 95% CI, 0.48-9.88; P = .31). The incidence of acute renal failure was similar across interventions; in Cohort 1 it was 3.6% for OPEN vs 2.1% for ENDO (HR, 1.6; 95% CI, 0.85-3.12; P = .14), and in Cohort 2, it was 4.2% OPEN vs 1.6% ENDO (HR, 2.86; 95% CI, 0.75-10.8; P = .12). The occurrence of venous thromboembolism was low overall and was similar between groups in Cohort 1 (OPEN 0.9%; ENDO 0.4%) and Cohort 2 (OPEN 0.5%; ENDO 0%). Rates of any non-SAEs in Cohort 1 were 23.4% in OPEN and 17.9% in ENDO (P = .013); in Cohort 2, they were 21.8% for OPEN and 19.9% for ENDO (P = .7). Rates for any SAEs in Cohort 1 were 35.3% for OPEN and 31.6% for ENDO (P = .15); in Cohort 2, they were 25.5% for OPEN and 23.6% for ENDO (P = .72). The most common types of non-SAEs and SAEs were infection, procedural complications, and cardiovascular events. CONCLUSIONS: In BEST-CLI, patients with CLTI who were deemed suitable candidates for open lower extremity bypass surgery had similar peri-procedural complications following either OPEN or ENDO revascularization: In such patients, concern about risk of peri-procedure complications should not be a deterrent in deciding revascularization strategy. Rather, other factors, including effectiveness in restoring perfusion and patient preference, are more relevant.

Telemedicine and Digital Health Applications in Vascular Surgery.

BACKGROUND: Telemedicine has the potential to revolutionize healthcare. While the development of digital health technologies for the management of patients with cardiovascular diseases has been increasingly reported, applications in vascular surgery have been far less specifically investigated. The aim of this review is to summarize applications related to telemedicine in vascular surgery, highlighting expected benefits, current limits and future directions. METHODS: The MEDLINE database was searched using a combination of keywords to identify studies related to telehealth/telemedicine in three main pathologies, including aortic, peripheral artery and carotid disease. A comprehensive literature review was performed to identify the type of digital application, intended use, expected benefits, strengths and limitations. RESULTS: Telemedicine can improve the management of patients through digital platforms allowing teleconsultation, telemonitoring or telecoaching. Intended use involved remote consultation with a vascular surgeon, applications to enhance education, self-management, follow-up or adherence to treatment or lifestyle changes. CONCLUSION: Telemedicine offers innovative perspectives to improve access to care in distant locations and optimize care through patients' empowerment and personalized follow-up, contributing to the development of precision medicine. Huge efforts remain necessary for its implementation in daily clinical practice and involve ethical, legal, technical, economic and cultural considerations.

Development of a convolutional neural network to detect abdominal aortic aneurysms.

Objective: We sought to train a foundational convolutional neural network (CNN) for screening computed tomography (CT) angiography (CTA) scans for the presence of infrarenal abdominal aortic aneurysms (AAAs) for future predictive modeling and other artificial intelligence applications. Methods: From January 2015 to January 2020, a HIPAA (Health Insurance and Accountability Act)-compliant, institutional review board-approved, retrospective clinical study analyzed contrast-enhanced abdominopelvic CTA scans from 200 patients with infrarenal AAAs and 200 propensity-matched control patients with non-aneurysmal infrarenal abdominal aortas. A CNN was trained to binary classification on the input. For model improvement and testing, transfer learning using the ImageNet database was applied to the VGG-16 base model. The image dataset was randomized to sets of 60%, 10%, and 30% for model training, validation, and testing, respectively. A stochastic gradient descent was used for optimization. The models were assessed by testing validation accuracy and the area under the receiver operating characteristic curve. Results: Preliminary data demonstrated a nonrandom pattern of accuracy and detectability. Iterations (≤10) of the model characteristics generated a final custom CNN model reporting an accuracy of 99.1% and area under the receiver operating characteristic curve of 0.99. Misjudgments were analyzed through review of the heat maps generated via gradient weighted class activation mapping overlaid on the original CT images. The greatest misjudgments were seen in small aneurysms (<3.3 cm) with mural thrombus. Conclusions: Preliminary data from a CNN model have shown that the model can accurately screen and identify CTA findings of infrarenal AAAs. This model serves as a proof-of-concept to proceed with potential future directions to include expansion to predictive modeling and other artificial intelligence-based applications.

Pediatric Renal Artery Stenosis: A 19-Year Experience in Management and Outcomes at a Tertiary Pediatric Hospital.

BACKGROUND: Renal artery stenosis (RAS) is an uncommon cause of pediatric hypertension. Guidelines for workup and management have not been established. The most widely reported etiology of the pediatric renovascular disease has been fibromuscular dysplasia; however, other etiologies including middle aortic syndrome (MAS) and vasculitides have been described. We reviewed cases of radiologically identified pediatric RAS and describe etiologies, management, and long-term clinical outcomes in our patients. METHODS: Reports for duplex ultrasound, computed tomography angiography, magnetic resonance imaging, and conventional angiography from an academic children's hospital between 2000 and 2019 were evaluated. Positive reports for RAS were confirmed by a vascular surgeon and a radiologist. Demographics, indications for evaluation, management, and long-term clinical outcomes were documented. Data are summarized as count (n), geometric mean, median, or standard deviation as appropriate. Univariate differences between treatment cohorts were analyzed using Chi-squared tests for categorical variables. Nonparametric paired Wilcoxon signed-rank test and Mann-Whitney U-test were used for the analysis of paired ordinal or continuous data. A statistical analysis was performed with SPSS software (SPSS Inc., Chicago, IL) with significance defined at a P < 0.05 level. RESULTS: Imaging for suspected RAS was performed on 984 children. Of the 38 patients with positive imaging for RAS, 60.5% were idiopathic, 31.5% (n = 12) had concomitant congenital/systemic comorbidity, and 21.0% (n = 8) had RAS and concomitant aortic pathology. Fibromuscular dysplasia only accounted for 13.2% (n = 5) of patients. Regarding management, 34.2% (n = 13) underwent invasive intervention, 23.7% (n = 9) underwent endovascular intervention alone, and 10.5% (n = 4) underwent endovascular plus surgical intervention. Conservative management was performed for 65.8% (n = 25) of patients at a long-term follow-up (33.8 months), 34.2% (n = 13) requiring only lifestyle changes, and 31.6% (n = 12) requiring only medical management. CONCLUSIONS: Pediatric RAS is a low-frequency disease and long-term outcomes have been under-reported. The incidence of associated aortic pathology in our intervention cohort appears higher than that was previously reported. A long-term follow-up demonstrated that up to 65.8% of patients could be managed successfully with conservative therapy.

Analysis of Traumatic Axillo-Subclavian Vessel Injuries: Endovascular Management is a Viable Option to Open Surgical Reconstruction.

BACKGROUND: In traumatic axillo-subclavian vessel injuries, endovascular repair has been increasingly described, despite ongoing questions regarding infection risk and long-term durability. We sought to compare the clinical and safety outcomes between endovascular and surgical treatment of traumatic axillo-subclavian vessel injuries. METHOD: A search query of the prospectively maintained PROOVIT registry for patients older than 18 years of age with a diagnosis of axillary or subclavian vessel injury between 2014-2019 was performed at a Level 1 Trauma Center. Patient demographics, severity of injury, Mangled Extremity Severity Score (MESS), Injury Severity Score (ISS), procedural interventions, complications, and patency outcomes were collected and analyzed. RESULTS: Twenty-three patients with traumatic axillo-subclavian vessel injuries were included. There were similar rates of penetrating and blunt injuries (48% vs. 52%, respectively). Eighteen patients (78%) underwent intervention: 11 underwent endovascular stenting or diagnostic angiography; 7 underwent open surgical repair. There was similar severity of arterial injuries between the endovascular and open surgical groups: transection (30% vs. 40%, respectively), occlusion (30% vs. 40%, respectively). The open surgical group had worse initial clinical comorbidities: higher ISS scores (17.0 vs 13.5, p = 0.034), higher median MESS scores (6 vs. 3.5, P = 0.001). The technical success for the endovascular group was 100%. The endovascular group had a lower estimated procedural blood loss (27.5 mL vs. 624 mL, P = 0.03). The endovascular arterial group trended toward a shorter length of hospital stay (5.6 days vs. 27.6 days, P = 0.09) and slightly reduced procedural time (191.0 min vs. 223.5 min, P = 0.165). Regarding imaging follow up (average of 60 days post-discharge), 7 patients (54%) underwent surveillance imaging (5 with duplex ultrasound, 2 with computed tomography angiography CTA) that demonstrated 100% patency. Regardless of ISS or MESS scores, at long term clinical follow up (average of 214 days), there were no limb losses, graft infections or vascular complications in either the endovascular or open surgical group. CONCLUSIONS: Endovascular treatment is a viable option for axillo-subclavian vessel injuries. Preliminary results demonstrate that endovascular treatment, when compared to open surgical repair, can have similar rates of technical success and long-term outcomes in patency, infection and vascular complications.

Factors Affecting One-Year Outcomes After Major Lower Extremity Amputation in the Vascular Quality Initiative Amputation Registry.

INTRODUCTION: Major lower extremity amputation (LEA) results in significant morbidity and mortality. This study identifies factors contributing to adverse long-term outcomes after major LEA. STUDY DESIGN: Amputations in the Vascular Quality Initiative (VQI) long-term follow-up database from 2012 to 2017 were included. Multivariable logistic regression determined which significant patient factors were associated with 1-year mortality, long-term functional status, and progression to higher level amputation within 1 year. RESULTS: 3440 major LEAs were performed and a mortality rate of 19.9% was seen at 1 year. Logistic regression demonstrated that 1-year mortality was associated with post-op myocardial infarction (MI) (odds ratio (OR) 1.7, CI 1.02-2.97, P = .04), congestive heart failure (CHF) (OR 1.9, confidence interval (CI) 1.56-2.38, P < .001), hypertension (HTN) (OR 1.31, CI 1.00-1.72, P = .05), chronic obstructive pulmonary disease (COPD) (OR 1.36, CI 1.13-1.63, P < .001), and dependent functional status (OR 2.01, CI 1.67-2.41, P < .001). A decline in ambulatory status was associated with COPD (OR 1.36, CI 1.09-1.68, P = .006). Dependent functional status was protective against revision to higher level amputation (OR .18, CI .07-.45, P < .001). CONCLUSION: In the VQI, 1-year mortality after major LEA is nearly 20% and associated with HTN, CHF, COPD, dependent functional status, and post-op MI. Decreased functional status at 1 year was associated with COPD, and progression to higher level amputation was less likely in patients with dependent functional status.

Health Care System-Wide Analysis Identifies High Radiation Use Factors and Behaviors in Surgery.

OBJECTIVE: Usage of radiation among various surgical specialists has not been comprehensively evaluated. A systems-based analysis evaluating intraoperative radiation can help identify high use factors and dose reduction behaviors leading to quality improvement initiatives. METHODS: A retrospective review of all operative fluoroscopic-guided procedures from 2010 to 2017 from 4 hospitals in a tertiary academic health care system was performed. RESULTS: One thousand two hundred fifty-two cases were analyzed, and notable trends in metrics including type of equipment, procedures, surgical field, surgical specialty, and dose reduction techniques were demonstrated. Higher radiation exposures were correlated with fixed vs. mobile C-arm usage (1229 mGy vs. 331 mGy, P = .001), abdominal/pelvic procedures (429.2 mGy vs. 274.0 mGy, P = .002), and embolization (2450.6 mGy vs. 328.2 mGy, P = .019). Vascular surgery averaged 40 times higher radiation exposure per patient than other specialties (613.3 mGy vs. 15.6 mGy, P = .001). Notably, vascular surgeons utilized dose reduction techniques less frequently than urology (21.5% vs. 70%, P = .001) but more than neurosurgery and orthopedics (21.5% vs. 1.3% and 0%, P = .001, respectively). CONCLUSIONS: A system-wide health care analysis identified vascular surgery procedures, use of a fixed C-arm, abdominal/pelvic procedures, and embolization cases as having the highest radiation exposure. These data can serve as baseline information for future quality improvement initiatives regarding fluoroscopy usage by surgeons.

5-Item Modified Frailty Index Predicts Outcomes After Below-Knee Amputation in the Vascular Quality Initiative Amputation Registry.

Patient frailty indices are increasingly being utilized to anticipate post-operative complications. This study explores whether a 5-factor modified frailty index (mFI-5) is associated with outcomes following below-knee amputation (BKA). All BKAs in the vascular quality initiative (VQI) amputation registry from 2012-2017 were reviewed. Preoperative frailty status was determined with the mFI-5 which assigns one point each for history of diabetes, chronic obstructive pulmonary disease or active pneumonia, congestive heart failure, hypertension, and nonindependent functional status. Outcomes included 30-day mortality, unplanned return to odds ratio (OR), post-op myocardial infarction (MI), post-op SSI, all-cause complication, revision to higher level amputation, disposition status, and prosthetic use. 2040 BKAs were performed. Logistic regression showed an increasing mFI-5 score that was associated with higher risk of combined complications (OR 1.22, confidence interval [CI] 1.07-1.38, P < .05), 30-day mortality (OR 1.60, CI 1.19-2.16, P < .05), post-op MI (OR 1.79, CI 1.30-2.45, P < .05), and failure of long-term prosthetic use (OR 1.17, CI 1.03-1.32, P < .05). In the VQI, every one-point increase in mFI-5 is associated with an increased risk of 22% for combined complications, 60% for 30-day mortality, nearly 80% for post-op MI, and 17% for failure of prosthetic use in BKA patients. The mFI-5 frailty index should be incorporated into preoperative planning and risk stratification.