Arterial dissection during peripheral vascular interventions.

OBJECTIVE: Arterial 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. METHODS: The 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. RESULTS: There 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. CONCLUSIONS: AD 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.

The evolution and impact of the Society for Vascular Surgery Resident and Student Program.

OBJECTIVE: There is an ongoing national shortage in the vascular surgery (VS) workforce. To increase interest in the specialty, the Society for Vascular Surgery (SVS) Resident and Student Outreach Committee (RSOC) developed a dedicated general surgery (GS) resident and medical student (MS) program at the Vascular Annual Meeting (VAM) and invested in a scholarship program to help reduce attendee expenses. This study assesses the program's effectiveness, correlating recipient feedback with the likelihood of matching into a VS training program. METHODS: Records related to the SVS VAM GS resident and MS program from 2013 to 2023 were reviewed, focusing on attendee evaluations of the program. The program included a simulation session from 2013 to 2019. VS training program match rates among scholarship recipients were determined. The annual average match rate in VS was used to divide the survey responses into two groups: below average (BA) and above average (AA) match rate groups. Survey responses were based on a 5-point Likert scale and allowed for comments. Responses were divided into high value, strongly favoring the activity (scores 4-5), and low value (scores 1-3) categories. The survey responses from the group of years with AA match rates were compared with the group of years with BA rates. RESULTS: The SVS awarded 1040 GS resident and MS travel scholarships over the 10 years assessed. Overall, applicants had a 43% success rate in receiving a scholarship. During the study period, the annual number of applicants increased, whereas the number of scholarships and match success rates significantly decreased. The average match rate into VS among scholarship recipients was 50.2%. The survey response rate was 33%. During AA match rate years, evaluations for simulation allotted time and lectures were significantly more likely to be high value compared with BA years. Simulation content and the residency fair consistently had the most favorable evaluations (>90% high value), and overall, the program had a consistently positive impact on recipients' interest in VS (>90% high value). Trainees in the AA group were significantly more likely to provide positive comments (73% vs 55%; P < .001). Numerous recipients commented on the need for a dedicated space to interact with faculty and mentors and highlighted simulation as the standout aspect of the program. CONCLUSIONS: The SVS VAM RSOC program is positively correlated with attendee interest in VS, with approximately 50% of scholarship recipients matching into the field. The quality of the program and the number of scholarships correlate with VS match rates. Additional investments in similar programs could help close the workforce gap.

Atherectomy - The Options, the Evidence, and When Should It Be Used.

The use of atherectomy for peripheral vascular interventions (PVIs) has increased exponentially and reached 18% of all PVI in the United States. The theoretical benefit on extensive arterial calcification relies on the concept of plaque modification and removal instead of displacement, as with other endovascular techniques. To date, there are no prospective studies comparing the different atherectomy technologies (directional, rotational, orbital, and laser). Moreover, most related prospective comparative studies have a small number of patients, and larger studies are single arm in patients with relatively mild to moderate disease burden. While available literature shows lower dissection risk and reduced bailout stenting, the superiority of this technology compared to other endovascular techniques has yet to be proven. Despite the lack of level 1 evidence to support its superiority, the lucrative reimbursement fueled the overuse of this technology as first-line therapy, particularly in office-based laboratories and ambulatory surgery centers. The use of atherectomy ought to be selective and complementary to other endovascular technologies, and individualized patient-level decision-making based on the practitioner's preference and expertise is essential to selectively incorporate atherectomy in managing complex atherosclerotic lesions.

The Impact of Ejection Fraction on Major Adverse Limb Events after Lower Extremity Revascularization.

BACKGROUND: Peripheral arterial disease (PAD) is commonly associated with coronary artery disease, and echocardiography is frequently performed before lower extremity revascularization (LER). However, the incidence of various echocardiographic findings in patients with PAD and their impact on the outcomes of LER has not been well studied. Reduced ejection fraction (EF) ≤ 40% is associated with increased major adverse limb events (MALE) after LER. METHODS: The electronic medical records of patients undergoing LER in a single center were reviewed. Patients were divided based on the presence or absence of reduced EF. Patient, transthoracic echocardiogram, procedural characteristics, and outcomes were compared between the 2 groups. RESULTS: A total of 1,114 patients (N = 131, 11.8% with reduced EF) underwent LER between 2013 and 2019. Patients with reduced EF were more likely to be male and have a history of coronary artery disease and heart failure. Furthermore, they were more likely to have diastolic dysfunction with moderate to severe mitral and tricuspid valve regurgitation. Patients with reduced EF were more likely to undergo LER for chronic limb-threatening ischemia, and to be treated with endovascular procedures. Perioperatively, patients with reduced EF were more likely to develop myocardial infarction. Lastly, the 2 groups had no difference in overall MALE or major amputation. However, on Kaplan-Meier curves, MALE-free survival was significantly lower for patients with reduced EF. Regression analysis demonstrated that indication and not EF was associated with MALE and MALE-free survival. CONCLUSIONS: Reduced EF is associated with decreased MALE-free survival for patients with PAD undergoing LER.

Intravascular Ultrasound Use is Associated with Improved Patency in Lower Extremity Peripheral Arterial Interventions.

BACKGROUND: Intravascular ultrasound (IVUS) facilitates detailed visualization of endoluminal anatomy not adequately appreciated on conventional angiography. However, it is unclear if IVUS use improves clinical outcomes of peripheral vascular interventions (PVIs) for peripheral arterial disease. This study aimed to evaluate the impact of IVUS on 1-year outcomes of PVI in the vascular quality initiative (VQI). METHODS: The VQI-PVI modules were reviewed (2016-2020). All patients with available 1-year follow-up after lower extremity PVI were included and grouped as IVUS-PVI or non-IVUS PVI based on use of IVUS. Propensity matching (1:1) was performed using demographics and comorbidities. One-year major amputation and patency rates were compared. A generalized estimating equation model was used to identify predictors of 1-year outcomes. Subgroup analysis based on Trans-Atlantic Intersociety Consensus (TASC) classification, treatment length and treatment modalities were performed using same modeling approaches. RESULTS: There were 56,633 procedures (non-IVUS PVI = 55,302 vs. IVUS-PVI = 1,331) in 44,042 patients. Propensity matching yielded a total cohort of 1,854 patients matched (1:1), with no baseline differences. Lower extremity revascularization for claudication was performed in 60.4%, while one-third (33.9%) had chronic limb threatening ischemia (CLTI). IVUS was more commonly used for lesions >15 cm in length (46.6% vs. 43.3%) and for aortoiliac disease (31.8% vs. 27.2%). Rates of atherectomy and stenting were significantly higher with IVUS-PVI (21.1% vs. 16.8%), while balloon angioplasty was less common (13.5% vs. 24.4%). One-year patency was better with IVUS-PVI (97.7% vs. 95.2%, P = 0.004). On subgroup analysis, IVUS (odds ratio [OR] 2.20, 95% confidence interval [CI] 1.29-3.75) was associated with improved patency in CLTI patients, TASC C or D lesions, and treatment length >15 cm. Adjunctive IVUS use during PVI did not significantly impact 1-year amputation (OR 1.7, 95% CI 0.78-3.91). On multivariable regression, adjunctive use of IVUS (OR 2.46 95% CI 1.43-4.25) and aortoiliac interventions (OR 2.91, 95% CI 1.09-7.75) were independent predictors of patency. Treatment modalities such as atherectomy, stenting or balloon angioplasty did not significantly impact patency at 1-year. CONCLUSIONS: IVUS during lower extremity PVI is associated with improved 1-year patency, when compared to angiography alone. Certain subgroups, such as CLTI patients, lesions>15 cm, and TASC C or D lesions might benefit from adjunctive use of IVUS.

Comparative Outcomes of Peripheral Vascular Interventions in Patients on Chronic Anticoagulation with Factor Xa Inhibitors and Vitamin K Antagonists.

BACKGROUND: In patients undergoing revascularization for peripheral arterial disease (PAD), low-dose Factor Xa inhibitors (FXaI) taken with aspirin improved limb and cardiovascular outcomes compared to aspirin alone. Furthermore, in atrial fibrillation and venous thromboembolism, FXaI are recommended over vitamin K antagonists (VKA) for chronic anticoagulation. While studies have evaluated different perioperative anticoagulation regimens in patients treated for PAD, the optimal regimen for chronic anticoagulation in patients with PAD undergoing peripheral vascular intervention (PVI) has not been determined. This analysis compares outcomes of patients after PVI that require chronic anticoagulation with FXaI and VKA. METHODS: The Vascular Quality Initiative-PVI database was used. Patients consistently treated with FXaI or VKA before the procedure, at discharge, and on long-term follow-up were defined as those receiving chronic anticoagulation. Patient demographics, procedural details, and perioperative and long-term outcomes were compared between FXaI and VKA groups. RESULTS: A total of 109,268 patients were analyzed, and 6,885 were chronically anticoagulated with FXaI (N = 2,427) or VKA (N = 4,458). Patients anticoagulated with VKA were more frequently males (65.3% vs. 61.0%, P < 0.001) with end-stage renal disease (9.7% vs. 4.6%, P < 0.001) and more likely to be treated for chronic limb-threatening ischemia (58.1% vs. 52.7%, P < 0.001). Rates of hematoma following PVI were significantly higher in patients taking VKA compared to FXaI (3.5% vs. 1.9%, P < 0.001). Multivariable logistic regression analysis showed that VKA were associated with increased perioperative hematoma than FXaI (odds ratio = 1.89 [1.30-2.82]). Compared to patients taking VKA, those receiving FXaI had lower rates of major amputation (6.7% vs. 8.4%, P = 0.020) and mortality (7.6% vs. 15.2%, P ≤ 0.001). Using Kaplan-Meier analysis, patients consistently anticoagulated with FXaI had improved amputation-free survival after PVI. Adjusting for significant patient and procedural characteristics, Cox proportional hazard regression demonstrated that there is an increased risk for major amputation or mortality in patients using VKA compared to FXaI (hazard ratio 1.61, [1.36-1.90]). CONCLUSIONS: Chronic anticoagulation with FXaI as compared to VKA was associated with superior perioperative and long-term outcomes in patients with PAD undergoing PVI. FXaI should be the preferred agents over VKA for chronic anticoagulation in patients with PAD undergoing PVI.

The Degree of Inferior Vena Cava Filter Tilt Associated with Challenging Retrieval.

OBJECTIVE: Inferior vena cava (IVC) filter tilt is associated with technical difficulties at the time of retrieval. However, the degree of tilt that predisposes patients to undergo complex or failed retrieval has not been defined. METHODS: The electronic charts of patients undergoing IVC filter removal between 2010 and 2019 at a single tertiary center were reviewed. Patient and procedural characteristics were recorded. Venograms of placement and retrieval procedures were reviewed, and IVC filter tilt was determined based on its deviation from the IVC axis. IVC diameter and the distance from the lowest renal vein were measured using corresponding filter's length for calibration. All measurements were performed by 3 reviewers and confirmed by 2 reviewers. Patients were divided into 2 groups: those who underwent successful removal procedures requiring standard retrieval methods ("simple retrieval group") and those who required advanced endovascular techniques or had failed completely IVC filter retrievals ("challenging retrieval group"). A regression analysis was performed to determine factors associated with challenging retrieval. RESULTS: There were 365 patients who underwent IVC filter retrieval (n=294 (80.6%) and n=71 (19.4%) in the simple and challenging groups, respectively) with no difference in age, sex, comorbidities or indication between the 2 groups. Failed retrieval occurred in 21 patients (5.8%) and was more common among patients requiring advanced endovascular techniques compared to standard techniques (18.0% vs. 3.2%, p < 0.001). In the overall cohort, the mean filter tilt at the time of retrieval was 4.9° ± 4.4° [0 - 27°], and 145 patients (39.7%) had a filter tilt ≥ 5.0°. Compared to the simple retrieval group, patients in the challenging group had significantly longer dwell time, greater tilt of IVC filter during placement and retrieval, as well as higher tilt change between the 2 venograms. There was no correlation between the access site during placement and challenging retrieval. However, patients undergoing filter placement via right jugular vein had lower filter tilt as compared to femoral access. Patients with filter tilt ≥ 5.0° were more likely to have a challenging filter retrieval compared to patients with ˂ 5.0° tilt (29.7% vs 12.7%, p<0.001). Regression analysis showed that tilt ≥ 5.0° (OR=1.18 [1.11-1.25]), dwell time (OR=1.04 [1.01-1.07]), and age (OR=0.97 [0.95-0.99]) were independently associated with challenging retrieval. CONCLUSION: IVC filter tilt ≥ 5.0°, dwell time and age are associated with challenging retrieval. Right jugular vein access, multiple imaging projections, and careful filter manipulation during deployment should be considered to maintain tilt at ˂ 5.0° and decrease the likelihood of challenging retrieval.

The Utilization of Protamine during Peripheral Vascular Interventions in the VQI.

BACKGROUND: Protamine administration was shown to reduce bleeding after carotid surgery but the role of protamine during peripheral vascular interventions (PVIs) remains unknown. This study evaluates the trend and outcomes of protamine use in the Vascular Quality Initiative (VQI). Our hypothesis is that the use of protamine is associated with decreased bleeding after PVI. METHODS: Patients undergoing elective PVI in the VQI (2016-2020) for peripheral arterial disease were reviewed and the utilization trend for protamine was described. The characteristics of patients undergoing PVI with and without protamine use were compared. After propensity score matching based on the patient's comorbidities, access site, and procedural characteristics, the perioperative outcomes of both groups were compared using multivariable Poisson regression to estimate adjusted rate ratios (aRRs) and 95% confidence intervals (95% CIs). RESULTS: The total number of patients was 131,618 and patients who received protamine constituted 29.8% of the sample (N = 38,191). After propensity matching, the total number of patients was 94,582, and patients who received protamine constituted 28.8% of the sample (N = 27,275). Protamine use significantly increased during the study period from 5.2 to 22.9%. Before propensity score matching, patients who received protamine were more likely to be white (79% vs. 76.8, P ≤ 0.001), smokers (80.5% vs. 78.5%, P ≤ 0.001), with medical comorbidities including hypertension (88.9% vs. 88.5%, P = 0.074), congestive heart failure (20.5% vs. 19.8%, P = 0.006), and chronic obstructive pulmonary disease (28.2% vs. 26.5%). They were also more likely to be on perioperative medications such as P2Y12 inhibitors (44.3% vs. 45, P = 0.013%) and statin (77.4% vs. 76.5%, P = 0.001) compared to patients who did not receive protamine. After propensity matching, there were no significant differences between the 2 groups. There was a significant decrease in bleeding during procedures where protamine was administered compared to no protamine (2.0% vs. 2.2%) (aRR, 0.89 [95% CI 0.80, 0.98]). Protamine was more likely to be given in procedures complicated by perforation (0.8% vs. 0.5%) (aRR, 1.48 [95% CI 1.24, 1.76]) and less likely to be given during procedures with distal embolization (0.4% vs. 0.7%) (aRR, 0.59 [95% CI 0.49, 0.73]). However, patients receiving protamine had significantly higher cardiac complications (1.4% vs. 1.1%) (aRR, 1.27 [95% CI 1.12, 1.43]). There was no significant difference in mortality between the 2 groups. CONCLUSIONS: Protamine use is associated with decreased perioperative bleeding but increased cardiac complications. Protamine should be selectively administered to patients at high risk of bleeding during PVI.

Insulin Requirement and Infrainguinal Bypass Outcomes in Patients with Peripheral Arterial Disease.

BACKGROUND: Diabetes mellitus (DM) is a major risk factor for peripheral artery disease. The association of DM with major adverse limb events (MALE) after lower extremity revascularization remains controversial, as patients with diabetes are typically analyzed as a single, homogenous group. Using a large national database, this study examines the impact of insulin use and glycemic control on the outcomes following infrainguinal bypass. The hypothesis is that prevalent insulin therapy and elevated hemoglobin A1c (HbA1c) are associated with an increased risk of MALEs after infrainguinal bypass in patients with DM and could therefore be used for risk stratification. METHODS: The Vascular Quality Initiative database files for infrainguinal bypass (2007-2021) were retrospectively reviewed. Patients with DM undergoing bypass for peripheral artery disease were included. Patients on dialysis or with prior kidney transplantation were excluded. The characteristics and outcomes of patients with insulin-requiring diabetes mellitus (IRDM) were compared to those of patients not requiring insulin (noninsulin-requiring diabetes mellitus [NIRDM]) prior to the bypass procedure. RESULTS: A total of 9,686 patients with DM (56% IRDM) underwent bypass. Patients with IRDM were significantly younger than patients with NIRDM, more likely to be female (P < 0.01), African American (P < 0.01), and Hispanic (P = 0.031), and more likely to have comorbidities and be categorized into American Society of Anesthesiologist classes IV-V. They were more likely to be treated for chronic limb-threatening ischemia (P < 0.001). Patients with IRDM had significantly higher perioperative complications with no difference in perioperative mortality between the 2 groups. Beyond the perioperative period, with a mean follow-up of 427 days, patients with IRDM had significantly lower crude rates of primary patency and higher crude rates of major amputation, MALE, and mortality compared to patients with NIRDM. Regression analyses demonstrated that insulin requirement, but not HbA1c, was independently associated with a higher risk of MALE (hazard ratio = 1.17 [1.06-1.29]) and mortality (hazard ratio = 1.28 [1.16-1.43]). CONCLUSIONS: Insulin requirement, but not HbA1c, is significantly associated with MALEs and survival after infrainguinal bypass in the Vascular Quality Initiative. Stratification of patients with DM based on their prevalent insulin use prior to infrainguinal bypass surgery could improve the prediction of outcomes of peripheral arterial bypass surgery in patients with diabetes.

The Use and Impact of Cilostazol on Patients Undergoing Endovascular Peripheral Interventions.

BACKGROUND: 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). METHODS: The Vascular Quality Initiative (VQI) database files for PVI were reviewed. Patients with PAD who underwent PVI for chronic limb threatening-ischemia or claudication 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 2 groups (preoperative cilostazol use versus no preoperative cilostazol use) were compared. The Kaplan-Meier method was used to determine outcomes. RESULTS: A total of 245,309 patients underwent PVI procedures and 6.6% (N = 16,366) were on cilostazol prior to intervention. Patients that received cilostazol were more likely to be male (62% vs 60%; P < 0.001), White (77% vs. 75%; P < 0.001), and smokers (83% vs. 77%; P < 0.001). They were less likely to have diabetes mellitus (50% vs. 56%; P < 0.001) and congestive heart failure (14% vs. 23%; P < 0.001). Patient on cilostazol were more likely to be treated for claudication (63% vs. 40%, P < 0.001), undergo prior lower extremity revascularization (55% vs. 51%, P < 0.001) and less likely to have undergone prior minor and major amputation (10% vs. 19%; P < 0.001) compared with patients who did not receive cilostazol. After 3:1 propensity matching, there were 50,265 patients included in the analysis with no differences in baseline characteristics. Patients on cilostazol were less likely to develop renal complications and more likely to be discharged home. Patients on cilostazol had significantly lower rates of long-term mortality (11.5% vs. 13.4%, P < 0.001 and major amputation (4.0% vs. 4.7%, P = 0.022). However, there were no significant differences in rates of reintervention, major adverse limb events, or patency after PVI. Amputation-free survival rates were significantly higher for patients on cilostazol, after 4 years of follow up (89% vs. 87%, P = 0.03). CONCLUSIONS: 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.

Anticoagulation in Patients with Premature Peripheral Artery Disease Undergoing Lower Extremity Revascularization.

BACKGROUND: Premature peripheral artery disease (PAD), defined by lower extremity revascularization (LER) at age ≤ 50 years, is associated with poor major adverse limb events. The early onset of disease is thought to be influenced by genetic factors that regulate homeostasis of the vascular wall and coagulation. The aim of this study is to investigate the effect of anticoagulation as an adjunct to antiplatelet therapy on the outcomes of LER in patients with premature PAD. METHODS: There were 8,804 patients with premature PAD on preoperative and postoperative antiplatelet therapy only and 1,236 patients on preoperative and postoperative anticoagulation plus antiplatelet therapy in the Vascular Quality Initiative peripheral vascular intervention, infrainguinal, and suprainguinal files. Propensity score matching (2:1) was performed between patients with premature PAD who were on antiplatelet therapy and those on anticoagulation plus antiplatelet therapy. Perioperative and 1-year outcomes were analyzed including reintervention, major amputation, and mortality. RESULTS: Patients on anticoagulation were more likely to have coronary artery disease (48.7% vs. 41.2%, P < 0.001), congestive heart failure (20.2% vs. 13.1%, P < 0.001), and have undergone prior LER (73.9% vs. 49.2%, P < 0.001) compared to patients on antiplatelet therapy only. They were also less likely to be independently ambulatory (74.2% vs. 81.8%, P < 0.001) and be on a statin medication (66.8% vs. 74.3%, P < 0.001) compared to patients on antiplatelet therapy only. Patients on anticoagulation were also less likely to be treated for claudication (38.1% vs. 48.6%, P < 0.001), and less likely to be treated with an endovascular procedure (64.8% vs. 73.8%, P < 0.001). After matching for baseline characteristics, there were 1,256 patients on antiplatelet therapy only and 628 patients on anticoagulation. Patients on anticoagulation were more likely to require a return to the operating room (3.7% vs. 1.6%, P < 0.001) and had higher perioperative mortality (1.1% vs. 0.3%, P = 0.032), but major amputation was not significantly different (1.8% vs. 1.6%, P = 0.798) compared to patients on antiplatelet therapy alone. At 1 year, amputation-free survival was higher in patients on antiplatelets only compared to patients on anticoagulation and antiplatelet medications (87.5% vs. 80.9%, log-rank P = 0.001). CONCLUSIONS: Anticoagulation in addition to antiplatelet therapy in patients with premature PAD undergoing LER is associated with increased reintervention and mortality at 1 year.

Carbon dioxide angiography during peripheral vascular interventions is associated with decreased cardiac and renal complications in patients with chronic kidney disease.

OBJECTIVE: Patients with chronic kidney disease (CKD) who undergo peripheral vascular interventions (PVI) with iodinated contrast are at higher risk of post-contrast acute kidney injury (PC-AKI). Carbon dioxide (CO2) angiography can reduce iodinated contrast volume usage in this patient population, but its impact on PC-AKI has not been studied. We hypothesize that CO2 angiography is associated with a decrease in PC-AKI in patients with advanced CKD. METHODS: The Vascular Quality Initiative PVI dataset from 2010 to 2021 was reviewed. Only patients with advanced CKD (estimated glomular filtration rate <45 ml/min/1.73 m2) treated for peripheral arterial disease were included. Propensity matching and multivariate logistic regression based on demographics, comorbidities, CKD stage, and indications were used to compare the outcomes of patients treated with and without CO2. RESULTS: There were 20,706 PVIs performed in patients with advanced CKD, and only 22% utilized CO2 angiography. Compared with patients treated without CO2, patients who underwent CO2 angiography were younger and less likely to be women or White, and more likely to have poor renal function, diabetes, cardiac comorbidities, and present with tissue loss. Propensity matching yielded well-matched groups with 4472 patients in each group. The procedural details after matching demonstrated 50% reduction in the volume of contrast used (32±33 vs 65±48 mL; P < .01). PVI with CO2 angiography was associated with lower rates of PC-AKI (3.9% vs 4.8%; P = .03) and cardiac complications (2.1% vs 2.9%; P = .03) without a significant difference in technical failure or major/minor amputations. Low contrast volumes (≤50 mL for CKD3, ≤20 mL for CKD4, and ≤9 mL for CKD5) are associated with reduced risk of PC-AKI (hazard ratio, 0.59; P < .01). CONCLUSIONS: CO2 angiography reduces iodinated contrast volume usage during PVI and is associated with decreased cardiac complications and PC-AKI. CO2 angiography is underutilized and should be considered for patients with advanced CKD who require endovascular therapy.

Virtual vascular surgery interest group during the coronavirus disease 2019 pandemic.

OBJECTIVES: Early exposure to vascular surgery at the medical student level positively influences one's decision to apply into an integrated vascular surgery residency program. Vascular surgery interest groups (VSIGs) are student-run and aim to facilitate such exposure, traditionally via in-person events. Social distancing during the coronavirus disease 2019 pandemic disrupted these interactions. This is a description of the virtual activities of a VSIG group during the 2020-2021 academic year and highlights their impact among medical students. METHODS: The virtual activities of the VSIG at the Yale School of Medicine were reviewed. Students received surveys prior and after activities to assess their impact. Preactivity and postactivity surveys using Likert scale (1 = completely disagree; 5 = completely agree) were administered and compared. Statistical significance was achieved with a P value of less than .05. RESULTS: A total of five virtual events were held: an Introductory Session (October 2020), a Simulation Session (November 2020), a Research Night (January 2021), a Journal Club (February 2021), and a National Match Panel (April 2021). The surveys of three events (Introductory Session, Simulation Session, and National Match Panel) were analyzed. Attendance at these events were 18, 55, and 103 respectively. The average presurvey response rate was 51.2% and the average postsurvey response rate was 27.46%. Students agreed that the Introductory Session increased their knowledge about vascular surgery as a subspecialty (4.22 ± 0.67) and that the session was valuable to their time (4.33 ± 1.00). The Simulation Session increased student's comfort with knot tying from 1.73 ± 0.89 to 3.21 ± 1.25 (P < .001). Students reported an increased understanding of residency program selection (2.39 ± 1.10 vs 3.21 ± 1.12; P = .018), the Electronic Residency Application Service application (2.16 ± 1.01 vs 3.00 ± 0.88; P = .007), and letters of recommendation (2.45 ± 1.07 vs 3.14 ± 1.17; P = .04). Students particularly had a significant increase in the understanding of the logistics of residency interviews, which were held virtually that year for the first time (1.84 ± 0.96 vs 3.29 ± 1.20; P < .001). CONCLUSIONS: Virtual VSIG activities were feasible and effective during the pandemic in promoting student engagement and interest in vascular surgery. Despite lifting social distancing measures, the virtual format could become a valuable tool to expand outreach efforts of the vascular surgery community to recruit talented medical students.

The management of patients with popliteal artery aneurysms presenting with acute limb ischemia.

OBJECTIVE: Endovascular popliteal artery aneurysm (PAA) repair has acceptable outcomes compared with open repair for elective therapy. Endovascular repair for urgent PAA causing acute limb ischemia (ALI) has not been well-studied. This project compares outcomes of urgent endovascular and open repair of PAA with ALI. METHODS: The Vascular Quality Initiative database for peripheral vascular interventions (PVIs) and infrainguinal bypass were reviewed for PAAs with ALI from 2010 to 2021. Only patients entered as having symptoms of ALI in the PVI module and ALI as indication in the infrainguinal bypass module were included. In addition, patients undergoing elective treatment were excluded and the sample analyzed was restricted to patients undergoing urgent and emergent open and endovascular repair. Patient demographics and comorbidities as well as procedural details were compared between the two groups. Perioperative complications up to 30 days were compared as well as long-term outcomes including major amputation and mortality at 1 year. RESULTS: Urgent PAA repair for ALI constituted 10.5% (n = 571) of all PAAs. Most urgent repairs were open (80.6%; n = 460) with 19.4% (n = 111) endovascular. The proportion of endovascular repair significantly increased from 16.7% in 2010 to 85.7% in 2021. Patients undergoing endovascular repair were older (71.2 ± 12.5 vs 68.0 ± 11.8; P = .011) than patients undergoing open repair. They were also more likely to have coronary artery disease (32.4% vs 21.7%; P = .006). Open PAA repair was associated with more bleeding complications (20.8% vs 2.7%; P < .001), longer postoperative length of stay (8.1 ± 9.3 days vs 4.9 ± 5.6 days; P < .001), and less likelihood of discharge to home (64.9% vs 70.3%; P = .051). Perioperative major amputation rate was 7.5% with no difference between the two treatment strategies up to 1 year. However, patients receiving endovascular repair had higher inpatient (1.1% vs 0%; P < .001), 30-day (6.3% vs 0.4%; P < .001), and 1-year (16.5% vs 8.4%; P = .02) mortality. Multivariable regression analysis suggested that endovascular repair was possibly associated with increased 30-day mortality, but not 1-year mortality. CONCLUSIONS: Endovascular PAA has exponentially increased from 2010 to 2021. Endovascular repair is associated with decreased complications and hospital length of stay. The increased perioperative mortality seen in this group is likely due to selection bias.

Characteristics and 1-year outcomes of patients with rupture of small abdominal aortic aneurysms.

OBJECTIVES: Ruptured abdominal aortic aneurysms (rAAA) are associated typically with a large sac diameter; however, some patients experience rupture before reaching operative thresholds for elective repair. We aim to investigate the characteristics and outcomes of patients who experience small rAAA. METHODS: The Vascular Quality Initiative database for open AAA repair and endovascular aneurysm repair from 2003 to 2020 were reviewed for all rAAA cases. Based on the 2018 Society for Vascular Surgery guidelines on operative size thresholds for elective repair, patients with infrarenal aneurysms of less than 5.0 cm in women or less than 5.5 cm in men were categorized as a small rAAA. Patients who met operative thresholds or had a concomitant iliac diameter 3.5 cm or greater were categorized as a large rAAA. Patient characteristics and perioperative as well as long-term outcomes were compared via univariate regression. Inverse probability of treatment weighting using propensity scores was used to examine the relationship between rAAA size and adverse outcomes. RESULTS: There were 3962 cases that met inclusion criteria, with 12.2% small rAAA. The mean aneurysm diameter was 42.3 mm and 78.5 mm in the small and large rAAA groups, respectively. Patients in the small rAAA group were significantly more likely to be younger, African American, have a lower body mass index, and had significantly higher rates of hypertension. Small rAAA were more likely to be repaired via endovascular aneurysm repair (P = .001). Hypotension was significantly less likely in patients with small rAAA (P<.001). Rates of perioperative myocardial infarction (P < .001), total morbidity (P < .004) and mortality (P < .001) were significantly higher for large rAAA cases. After propensity matching, there was no significant difference in mortality between the two groups, but smaller rAAA was associated with lower rates of myocardial infarction (odds ratio, 0.50; 95% confidence interval, 0.31-0.82). On long-term follow-up, no difference in mortality was noted between the two groups. CONCLUSIONS: Patients presenting with small rAAA represent 12.2% of all rAAA and are more likely to be African American. Small rAAA is associated with similar risk of perioperative and long-term mortality compared with rupture at larger size after risk adjustment.

High-Risk Characteristics for Clinical Failure after Isolated Femoropopliteal Peripheral Vascular Interventions.

BACKGROUND: Recent studies suggesting increased late mortality with paclitaxel-coated devices (PCDs) in femoropopliteal peripheral vascular interventions (PVIs) prompted the US Food and Drug Administration to recommend limiting the use of PCDs to "patients at particularly high risk for restenosis". This study's aim is to characterize patients at high risk for restenosis and develop a risk score to guide clinicians in selecting patients for treatment with PCDs. METHODS: Patients who underwent isolated femoropopliteal PVI for claudication or rest pain from 2016-2019 in the Vascular Quality Initiative were included. Patients who received intervention with a PCD, hybrid procedures, died within 1 year, or had missing follow-up data were excluded. The primary end point was clinical failure at 1 year defined as > 50% restenosis, loss of patency, reintervention, or major amputation. Data were split randomly into 2/3 for development and 1/3 for validation. A parsimonious multivariable hierarchical logistic regression for clinical failure was developed and a risk score was created using beta-coefficients. The risk score was applied to the validation dataset and tested for goodness-of-fit and discrimination. RESULTS: Among 4,856 treated patients, 718 (14.8%) experienced clinical failure within 1 year. Clinical failure was associated with age ≤ 50 years, female sex (48.1% vs. 39.5%), insulin-dependent diabetes (29.9% vs. 23.1%), creatinine > 2.0 mg/dL (9.9% vs. 5.7%), prior ipsilateral lower extremity revascularization (48.5% vs. 38.5%), prior ipsilateral minor amputation (5.3% vs. 1.7%), rest pain versus claudication (30.8% vs. 18.7%), occlusion length ≥ 20 cm (18.8% vs. 15.0%), and Trans-Atlantic Inter-Society Consensus II Classification C or D (40.4% vs. 28.0%), all P ≤ 0.01. Risk score development was performed using a multivariable regression. The model demonstrated good fit and discrimination (C-statistic 0.71 in development and 0.72 in validation dataset). Predicted clinical failure was 8.9% for standard-risk (45.9% of interventions), 15.5% for high-risk (44.2% of interventions), and 33.8% for very high-risk patients (9.8% of interventions). CONCLUSIONS: A novel risk score was created with good discrimination for identifying patients at high risk for clinical failure at 1 year after femoropopliteal PVI for claudication and rest pain. Patients at high risk and very high risk for clinical failure may benefit from alternative strategies including PCDs.

Variability in Antithrombotic Therapy after Infrainguinal Lower Extremity Bypass.

BACKGROUND: Antiplatelet monotherapy is recommended after infrainguinal lower extremity bypass (LEB). However, there is a paucity of high-quality data to guide therapy, and antiplatelet therapy is often prescribed in combination with anticoagulation. We therefore aimed to assess the variability in the use of antithrombotic therapy after infrainguinal LEB. METHODS: The Vascular Quality Initiative dataset (2015-2021) was retrospectively reviewed to determine discharge patterns of antithrombotic therapy for all patients undergoing infrainguinal LEB. Monotherapy on discharge was defined as either single antiplatelet therapy (SAPT) or single anticoagulant (SAC). Combination therapy was dual antiplatelet therapy (DAPT), anticoagulant + antiplatelet (ACAP), or triple therapy. Hierarchical multivariable logistic regression with random effects for physician and center was used to identify predictors of combination therapy. Median odds ratios (MOR) were derived to quantify degree of variability in antithrombotic therapy. RESULTS: There were 29,507 patients undergoing infrainguinal LEB (monotherapy = 10,634 vs. combination therapy = 18,873). SAPT (90.6%) was the most common form of monotherapy, while DAPT (57.7%) and ACAP (34.6%) were the most common combination therapies. Patients undergoing LEB to popliteal targets were more likely to be prescribed monotherapy (SAC or SAPT) than to infra-popliteal targets (60.6% vs. 56.6%, P < 0.001). Combination therapy (DAPT, ACAP, or triple therapy) was more often used in patients with tibial or plantar arteries as the bypass target. Patients undergoing bypass using autogenous vein were more likely to receive monotherapy compared with those receiving other conduits (64.8% vs. 52.9%, P < 0.001), while patients with prosthetic grafts were more likely to receive combination therapy (37.9% vs. 28.2%, P < 0.001). There were no significant differences in postoperative bleeding (P = 0.491) or 30-day mortality (P = 0.302) between the two groups. Prior peripheral vascular interventions (PVI) (odds ratio [OR]: 1.89, 95% confidence interval [CI]: 1.79-1.99), concomitant PVI (OR: 1.83, 95% CI: 1.66-2.02), prosthetic graft use (OR: 1.74, 95% CI: 1.64-1.85), prior percutaneous coronary intervention (OR: 1.53, 95% CI: 1.43-1.65), plantar distal target (OR: 1.46, 95% CI: 1.29-1.65), alternative conduits (OR: 1.39, 95% CI: 1.25-1.53), and tibial distal targets (OR: 1.36, 95% CI: 1.28-1.44) were independent predictors of combination therapy in a multivariable regression model. Upon adjusting for patient-level factors, there was significant physician-level (MOR: 1.65, 95% CI 1.61-1.67) and center-level (MOR: 1.64, 95% CI 1.57-1.69) variability in the selection of antithrombotic therapy. CONCLUSIONS: Significant physician- and center-level variability in the use of antithrombotic regimens after infrainguinal bypass reflects the paucity of available evidence to guide therapy. Pragmatic trials are needed to assess antithrombotic strategies and guide recommendations aimed at optimizing cardiovascular and graft-specific outcomes after LEB.

Incidence and Significance of Deep Venous Reflux in Patients Treated with Saphenous Vein Ablation.

BACKGROUND: Venous ablation (VA) of the saphenous vein is the most common procedure performed for venous insufficiency. The incidence of concomitant deep venous reflux (DVR) in patients undergoing VA is unknown. Our hypothesis is that patients undergoing saphenous VA with concomitant DVR exhibit a higher clinical, etiology, anatomy, and pathophysiology (CEAP) stage and less relief after VA compared to patients without DVR. METHODS: Electronic medical records of patients treated with saphenous VA at a tertiary care center from March 2012 to June 2016 were reviewed. Patients were divided into 2 groups based on presence or absence of DVR on initial ultrasound (US) before saphenous VA. Patient characteristics and outcomes were compared. A telephone survey was conducted to assess long-term symptomatic relief, compliance with compression, and pain medication use. Subgroup analysis of patients with post-thrombotic versus primary DVR was performed. RESULTS: 362 patients underwent 497 ablations, and the incidence of DVR (>1 sec) was 20% (N = 71). Patients with DVR were significantly more likely to be male (46.4% vs. 32.1%, P = 0.021) and of Black race (21.2% vs. 5.5%, P = 0.0001) compared to patients without DVR. Patients with DVR were more likely to have a history of deep vein thrombosis (DVT) (15.1% vs. 7.9%, P = 0.045), but there was no difference in other comorbidities. There was no significant difference in presenting symptoms, CEAP stage, or symptom severity based on numeric rating scale (NRS) (0-10) for pain and swelling. Clinical success of saphenous VA was comparable between the 2 groups, but patients with DVR were more likely to develop endovenous heat-induced thrombosis (EHIT) II-IV (6% vs. 1%, P = 0.002). After a mean follow-up of 26 months, there was still no difference in pain or swelling scores, but patients with DVR were more likely to use compression stockings and used them more frequently. Only 11 of 71 patients with DVR had a history of DVT. Patients with post-thrombotic DVR were significantly older than patients with primary DVR (67.3 vs. 57.2, P = 0.038) and exhibited a trend toward more advanced venous disease (C4-C6: 45.4% vs. 33.3%, P = 0.439). CONCLUSIONS: In this study, 20% of patients undergoing saphenous VA demonstrated DVR, which was more common in Black men. Presence of DVR is associated with increased risk of EHIT after saphenous VA but does not seem to impact disease severity or clinical relief after ablation. Larger studies are needed to understand outcome differences between post-thrombotic and primary DVR.

Utility of Hook Sign in the Diagnosis of Median Arcuate Ligament Syndrome.

BACKGROUND: Median arcuate ligament syndrome (MALS) is a clinical syndrome caused by compression of the celiac artery by the median arcuate ligament that often manifests with nonspecific abdominal pain. Identification of this syndrome is often dependent on imaging of compression and upward bending of the celiac artery by lateral computed tomography angiography, the so-called "hook sign." The purpose of this study was to assess the relationship of radiologic characteristics of the celiac artery to clinically relevant MALS. METHODS: An institutional review board-approved retrospective chart review from 2,000 to 2,021 of 293 patients at a tertiary academic center diagnosed with celiac artery compression (CAC) was performed. Patient demographics and symptoms of 69 patients who were diagnosed with symptomatic MALS were compared to 224 patients without MALS (but with CAC) per electronic medical record review. Computed tomography angiography images were reviewed and the fold angle (FA) was measured. The presence of a hook sign (defined as a visual FA < 135°), as well as stenosis (defined as >50% of luminal narrowing on imaging) were recorded. Wilcoxon rank-sum test and Chi-squared test were used for comparative analysis. Logistic model was run to relate the presence of MALS with comorbidities and radiographic findings. RESULTS: Imaging was available in 59 patients (25 males, 34 females) and 157 patients (60 males, 97 females) with and without MALS, respectively. Patients with MALS were more likely to have a more severe FA (120.7 ± 33.6 vs. 134.8 ± 27.9, P = 0.002). Males with MALS were also more likely to have a more severe FA compared with males without MALS (111.1 ± 33.7 vs. 130.4 ± 30.4, P = 0.015). In patients with body mass index (BMI) >25, MALS patients also had narrower FA compared with patients without MALS (112.6 ± 30.5 vs. 131.7 ± 30.3, P = 0.001). The FA was negatively correlated with BMI in patients with CAC. The hook sign and stenosis were associated with diagnosis of MALS (59.3% vs. 28.7%, P < 0.001, and 75.7% vs. 45.2%, P < 0.001, respectively). In logistic regression, pain, stenosis, and a narrow FA were statistically significant predictors of the presence of MALS. CONCLUSIONS: The upward deflection of the celiac artery in patients with MALS is more severe compared with patients without MALS. Consistent with prior literature, this bending of the celiac artery is negatively correlated with BMI in patients with and without MALS. When demographic variables and comorbidities are considered, a narrow FA is a statistically significant predictor of MALS. Regardless of MALS diagnosis, a hook sign was associated with narrower FA. While demographics and imaging findings may inform MALS diagnosis, clinicians should not rely on a visual assessment of a hook sign but should quantitatively measure the anatomic bending angle of the celiac artery to assist with the diagnosis and understand the outcomes.

Sex differences in long-term outcomes of patients with deep vein thrombosis.

OBJECTIVE: Sex differences in short-term outcomes of patients with deep vein thrombosis (DVT) have been reported, but differences in long-term outcomes remain poorly characterized. This study aimed to evaluate sex differences in long-term mortality, venous thromboembolism (VTE)-related mortality, and bleeding-related mortality in patients with DVT at a tertiary care center. METHODS: A retrospective chart review from 2012 to 2018 of all consecutive patients diagnosed with DVT was performed. Patients were grouped by sex, and baseline characteristics and treatment modalities were compared. Long-term outcomes of recurrent VTE, bleeding, and related mortalities were analyzed. Multivariable regression analysis was performed to determine factors associated with overall mortality. RESULTS: A total of 1043 (female = 521 and male = 522) patients with DVT were captured in this study period. Female patients were older (64.7 vs 61.6 years old, p = 0.01) and less likely to be obese (68.2% vs. 71.1%, p = 0.04),but had a higher average Caprini score (6.73 vs 6.35, p = 0.04). There was no difference in anatomic extent of DVT, association with PE, and severity of PE between sexes. Most patients (80.5%) were treated with anticoagulation, with no differences in choice of anticoagulant or duration of anticoagulation between females and males. Male patients were more likely to undergo catheter-directed thrombolysis (CDT) for DVT (4.2% vs 1.7%, p = 0.02) and PE (2.7% vs 0.9%, p = 0.04). Female patients were more likely to receive systemic thrombolysis for PE (2.9% vs 1.1%, p = 0.05). After an average 2.3 years follow-up, there was significantly higher bleeding complications among females (22.2% vs 16.7%, p = 0.027). The overall mortality rate was 33.5% and not different between males and females. Females were more likely to experience VTE-related mortality compared to males (3.3% vs 0.6%, p = 0.002). On regression analysis, older age (OR = 1.04 [1.03-1.06]), cancer (OR = 7.64 [5.45-10.7]), and congestive heart failure (OR = 3.84 [2.15-6.86]) were independently associated with overall mortality. CONCLUSIONS: In this study, there was no difference in overall long-term mortality between sexes for patients presenting with DVT. However, females had increased risk of long-term bleeding and VTE-related mortality compared to males.