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

BACKGROUND: 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° [0c27°], 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° (odds ratio [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. CONCLUSIONS: 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.

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.

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.

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.

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.

Sex differences in arterial identity correlate with neointimal hyperplasia after balloon injury.

BACKGROUND: Endovascular treatment of atherosclerotic arterial disease exhibits sex differences in clinical outcomes including restenosis. However, sex-specific differences in arterial identity during arterial remodeling have not been described. We hypothesized that sex differences in expression of the arterial determinant erythropoietin-producing hepatocellular receptor interacting protein (Ephrin)-B2 occur during neointimal proliferation and arterial remodeling. METHODS AND RESULTS: Carotid balloon injury was performed in female and male Sprague-Dawley rats without or 14 days after gonadectomy; the left common carotid artery was injured and the right carotid artery in the same animal was used as an uninjured control. Arterial hemodynamics were evaluated in vivo using ultrasonography pre-procedure and post-procedure at 7 and 14 days and wall composition examined using histology, immunofluorescence and Western blot at 14 days after balloon injury. There were no significant baseline sex differences. 14 days after balloon injury, there was decreased neointimal thickness in female rats with decreased smooth muscle cell proliferation and decreased type I and III collagen deposition, as well as decreased TNFα- or iNOS-positive CD68+ cells and increased CD206- or TGM2-positive CD68+ cells. Female rats also showed less immunoreactivity of VEGF-A, NRP1, phosphorylated EphrinB2, and increased Notch1, as well as decreased phosphorylated Akt1, p38 and ERK1/2. These differences were not present in rats pretreated with gonadectomy. CONCLUSIONS: Decreased neointimal thickness in female rats after carotid balloon injury is associated with altered arterial identity that is dependent on intact sex hormones. Alteration of arterial identity may be a mechanism of sex differences in neointimal proliferation after arterial injury.

Elucidating the Role of the AFX2 Endograft in Endovascular Treatment of Aortic Pathology.

BACKGROUND: The purpose of this study is to elucidate the role of the AFX2 platform in the endovascular treatment of aortic pathology. METHODS: All procedures by a single surgeon resulting in implantation of a bifurcated unibody stent graft were reviewed retrospectively. Indications for selection of the AFX2 endograft in each case were evaluated. Aortic anatomy was determined via review of pre-operative computed tomography (CT) scans. Cumulative event probabilities for endoleak, reintervention, and mortality were estimated. Patient and procedural details were described using mean, standard deviation, medians, and interquartile range (IQR). Kaplan-Meier survival analysis estimated freedom from mortality and reintervention. Cumulative incidence probabilities were calculated as one minus the Kaplan-Meier estimator. RESULTS: Between March 2018 and December 2020, the author (NN) used 142 aortic endografts in 142 patients. Of these, 46 (32.4%) were AFX2 endografts and the remaining were modular bifurcated devices, predominantly Medtronic Endurant II and Terumo Treo. No AFX-Strata or AFX-Duraply devices were placed. Amongst the patients who received an AFX2, mean age was 71.3 +/- 9.8 years with 84.8% male. Median operative time was 116 (86-166) min, with contrast dose of 79 (41-120) milliliters and fluoroscopy time of 12 (8.6-18) min. Overall, 78.3% (n = 36) of AFX2 devices were placed in aortas with maximum true lumen diameter <5.0 cm. Median postoperative follow-up was 1.7 years (IQR 1.0-2.4 years), with a maximum follow-up of 3.6 years. There was 1 patient lost to follow-up at 5 months. The 2-year incidence of type II endoleak, reintervention, and all-cause mortality was 12.7% (95% confidence interval CI, 0-29.6%), 2.2% (95% CI, 0-6.3%), and 11.3% (95% CI, 0.1-2.1.2%), respectively. There were no type I or III endoleaks. CONCLUSIONS: The AFX2 endograft plays a safe and effective role in treatment of infrarenal aortic pathologies that may be otherwise more technically challenging for traditional modular, bifurcated devices.

The State of Vascular Surgery Interest Groups in North America.

BACKGROUND: Vascular surgery interest groups (VSIGs) raise awareness and attract medical students to the specialty. There has been a plateauing of applicants interested in integrated programs. The goal of this survey was to assess the activities of VSIGs and identify factors associated with matriculation into vascular surgery residency. METHODS: A survey was administered to members of the association of program directors in vascular surgery. It inquired about the presence of a VSIG at the corresponding medical schools. The program directors at institutions lacking VSIGs were asked about possible hurdles in establishing one. The rest of the survey focused on the different activities of the VSIG. The VSIGs were divided into low enrollment if less than 10% of the students in that group pursue vascular surgery training and high enrollment if greater than 10% of the students pursue vascular surgery. Chi-squared test was used for comparison. RESULTS: There were 65/123 programs that responded (53% response rate). The responses came most commonly from programs in the Northeast (36.9%). Only 37% (n = 24) had a VSIG at their institutions. Lack of time (65.2%) and lack of a student champion (60.9%) were the most common hurdles encountered by the program directors who considered establishing a VSIG. Comparing the 2 groups of VSIGs, there was no difference in terms of the training paradigm, experience of program director, or geographical location. The VSIGs had comparable duration of activity, number of students, and meeting frequency. There was no difference in clinical exposure outside the curriculum between the 2 groups with observation on the wards and in clinic being most common. Endovascular simulation was significantly (P = 0.01) more common in low enrollment (83.3%) compared with high enrollment (33.3%) VSIG. There was a trend in the high enrollment group for more vascular anastomosis training (75% vs. 66.7%) that did not reach statistical significance (P = 0.65). There was no difference between the 2 groups in career development opportunities and education activities. Most VSIGs (75%) operated with a budget of less than $1,000 based on divisional or departmental funding (low enrollment = 66.7% versus high enrollment = 41.7%, P = 0.22). CONCLUSIONS: Only one-third of the vascular surgery training programs have an associated VSIG. Vascular surgery training programs should promote VSIG formation with equal emphasis on endovascular and open surgery, thus providing medical students an early exposure to the specialty.

Discrepancy in Outcomes after Revascularization for Chronic Limb-Threatening Ischemia Warrants Separate Reporting of Rest Pain and Tissue Loss.

BACKGROUND: Chronic limb-threatening ischemia (CLTI) manifests as rest pain (RP) and tissue loss (TL). Outcomes of lower extremity revascularization (LER) for CLTI have traditionally been evaluated as a single entity and compared with claudication. We hypothesize that patients presenting with TL have worse short-term outcomes after LER, compared to patients with RP. METHODS: The National Inpatient Sample was reviewed between 2009 and 2013. All patients undergoing LER for TL and RP were identified. Patient characteristics, Charlson Comorbidity Index (CCI), length of stay, rates of inpatient major amputation, and mortality after LER were noted. Multivariable regression analysis was performed to identify predictors of inpatient mortality and major amputation between the 2 groups. RESULTS: A total of 218,628 patients underwent LER (RP = 76,108, TL = 142,519). Patients with TL were more likely to undergo endovascular LER (RP = 31.3% vs. TL = 48.7%; P < 0.001). Patients with TL had higher comorbidities as suggested by increased likelihood of having CCI ≥3 (RP = 22.9% vs. TL = 40.3%; P < 0.001). The mean costs were significantly higher in the TL group (RP = $23,795 vs. TL = $31,470; P < 0.001). There was a significantly higher rate of major amputation (RP = 1.3% vs. TL = 6.6%; P < 0.001) and inpatient mortality (RP = 0.9% vs. TL = 1.9%; P < 0.001) after LER for TL. On multivariable analysis, TL was independently associated with increased major amputation (odds ratio [OR] 4.93, 95% confidence interval [CI] 4.18-5.81) and increased mortality (OR 1.42, 95% CI 1.16-1.74) compared to RP. CONCLUSIONS: There is significant discrepancy in outcomes of LER for TL and RP. TL is independently associated with major amputation and inpatient mortality. Outcomes of LER for TL and RP should be reported separately for better benchmarking.

Alternative Endograft Aortoiliac Reconstruction for Iliac Branch Endoprostheses.

BACKGROUND: Endovascular treatment of complex common iliac artery (CIA) and internal iliac artery (IIA) aneurysms using iliac branch endoprostheses (IBE) has proven safe and effective. Instructions for use (IFU) require deployment of current IBE technology with the corresponding manufacturer's modular bifurcated aortic endograft. Concomitant aortoiliac occlusive disease, inadequate renal artery-iliac bifurcation length, and unfavorable aortic anatomy preclude on-label IBE deployment. This study aimed to evaluate the technical feasibility and safety of Alternative Endograft Aortoiliac Reconstruction (AEGAR) for branched endovascular treatment of complex iliac artery aneurysms. METHODS: In 7 consecutive patients with CIA or IIA aneurysms, computed tomography angiography (CTA) and center-line reconstruction revealed aortoiliac anatomy incompatible with the current IBE IFU due to inadequate proximal CIA landing zone (n = 7), inadequate renal artery to iliac bifurcation length (n = 2), compromised aortic anatomy (n = 3), or short infrarenal neck <15 mm (n = 1), either alone or in combination. To overcome these restrictions and facilitate IBE deployment, aortoiliac reconstruction was performed using the Endologix AFX, Endologix Ovation limbs or the Medtronic Endurant II platforms (AEGAR technique). All internal iliac artery reconstructions and external iliac artery extensions were performed using the Gore VBX or Viabahn stent grafts. Technical success was defined as successful delivery of all endograft components without migration or endoleak. RESULTS: The mean patient age was 69 years (range 52-82 years; 6 male). Four patients had bilateral CIA aneurysms and 3 patients had unilateral CIA aneurysms (mean diameter 4.3cm; range 2.2-7 cm). There were 13 IIA VBX stent grafts used for a total of 9 IIAs treated with IBE (bilateral IBE = 2 patients). The mean fluoroscopy time was 38.8 min (range 21.3-64.3 min) and the mean contrast volume was 168.5 mL (range 122-226 mL). Technical success was achieved in all patients and there were no perioperative complications. Mean hospital-stay was 2.2 days (range 1-3 days). Follow-up ranged from 82-957 days (mean = 487 days). At last follow-up, all patients were alive without cardiovascular morbidity; and CTA revealed stable or decreased aneurysm size, patent endografts, and no evidence of endoleak or migration. CONCLUSIONS: The AEGAR technique can be used to safely and effectively overcome certain aortoiliac anatomic constraints that preclude use of current IBE technology. We encourage broader use of these alternative endografts in pertinent anatomic configurations.

A national post-Match webinar panel improves knowledge and preparedness of medical students interested in vascular surgery training.

BACKGROUND: The current shortage of vascular surgeons is projected to worsen. Compared with other surgical residency programs, integrated vascular surgery residency (IVSR) offers fewer training positions and attracts fewer applicants. As a result, only a few medical students from each school match into the specialty, and conventional resources like Match panels are not available to students interested in vascular surgery. We hypothesize that a national post-Match panel webinar will improve medical students' knowledge of the IVSR application process. METHODS: A panel of four recently matched medical students shared their experiences on their successful Match into an IVSR through a 65-minute-long national webinar. Data were collected from students who attended the webinar through anonymous online surveys before and after the panel discussion. The participants' self-reported understanding of the IVSR was assessed using a 5-point Likert scale for 11 questions. Objective knowledge of the IVSR Match process was assessed using five data-based questions. All prewebinar and postwebinar responses were paired and compared using bivariate analysis. RESULTS: A total of 76 participants completed both the prewebinar and postwebinar surveys. The majority of respondents were first-year medical students (51.3%) and attended medical school in the Northeast (38.2%). Among these respondents, 57.6% indicated that their home institution had an IVSR program, 44.7% had an active vascular surgery interest group (VSIG), 14.5% had previously attended a vascular surgery conference, and 28.9% were very likely to apply into an IVSR. After the webinar, more students correctly identified the number of currently existing IVSR training positions (76.3% vs 89.5%; P = .002), duration of IVSR (56.6% vs 85.5%; P < .001), and median Step 1 score (50% vs 84.2%; P < .001) and minimum number of applications (38.2% vs 65.8%; P < .001) recommended for a successful Match into IVSR. Students who had a VSIG at their home institution were found to have a better baseline knowledge of the IVSR based on their higher aggregate scores on the data-based questions (3.4 ± 1 vs 1.9 ± 1.2; P < .001) compared with those without one. CONCLUSIONS: A national webinar run by recently matched students can effectively improve medical students' understanding of the IVSR application process. Students with a VSIG at their institutions have a better baseline knowledge of IVSR. In addition to expanding the VSIG, instituting an annual national postmatch webinar may help students become better prepared applicants and improve the overall application pool.

Trends and perioperative outcomes of patients with human immunodeficiency virus (HIV) undergoing lower extremity revascularization.

The development of highly active antiretroviral therapy (HAART) has significantly improved the life expectancy of patients with human immunodeficiency virus (HIV), but has led to the rise of chronic conditions including peripheral artery disease (PAD). However, trends and outcomes among patients with HIV undergoing lower extremity revascularization are poorly characterized. The aim of this study was to investigate the trends and perioperative outcomes of lower extremity revascularization among patients with HIV and PAD in a national database. The National Inpatient Sample (NIS) was reviewed between 2003 and 2014. All hospital admissions with a diagnosis of PAD undergoing lower extremity revascularization were stratified based on HIV status. Outcomes were assessed using propensity score matching and multivariable regression. Among all patients undergoing lower extremity revascularization for PAD, there was a significant increase in the proportion of patients with HIV from 0.21% in 2003 to 0.52% in 2014 (p < 0.01). Patients with HIV were more likely to be younger, male, and have fewer comorbidities, including coronary artery disease and diabetes, at the time of intervention compared to patients without HIV. With propensity score matching and multivariable regression, HIV status was associated with increased total hospital costs, but not length of stay, major amputation, or mortality. Patients with HIV with PAD who undergo revascularization are younger with fewer comorbidities, but have increased hospital costs compared to those without HIV. Lower extremity revascularization for PAD is safe for patients with HIV without increased risk of in-hospital major amputation or mortality, and continues to increase each year.

A survey of vascular specialists' practice patterns of inferior vena cava filter placement and retrieval.

OBJECTIVES: The placement of inferior vena cava filters (IVCF) continues to rise. Vascular specialists adopt different practices based on local expertise. This study was performed to assess the attitudes of vascular specialists towards the placement and retrieval of IVCF. METHODS: An online survey of 28 questions related to practice patterns regarding IVCF was administered to 1429 vascular specialists. Vascular specialists were categorized as low volume if they place less than three IVCF per month and high volume if they place at least three IVCF per month. The responses of high volume and low volume were compared using two-sample t-tests and Chi-square tests. RESULTS: A total of 259 vascular specialists completed the survey (18% response rate). There were 191 vascular surgeons (74%) and 68 interventional radiologists (26%). The majority of responders were in academic practice (67%) and worked in tertiary care centers (73%). The retrievable IVCF of choice was Celect (27%) followed by Denali (20%). Forty-two percent used a temporary IVCF and left it in situ instead of using a permanent IVCF. Eighty-two percent preferred placing the tip of the IVCF at or just below the lowest renal vein. Thirty-one percent obtained a venous duplex of the lower extremities prior to retrieval while 24% did not do any imaging. There were 132 (51%) low volume vascular specialists and 127 (49%) high volume vascular specialists. Compared to low volume vascular specialists, significantly more high volume vascular specialists reported procedural times of less than 30 min for IVCF retrieval (57% vs. 42%, P = 0.026). There was a trend for high volume to have fewer unsuccessful attempts at IVCF retrieval but that did not reach statistical significance ( P = .061). High volume were more likely to have attempted multiple times to retrieve an IVCF (66% vs. 33%, P < .001), and to have used bronchoscopy forceps (32% vs. 14%, P = .001) or a laser sheath (14% vs. 2%, P < .001) for IVCF retrieval. In general, vascular specialists were not comfortable using bronchoscopy forceps (65%) or a laser sheath (82%) for IVCF retrieval. CONCLUSIONS: This study underscores significant variability in vascular specialists practice patterns regarding IVCF. More studies and societal guidelines are needed to define best practices.

Management of isolated calf vein thrombosis in cancer patients.

The treatment of isolated calf vein thrombosis remains widely debated. This study highlights the characteristics of isolated calf vein thrombosis in cancer patients and compares to isolated calf vein thrombosis in patients without history of cancer. Between July 2013 and April 2014, a retrospective chart review of consecutive patients with isolated calf vein thrombosis was performed recording patient risk factors, ultrasound characteristics of the thrombus, treatment modalities, long-term recurrence of venous-thromboembolism, incidence of bleeding, and mortality. Of 131 patients with isolated calf vein thrombosis, 53 (40.1%) had history of cancer. Isolated calf vein thrombosis occurred at an older age in cancer patients (66.7 vs 58.5 years, p = 0.004). The anatomical characteristics of isolated calf vein thrombosis on ultrasound were comparable in both groups. Isolated calf vein thrombosis in cancer patients was less likely to be treated with anticoagulation (60.4% vs 80.8%, p = 0.018). However, a trend towards higher incidence of bleeding after initiation of anticoagulation for isolated calf vein thrombosis in cancer patients (11.3% vs 6.4%, p = 0.351) was noted. Mortality in cancer patients was higher (37.7% vs 9.00%, p < 0.001) but was unrelated to isolated calf vein thrombosis or its treatment. In conclusion, the risks of bleeding seem to exceed the benefits of anticoagulation in approximately 50% of cancer patients with isolated calf vein thrombosis. The management of isolated calf vein thrombosis does not seem to impact the survival of cancer patients.

Endovascular treatment of renal vein thrombosis in a young patient with lung transplant.

Spontaneous renal vein thrombosis is a rare entity. A 28-year-old woman with a history of a double-lung transplant was admitted with flank pain and found to have acute kidney injury. A magnetic resonance venogram demonstrated isolated left renal vein thrombosis with extension into the inferior vena cava. Initial management with therapeutic anticoagulation and hydration was unsuccessful. Thus, pharmacochemical thrombectomy was performed. A temporary suprarenal inferior vena cava filter was placed for intraoperative pulmonary prophylaxis. The patient's renal function returned to baseline and remained normal 13 months later. Early incorporation of percutaneous pharmacomechanical thrombectomy can improve renal function when medical therapy alone is unsuccessful.

The radiographic relationship of the femoral head, inguinal ligament, and common femoral artery bifurcation for optimal vascular access.

Objective: Common femoral artery (CFA) access is commonly used for endovascular interventions. Access site complications contribute to significant morbidity and mortality. This study characterizes the radiographic variability in the relationship of the femoral head, the inguinal ligament, and the CFA bifurcation, to identify the zone of optimal CFA access. Methods: Human cadaver dissection of the inguinal ligament and CFA bifurcation was performed. The inguinal ligament and CFA bifurcation were marked with radiopaque pins and plain anteroposterior radiographs were obtained. Radiographic measurements of the femoral head length, the distance of the top of the femoral head to the inguinal ligament, and to the CFA bifurcation were obtained. Results were reported as percentage of femoral head covered by the inguinal ligament or the CFA bifurcation relative to the top of the femoral head. A heatmap was derived to determine a safe access zone between the inguinal ligament and CFA bifurcation. Results: Forty-five groin dissections (male, n = 20; female, n = 25) were performed in 26 cadavers. The mean overlap of the inguinal ligament with the femoral head was 11.2 mm (range, -19.4 to 27.4 mm). There were no age (<85 vs ≥85 years) or sex-related differences. In 82.6% of cadaveric CFA exposures, there was overlap between the inguinal ligament and femoral head (mean, 27.7%; range, -85.7% to 70.1%), with 55.6% having a >25% overlap. In 11.1%, there was an overlap between the lower one-third of the femoral head and the CFA bifurcation. Cumulatively, heatmap analysis depicted a >80% likelihood of avoiding the inguinal ligament and CFA bifurcation below the midpoint of the femoral head. Conclusions: Significant variability exists in the relationship between the inguinal ligament, CFA bifurcation, and the femoral head, suggesting the lack of a consistently safe access zone. The safest access zone in >80% of patients lies below the radiographic midpoint of the femoral head and the inferior aspect of the femoral head.

A central arteriovenous fistula reduces systemic hypertension in a mouse model.

Objective: A central arteriovenous fistula (AVF) has been proposed as a potential novel solution to treat patients with refractory hypertension. We hypothesized that venous remodeling after AVF creation in the hypertensive environment reduces systemic blood pressure but results in increased AVF wall thickness compared with remodeling in the normotensive environment. Methods: A central AVF was performed in C57BL6/J mice previously made hypertensive with angiotensin II (Ang II); mice were sacrificed on postoperative day 7 or 21. Results: In mice treated with Ang II alone, the mean systolic blood pressure increased from 90 ± 5 mmHg to 160 ± 5 mmHg at day 21; however, in mice treated with both Ang II and an AVF, the blood pressure decreased with creation of an AVF. There were significantly more PCNA-positive cells, SM22α/PCNA-positive cells, collagen I deposition, and increased Krüppel-like Factor 2 immunoreactivity in hypertensive mice with an AVF compared with normotensive mice with an AVF. Conclusions: These data show that a central AVF decreases systemic hypertension as well as induces local alterations in venous remodeling.

Iliac branch endoprosthesis for repair of a common iliac artery aneurysm in Loeys-Dietz syndrome type 3.

The commercial availability of the iliac branch endoprosthesis (IBE) has permitted endovascular repair of iliac artery aneurysms with the preservation of pelvic circulation. However, the device instructions for use require certain anatomic criteria that can limit deployment in ≤30% of patients. Moreover, branched endovascular treatment of common iliac artery aneurysms with IBE in patients with connective tissue disorders such as Loeys-Dietz syndrome has not been described. In the present report, we have described our technique of alternative endograft aortoiliac reconstruction to overcome anatomic barriers to IBE placement in a patient with a giant common iliac artery aneurysm in the setting of a rare pathogenic variant in the SMAD3 gene.

Arm ischemia in a 4-year-old boy with supracondylar fracture of the humerus due to constraining bands over the brachial artery.

Supracondylar humerus fractures are common in children and can compromise the brachial artery in 5% to 15% of cases. A 4-year-old boy with a left supracondylar fracture developed upper extremity ischemia after pinning of the fracture. Computed tomography angiography revealed cutoff of flow in the brachial artery. Intraoperatively, he was found to have bands tethering the artery into the fracture, obstructing the blood flow. The orthopedic pins were removed, and the constraining bands were lysed to free the artery, with reconstitution of flow confirmed by intraoperative angiography. The fracture was reduced and stabilized, and the patient recovered well with normal arterial flow on follow-up ultrasound after 3 months.

EphB4 monomer inhibits chronic graft vasculopathy in an aortic transplant model.

T cells and macrophages play an important role in the formation of allograft vasculopathy, which is the predominant form of chronic rejection in cardiac transplants. Arteries express Ephrin-B2 as a marker of arterial identity, whereas circulating monocytes express the cognate receptor EphB4, which facilitates monocyte adhesion to the endothelial surface. Adherent monocytes transmigrate and differentiate into macrophages that activate T cells and are a main source of tissue damage during rejection. We hypothesized that inhibition of Ephrin-B2-EphB4 binding would decrease immune cell accumulation within a transplanted graft and prevent allograft vasculopathy. We used EphB4 monomer to inhibit Ephrin-B2-EphB4 binding in a rat infrarenal aortic transplant model. Rats treated with EphB4 monomer had fewer macrophages and T cells in the aortic allografts at 28 days, as well as significantly less neointima formation. These data show that the Ephin-B2-EphB4 axis may be an important target for prevention or treatment of allograft vasculopathy.