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.

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.

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.

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.

Systematic review of inferior vena cava atresia.

OBJECTIVE: Inferior vena cava (IVC) atresia is a rare venous anomaly characterized by absence of the IVC. It has been associated with deep vein thrombosis (DVT) and other congenital anomalies. The aim of the present study is to provide a comprehensive summary of the literature on IVC atresia and discuss the presentation and outcomes of patients with IVC atresia. METHODS: A systematic review of the English literature up to April 2020 was performed. The presentations and treatments reported were noted and compared between the two sexes. The IVC atresia cases were further stratified into isolated IVC atresia and IVC atresia associated with other congenital anomalies. RESULTS: A total of 412 abstracts were screened, with 178 reports included. A total of 376 patients were analyzed. Overall, males seem to be more affected than females, with a ratio of almost 2:1 (male, 227 [64.1%]; vs female, 127 [35.8%]). However, females were more likely to have congenital IVC atresia compared with males (46.1% vs 21.3%; P < .001). The mean age at presentation was 27.9 ± 18.0 years (range, 0-77 years), with no differences between the sexes. Most patients with IVC atresia presented with DVT (n = 242 of 376; 64.3%), with the iliac veins most often affected (n = 159 of 242; 65.7%). No difference was found in the reported proportion of patients presenting with DVT between the two sexes. The symptom presentation was similar, with leg pain and swelling the most common in both sexes. The patients were treated either medically with anticoagulation or surgically (open or endovascular). No mortality was reported with isolated IVC atresia in either treatment group. However, the mortality of patients with IVC atresia associated with other congenital anomalies was 11.7%. CONCLUSIONS: IVC atresia is more common in males but seems to have a predilection for females in the setting of other congenital anomalies. Most patients present with leg pain and swelling related to the development of DVT. Open and endovascular surgical interventions to treat IVC atresia have been reported in 18.3% of patients reviewed, with acceptable mid-term results in terms of patency and symptomatic relief.

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.

Effect of inferior vena cava filter placement position on device complications.

BACKGROUND: Indwelling inferior vena cava (IVC) filters can cause complications, including penetration into surrounding structures, migration, and thrombosis of the vena cava. Computational fluid dynamics suggests juxtarenal placement of IVC filters decreases the risk of thrombosis; however, this has not been explored clinically. The present study examines the effect of filter placement position on long-term device complications with an emphasis on IVC thrombosis. We hypothesized that IVC filters placed further caudal to the renal veins were more likely to develop long-term thrombosis. METHODS: A retrospective review of the medical records of patients receiving IVC filters at a single tertiary center between 2008 and 2016 was performed. Patients missing follow-up or procedural imaging data were excluded. The placement procedure venograms were reviewed, and the distance from the filter apex to the more inferior renal vein was measured using reported IVC filter lengths for calibration. The patients were divided into three groups according to the tip position relative to the more inferior renal vein: at or superior (group A), 1 to 20 mm inferior (group B), and >20 mm inferior (group C). The patient and procedural characteristics and outcomes were compared between the three groups. The primary end points were IVC thrombosis and device-related mortality. RESULTS: Of 1497 eligible patients, 267 (17.8%) were excluded. The most common placement position was group B (64.0%). The mean age was lowest in group C, followed by groups A and B (age, 59.5 years, 64.6 years, and 62.2 years, respectively; P = .003). No statistically significant differences were found in the distribution of sex or the measured comorbidities. Group C was the most likely to receive jugular access (group C, 71.7%; group A, 48.3%; group B, 62.4%; P < .001) and received more first-generation filters (group C, 58.5%; group A, 46.6%; group B, 52.5%; P = .045). The short-term (<30-day) and long-term (≥30-day) outcomes, including access site hematoma, deep vein thrombosis, and pulmonary embolism, were uncommon, with no differences between the groups. Cases of symptomatic filter penetration, migration, and fracture were rare (one, one, and three cases, respectively). Although a pattern of increasing thrombosis with more inferior placement was found, the difference between groups was not statistically significant (group A, 1.5%; group B, 1.8%; group C, 2.5%; P = .638). No cases of device-related mortality occurred. All-cause mortality after a mean follow-up of 2.6 ± 2.3 years was 41.3% and did not vary significantly between the groups (P = .051). Multivariate logistic regression revealed that placement position did not predict for short- or long-term deep vein thrombosis, pulmonary embolism, IVC thrombosis, or all-cause mortality after adjustment for the baseline patient characteristics. CONCLUSIONS: IVC filters have low rates of short- and long-term complications, including IVC thrombosis. The placement position did not affect the occurrence of device complications in this study.

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.

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.

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.

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.

Placement and retrieval of bilateral iliac vein filters in patients with mega cava.

Temporary interruption of the inferior vena cava is the recommended treatment to prevent pulmonary embolism in patients with venous thromboembolism (VTE) and active contraindications for therapeutic anticoagulation. In patients with mega cava (diameter >30 mm), temporary inferior vena cava filters are contraindicated. In the present report, we have described the successful placement and retrieval of bilateral iliac vein filters in two patients with VTE, mega cava, and active contraindications for therapeutic anticoagulation. At the last follow-up, both patients had recovered without recurrent VTE and had had all filters successfully retrieved without complications.

A narrative review on the application of high-intensity focused ultrasound for the treatment of occlusive and thrombotic arterial disease.

Objectives: High-intensity focused ultrasound (HIFU) is a noninvasive therapeutic modality with a variety of applications. It is approved for the treatment of essential tremors, ablation of prostate, hepatic, breast, and uterine tumors. Although not approved for use in the treatment of atherosclerotic arterial disease, there is a growing body of evidence investigating applications of HIFU. Currently, percutaneous endovascular techniques are predominant for the treatment of arterial pathology; however, there are no endovascular techniques of HIFU available. This study aims to review the state of current evidence for the application of HIFU in atherosclerotic arterial disease. Methods: All English-language articles evaluating the effect of HIFU on arterial occlusive and thrombotic disease until 2021 were reviewed. Both preclinical and human clinical studies were included. Study parameters such as animal or clinical model and outcomes were reviewed. In addition, details pertaining to settings on the HIFU device used were also reviewed. Results: In preclinical models, atherosclerotic plaque progression was inhibited by HIFU, through decreases in oxidized low-density lipoprotein cholesterol and increases in macrophage apoptosis. Additionally, HIFU promotes angiogenesis in hindlimb ischemic models by the upregulation of angiogenic and antiapoptotic factors, with increased angiogenesis at higher line densities of HIFU. HIFU also promotes thrombolysis and conversely induces platelet activation at low frequencies and higher intensities. Various clinical studies have attempted to translate some of these properties and demonstrated positive clinical outcomes for arterial recanalization after thrombotic stroke, decreased atherosclerotic plaque burden in carotid arteries, increase in tissue perfusion and a decrease in diameter stenosis in patients with atherosclerotic arterial disease. Conclusions: In current preclinical and clinical data, the safety and efficacy of HIFU shows great promise in the treatment of atherosclerotic arterial disease. Future focused studies are warranted to guide the refinement of HIFU settings for more widespread adoption of this technology.

Bioinformatics identifies predictors of arteriovenous fistula maturation.

BACKGROUND: Arteriovenous fistulae (AVF) are the preferred access for hemodialysis but still have poor rates of maturation and patency limiting their clinical use. The underlying mechanisms of venous remodeling remain poorly understood, and only limited numbers of unbiased approaches have been reported. METHODS: Biological Gene Ontology (GO) term enrichment analysis and differentially expressed genes (DEG) analysis were performed for three AVF datasets. A microRNA enrichment analysis and L1000CDS2 query were performed to identify factors predicting AVF patency. RESULTS: The inflammatory and immune responses were activated during both early and late phases of AVF maturation, with upregulation of neutrophil and leukocyte regulation, cytokine production, and cytokine-mediated signaling. In men with failed AVF, negative regulation of myeloid-leukocyte differentiation and regulation of macrophage activation were significantly upregulated. Compared to non-diabetic patients, diabetic patients had significantly reduced immune response-related enrichment such as cell activation in immune response, regulation of immune-effector process, and positive regulation of defense response; in addition, diabetic patients showed no enrichment of the immune response-regulating signaling pathway. CONCLUSIONS: These data show coordinated, and differential regulation of genes associated with AVF maturation, and different patterns of several pathways are associated with sex differences in AVF failure. Inflammatory and immune responses are activated during AVF maturation and diabetes may impair AVF maturation by altering these responses. These findings suggest several novel molecular targets to improve sex specific AVF maturation.

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.

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.

Aortic remodeling and competitive flow after surgical treatment of aortic dissection.

Aortic remodeling after dissection is poorly understood and remains a focus of current research. In the present report, we have described the cases of two patients with acute lower extremity ischemia related to malperfusion from aortic dissection treated with extra-anatomic axillobifemoral bypass. During long-term follow-up, aortic remodeling led to reinstitution of flow through the native aorta. This resulted in competitive flow, leading to complete thrombosis of the extra-anatomic conduits. These cases highlight the occurrence of spontaneous aortic recanalization and subsequent competitive flow, two vascular phenomena that are not well understood but can significantly affect patient outcomes.