Endothelial TGF-ß Signaling Regulates Endothelial-Mesenchymal Transition During Arteriovenous Fistula Remodeling in Mice With Chronic Kidney Disease.

BACKGROUND: Arteriovenous fistulae (AVFs) are the preferred vascular access for hemodialysis in patients with end-stage kidney disease. Chronic kidney disease (CKD) is associated with endothelial injury, impaired AVF maturation, and reduced patency, as well as utilization. Because CKD is characterized by multiple pathophysiological processes that induce endothelial-to-mesenchymal transition (EndMT), we hypothesized that CKD promotes EndMT during venous remodeling and that disruption of endothelial TGF (transforming growth factor)-ß signaling inhibits EndMT to prevent AVF failure even in the end-stage kidney disease environment. METHODS: The mouse 5/6 nephrectomy and aortocaval fistula models were used. CKD was created via 5/6 nephrectomy, with controls of no (0/6) or partial (3/6) nephrectomy in C57BL/6J mice. AVFs were created in mice with knockdown of TGF-ßR1/R2 (TGF-ß receptors type 1/2) in either smooth muscle cells or endothelial cells. AVF diameters and patency were measured and confirmed by serial ultrasound examination. AVF, both murine and human, were examined using Western blot, histology, and immunofluorescence. Human and mouse endothelial cells were used for in vitro experiments. RESULTS: CKD accelerates TGF-ß activation and promotes EndMT that is associated with increased AVF wall thickness and reduced patency in mice. Inhibition of TGF-ß signaling in both endothelial cells and smooth muscle cells decreased smooth muscle cell proliferation in the AVF wall, attenuated EndMT, and was associated with reduced wall thickness, increased outward remodeling, and improved AVF patency. Human AVF also showed increased TGF-ß signaling and EndMT. CONCLUSIONS: CKD promotes EndMT and reduces AVF patency. Inhibition of TGF-ß signaling, especially disruption of endothelial cell-specific TGF-ß signaling, attenuates EndMT and improves AVF patency in mouse AVF. Inhibition of EndMT may be a therapeutic approach of translational significance to improve AVF patency in human patients with CKD.

Association of Socioeconomic Status, Sex, Racial, and Ethnic Identity With Sustained and Cultivated Careers in Surgery.

OBJECTIVE: Examine the association between sex, race, ethnicity, and family income, and the intersectionality between these identities, and sustained or cultivated paths in surgery in medical school. METHODS: This retrospective cohort study examines US medical students who matriculated in academic years 2014-2015 and 2015-2016. Data were provided by the Association of American Medical Colleges, including self-reported sex, race, ethnicity, family income, interest in surgery at matriculation, and successful placement into a surgical residency at graduation. This study examined 2 outcomes: (1) sustained path in surgery between matriculation and graduation for students who entered medical school with an interest in surgery and (2) cultivated path in surgery for students who entered medical school not initially interested in surgery and who applied to and were successfully placed into a surgical residency at graduation. RESULTS: Among the 5074 students who reported interest in surgery at matriculation, 2108 (41.5%) had sustained path in surgery. Compared to male students, female students were significantly less likely to have sustained path in surgery [adjusted relative risk (aRR): 0.92 (0.85-0.98)], while Asian (aRR: 0.82, 95% CI: 0.74-0.91), Hispanic (aRR: 0.70, 95% CI: 0.59-0.83), and low-income (aRR: 0.85, 95% CI: 0.78-0.92) students were less likely to have a sustained path in surgery compared to their peers. Among the 17,586 students who reported an initial interest in a nonsurgical specialty, 1869 (10.6%) were placed into a surgical residency at graduation. Female students, regardless of race/ethnic identity and income, were significantly less likely to have cultivated paths in surgery compared to male students, with underrepresented in medicine female students reporting the lowest rates. CONCLUSIONS AND RELEVANCE: This study demonstrates the significant disparity in sustained and cultivated paths in surgery during undergraduate medical education. Innovative transformation of the surgical learning environment to promote surgical identity development and belonging for females, underrepresented in medicine, and low-income students is essential to diversify the surgical workforce.

Disturbed flow in the juxta-anastomotic area of an arteriovenous fistula correlates with endothelial loss, acute thrombus formation, and neointimal hyperplasia.

Clinical failure of arteriovenous neointimal hyperplasia (NIH) fistulae (AVF) is frequently due to juxta-anastomotic NIH (JANIH). Although the mouse AVF model recapitulates human AVF maturation, previous studies focused on the outflow vein distal to the anastomosis. We hypothesized that the juxta-anastomotic area (JAA) has increased NIH compared with the outflow vein. AVF was created in C57BL/6 mice without or with chronic kidney disease (CKD). Temporal and spatial changes of the JAA were examined using histology and immunofluorescence. Computational techniques were used to model the AVF. RNA-seq and bioinformatic analyses were performed to compare the JAA with the outflow vein. The jugular vein to carotid artery AVF model was created in Wistar rats. The neointima in the JAA shows increased volume compared with the outflow vein. Computational modeling shows an increased volume of disturbed flow at the JAA compared with the outflow vein. Endothelial cells are immediately lost from the wall contralateral to the fistula exit, followed by thrombus formation and JANIH. Gene Ontology (GO) enrichment analysis of the 1,862 differentially expressed genes (DEG) between the JANIH and the outflow vein identified 525 overexpressed genes. The rat jugular vein to carotid artery AVF showed changes similar to the mouse AVF. Disturbed flow through the JAA correlates with rapid endothelial cell loss, thrombus formation, and JANIH; late endothelialization of the JAA channel correlates with late AVF patency. Early thrombus formation in the JAA may influence the later development of JANIH.NEW & NOTEWORTHY Disturbed flow and focal endothelial cell loss in the juxta-anastomotic area of the mouse AVF colocalizes with acute thrombus formation followed by late neointimal hyperplasia. Differential flow patterns between the juxta-anastomotic area and the outflow vein correlate with differential expression of genes regulating coagulation, proliferation, collagen metabolism, and the immune response. The rat jugular vein to carotid artery AVF model shows changes similar to the mouse AVF model.

Anatomic patterns in claudicants who fail supervised exercise therapy.

OBJECTIVE: Patients with intermittent claudication (IC) from peripheral arterial disease (PAD) have significant improvement with supervised exercise therapy (SET). However, many patients have progressive disease that will ultimately require revascularization. We sought to determine whether the anatomic patterns of PAD were associated with response to SET. METHODS: We prospectively enrolled patients with IC at the West Haven, Connecticut Veterans Health Administration between June 2019 and June 2022. Patients were classified based on the level of their arterial disease with >50% obstruction. SET failure was defined as progressive symptoms or development of critical limb-threatening ischemia (CLTI) requiring revascularization. RESULTS: Thirty-eight patients with PAD were included. Thirteen patients (34.2%) had significant common femoral artery (CFA) disease, and 25 (65.8%) had non-CFA disease. Over a median follow-up of 1407 days, 11 patients (84.6%) with CFA disease failed SET as compared with three patients (12.0%) with non-CFA disease (P < .001). Patients with CFA disease were more likely to develop CLTI (46.2% vs 4.0%; P = .001) and have persistent symptoms (38.5% vs 8.0%; P = .02). Patients with CFA disease had significantly lower post-SET ankle-brachial index (0.58 ± 0.14 vs 0.77 ± 0.19; P = .03). In multivariate analysis, the only variable associated with SET failure was CFA disease location (odds ratio, 68.75; 95% confidence interval, 5.05-936.44; P = .001). CONCLUSIONS: Patients with IC from high-grade CFA atherosclerosis are overwhelmingly likely to fail SET, potentially identifying a subset of patients who benefit from upfront revascularization.

Recent advances and controversial issues in the optimal management of asymptomatic carotid stenosis.

OBJECTIVE: The optimal management of patients with asymptomatic carotid stenosis (AsxCS) is enduringly controversial. We updated our 2021 Expert Review and Position Statement, focusing on recent advances in the diagnosis and management of patients with AsxCS. METHODS: A systematic review of the literature was performed up to August 1, 2023, using PubMed/PubMed Central, EMBASE and Scopus. The following keywords were used in various combinations: "asymptomatic carotid stenosis," "carotid endarterectomy" (CEA), "carotid artery stenting" (CAS), and "transcarotid artery revascularization" (TCAR). Areas covered included (i) improvements in best medical treatment (BMT) for patients with AsxCS and declining stroke risk, (ii) technological advances in surgical/endovascular skills/techniques and outcomes, (iii) risk factors, clinical/imaging characteristics and risk prediction models for the identification of high-risk AsxCS patient subgroups, and (iv) the association between cognitive dysfunction and AsxCS. RESULTS: BMT is essential for all patients with AsxCS, regardless of whether they will eventually be offered CEA, CAS, or TCAR. Specific patient subgroups at high risk for stroke despite BMT should be considered for a carotid revascularization procedure. These patients include those with severe (≥80%) AsxCS, transcranial Doppler-detected microemboli, plaque echolucency on Duplex ultrasound examination, silent infarcts on brain computed tomography or magnetic resonance angiography scans, decreased cerebrovascular reserve, increased size of juxtaluminal hypoechoic area, AsxCS progression, carotid plaque ulceration, and intraplaque hemorrhage. Treatment of patients with AsxCS should be individualized, taking into consideration individual patient preferences and needs, clinical and imaging characteristics, and cultural, ethnic, and social factors. Solid evidence supporting or refuting an association between AsxCS and cognitive dysfunction is lacking. CONCLUSIONS: The optimal management of patients with AsxCS should include BMT for all individuals and a prophylactic carotid revascularization procedure (CEA, CAS, or TCAR) for some asymptomatic patient subgroups, additionally taking into consideration individual patient needs and preference, clinical and imaging characteristics, social and cultural factors, and the available stroke risk prediction models. Future studies should investigate the association between AsxCS with cognitive function and the role of carotid revascularization procedures in the progression or reversal of cognitive dysfunction.

An international, multispecialty, expert-based Delphi Consensus document on controversial issues in the management of patients with asymptomatic and symptomatic carotid stenosis.

OBJECTIVE: Despite the publication of various national/international guidelines, several questions concerning the management of patients with asymptomatic (AsxCS) and symptomatic (SxCS) carotid stenosis remain unanswered. The aim of this international, multi-specialty, expert-based Delphi Consensus document was to address these issues to help clinicians make decisions when guidelines are unclear. METHODS: Fourteen controversial topics were identified. A three-round Delphi Consensus process was performed including 61 experts. The aim of Round 1 was to investigate the differing views and opinions regarding these unresolved topics. In Round 2, clarifications were asked from each participant. In Round 3, the questionnaire was resent to all participants for their final vote. Consensus was reached when ≥75% of experts agreed on a specific response. RESULTS: Most experts agreed that: (1) the current periprocedural/in-hospital stroke/death thresholds for performing a carotid intervention should be lowered from 6% to 4% in patients with SxCS and from 3% to 2% in patients with AsxCS; (2) the time threshold for a patient being considered "recently symptomatic" should be reduced from the current definition of "6 months" to 3 months or less; (3) 80% to 99% AsxCS carries a higher risk of stroke compared with 60% to 79% AsxCS; (4) factors beyond the grade of stenosis and symptoms should be added to the indications for revascularization in AsxCS patients (eg, plaque features of vulnerability and silent infarctions on brain computed tomography scans); and (5) shunting should be used selectively, rather than always or never. Consensus could not be reached on the remaining topics due to conflicting, inadequate, or controversial evidence. CONCLUSIONS: The present international, multi-specialty expert-based Delphi Consensus document attempted to provide responses to several unanswered/unresolved issues. However, consensus could not be achieved on some topics, highlighting areas requiring future research.

Wound Healing Society 2023 update on guidelines for arterial ulcers.

The Wound Healing Society guidelines for the treatment of arterial insufficiency ulcers were originally published in 2006, with the last update in 2014. These guidelines provided recommendations, along with their respective levels of evidence, on seven categories: diagnosis, surgery, infection control, wound bed preparation, dressings, adjuvant therapy and long-term maintenance. Over the last 9 years, additional literature regarding these aspects of arterial ulcer management has been published. An advisory panel comprised of academicians, clinicians and researchers was chosen to update the 2014 guidelines. Members included vascular surgeons, internists, plastic surgeons, anaesthesiologists, emergency medicine physicians and dermatologists, all with expertise in wound healing. The goal of this article is to evaluate relevant new findings upon which an updated version of the guidelines will be based.

Association between Preoperative Neutrophil-lymphocyte Ratio and All-cause Mortality in Patients Treated with Thoracic Endovascular Aortic Repair for Degenerative Thoracic Aortic Aneurysm.

PURPOSE: The neutrophil-lymphocyte ratio (NLR) has been increasingly recognized as a reliable surrogate marker for predicting mortality in clinical practice. This study determined the predictive ability of NLR for overall mortality after thoracic endovascular aortic repair (TEVAR) for degenerative thoracic aortic aneurysm (TAA). METHODS: Data from patients treated with TEVAR for degenerative TAA at our university hospital from January 2013 to December 2021 were evaluated. The preoperative NLR was calculated by dividing the absolute neutrophil count by the absolute lymphocyte count. RESULTS: One hundred-three patients were included in this study. During a 9-year follow-up, 32 patients (31.1%) died. Multivariable analyses showed that age (hazard ratio [HR], 1.06; 95% confidence interval [CI], 1.00-1.12; p = 0.021), ischemic heart disease (HR, 2.13; 95% CI, 1.05-4.36; p = 0.038), and NLR (HR, 1.36; 95% CI, 1.08-1.72; p = 0.009) predicted all-cause mortality after TEVAR. A receiver operating characteristic curve determined the optimal cut-off value of NLR to predict all-cause mortality was 3.48. CONCLUSIONS: An elevated preoperative NLR is indicative of a higher likelihood of all-cause mortality in patients treated with TEVAR for degenerative TAA, suggesting that NLR could serve as a possible biomarker for stratifying patients at risk of overall mortality after TEVAR.

Reduced Muscle Mass and Muscle Quality in Patients with Intermittent Claudication due to Peripheral Artery Disease.

BACKGROUND: Peripheral arterial disease (PAD) is associated with reduced muscle mass and quality, but the effects of leg ischemia caused by PAD on muscle quality remain poorly understood. The purpose of this study was to evaluate leg muscle mass and muscle quality in patients with intermittent claudication due to PAD using bioelectrical impedance analysis (BIA). METHODS: One hundred forty-one patients with intermittent claudication due to PAD who visited Tokyo Medical University Hospital from April 2019 to April 2020 were retrospectively analyzed. Leg ischemia was assessed using ankle-brachial pressure index (ABI). The skeletal muscle mass (SMM) assessed leg muscle mass, while the phase angle (PhA) assessed leg muscle quality using BIA. RESULTS: A total of 282 legs in 141 patients were included in the analysis. Leg PhA and SMM showed a decreasing trend according to the severity of leg ischemia (borderline/no ischemia: 2.80 ± 0.50 kg/m2, 4.38 ± 0.94°; mild ischemia: 2.83 ± 0.49 kg/m2, 4.33 ± 1.03°; moderate/severe ischemia: 2.50 ± 0.40 kg/m2, 3.89 ± 0. 88°; P < 0.001 and P = 0.020, respectively). The ABI was moderately correlated with leg SMM (B = 0.347, ß = 0.134, P < 0.001) and leg PhA (B = 0.577, ß = 0.111, P = 0.013) after adjustment for all significant covariates. Leg PhA was moderately correlated with leg SMM (r = 0.318, P < 0.001). CONCLUSIONS: Leg ischemia, especially when moderate or severe, has an adverse effect on both muscle mass and quality in the lower extremities and is associated with skeletal muscle myopathy.

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

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

An International, Expert-Based Delphi Consensus Document on Controversial Issues about TransCarotid Artery Revascularization (TCAR).

OBJECTIVE: TransCarotid Artery Revascularization (TCAR) has emerged as an alternative therapeutic modality to carotid endarterectomy (CEA) and transfemoral carotid artery stenting (TFCAS) for the management of patients with carotid artery stenosis. However, certain issues regarding the indications and contraindications of TCAR remain unanswered or unresolved. The aim of this international, expert-based Delphi Consensus document was to attempt to provide some guidance on these topics. METHODS: A 3-Round Delphi Consensus process was performed including 29 experts. The aim of Round 1 was to investigate the differing views and opinions of the participants. Round 2 was carried out after the results from the literature on each topic were provided to the participants. During Round 3, the participants had the opportunity to finalize their vote. RESULTS: Most participants agreed that TCAR can/can probably/possibly be performed within 14 days of a cerebrovascular event, but it is best to avoid it in the first 48 hours. It was felt that TCAR cannot/should not replace TFCAS or CEA, as each procedure has specific indications and contraindications. Symptomatic patients >80 years should probably be treated with TCAR rather than with TFCAS. TCAR can/can probably be used for the treatment of restenosis following CEA/TFCAS. Finally, there is a need for a randomized controlled trial to provide better evidence for the unresolved issues. CONCLUSIONS: This Delphi Consensus document attempted to assist the decision-making of physicians/interventionalists/vascular surgeons involved in the management of carotid stenosis patients. Furthermore, areas requiring additional research were identified. Future studies and randomized controlled trials should provide more evidence to address the unanswered questions regarding TCAR.

Clinician perspectives regarding CYP2C19 genotype testing in patients with critical limb ischemia: A Delphi approach.

OBJECTIVES: Antiplatelet therapy is an essential element in the management of patients with arterial vascular disease. In peripheral arterial disease (PAD), dual antiplatelet therapy (DAPT), primarily clopidogrel and aspirin, is routinely prescribed following intervention. There is sparse data regarding the need for DAPT, the appropriate duration, or the heterogeneity of treatment effects for antiplatelet regimens across patients, leading to potential uncertainty and heterogeneity around treatment practices. An example of heterogeneity of treatment effects is a patients' metabolizer status for the use of clopidogrel. The aim of the study was to (1) assess clinicians' knowledge of and attitudes toward managing patients with CYP2C19 mutations, (2) identify barriers to implementation of CYP2C19 testing and management policies, and (3) reach consensus for CYP2C19 testing and management strategies for patients with PAD who undergo peripheral vascular interventions (PVI). METHODS: A modified Delphi method was used to establish consensus amongst PAD interventionalists around CYP2C19 testing. All practicing Yale New Haven Hospital PAD interventionalists with backgrounds in interventional cardiology, vascular surgery, or interventional radiology were approached by email for participation. Round 1 included the collection of baseline demographic questions, knowledge questions, and three statements for consensus. Knowledge questions were rated on a 0-10 Likert scale with the following anchors: 0 ("Not at all"), 5 ("Neutral), and 10 ("Very Much"). Participants were asked to rate the importance of the three consensus statements on a 9-point Likert scale from 1 ("Strongly Disagree") to 10 ("Strongly Agree"). In Round 2, participants were shown the same consensus statements, the median response of the group from the previous round, and their previous answers. Participants were instructed to revise their rating using the results from the previous round. This process was repeated for Round 3. RESULTS: Of the 28 experts invited to participate, 13 agreed (46%). Participants were predominantly male (92.3%) and white (61.5%) with representation from interventional cardiology (46.2%) and vascular surgery (53.8%). Most participants reported more than 10+ years in practice (61.5%). PAD interventionalists felt they would benefit from more education regarding CYP2C19 mutations (median score 8.0, interquartile range 5.0-8.5). They indicated some familiarity with CYP2C19 mutations (7.0, 6.0-9.5) but did not feel strongly that CYP2C19 was important to their practice (6.0, 5.5-7.5). In each round, the median responses for the three consensus statements were 5, 6, and 9, respectively. With each successive round the interquartile range narrowed indicative of evolving consensus but did not reach the prespecified interquartile range for consensus of 1 for any of the statements. CONCLUSIONS: PAD interventionalists practicing at an academic health system recognize the heterogenous response of their patients to clopidogrel therapy but are unsure when to leverage genetic testing to improve outcomes for their patients. Our study identified gaps regarding PAD interventionalists' knowledge, perceived barriers, and attitudes toward CYP2C19 testing in PAD. This information highlights the need for randomized data on genetic testing for clopidogrel responsiveness in peripheral vascular disease following intervention to help guide antiplatelet management.

Carotid artery stenting versus carotid endarterectomy for symptomatic or asymptomatic extracranial carotid stenosis: A national cohort study.

INTRODUCTION: Stroke is now the 5th leading cause of death in the United States, and carotid artery stenosis is the cause of about 20% to 25% of strokes. We hypothesized that CAS may be an alternative to CEA in both symptomatic and asymptomatic patients with carotid artery stenosis. METHODS: We evaluated the clinical characteristics, adverse events and mortality of patients with carotid artery stenosis comparing CEA vs. CAS using data from a national population-based cohort study from January 1, 2016, to December 30, 2020. RESULTS: We evaluated 374,875 patients with carotid stenosis, of whom 344,020 had asymptomatic carotid stenosis and 30,855 had symptomatic carotid stenosis. CAS was associated with higher mortality in both symptomatic and asymptomatic carotid stenosis, compared to CEA, with the trend slightly decreasing for both interventions from the years 2018-2020. CEA was associated with lower adverse events in both symptomatic and asymptomatic carotid stenosis, compared to CAS. CONCLUSIONS: Our current data suggest a benefit of CEA over CAS for both symptomatic and asymptomatic carotid stenosis with lower complications, lower mortality and a higher rate of discharge. However, this is not a head-to-head comparison as it becomes selection bias for this procedure; therefore, further prospective head-to-head comparison between 2 groups in the same patient population is needed.

Safety of Carotid Endarterectomy for Symptomatic Stenosis by Age: Meta-Analysis With Individual Patient Data.

BACKGROUND: There is uncertainty whether elderly patients with symptomatic carotid stenosis have higher rates of adverse events following carotid endarterectomy. In trials, recurrent stroke risk on medical therapy alone increased with age, whereas operative stroke risk was not related. Few octogenarians were included in trials and there has been no systematic analysis of all study types. We aimed to evaluate the safety of carotid endarterectomy in symptomatic elderly patients, particularly in octogenarians. METHODS: We did a systematic review and meta-analysis of studies (from January 1, 1980 through March 1, 2022) reporting post carotid endarterectomy risk of stroke, myocardial infarction, and death in patients with symptomatic carotid stenosis. We included observational studies and interventional arms of randomized trials if the outcome rates (or the raw data to calculate these) were provided. Individual patient data from 4 prospective cohorts enabled multivariate analysis. RESULTS: Of 47 studies (107 587 patients), risk of perioperative stroke was 2.04% (1.94-2.14) in octogenarians (390 strokes/19 101 patients) and 1.85% (1.75-1.95) in nonoctogenarians (1395/75 537); P=0.046. Perioperative death was 1.09% (0.94-1.25) in octogenarians (203/18 702) and 0.53% (0.48-0.59) in nonoctogenarians (392/73 327); P<0.001. Per 5-year age increment, a linear increase in perioperative stroke, myocardial infarction, and death were observed; P=0.04 to 0.002. However, during the last 3 decades, perioperative stroke±death has declined significantly in octogenarians (7.78% [5.58-10.55] before year 2000 to 2.80% [2.56-3.04] after 2010); P<0.001. In Individual patient data multivariate-analysis (5111 patients), age ≥85 years was independently associated with perioperative stroke (P<0.001) and death (P=0.005). Yet, survival was similar for octogenarians versus nonoctogenarians at 1-year (95.0% [93.2-96.5] versus 97.5% [96.4-98.6]; P=0.08), as was 5-year stroke risk (11.93% [9.98-14.16]) versus 12.78% [11.65-13.61]; P=0.24). CONCLUSIONS: We found a modest increase in perioperative risk with age in symptomatic patients undergoing carotid endarterectomy. As stroke risk increases with age when on medical therapy alone, our findings support selective urgent intervention in symptomatic elderly patients.

Sex hormones impact early maturation and immune response in the arteriovenous fistula mouse model.

Arteriovenous fistulae (AVF) fail to mature more frequently in female patients compared with male patients, leading to inferior outcomes and decreased utilization. Since our mouse AVF model recapitulates sex differences in human AVF maturation, we hypothesized that sex hormones mediate these differences during AVF maturation. C57BL/6 mice (9-11 wk) were treated with aortocaval AVF surgery and/or gonadectomy. AVF hemodynamics were measured via ultrasound (days 0-21). Blood was collected for FACS and tissue for immunofluorescence and ELISA (days 3 and 7); wall thickness was assessed by histology (day 21). Inferior vena cava shear stress was higher in male mice (P = 0.0028) after gonadectomy, and they had increased wall thickness (22.0 ± 1.8 vs. 12.7 ± 1.2 µm; P < 0.0001). Conversely, female mice had decreased wall thickness (6.8 ± 0.6 vs. 15.3 ± 0.9 µm; P = 0.0002). Intact female mice had higher proportions of circulating CD3+ T cells on day 3 (P = 0.0043), CD4+ (P = 0.0003) and CD8+ T cells (P = 0.005) on day 7, and CD11b+ monocytes on day 3 (P = 0.0046). After gonadectomy, these differences disappeared. In intact female mice, CD3+ T cells (P = 0.025), CD4+ T cells (P = 0.0178), CD8+ T cells (P = 0.0571), and CD68+ macrophages (P = 0.0078) increased in the fistula wall on days 3 and 7. This disappeared after gonadectomy. Furthermore, female mice had higher IL-10 (P = 0.0217) and TNF-α (P = 0.0417) levels in their AVF walls than male mice. Sex hormones mediate AVF maturation, suggesting that hormone receptor signaling may be a target to improve AVF maturation.NEW & NOTEWORTHY After arteriovenous fistula creation, females have lower rates of maturation and higher rates of failure than males. In a mouse model of venous adaptation that recapitulates human fistula maturation, sex hormones may be mechanisms of the sexual dimorphism: testosterone is associated with reduced shear stress, whereas estrogen is associated with increased immune cell recruitment. Modulating sex hormones or downstream effectors suggests sex-specific therapies and could address disparities in sex differences in clinical outcomes.

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.

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.

Safety and efficacy of thoracic endovascular aortic repair for acute Stanford type B aortic dissection with retrograde type A intramural hematoma.

OBJECTIVE: The aim of this study was to evaluate safety and efficacy of thoracic endovascular aortic repair (TEVAR) for acute Stanford type B aortic dissection (TBAD) with retrograde type A intramural hematoma (TAIMH). METHODS: Patients with acute TBAD with retrograde TAIMH treated with TEVAR between January 1, 2014, to March 31, 2022, were retrospectively reviewed. Aortic diameter and distance were measured using the 3D Slicer image computing platform. Patients' characteristics, procedural, in-hospital and follow-up data, and aortic remodeling were analyzed. RESULTS: Fifty-two patients (average age, 52.6 years; 42 males [80.8%]) were included. The median interval from symptom onset to TEVAR was 11 days (interquartile range, 7.0-16.8 days). The maximal diameter of the ascending aorta (AA) was <50 mm, and the hematoma thickness in the AA was ≤10 mm in all patients. Both the in-hospital and 30-day mortality rates were 0%. The 30-day complication rate was 11.5%. The overall cumulative survival rates were 100% at 1 year, 97.1% at 3 years, and 92.6% at 5 years. Four of 52 patients (7.7%) developed retrograde type A aortic dissection at 10 days to 4 months postoperatively, and one of 52 patients (1.9%) developed an isolated AA dissection 4 months postoperatively; these five patients were treated and alive at late follow-up in March 2022. The rates of cumulative freedom from thoracic aortic re-intervention were 93.7% at 1 year and 90.7% at 5 years. Positive AA remodeling was observed in 92.3% (48/52) of patients during follow-up. The maximal diameter of AA (mean ± standard error of mean) at admission was 42.7 ± 0.8 mm, which decreased to 39.5 ± 0.9 mm at last follow-up. The maximal AA hematoma thickness at admission was 7.6 ± 0.3 mm, which reduced to 2.2 ± 0.9 mm at last follow-up. CONCLUSIONS: For selected patients of acute Stanford TBAD with retrograde TAIMH, endovascular repair may be a safe, effective, and durable alternative treatment, if the maximum diameter of the AA is <50 mm and the intramural hematoma thickness in the AA is ≤10 mm.

Association of simple renal cysts to aneurysm sac shrinkage in true thoracic aortic aneurysms after thoracic endovascular aortic repair.

BACKGROUND: An increased prevalence of thoracic aortic aneurysms (TAA) has been demonstrated in patients with simple renal cysts (SRC); patients with SRC have a less elastic aortic wall than those without SRC. The purpose of this study was to evaluate aneurysm sac shrinkage after thoracic endovascular aortic repair (TEVAR) for true TAA in patients with and without SRC. METHODS: One hundred three patients with true aneurysms of the thoracic aorta who underwent TEVAR at our university hospital from November 2013 to December 2021 were included in this study. Aneurysm sac size was compared between that on baseline preoperative computed tomography and that on postoperative computed tomography scans at 1 year. A change in aneurysm sac size ≥5 mm was considered to be significant, whether due to expansion or shrinkage. RESULTS: The patients were divided into two groups: those with SRC (46 patients [45%]) and those without SRC (57 patients [55%]). At 1 year, there was a significant difference in the proportion of aneurysm sac shrinkage between patients with SRC and those without SRC (23.9% vs 59.6%; P < .001). Patients with SRC showed significantly less aneurysm sac shrinkage than those without SRC (-1.8 ± 5.6 mm vs -5.1 ± 6.6 mm; P = .009). Univariable and multivariable analyses showed that the initial sac diameter (odds ratio, 1.08; 95% confidence interval, 1.03-1.14; P = .002) and the presence of SRC (odds ratio, 0.15; 95% confidence interval, 0.06-0.40; P < .001) were positively and negatively associated with aneurysm sac shrinkage after TEVAR, respectively. CONCLUSIONS: The presence of a SRC was independently associated with failure of aneurysm sac shrinkage after TEVAR for true TAA. This suggests that the presence of a SRC may be a predictor for the failure of aneurysm sac shrinkage after TEVAR.

Endothelial Cell TGF-ß (Transforming Growth Factor-Beta) Signaling Regulates Venous Adaptive Remodeling to Improve Arteriovenous Fistula Patency.

BACKGROUND: Arteriovenous fistulae (AVF) are the gold standard for vascular access for hemodialysis. Although the vein must thicken and dilate for successful hemodialysis, excessive wall thickness leads to stenosis causing AVF failure. Since TGF-ß (transforming growth factor-beta) regulates ECM (extracellular matrix) deposition and smooth muscle cell (SMC) proliferation-critical components of wall thickness-we hypothesized that disruption of TGF-ß signaling prevents excessive wall thickening during venous remodeling. METHODS: A mouse aortocaval fistula model was used. SB431542-an inhibitor of TGF-ß receptor I-was encapsulated in nanoparticles and applied to the AVF adventitia in C57BL/6J mice. Alternatively, AVFs were created in mice with conditional disruption of TGF-ß receptors in either SMCs or endothelial cells. Doppler ultrasound was performed serially to confirm patency and to measure vessel diameters. AVFs were harvested at predetermined time points for histological and immunofluorescence analyses. RESULTS: Inhibition of TGF-ß signaling with SB431542-containing nanoparticles significantly reduced p-Smad2-positive cells in the AVF wall during the early maturation phase (days 7-21) and was associated with decreased AVF wall thickness that showed both decreased collagen density and decreased SMC proliferation. SMC-specific TGF-ß signaling disruption decreased collagen density but not SMC proliferation or wall thickness. Endothelial cell-specific TGF-ß signaling disruption decreased both collagen density and SMC proliferation in the AVF wall and was associated with reduced wall thickness, increased outward remodeling, and improved AVF patency. CONCLUSIONS: Endothelial cell-targeted TGF-ß inhibition may be a translational strategy to improve AVF patency.