Objective Although lower extremity bypass (LEB) may be the only viable option for limb salvage in selected patients with chronic limb threatening ischemia (CLTI), it carries significant postprocedural risks. Previous studies on the impact of body mass index (BMI) and LEB typically extrapolated data from national databases, which may be skewed by data abstracted from hospitals with vascular residency or fellowship training programs. The scarcity of data from non-teaching hospitals does not permit a comprehensive picture of outcomes. Methods We queried the Blue Cross Blue Shield Michigan Cardiovascular Consortium (BMC2) registry data to identify patients who underwent elective LEB. Cases with patients younger than 18 years old, in-hospital death, missing data, or emergent procedures, LEB for popliteal artery entrapment syndrome or trauma were excluded. Patient demographic characteristics are summarized into five BMI categories: underweight (BMI < 18.5), healthy weight (BMI≥18.5 & < 25), overweight (BMI ≥25 & < 30), Class I Obesity (BMI ≥ 30 & < 35) and Class II or III Obesity (BMI ≥ 35). Primary outcomes included 30-day and 1-year wound complications and amputation. Secondary outcomes included major adverse cardiac events (MACE) and their constituent elements (mortality, myocardial infarction (MI), stroke). Unadjusted differences were tested using F-tests from one-way ANOVAs, Kruskal-Wallis tests, or chi-square tests, depending on the variable type and distribution. These tests, when significant, were followed by Bayesian mixed effects logistic regression models to control for site, demographic and comorbidity differences between exposure groups. Bayesian models are interpreted as significant if the 95% credible intervals around the odds ratios do not include 1.00. Results Between January 2016-December 2024, 7,676 patients underwent elective LEB, with a mean age of 67 years old. The study cohort was divided into five different BMI categories as follows: underweight (n=297, 3.9 %), healthy weight (n=2,325, 30.3%), overweight (n=2,639, 34.4 %), class I obesity (n=1,528, 19.9 %), class II or III obesity (n=887, 11.5 %). Using healthy weight patients as reference, adjusted analysis of primary outcomes demonstrated that class II/III obesity patients had significantly higher odds of 30-day and 1-year wound complications (30-day: odds ratio (OR), 1.728; 95% credible interval (CI), 1.31-2.279; 1-year: OR 1.881; 95% CI, 1.457-2.431). Interestingly, obese patients demonstrated lower odds of 1-year major amputations (class I obesity: OR, 0.74; 95% CI, 0.55-1.00; class II/III obesity: OR, 0.58; 95% CI, 0.39-0.86). For secondary outcomes, overweight and class I obesity patients had lower odds of 30-day mortality (overweight: OR 0.356; 95% CI, 0.167-0.725; class I obesity: OR 0.38; 95% CI, 0.147-0.829). Class I obesity patients also had lower odds of 1-year mortality (OR 0.727; 95% CI, 0.537-0.981). There were no differences in 30-day and 1-year MACE across all BMI cohorts. Conclusion The positive linear relationship between BMI and post-LEB wound complications may not preclude obese CLTI patients from elective LEB. Nevertheless, patients with higher BMI should be counseled on higher risks of wound complications after LEB.

Background: Endotheliitis in severe SARS-CoV-2 (CoV2) results in increased cellular adhesion molecules (CAMs) and procoagulant molecules (PCMs). Cell surface CAMs increase endothelial cell (EC) interactions with circulating immune cells (IC). Increased EC-IC interactions and a procoagulant EC phenotype augment immunothrombotic risk during CoV2 infection. Prophylactic anticoagulants during CoV2 infection are associated with unacceptably high bleeding risk. New targets to treat endotheliitis are required. Hypothesis: We hypothesize JAK/STAT inhibition ameliorates kmt2a induction to reduce endotheliitis and immunothrombosis in SARS-CoV-2 infection. Aims: Identify transcriptional regulators of kmt2a induction in SARS-CoV-2 infection. Methods: C57Bl/6 mice were infected with murine adapted SARS-CoV-2 (MA10). Murine venous endothelial (mVEC) and hemangoendothelioma (EOMA) cells were infected with murine betacoronavirus (MHV-A59) and treated with Tofacitinib (50 nM). Luciferase reporter plasmid was constructed with kmt2a promoter upstream and leukocyte adhesion assay was performed using RAW 264.7 cells. Results: In vivo MA10 infection significantly increased CAMs in lungs of C57Bl/6 mice. mVEC infection significantly increased transcription of CAM esel through MLL1 H3K4me3 . STAT1 was significantly enriched on the promoter of kmt2a in the setting of MHV-A59 infection. JAK/STAT inhibition significantly reduced kmt2a and sele transcripts leading to decreased leukocyte adhesion. JAK/STAT inhibition also decreased luciferase activity in the setting of upstream kmt2a promoter. Conclusion: Kmt2a/MLL1 positively regulates CoV-2 induction of CAMs and PCMs and endothelial inflammation via positive regulation of CAM gene transcription, and resultant EC-IC interactions. JAK/STAT inhibition may represent a therapeutic target to ameliorate immunothrombotic risk during CoV-2 infection.

Background: Toll-like receptor 4 (TLR4) signaling via innate immune cells has been implicated in thromboinflammation, but the in vivo role of TLR4 in venous thrombus resolution is not fully investigated. Objectives: Based on prior observations that monophosphoryl lipid A (MPLA) enhances expression of fibrinolytic and inflammatory mediators in macrophages in vitro and that urokinase activity is reduced in TLR4 fl/fl Lyz2-Cre + mice in vivo, we hypothesized that monocyte/macrophage (MO/Mφ) TLR4 signaling regulates thrombus resolution and vein wall remodeling. Methods: Venous thrombosis was induced using inferior vena cava (IVC) stenosis and stasis models in wild-type, global TLR4 knockout (TLR4 -/- ), and TLR4 fl/fl Lyz2-Cre +/- mice. Thrombus burden, fibrinolytic activity, inflammatory signaling, and vein wall remodeling were assessed by histologic, immunohistochemical, and molecular analyses. Systemic TLR4 activation was achieved by intraperitoneal administration of MPLA (20 µg/day, total 40 µg). For adoptive transfer experiments, bone marrow–derived monocytes/macrophages (BMDMs) from wild-type or TLR4 -/- donors were administered intraperitoneally before and after thrombosis induction to assess their functional contribution within distinct host backgrounds. Results: Impaired MO/Mφ TLR4 signaling was associated with significantly reduced intrathrombus urokinase and matrix metalloproteinase activity and delayed thrombus resolution, reflected by an increased thrombus weight-to-length ratio in the 7-day IVC stenosis model (p <0.05). Systemic TLR4 activation with MPLA enhanced thrombus resolution (p=0.019) but was accompanied by increased macrophage accumulation (p=0.013) and collagen content (p=0.080) in wild-type mice. Adoptive transfer experiments demonstrated that wild-type hosts receiving TLR4 -/- MO/Mφs exhibited significantly lower IVC weight than TLR4 -/- hosts receiving wild-type MO/Mφs (p=0.018). Conclusions: TLR4 signaling exerts dual distinct roles during venous thrombus resolution, promoting fibrinolytic thrombus clearance while concurrently shaping inflammatory and fibrotic remodeling of the vein wall. These findings establish intraperitoneally administered MO/Mφs can migrate to venous thrombi and functionally influence post-thrombotic remodeling. Although pharmacologic TLR4 activation enhances thrombus resolution, it also augments vascular inflammation and fibrosis, highlighting the need for cell-specific or thrombus-targeted immunomodulatory strategies.

Background: In-stent restenosis (ISR) and re-thrombosis (RT) are pathological processes that develop after venous stenting, leading to late stent failure. Currently, post-stenting medical management primarily targets the coagulation cascade, but neglects to address associated inflammation subsequent vascular fibrosis, which are linked to the interactions between venous endothelial cells and immune cells. Objective: To determine cell-specific gene expression profiles that contribute to venous stent failure. Methods: We performed single-cell RNA sequencing (scRNA-seq) analysis of native femoral veins and stent acute RT and ISR, characterized by old thrombus/diffuse intimal thickening (DIT). Selected specific cell-expression profiles were confirmed using immunohistochemistry (IHC). Results: Using scRNA-seq, we identified the cell landscape in human deep veins and RT and ISR processes. Clustering analysis of transcriptional profiles identified 12 cell lineages using SingleR, Further sub-clustering of the main cell clusters identified 6 endothelial (mature venous endothelial cells/EC: EPHB4+ NR2F2+, Inflammatory EC: SELE+ ICAM1+ VCAM1+), 3 vascular smooth muscle (VSMC) (Contractile: SPEG+ SMTN+, Synthetic/Transitioning VSMC: ACTA2+ TAGLN+, and Fibroblast-like: SERPINE1+, DUSP6+), 4 fibroblast (Inflammatory: NLRP3+, MRC1+, Matrix-producing: MMP2+ COL1A1+, Senescent: DEPP1+ CCL2+), and 5 monocyte/macrophage (Mo/MΦ) subpopulations. The cellular composition reverted to primarily vascular structural cells in ISR compared to circulating cells in RT. Gene enrichment analysis on VECs and VSMCs subsets identified inflammation, hypoxia, and PI3K-Akt-mTOR as common upregulated pathways in both RT and ISR. Figure 1. A-F. Conclusions: A single-cell analysis of native deep veins, RT, and ISR reveal how the gene expression landscape is altered in these pathologic processes, providing a cell specific transcriptomic map to nominate causal target genes.

Objective: Deep vein thrombosis (DVT) is a debilitating and costly condition treated by anti-coagulation, thrombectomy, or thrombolysis. These treatments prevent thrombus propagation, but increase the risk of bleeding, infection, and re-thrombosis, and fail to promote the natural thrombus resolution. Thrombus resolution is mediated by the hypoxia-inducible factor 1 (HIF1)-vascular endothelial growth factor (VEGF) pathway. Our aim was to determine whether FDA-approved HIF1 agonists can be repurposed to safely treat murine DVT. Approach and Results: DVT was induced by inferior vena cava stenosis in male and female C57BL/6J mice (3-4m old). Mice were treated with oral vehicle or a clinically equivalent regimen of Rabeprazole (a novel HIF1 agonist), Vadadustat or Daprodustat (known HIF1 agonists). To assess efficacy, treatments were started at day 1 post-thrombus induction, when the thrombus is fully formed (Fig. 1A). By day 7, when thrombus resolution is underway, treatment with each drug resulted in increased levels of active (nuclear) HIF1α in the thrombus and surrounding vein (Fig. 1B), along with increased levels of the HIF1 target, VEGF (Fig. 1C). Using proteome profiling, we next identified drug-specific signatures of pro-resolution proteins that were induced in the thrombus and vein (Fig. 1D). Treatment with each drug reduced thrombus length (Fig. 1E), weight (Fig. 1F), and volume (Fig. 1G, H) by >50% at day 7, which was accompanied in the Vadudustat and Daprodustat groups by >2-fold increases in vein recanalization (Fig. 1G, I). None of the drugs altered hematocrit at day 7 (Fig. 1J). To extend our safety assessments of the most effective drug, mice were pre-treated with Daprodustat for 6 days prior to thrombus induction (Fig. 2A). At day 1 post-thrombus induction, Daprodustat did not alter thrombus formation (length, Fig. 2B; or weight, Fig. 2C), the proteome profile of 53 circulating inflammatory cytokines (Fig. 2D), or inflammation (Fig. 2E-G) or vascular permeability (Fig. 2H-J) in the liver, kidney, or quadriceps. Finally, using a clinically equivalent regimen of an FDA-approved VEGF inhibitor (Bevacizumab, Fig. 3A, B), we showed that Daprodustat-driven increases in thrombus resolution are dependent upon VEGF (Fig. 3C). Conclusions: Three different FDA-approved HIF1 agonists safely and effectively promote venous thrombus resolution in mice. Repurposing of FDA-approved HIF1 agonists represents a viable therapeutic option for the treatment of DVT.

BACKGROUND:Post-thrombotic syndrome (PTS) develops in 20-50% of patients following deep vein thrombosis (DVT) due to persistent vein wall injury, inflammation, and fibrotic remodeling. Current anticoagulant therapies do not directly address PTS pathogenesis and carry bleeding risks. We characterized the extracellular matrix (ECM) components and evaluated whether pharmacological inhibition of α6β1 integrin with pranlukast (PLK) could modulate post-thrombotic vein wall injury in a preclinical DVT model. METHODS:ECM protein composition was characterized in C57BL/6 mice by western blotting of IVC harvested after IVC ligation from 4 to 21 days, identifying the laminin-α6β1 integrin axis as a therapeutic target. Presence of α6β1 was confirmed via immunofluorescence in post-thrombotic mice up to 21 days. Pranlukast (PLK), a candidate α6β1 integrin antagonist, was tested in vitro and in vivo. Venous endothelial cells were treated with PLK to assess transcription of integrins (Itga6, Itgb1) and inflammation markers (sele). In vivo, C57BL/6 mice received PLK or vehicle before and after IVC ligation. Thrombus characteristics, vein wall remodeling, integrin protein expression, and cellular composition were evaluated. RESULTS:Laminin, fibrin, thrombomodulin, and fibronectin were present in the post-thrombotic IVC in mice. The ECM protein laminin and its primary receptor, α6β1 integrin (CD49f/CD29), were highly expressed up to 21 days post-thrombosis in the vein wall. In vitro, PLK treatment significantly decreased transcription of Itga6, Itgb1, and sele after 24 hours. PLK did not affect thrombus formation, with comparable thrombus weights and lengths across groups, demonstrating a safety profile. The administration of PLK was associated with decreased levels of α6 and β1 integrins in the vein wall and thrombus, but also with a significant reduction in vein wall thickness (VWT) (PLK: 44.95 μm ±5.09, DMSO: 56.84 μm ±6.54, p=0.0081) at 8 days and in proinflammatory monocytes (CCR2+) compared to control (PLK: 14.73 ±1.69, DMSO: 23.15 ±2.38, p<0.0001). CONCLUSIONS:This study demonstrates that targeting α6β1 integrin with PLK reduces vein wall fibrotic injury following experimental DVT without altering thrombus formation. These findings identify a novel, non-anticoagulant therapeutic strategy for PTS prevention that warrants further investigation in chronic models and translational studies.

BACKGROUND:Appropriate allocation of consult service resources is essential to reduce burnout. This study analyzed vascular surgery consults to compare referring services' perceived urgency with actual need for urgent therapy. METHODS:A randomized sample of 1,279 consults for patients of >18 years from 2019 to 2023 was retrospectively reviewed. Consults were evaluated for indication and whether surgery occurred inpatient or outpatient. Perceived urgency was designated as STAT or routine by the referring team placing the consult. "True" urgency was defined by whether a vascular procedure occurred during the same hospitalization. Agreement was defined as matched perceived and true urgency. Logistic regression identified predictors of agreement by vascular pathology, consulting service, and time of day, adjusting for race, sex, and age. RESULTS:Overall, 67.0% of consults demonstrated agreement between perceived and true urgency. Routine consults were accurate in 77.6% of cases versus 22.1% of STAT consults, resulting in inpatient intervention (P < 0.001). Agreement was lowest for peripheral arterial disease (PAD), acute limb ischemia (ALI), and compartment syndrome (P < 0.05) and higher for aneurysmal, mesenteric ischemia, cerebrovascular, and venous diseases (P < 0.05). Intensive care unit (ICU) consults had lower agreement (adjusted odds ratio [aOR] 0.53, P < 0.001), while medicine consults had higher agreement (aOR 1.41, P < 0.05) compared to the emergency department (ED). Agreement was lowest for consults placed between 00:00-02:59 and 15:00-17:59. CONCLUSION:Discrepancies exist between perceived and true urgency of vascular consults, particularly from the ICU and for PAD, ALI, and compartment syndrome, highlighting an opportunity for targeted education to improve inpatient workflow.

Background: Deep vein thrombosis (DVT) leads to post-thrombotic syndrome (PTS) in around 30-50% of patients despite anticoagulation. Catheter-based thrombectomy/ thrombolysis (CDT) lacks consistent efficacy in preventing PTS. Locally delivered steroids such as dexamethasone (DEX), are currently under clinical evaluation as an adjunct to CDT in the DEXTERITY-AFP trial (NCT04862468) with the aim of reducing PTS, but minimal mechanistic data for DEX exists regarding DVT resolution. Here, we hypothesized that perivascular local DEX will improve DVT resolution and reduce vein wall fibrosis in experimental murine DVT. Method: Male C57BL/6J mice (n=146) underwent complete inferior vena cava (IVC) ligation to induce stasis DVT on day 0, followed by surgical de-ligation on day 2 to simulate CDT/MT and spur restoration of blood flow (RBF), as determined by a non-invasive ultrasound (IVC flow velocity > 0 mL/sec). On day 2, periadventitial PBS or DEX (0.05–0.5 mg/mouse) was administered via a 30G needle, followed by serial ultrasonography to evaluate RBF. On day 8, thrombus burden and vein wall remodeling were assessed using immunohistochemistry, RNA sequencing, and qRT-PCR. Results: DEX 0.1mg/mouse significantly reduced day 8 thrombus burden (p=0.0006), thrombus weight (p=0.008), and intra-thrombus CD68+ macrophages (p=0.007) in IVC DVT (Fig. A). Higher (0.2–0.5 mg/mouse) and lower (0.05 mg/mouse) DEX doses also did not worsen thrombus burden. DEX 0.1mg/mouse decreased day 8 vein wall collagen thickness (p=0.0001), DDR2+ fibroblasts (p=0.001) and CD68+ macrophages (p=0.04) in vein wall and perivascular region (Fig. B, C) and improved mean blood flow velocity in thrombosed IVCs on days 4-8. Predictively, the day 4 RBF+ status correlated with reduced day 8 vein wall collagen thickness with DEX reducing VWCT irrespective of RBF status (RBF+PBS; 62.04µm, RBF-PBS; 51.31µm, RBF-DEX; 29.05µm, RBF+DEX; 20.63µm, Fig. D). Further, global transcriptome of DEX/PBS treated vein walls revealed downregulation of collagen synthesis pathways (Fig. E), supporting the antifibrotic effects of DEX. Conclusion: In conclusion, locally delivered DEX improves murine stasis DVT resolution by improving early venous blood flow, and then reducing thrombus burden, vein wall injury, and macrophage content. These findings underscore the potential of targeted perivascular steroid therapy as an adjuvant to CDT in patients undergoing thrombectomy and provide mechanistic support for the DEXTERITY trials.

OBJECTIVE:With the proliferation of different carotid interventions, there is a need to understand the costs and reimbursements for different procedures and what perioperative factors drive cost. We evaluated the charges and reimbursements for carotid endarterectomies (CEAs) and transcervical carotid artery revascularization (TCAR) across surgical and payer groups. METHODS:We conducted a single-institution retrospective cohort study, from January 1, 2014, to July 1, 2025. Using Epic Systems reporting tools, procedural charges, reimbursements (hospital and professional), and patient characteristics were extracted. The U.S. Bureau of Labor Statistics inflation calculator was used to standardize prices to January 2025 levels. RESULTS:We performed 811 CEAs (31 with jaw subluxation) and 159 TCAR on 931 unique patients at our institution. Hospital reimbursements favored TCAR (TCAR $66,113.57 > endarterectomy $38,323) and professional reimbursements favored endarterectomy (endarterectomy $1707 > TCAR $1397). Higher TCAR operating room (OR) charges are driven by the higher cost of the TCAR system. The average TCAR system charge was $13,319 with an additional $9147 charge per stent ($22,466 total). The TCAR system outweighs the cost savings from shorter TCAR OR cases (TCAR 164.60 minutes vs endarterectomy 221.79 minutes), with cost savings of $10,809 at an average TCAR OR time of $189 per minute after the first 60 minutes. In comparison, adjuncts for complex endarterectomies such as jaw subluxation, are a fraction of the cost of a TCAR system. Different practice patterns can also affect billing and reimbursements, where neurosurgery endarterectomy charges and reimbursements were significantly different from those of vascular surgery. CONCLUSIONS:The choice of intervention option (TCAR or endarterectomy) and local practice patterns are the major drivers of charges and reimbursements for carotid interventions. Our institution is incentivized to perform TCARs due to reimbursements greatly outstripping endarterectomy. However, device costs greatly outweigh OR time savings. CEA remains a significantly less expensive means of managing carotid stenosis compared with TCAR, even with adjuncts such as jaw subluxation or neuromonitoring. Notably, charges differed dramatically from reimbursements, underscoring the divergence of charges from true payments.