Background: Venous malformation (VM) is the most frequent type of congenital vascular malformation. In terms of functional outcome local sclerotherapy remains the most important therapeutic tool. For planning and correct estimation and prevention of complications, an exact anatomical classification of the VM is crucial. Not only the drainage, as assessed in the established classification, but also the phlebographic aspect of the internal VM structure itself plays a decisive role. In order to integrate this aspect, we aim to validate a proposal for a revised phlebographic VM classification distinguishing non-lacunar (a) and lacunar (b) types. Methods: We retrospectively analyzed all patients with VM in whom a direct puncture phlebography was performed in our clinic between 2009 and 2018 to assess morphology and flow characteristics. Phlebographic assessment included: (I) differentiation of non-lacunar vs. lacunar type; (II) drainage assignment according to the existing classification; (III) adjusted classification combining both. Inter-reader agreement was measured in percentage as well as by the Cohen's kappa coefficient (kappa). Results: Overall 26 patients were classified as non-lacunar (a) and 41 patients as lacunar (b) VM. For this categorization, inter-reader agreement was 96% (kappa=0.91). Classical Puig classification into types I, II, III and IV showed 87% inter-reader agreement (kappa=0.78). For the adjusted classification adding the non-lacunar or lacunar characteristic to type I-IV an agreement of 82% (kappa=0.77) was achieved. Conclusions: Phlebographic differentiation into non-lacunar and lacunar VM is feasible and reliable to distinguish phenotypic subgroups of patients with VM. We therefore propose to integrate this parameter of the internal VM structure into the existing classification.

Arteriovenous malformations (AVM) are benign vascular anomalies prone to pain, bleeding, and progressive growth. AVM are mainly caused by mosaic pathogenic variants of the RAS-MAPK pathway. However, a causative variant is not identified in all patients. Using ultra-deep sequencing, we identified novel somatic RIT1 delins variants in lesional tissue of three AVM patients. RIT1 encodes a RAS-like protein that can modulate RAS-MAPK signaling. We expressed RIT1 variants in HEK293T cells, which led to a strong increase in ERK1/2 phosphorylation. Endothelial-specific mosaic overexpression of RIT1 delins in zebrafish embryos induced AVM formation, highlighting their functional importance in vascular development. Both ERK1/2 hyperactivation in vitro and AVM formation in vivo could be suppressed by pharmacological MEK inhibition. Treatment with the MEK inhibitor trametinib led to a significant decrease in bleeding episodes and AVM size in one patient. Our findings implicate RIT1 in AVM formation and provide a rationale for clinical trials with targeted treatments.

PIK3CA variants are known to cause vascular malformations. We were interested in studying the phenotypic spectrum, the location within the PIK3CA gene, and the variant allele frequency (VAF) of somatic PI3KCA variants in vascular malformations. Clinical data of consecutive patients with extracranial/extraspinal vascular malformations were collected in the context of the VASCOM cohort (2008-2022, n = 558). Starting October 2020, biopsy samples were tested with the TSO500 gene panel (Illumina). All consenting patients with PIK3CA variants were included in this study. Eighty-nine patients had available genetic results by June 2022. PIK3CA variants (n = 25) were found in 16 simple/combined (nonsyndromic) vascular malformations and in nine vascular malformations associated with other anomalies (syndromic). Four hotspot variants in exons 9 and 20 (c.1624G>A, c.1633G>A, c.3140A>G, c.3140A>T) were identified in 16/25 patients (VAF 0.9%-9.7%). Six non-hotspot variants (c.328_330del, c.323_337del, c.353G>A, c.1258T>C, c.3132T>A, c.3195_3203delinsT) were detected in nine patients (VAF 3.6%-31.7%). Non-hotspot variants were more frequent in syndromic than nonsyndromic vascular malformations (p = 0.0034) and exhibited a higher VAF than hotspot variants (p = 0.0253). Our study contributes to the growing body of knowledge of the genetic background in vascular malformations. Further studies will enrich the ever-growing list of pathogenic PIK3CA variants associated with vascular malformations.

ID 18996 Poster Board 573 The kappa opioid receptor (KOR) represents a highly desirable therapeutic target for treating not only pain but also addiction and affective disorders. The development of KOR analgesics, however, has been hindered by the hallucinogenic side effects mediated by KOR signaling. The initiation of KOR signaling requires the Gi/o family proteins. However, how hallucinogens exert their actions via KOR and how KOR determines the G protein subtype selectivity are not well understood. Here we determined the active-state structures of KOR in complex with G protein heterotrimers by cryo-electron microscopy (Cryo-EM). Comparisons of these structures reveal molecular determinants critical for KOR-G protein interactions as well as key elements governing Gi/o family subtype selectivity and KOR ligand selectivity. These results provide novel insights into the actions of opioids and G protein-coupling specificity at KOR and establish a foundation to explore the therapeutic potential of pathway-selective agonists of KOR.

ID 17740 Poster Board 89 Opioid receptor ligands like morphine are effective targets for pain relief. However, these pain relievers can cause severe negative side effects via downstream signaling pathways. The sodium (Na+) binding site has been found to be conserved among many G protein-coupled receptors (GPCRs) including opioid receptors where Na+ acts as a negative allosteric modulator of GPCR activation and signaling. Targeting the Na+ binding site could alter downstream signaling pathways and reduce common side effects. We explored the functional effect of engaging both the delta opioid receptor (DOR) allosteric Na+ site and orthosteric site using structure-based design of bitopic ligands. To validate our design strategy of targeting the Na+ site, we solved cryoEM structures of two lead compounds, C5 and C6, bound to DOR. The structures highlight key gatekeeper and ligand-Na+ site interactions which control efficacy and potency at two key GPCR signaling pathways, G-protein and beta-arrestin. While C5 is a full agonist that activates both pathways at DOR, C6 behaves as a partial agonist with less liability to promote potent side-effects. In mice, C6 showed analgesic actions in a neuropathic pain assay without convulsions. Convulsions have prevented the clinical usage of first-generation classical DOR agonists, supporting the idea that targeting the sodium site may be an avenue toward developing safer analgesics.

Objective: In recent years, genotypic characterization of congenital vascular malformations (CVMs) has gained attention; however, the spectrum of clinical phenotype remains difficult to attribute to a genetic cause and is rarely described in the adult population. The aim of this study is to describe a consecutive series of adolescent and adult patients in a tertiary center, where a multimodal phenotypic approach was used for diagnosis.Methods: We analyzed clinical findings, imaging, and laboratory results at initial presentation, and set a diagnosis ac-cording to the International Society for the Study of Vascular Anomalies (ISSVA) classification for all consecutively registered patients older than 14 years of age who were referred to the Center for Vascular Malformations at the University Hospital of Bern between 2008 and 2021.Results: A total of 457 patients were included for analysis (mean age, 35 years; females, 56%). Simple CVMs were the most common (n = 361; 79%), followed by CVMs associated with other anomalies (n = 70; 15%), and combined CVMs (n = 26; 6%). Venous malformations (n = 238) were the most common CVMs overall (52%), and the most common simple CVMs (66%). Pain was the most frequently reported symptom in all patients (simple, combined, and vascular malformation with other anomalies). Pain intensity was more pronounced in simple venous and arteriovenous malformations. Clinical problems were related to the type of CVM diagnosed, with bleeding and skin ulceration in arteriovenous malformations, localized intra-vascular coagulopathy in venous malformations, and infectious complications in lymphatic malformations. Limb length difference occurred more often in patients with CVMs associated with other anomalies as compared with simple or com-bined CVM (22.9 vs 2.3%; P < .001). Soft tissue overgrowth was seen in one-quarter of all patients independent of the ISSVA group. Conclusions: In our adult and adolescent population with peripheral vascular malformations, simple venous malfor-mations predominated, with pain as the most common clinical symptom. In one-quarter of cases, patients with vascular malformations presented with associated anomalies on tissue growth. The differentiation of clinical presentation with or without accompanying growth abnormalities need to be added to the ISSVA classification. Phenotypic characterization considering vascular and non-vascular features remains the cornerstone of diagnosis in adult as well as pediatric patients.

Objectives:. Parkes Weber syndrome (PWS) is a rare disorder that combines overgrowth, capillary malformations, and arteriovenous malformations (AVM)/arteriovenous fistulas, for which underlying activating mutations in the ras/mitogen-activated protein kinase/extracellular-signal-regulated kinase signaling pathway have been described. The clinical overlap with Klippel-Trenauny syndrome, associated with mutations in PIK3CA, is significant. This case series aimed to elaborate on the phenotypic description of PWS, to underline its clinical overlap with Klippel-Trenauny syndrome and nonsyndromic AVM, and to evaluate the contribution of genotypic characterization to the diagnosis. Methods:. All patients diagnosed with PWS upon enrollment in the Bernese VAScular COngenital Malformations (VASCOM) cohort were included. The diagnostic criteria of PWS were retrospectively reviewed. A next-generation sequencing (NGS) gene panel (TSO500, Illumina) was used on tissue biopsy samples. Results:. Overall, 10/559 patients of the VAScular COngenital Malformations cohort were initially diagnosed with PWS. Three patients were reclassified as nonsyndromic AVM (Kristen Rat Sarcoma Viral oncogene homolog [KRAS], KRAS+tumor protein p53, and protein tyrosine phosphatase non-receptor type 11). Finally, 7 patients fulfilled all clinical diagnostic criteria of PWS. Genetic testing was available in 5 PWS patients. Only 1 patient had the classic RASA1 mutation; another patient had mutations in G protein subunit alpha q (GNAQ) and phosphatase and tensin homolog. In a third case, a PIK3CA mutation was detected. In 2 patients, no mutations were identified. Conclusion:. Overgrowth syndromes with vascular malformations are rare and their clinical overlap hampers the classification of individual phenotypes under specific syndrome labels, sometimes even despite genetic testing. To provide optimal patient care, an accurate phenotypic description combined with the identification of molecular targets for precision medicine may be more meaningful than the syndrome classification itself.

ID 52769 Poster Board 538 Opioids are used for the treatment of acute to severe pain. Usage of opioids also produces liabilities like respiratory depression and addiction, which in combination with illicit use of fentanyl and designer analogs has contributed to the opioid epidemic. Most approaches to design safer opioids have been restricted to targeting the orthosteric binding sites. We have recently reported a novel strategy to design functionally selective opioids by targeting the sodium binding allosteric site in the mu opioid receptor (MOR). The lead ligand C6 guano engages a key residue Asp2.50 in the sodium site through a salt bridge with a guanidine group in the ligand. C6 guano shows MOR dependent antinociception with reduced adverse effects seen with clinically used opioids (Faouzi et al., Nature 2023, 613, 767–774). While representing a significant advance in the design of opioids, C6 guano is supraspinally active because of the polar and charged guanidine group. Using the cryo-EM structure of C6 guano bound to MOR, we designed second generation analogs to optimize the systemic activity of C6 guano. Characterization of analogs led to the identification of a fentanyl-derived compound named RO-76 which in TRUPATH assays showed reduced efficacy at all Gi/o/z subtypes and no measurable efficacy at β-arrestin-1/2 and labelled unique transducers in APEX2 proximity labeling assays. Unlike C6 guano which showed direct engagement of the sodium site, RO-76 interacted with the sodium site residues through a water in cryo-EM of RO-76 bound to MOR-Gi complex. Previous high-resolution structures of MOR have predicted the presence of a polar cavity in the sodium binding pocket, but these waters have not been rationally targeted before at MOR or other GPCRs to the best of our knowledge. In mice, the drug was systemically active in tail withdrawal assays, and showed reduced respiratory depression and conditioned place preference compared to morphine. In summary, we envision that targeting the sodium binding site may be a potential avenue to both probe the role of the sodium site in MOR function as well as development of a new class of analgesics in the near future. Support and sponsors: Center for Clinical Pharmacology University of Health Sciences and Pharmacy at St. Louis National Institute of Drug Abuse

Arterial and venous thrombosis constitute a major source of morbidity and mortality worldwide. Association between thrombotic complications and cardiovascular and other chronic inflammatory diseases are well described. Inflammation and subsequent initiation of thrombotic events, termed immunothrombosis, also receive growing attention but are still incompletely understood. Nevertheless, the clinical relevance of aberrant immunothrombosis, referred to as thromboinflammation, is evident by an increased risk of thrombosis and cardiovascular events in patients with inflammatory or infectious diseases. Proinflammatory mediators released from platelets, complement activation, and the formation of NETs (neutrophil extracellular traps) initiate and foster immunothrombosis. In this review, we highlight and discuss prominent and emerging interrelationships and functions between NETs and other mediators in immunothrombosis in cardiovascular disease. Also, with patients with chronic kidney disease suffering from increased cardiovascular and thrombotic risk, we summarize current knowledge on neutrophil phenotype, function, and NET formation in chronic kidney disease. In addition, we elaborate on therapeutic targeting of NETs-induced immunothrombosis. A better understanding of the functional relevance of antithrombotic mediators which do not increase bleeding risk may provide opportunities for successful therapeutic interventions to reduce thrombotic risk beyond current treatment options.

AbstractAimsOptimal endovascular management of intermittent claudication (IC) remains disputed. This systematic review and meta-analysis compares efficacy and safety outcomes for balloon angioplasty (BA), bare-metal stents (BMS), drug-coated balloons (DCB), drug-eluting stents (DES), covered stents, and atherectomy.Methods and resultsElectronic databases were searched for randomized, controlled trials (RCT) from inception through November 2021. Efficacy outcomes were primary patency, target-lesion revascularization (TLR), and quality-of-life (QoL). Safety endpoints were all-cause mortality and major amputation. Outcomes were evaluated at short-term (<1 year), mid-term (1–2 years), and long-term (≥2 years) follow-up. The study was registered on PROSPERO (CRD42021292639). Fifty-one RCTs enrolling 8430 patients/lesions were included. In femoropopliteal disease of low-to-intermediate complexity, DCBs were associated with higher likelihood of primary patency [short-term: odds ratio (OR) 3.21, 95% confidence interval (CI) 2.44–4.24; long-term: OR 2.47, 95% CI 1.93–3.16], lower TLR (short-term: OR 0.33, 95% CI 0.22–0.49; long-term: OR 0.42, 95% CI 0.29–0.60) and similar all-cause mortality risk, compared with BA. Primary stenting using BMS was associated with improved short-to-mid-term patency and TLR, but similar long-term efficacy compared with provisional stenting. Mid-term patency (OR 1.64, 95% CI 0.89–3.03) and TLR (OR 0.50, 95% CI 0.22–1.11) estimates were comparable for DES vs. BMS. Atherectomy, used independently or adjunctively, was not associated with efficacy benefits compared with drug-coated and uncoated angioplasty, or stenting approaches. Paucity and heterogeneity of data precluded pooled analysis for aortoiliac disease and QoL endpoints.ConclusionCertain devices may provide benefits in femoropopliteal disease, but comparative data in aortoiliac arteries is lacking. Gaps in evidence quantity and quality impede identification of the optimal endovascular approach to IC.

Heparin-induced thrombocytopenia (HIT) is a life-threatening complication associated with high medical costs. Factor Xa inhibitors gradually replace approved treatment with intravenous direct thrombin inhibitors despite their off-label indication, because of easier management and favorable economic profile. Whether they are cost-effective remains unclear. We evaluated the cost-effectiveness of approved and off-label anticoagulants in patients with suspected HIT, based on census data from the largest Swiss hospital between 2015 and 2018. We constructed a decision tree model that reflects important clinical events associated with HIT. Relevant cost data were obtained from the finance department or estimated based on the Swiss-wide cost tariff. We estimated averted adverse events (AEs) and incremental cost-effectiveness ratio as primary outcome parameters. We performed deterministic and probabilistic sensitivity analyses with 2000 simulations to assess the robustness of our results. In the base-case analysis, the total cost of averting 1 AE was 49 565 Swiss francs (CHF) for argatroban, 30 380 CHF for fondaparinux, and 30 610 CHF for rivaroxaban; after adjusting for 4Ts score: 41152 CHF (argatroban), 27 710 CHF (fondaparinux), and 37 699 CHF (rivaroxaban). Fondaparinux and rivaroxaban were more clinically effective than argatroban, with AEs averted of 0.820, 0.834, and 0.917 for argatroban, fondaparinux, and rivaroxaban, respectively. Treatment with fondaparinux resulted in less cost and more AEs averted, hence dominating argatroban. Results were most sensitive to AE rates and prolongation of stay. Monte Carlo simulations affirmed our base-case analysis. This is the first cost-effectiveness analysis comparing argatroban with fondaparinux and rivaroxaban using primary data. Fondaparinux and rivaroxaban resulted in more averted AEs, but fondaparinux had greater cost savings. Fondaparinux could be a viable alternative to argatroban.

Atherosclerotic vascular disease remains the most common cause of ischemia, myocardial infarction, and stroke. Vascular function is determined by structural and functional properties of the arterial vessel wall, which consists of three layers, namely the adventitia, media, and intima. Key cells in shaping the vascular wall architecture and warranting proper vessel function are vascular smooth muscle cells in the arterial media and endothelial cells lining the intima. Pathological alterations of this vessel wall architecture called vascular remodeling can lead to insufficient vascular function and subsequent ischemia and organ damage. One major pathomechanism driving this detrimental vascular remodeling is atherosclerosis, which is initiated by endothelial dysfunction allowing the accumulation of intimal lipids and leukocytes. Inflammatory mediators such as cytokines, chemokines, and modified lipids further drive vascular remodeling ultimately leading to thrombus formation and/or vessel occlusion which can cause major cardiovascular events. Although it is clear that vascular wall remodeling is an elementary mechanism of atherosclerotic vascular disease, the diverse underlying pathomechanisms and its consequences are still insufficiently understood.

Atherosclerosis, a lipid-driven inflammatory disease, is the main underlying cause of cardiovascular diseases (CVDs) both in men and women. Sex-related dimorphisms regarding CVDs and atherosclerosis were observed since more than a decade ago. Inflammatory mediators such as cytokines, but also endothelial dysfunction, vascular smooth muscle cell migration and proliferation lead to vascular remodelling but are differentially affected by sex. Each year a greater number of men die of CVDs compared with women and are also affected by CVDs at an earlier age (40-70 years old) while women develop atherosclerosis-related complications mainly after menopause (60+ years). The exact biological reasons behind this discrepancy are still not well-understood. From the numerous animal studies on atherosclerosis, only a few include both sexes and even less investigate and highlight the sex-specific differences that may arise. Endogenous sex hormones such as testosterone and oestrogen modulate the atherosclerotic plaque composition and the frequency of such plaques. In men, testosterone seems to act like a double-edged sword as its decrease with ageing correlates with an increased risk of atherosclerotic CVDs, while testosterone is also reported to promote inflammatory immune cell recruitment into the atherosclerotic plaque. In premenopausal women, oestrogen exerts anti-atherosclerotic effects, which decline together with its level after menopause resulting in increased CVD risk in ageing women. However, the interplay of sex hormones, sex-specific immune responses and other sex-related factors is still incompletely understood. This review highlights reported sex differences in atherosclerotic vascular remodelling and the role of endogenous sex hormones in this process.

Background: PIK3CA (activating mutations of the p110a subunit of phosphatidylinositol 3-kinases)-related overgrowth spectrums (PROS) include a variety of clinical presentations that are associated with hypertrophy of different parts of the body. We performed a systematic literature review to assess the current treatment options and their efficacy and safety for PROS. Methods: A literature search was performed in Embase, MEDLINE (Ovid), Web of Science Core Collection, Cochrane Central Register of Controlled Trials, ClinicalTrials.gov, and Google Scholar to retrieve studies on the treatment of hy-pertrophy in PROS. Randomized controlled trials, cohort studies, and case series with $10 patients were included in the present review. The titles, abstracts, and full text were assessed by two reviewers independently. The risk of bias was assessed using the Newcastle-Ottawa scale. Results: We included 16 studies of the treatment of hypertrophy in PROS patients, 13 (81.3%) from clinical retrospective studies and 3 (13.7%) from prospective cohort studies. The risk of bias grade was low for 2, medium for 12, and high for 2 studies. Of the 16 studies, 13 reported on surgical treatment and 3 reported pharmacologic treatment using phospha-tidylinositol-3-kinase (PI3K)/mammalian target of rapamycin (mTOR) pathway inhibitors in PROS patients. In 3 studies, PROS was defined by a mutation in the PIK3CA gene, and 13 studies relied on a clinical definition of PROS. Surgical therapy was beneficial for a specific subgroup of PROS (macrodactyly). However, little has been reported concerning surgery and the potential benefits for other PROS entities. The reported side effects after surgical therapy were mostly prolonged wound healing or scarring. PI3K/mTOR pathway inhibition was beneficial in patients with PROS by reducing hypertrophy and systemic symptoms. The adverse effects reported included infection, changes in blood count, liver enzymes, and metabolic measures. Conclusions: Surgery is a locally limited treatment option for specific types of PROS. A promising treatment option for PROS is pharmacologic PIK3CA inhibition. However, the level of evidence on the treatment of overgrowth in PROS patients is limited.

Objective: Arteriovenous malformations of the lower extremities (AVM(LE)) can present as simple or complex combined or syndromic forms (eg, Parkes Weber Syndrome). We aimed to characterize the differences in clinical presentation and natural history of these potentially life- and limb-threatening congenital vascular malformations. Methods: We conducted a retrospective analysis of a consecutive series of patients with AVMLE who presented to a tertiary referral center in Switzerland between 2008 and 2018. Clinical baseline characteristics, D-dimer level, and course were summarized and differences between simple, non-syndromic and combined or syndromic AVMLE determined. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using logistic regression models. Results: Overall, 506 patients were prospectively enrolled in the Bernese Congenital Vascular Malformation Registry, 31 (6%) with AVMLE. There were 16 women and 15 men, with a mean age of 18 years at first diagnosis (range, 1 month to 72 years). Simple AVMLE was present in 22 (71%) and combined or syndromic AVMLE with limb overgrowth in 9 patients (29%), respectively. Common symptoms and signs were pain (n = 25; 81%), swelling (n = 21; 68%), and soft tissue hypertrophy (n = 13; 42%). Among combined or syndromic patients, three patients died from wound infection with sepsis or disseminated intravascular coagulation with bleeding complications (intracranial hemorrhage and bleeding from extensive leg ulcers). Combined or syndromic patients presented more often with bleeding (67% vs 5%; P < .001), malformation-related infection (44% vs 5%; P = .017) and leg length difference (56% vs 14%; P = .049). D-dimer levels were elevated (mean, 17,256 mg/L; range, 1557-80,000 mg/L) and angiographic appearance showed complex, mixed type of AVMs, including interstitial type IV, in all patients with combined or syndromic AVMLE. Conclusions: Patients with congenital simple AVMLE most often present with benign clinical features and rarely with complications related to hemodynamic changes. Patients with combined or syndromic AVMLE often face serious outcomes dominated by complications other than direct high-flow-related heart failure.

BACKGROUND:Endovenous stent placement has become a first-line approach to prevent post-thrombotic syndrome in patients with chronic post-thrombotic obstruction (PTO) or nonthrombotic iliac vein lesions if conservative management fails. This study aims to identify factors associated with loss of patency to facilitate patient selection for endovenous stenting. METHODS:We retrospectively analyzed 108 consecutive patients after successful endovenous stenting for chronic vein obstruction performed at a single institution from January 2008 to July 2020. Using multivariable logistic regression, we explored potential predictive factors for loss of stent patency, including baseline demographics, post-thrombotic changes, and peak flow velocities measured in the common femoral vein (CFV), deep femoral vein, and femoral vein (FV) using duplex ultrasound examination. RESULTS:The mean follow-up duration was 41 ± 26 months, and participants had a mean age of 47.4 ± 15.4 years with 46.3% women. Ninety (83.3%) patients had PTO and 18 (16.7%) had nonthrombotic iliac vein lesions, predominantly due to May-Thurner syndrome. Loss of patency occurred in 20 (18.5%) patients, all treated for PTO. Comorbidities, side of intervention, and sex did not differ between patients with occluded and patent stents. Stent occlusion was more common with increasing number of stents implanted (P < .001) and with distal stent extension into and beyond the CFV (P < .001). Preinterventional predictive factors for stent occlusion were lower duplex ultrasound peak velocity in the CFV (odds ratio [OR]: 7.52, 95% confidence interval [CI]: 2.54-22.28; P < .001) and FV (OR: 10.75, 95% CI: 2.07-55.82; P < .005), and post-thrombotic changes in the deep femoral vein (OR: 4.51, 95% CI: 1.53-13.25; P = .006) and FV (OR: 3.62: 95% CI: 1.11-11.84; P = .033). Peak velocities of ≤7 cm/s (interquartile range: 0-20 cm/s) in the CVF and ≤8 cm/s (interquartile range: 5-10 cm/s) in the FV were significantly associated with loss of patency. CONCLUSIONS:Insufficient venous inflow as assessed by low peak velocities in the CFV and FV as well as post-thrombotic findings represent reliable risk predictors for stent occlusions, warranting their inclusion into the decision-making process for invasive treatment of PTO.