Ligand and G-protein selectivity in the κ-opioid receptor.

The κ-opioid receptor (KOR) represents a highly desirable therapeutic target for treating not only pain but also addiction and affective disorders1. However, the development of KOR analgesics has been hindered by the associated hallucinogenic side effects2. The initiation of KOR signalling requires the Gi/o-family proteins including the conventional (Gi1, Gi2, Gi3, GoA and GoB) and nonconventional (Gz and Gg) subtypes. How hallucinogens exert their actions through KOR and how KOR determines G-protein subtype selectivity are not well understood. Here we determined the active-state structures of KOR in a complex with multiple G-protein heterotrimers-Gi1, GoA, Gz and Gg-using cryo-electron microscopy. The KOR-G-protein complexes are bound to hallucinogenic salvinorins or highly selective KOR agonists. 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. Furthermore, the four G-protein subtypes display an intrinsically different binding affinity and allosteric activity on agonist binding at KOR. These results provide insights into the actions of opioids and G-protein-coupling specificity at KOR and establish a foundation to examine the therapeutic potential of pathway-selective agonists of KOR.

NETs-Induced Thrombosis Impacts on Cardiovascular and Chronic Kidney Disease.

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.

Somatic RIT1 delins in arteriovenous malformations hyperactivate RAS-MAPK signaling amenable to MEK inhibition.

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.

Endovascular revascularization strategies for aortoiliac and femoropopliteal artery disease: a meta-analysis.

AIMS: Optimal 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 RESULTS: Electronic 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. CONCLUSION: Certain 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.

Sex-specific and hormone-related differences in vascular remodelling in atherosclerosis.

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.

Comparison Between Interwoven Nitinol and Drug Eluting Stents for Endovascular Treatment of Femoropopliteal Artery Disease.

OBJECTIVES: Information on performance of different stent platforms in endovascular revascularisation of femoropopliteal lesions is controversial and scarce. METHODS: Interwoven nitinol (INS, Supera) were compared with drug eluting (DES, Zilver PTx) stents with primary intervention for femoropopliteal lesions. The primary endpoint was time to clinically driven target lesion revascularisation (CD-TLR) within 12 months. Secondary endpoints were time to death, amputation and composite of death, amputation and CD-TLR. Due to the retrospective analysis, inverse probability treatment weighted (IPTW) Cox models were calculated to reach more similar patient populations with weights for the average treatment effect of the population. The two sensitivity analyses were propensity score matching and adjustment for covariates. RESULTS: At 12 months, the cumulative incidence of CD-TLR in the INS group (13%) and DES group (18%) did not differ (HR 1.36, 95% CI 0.56-3.31). A significant interaction between stents used and grade of calcification was observed (p = .006). HR for CD-TLR was 6.4 (95% CI 1.3-32.5) in none to mildly calcified favouring INS, and 0.3 (95% CI 0.1-1.3) for moderate to severely calcified lesions favouring DES. Stent efficiency did not differ comparing treatment of popliteal lesions (HR 0.80; 95% CI 0.21-3.13). Sensitivity analyses confirmed the primary efficacy outcome for either adjusted (HR 1.16; 95% CI 0.51-2.62) or matched analysis (HR 1.35; 95% CI 0.50-3.62)). Interaction of stents with calcification grade was lost for adjusted (HR 0.28; 95% CI 0.06-1.19) and matched analysis (HR 0.53; 95% CI 0.10-2.91). CONCLUSION: Both stents (INS and DES) showed comparable results regarding CD-TLR in femoropopliteal lesions, so that one stent could not be favoured over the other, even for calcified or popliteal artery lesions.

GPCR-G protein selectivity revealed by structural pharmacology.

Receptor-G protein promiscuity is frequently observed in class A G protein-coupled receptors (GPCRs). In particular, GPCRs can couple with G proteins from different families (Gαs, Gαq/11, Gαi/o, and Gα12/13) or the same family subtypes. The molecular basis underlying the selectivity/promiscuity is not fully revealed. We recently reported the structures of kappa opioid receptor (KOR) in complex with the Gi/o family subtypes [Gαi1, GαoA, Gαz, and Gustducin (Gαg)] determined by cryo-electron microscopy (cryo-EM). The structural analysis, in combination with pharmacological studies, provides insights into Gi/o subtype selectivity. Given the conserved sequence identity and activation mechanism between different G protein families, the findings within Gi/o subtypes could be likely extended to other families. Understanding the KOR-Gi/o or GPCR-G protein selectivity will facilitate the development of more precise therapeutics targeting a specific G protein subtype.

A proposal for a revision of the phlebographic classification of congenital venous malformations.

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 (κ). 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% (κ=0.91). Classical Puig classification into types I, II, III and IV showed 87% inter-reader agreement (κ=0.78). For the adjusted classification adding the non-lacunar or lacunar characteristic to type I-IV an agreement of 82% (κ=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.

Structure-Guided Design of Partial Agonists at an Opioid Receptor.

The persistence of chronic pain and continuing overdose deaths from pain-relieving opioids targeting µ opioid receptor (µOR) have fueled the need for reliable long-term analgesics which use different targets and mechanisms. The δ opioid receptor (δOR) is a potential alternative target for non-addictive analgesics to alleviate chronic pain, made more attractive by its lack of respiratory depression associated with µOR agonists. However, early δOR full agonists were found to induce seizures, precluding clinical use. Partial δOR agonists may offer more controlled activation of the receptor compared to full agonists, but the development of such ligands has been hindered by uncertainty over the molecular mechanism mediating partial agonism. Using a structure-based approach, we explored the engagement of the sodium binding pocket in δOR and developed a bitopic ligand, C6-Quino, predicted to be a selective δOR partial agonist. Functional studies of C6-Quino revealed that it displayed δOR partial agonist activity at both G-protein and arrestin pathways. Its interaction with the sodium pocket was confirmed and analyzed using a single particle cryo-EM. Additionally, C6-Quino demonstrated favorable chemical and physiological properties like oral activity, and analgesic activity in multiple chronic pain models. Notably, µOR-related hyperlocomotion and respiratory depression, and δOR-related convulsions, were not observed at analgesic doses of C6-Quino. This fundamentally new approach to designing δOR ligands provides a blueprint for the development of partial agonists as safe analgesics and acts as a generic method to optimize signaling profiles of other Class A GPCRs.

The COVID-19 pandemic, well-being, and transitions to post-secondary education.

This study examines the immediate and intermediate effects of the COVID-19 pandemic on the well-being of two high school graduation cohorts (2020 and 2021) and how changes in well-being affect students' educational plans and outcomes. Our unique panel data on 3697 students from 214 schools in 8 German federal states contain prospective survey information on three dimensions of well-being: mental health problems, self-rated health, and life satisfaction. Data is collected several months before (fall 2019), shortly before and soon after (spring 2020) as well as several months after (fall/winter 2020/21) the beginning of the COVID-19 pandemic. Applying difference-in-differences designs, random effect growth curve models, and linear regression models, we find that school closures had a positive immediate effect on students' well-being. Over the course of the pandemic, however, well-being strongly declined, mainly among the 2021 graduation cohort. We show that a strong decline in mental health is associated with changes in educational and career plans and transition outcomes. As adverse life experiences in adolescence are likely to accumulate over the life course, this study is the first to exhibit potential long-lasting negative effects of the COVID-19 pandemic on education and careers of young individuals.

Criteria to predict midterm outcome after stenting of chronic iliac vein obstructions (PROMISE trial).

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.

Clinical phenotype of adolescent and adult patients with extracranial vascular malformation.

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 according 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 intravascular 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 combined 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 malformations 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.

Molecular mechanism of biased signaling at the kappa opioid receptor.

The κ-opioid receptor (KOR) has emerged as an attractive drug target for pain management without addiction, and biased signaling through particular pathways of KOR may be key to maintaining this benefit while minimizing side-effect liabilities. As for most G protein-coupled receptors (GPCRs), however, the molecular mechanisms of ligand-specific signaling at KOR have remained unclear. To better understand the molecular determinants of KOR signaling bias, we apply structure determination, atomic-level molecular dynamics (MD) simulations, and functional assays. We determine a crystal structure of KOR bound to the G protein-biased agonist nalfurafine, the first approved KOR-targeting drug. We also identify an arrestin-biased KOR agonist, WMS-X600. Using MD simulations of KOR bound to nalfurafine, WMS-X600, and a balanced agonist U50,488, we identify three active-state receptor conformations, including one that appears to favor arrestin signaling over G protein signaling and another that appears to favor G protein signaling over arrestin signaling. These results, combined with mutagenesis validation, provide a molecular explanation of how agonists achieve biased signaling at KOR.

Moderate correlations of in vitro versus in vivo pharmacokinetics questioning the need of early microsomal stability testing.

BACKGROUND/AIMS: Putative in vitro-in vivo correlations of pharmacokinetic (PK) parameters are regarded as a prerequisite to filter hits derived from high-throughput screening (HTS) approaches for subsequent murine in vivo PK studies. METHODS: In this study, we assessed stabilities in rat and human microsomes of 121 compounds from an early, academic drug discovery programme targeting the (pro)renin receptor and correlated the respective data with single-dose, in vivo PK parameters of 22 hits administered intravenously in rats. RESULTS: After transformation of in vitro half-lives to predicted in vivo hepatic clearances, r(2) regarding in vitro-in vivo clearance correlations were 0.31 and 0.27 for the rat and human species, respectively. CONCLUSIONS: Our data concerning structurally diverse real-world compounds indicate that microsomal stability testing is not a tool to triage early compounds for in vivo PK testing.

Cost-effectiveness analysis of alternative anticoagulation in suspected heparin-induced thrombocytopenia.

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: 41 152 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.

Inflammatory Mediators in Atherosclerotic Vascular Remodeling.

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.

Clinical presentation of simple and combined or syndromic arteriovenous malformations.

OBJECTIVE: Arteriovenous malformations of the lower extremities (AVMLE) 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 µg/L; range, 1557-80,000 µg/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.

A systematic review of the safety and efficacy of currently used treatment modalities in the treatment of patients with PIK3CA-related overgrowth spectrum.

BACKGROUND: PIK3CA (activating mutations of the p110α 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 hypertrophy 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 phosphatidylinositol-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.

Capillary-venule malformation is a microfistulous variant of arteriovenous malformation.

OBJECTIVE: To describe typical clinical presentation of patients with microfistular, capillary-venule (CV) malformation as a variant form of arteriovenous malformations (AVM). METHODS: A retrospective clinical analysis of 15 patients with CV-AVM confirmed by a computational flow model enrolled in a prospective database of patients with congenital vascular malformation between January 2008 and May 2018. RESULTS: The mean age of the patients at first time of presentation was 30 years with balanced sex ratio. Presentation was dominated by soft tissue hypertrophy (n = 12 [80.0%]) and atypical varicose veins (n = 11 [73.3%]). The anatomic location of enlarged varicose veins gave no uniform pattern and did not correspond with the typical picture of primary varicose vein disease. Most often, symptomatic CV-AVM was found at the lower extremities in this series of unselected patients. The most frequent compartment affected was the subcutis (n = 14 [93.3%]), involvement of muscle was recorded in one-third and cutis in one-fourth of patients. CONCLUSIONS: A high grade of clinical suspicion is needed to recognize CV-AVM and to prevent inadequate therapy owing to missed diagnosis.