Angiogenic and prothrombotic markers in extensive slow-flow vascular malformations: implications for antiangiogenic/antithrombotic strategies

Association of Angiopoetin-2 and TNF-α With Bleeding During Left Ventricular Assist Device Support: Analysis From the PREVENT Biorepository

The purpose of this study was to describe the changes in plasma levels of angiogenic and inflammatory biomarkers, specifically Ang-2 and TNF-α, in patients receiving HeartMate II (HMII) left ventricular assist device (LVAD) and correlate them with nonsurgical bleeding. It has been shown that angiopoietin-2 (Ang-2) and tissue necrosis factor-α (TNF-α) may be linked to bleeding in LVAD patients. This study utilized biobanked samples prospectively collected from the PREVENT study, a prospective, multicenter, single-arm, nonrandomized study of patients implanted with HMII. Paired serum samples were obtained in 140 patients before implantation and at 90 days postimplantation. Baseline demographics were as follows: age 57 ± 13 years, 41% had ischemic etiology, 82% male, and 75% destination therapy indication. In the 17 patients with baseline elevation of both TNF-α and Ang-2, 10 (60%) experienced a significant bleeding event within 180 days postimplant compared with 37 of 98 (38%) patients with Ang-2 and TNF-α below the mean ( p = 0.02). The hazard ratio for a bleeding event was 2.3 (95% CI: 1.2-4.6) in patients with elevated levels of both TNF-α and Ang-2. In the PREVENT multicenter study, patients with elevations in serum Angiopoietin-2 and TNF-α at baseline before LVAD implantation demonstrated increased bleeding events after LVAD implantation.

A histological study of vascular wall resident stem cells in venous malformations

Vascular wall resident stem cells (VW-SCs) play a key role in vascular formation and remodeling under both physiological and pathological situations. They not only serve as a reservoir to supply all types of vascular cells needed, but also regulate vascular homeostasis by paracrine effects. Venous malformations (VMs) are common congenital vascular malformations which are just characterized by the deficient quantity and abnormal function of vascular cells. However, the existence and role of VW-SCs in VMs is still unclear at present. In this study, the level and distribution of VW-SCs in 22 specimens of VMs were measured by immunochemistry, double-labeling immunofluorescence, and qPCR, followed by the Spearman rank correlation test. We found that both the protein and mRNA expression levels of CD34, vWF, VEGFR2, CD44, CD90, and CD105 were significantly downregulated in VMs compared with that in normal venules. VW-SCs were sporadically distributed or even absent within and outside the endothelium of VMs. The expression of the VW-SC-related markers was positively correlated with the density of both endothelial cells and perivascular cells. All those results and established evidence indicated that VW-SCs were more sporadically distributed with fewer amounts in VMs, which possibly contributing to the deficiency of vascular cells in VMs.

Intravenous administration of umbilical cord lining stem cells in left ventricular assist device recipient: Rationale and design of the uSTOP LVAD BLEED pilot study

Background

Left ventricular assist device (LVAD) implantation provides a robust survival advantage, however despite improvements in mortality, the adverse event burden of durable mechanical circulatory support remains high. Bleeding complications are one such significant complication. The uSTOP LVAD BLEED (Utilization of umbilical cord lining Stem cells TO Prevent LVAD associated angiodysplastic BLEEDing) pilot study is designed to evaluate the safety and tolerability of escalating doses of umbilical cord lining stem cells (ULSCs) in LVAD recipients to ameliorate the dysregulation of angiogenic factors seen in this population.

Design

This Phase Ia single-ascending dose pilot study will evaluate the IV administration of ULSCs in stable out-patients supported with an LVAD. In a 3 + 3 design, a maximum of 18 patients will receive an IV infusion of ULSCs.

Main outcome measures

The primary endpoints are safety and tolerability, secondary exploratory endpoints will include biomarker evaluation of angiogenic dysregulation.

Summary

This represents a novel cell type and route of administration in this population, while collecting initial data regarding the magnitude and duration of effects of cell therapy, and assessing the possibility of decreasing bleeding by a strategy of vascular stabilization.

Clinical trial registration

ClinicalTrials.gov Identifier: NCT04811261. https://clinicaltrials.gov/ct2/show/NCT04811261.

Molecular basis for pericyte-induced capillary tube network assembly and maturation

Here we address the functional importance and role of pericytes in capillary tube network assembly, an essential process that is required for vascularized tissue development, maintenance, and health. Healthy capillaries may be directly capable of suppressing human disease. Considerable advances have occurred in our understanding of the molecular and signaling requirements controlling EC lumen and tube formation in 3D extracellular matrices. A combination of SCF, IL-3, SDF-1α, FGF-2 and insulin ("Factors") in conjunction with integrin- and MT1-MMP-induced signaling are required for EC sprouting behavior and tube formation under serum-free defined conditions. Pericyte recruitment to the abluminal EC tube surface results in elongated and narrow tube diameters and deposition of the vascular basement membrane. In contrast, EC tubes in the absence of pericytes continue to widen and shorten over time and fail to deposit basement membranes. Pericyte invasion, recruitment and proliferation in 3D matrices requires the presence of ECs. A detailed analysis identified that EC-derived PDGF-BB, PDGF-DD, ET-1, HB-EGF, and TGFβ1 are necessary for pericyte recruitment, proliferation, and basement membrane deposition. Blockade of these individual factors causes significant pericyte inhibition, but combined blockade profoundly interferes with these events, resulting in markedly widened EC tubes without basement membranes, like when pericytes are absent.

Sirolimus (Rapamycin) for Slow-Flow Malformations in Children: The Observational-Phase Randomized Clinical PERFORMUS Trial

Importance

Sirolimus is increasingly being used to treat various vascular anomalies, although evidence of its efficacy is lacking.

Objective

To assess the efficacy and safety of sirolimus for children with slow-flow vascular malformations to better delineate the indications for treatment.

Design, Setting and Participants

This multicenter, open-label, observational-phase randomized clinical trial included 59 children aged 6 to 18 years with a slow-flow vascular malformation who were recruited between September 28, 2015, and March 22, 2018, in 11 French tertiary hospital centers. Statistical analysis was performed on an intent-to-treat basis from December 4, 2019, to November 10, 2020.

Interventions

Patients underwent an observational period, then switched to an interventional period when they received oral sirolimus (target serum levels, 4-12 ng/mL). The switch time was randomized from month 4 to month 8, and the whole study period lasted 12 months for each patient.

Main Outcomes and Measures

The primary outcome was change in the volume of vascular malformations detected on magnetic resonance imaging scan (with centralized interpretation) per unit of time (ie, between the interventional period and the observational period). Secondary outcomes included subjective end points: pain, bleeding, oozing, quality of life, and safety.

Results

Among the participants (35 girls [59.3%]; mean [SD] age, 11.6 [3.8] years), 22 (37.3%) had a pure venous malformation, 18 (30.5%) had a cystic lymphatic malformation, and 19 (32.2%) had a combined malformation, including syndromic forms. Variations in the volume of vascular malformations detected on magnetic resonance imaging scans associated with the duration period were not overall significantly different between the interventional period and the observational period (all vascular malformations: mean [SD] difference, -0.001 [0.007]; venous malformations: mean [SD] difference, 0.001 [0.004]; combined malformations: mean [SD] difference, 0.001 [0.009]). However, a significant decrease in volume was observed for children with pure lymphatic malformations (mean [SD] difference, -0.005 [0.005]). Overall, sirolimus had positive effects on pain, especially for combined malformations, and on bleeding, oozing, self-assessed efficacy, and quality of life. During sirolimus treatment, 56 patients experienced 231 adverse events (5 serious adverse events, none life-threatening). The most frequent adverse event was an oral ulcer (29 patients [49.2%]).

Conclusions and Relevance

This observational-phase randomized clinical trial allows for clarifying the goals of patients and families when starting sirolimus therapy for children older than 6 years. Pure lymphatic malformations seem to be the best indication for sirolimus therapy because evidence of decreasing lymphatic malformation volume per unit of time, oozing, and bleeding and increasing quality of life was found. In combined malformations, sirolimus significantly reduced pain, oozing, and bleeding. Benefits seemed lower for pure venous malformations than for the 2 other subgroups, also based on symptoms.

Trial Registration

ClinicalTrials.gov Identifier: NCT02509468; clinicaltrialsregister.eu Identifier: 2015-001096-43.

Mosaic abnormalities of the skin: review and guidelines from the European Reference Network for rare skin diseases

BACKGROUND

Cutaneous mosaicism is an area of dermatology in which there has been an explosion of knowledge within the current decade. This has led to fundamental changes in the understanding of the conditions in this field, and to an ongoing paradigm shift in the approach to management of mosaic skin disorders.

OBJECTIVES

To lay out the general principles of mosaicism as they are currently understood, summarize the known cutaneous mosaic abnormalities of the skin with associated phenotypic and genotypic information, review the latest trials on targeted therapies and propose guidelines for the general approach to a patient with suspected mosaicism.

METHODS

This was a consensus expert review as part of the European Reference Network project (ERN-Skin).

CONCLUSIONS

This study provides clinicians with a practical approach to the patient with suspected mosaicism, redefines mosaicism for the modern genetic era, and proposes a new classification system based on genetic mechanism. What's already known about this topic? Cutaneous mosaicism is a complex field of dermatology that encompasses most birthmarks, and many rare syndromes. Some cutaneous patterns are known to be seen in mosaicism. Very few treatment options are available for most mosaic abnormalities of the skin. Recent high-sensitivity genetic techniques have led to an explosion of knowledge about genotype and phenotype in the literature. What does this study add? Expert consensus from the European Reference Network project. Review of knowledge of confirmed mosaic abnormalities of the skin, including cutaneous phenotype, extracutaneous associated features and genotype. Proposed new classification of mosaic abnormalities of the skin by genetic mechanism and therefore inheritance potential. Practical tips on correct sample collection and genetic investigation. Review of trials of targeted therapies. Guidelines for a practical clinical approach to the patient with suspected mosaicism.

Dermatofibrosarcoma protuberans coexisting in a patient with a vascular malformation-a rare coincidence

Dermatofibrosarcoma protuberans with fibrosarcomatous differentiation (DFSP-FS) is a rare soft tissue tumor with more aggressive behavior and it is not clear what causes this type of skin cancer. We describe the case of a 48-year-old woman who was born with a vascular malformation in the sternal region and presented suddenly with a soft tissue sarcoma (DFSP-FS) in the same territory. She was initially treated by embolization as the sarcoma was misdiagnosed but the tumor within 6 months seemed to be growing rapidly and reached a giant dimension with ulceration and required surgical intervention. The patient underwent a surgical removal of the mass but as the pathology report included a DFSP-FS with close margins,a second operation was required. A wide local excision was performed and reconstruction of defect by using bilateral pectoralis major muscle flaps and a full thickness skin graft from the abdominal wall. Post operatively the patient was treated with radiotherapy.

Tumor necrosis factor-α levels and non-surgical bleeding in continuous-flow left ventricular assist devices

BACKGROUND

Non-surgical bleeding (NSB) due to angiodysplasia is common in left ventricular assist device (LVAD) patients. Thrombin-induced angiopoietin-2 (Ang-2) expression in LVAD patients leads to altered angiogenesis and is associated with lower angiopoietin-1 (Ang-1) and increased NSB. However, the mechanism for decreased Ang-1, made by pericytes, is unknown and the origin of thrombin in LVAD patients is unclear. We hypothesized that high tumor necrosis factor-α (TNF-α) levels in LVAD patients induce pericyte apoptosis, tissue factor (TF) expression and vascular instability.

METHODS

We incubated cultured pericytes with serum from patients with heart failure (HF), LVAD or orthotopic heart transplantation (OHT), with or without TNF-α blockade. We performed several measurements: Ang-1 expression was assessed by reverse transcript-polymerase chain reaction (RT-PCR) and pericyte death fluorescently; TF expression was assessed by RT-PCR in cultured endothelial cells incubated with patient plasma with or without TNF-α blockade; and TF expression was assessed in endothelial biopsy samples from these patients by immunofluorescence. We incubated cultured endothelial cells on Matrigel with patient serum with or without TNF-α blockade and determined tube formation by microscopy.

RESULTS

Serum from LVAD patients had higher levels of TNF-α, suppressed Ang-1 expression in pericytes, and induced pericyte death, and there was accelerated endothelial tube formation compared with serum from patients without LVADs. TF was higher in both plasma and endothelial cells from LVAD patients, and plasma from LVAD patients induced more endothelial TF expression. All of these effects were reversed or reduced with TNF-α blockade. High levels of TNF-α were associated with increased risk of NSB.

CONCLUSIONS

Elevated TNF-α in LVAD patients is a central regulator of altered angiogenesis, pericyte apoptosis and expression of TF and Ang-1.

A Diagnostic Program of Vascular Tumor and Vascular Malformations in Children According to Modern Classification

The aim of the study was to analyze the cohort of inpatient children with vascular anomalies according to the globally accepted classification introduced by the ISSVA.

METHODS

The study included 205 inpatient children within the time period of the years 2010-2015. Types of vascular anomalies (VAs), age of patients, diagnostic procedures, and anatomical localization of VAs were analyzed.

RESULTS

65 patients of first year of life had vascular tumors, with prevalence of infantile hemangiomas (IHs) in 57 (87.7%) patients. 45 children had IHs localized within soft tissues, whereas 7 patients suffered from IHs of the liver, and 5 children from IHs of the respiratory tract. Most patients with soft tissue IHs were diagnosed only with ultrasound; СT or MRI diagnostics were performed on 5 (8.8%) patients, and biopsy was carried out in 2 (4.4%) children. Vascular malformations (VM) were diagnosed in 140 (68.3%) patients. Ultrasound investigation (US) was the screening method. MRI was performed to confirm the diagnosis of low-flow VM, whereas for high-flow VM CT angiography and selective angiography were useful. Venous malformations were diagnosed in 17 (12.1%) patients, and 112 (80.0%) had cystic LM, among them children under the age of 2 years prevailed. Arteriovenous malformations were diagnosed in 5 (3.8%) patients, ages 2-14 years.

CONCLUSIONS

Clinical manifestations of vascular anomalies have clear age features. Among hospitalized children vascular tumors add up to 31.7% and VM - up to 68.3%.

Interdisciplinary Management of Head and Neck Vascular Anomalies: Clinical Presentation, Diagnostic Findings and Minimalinvasive Therapies

OBJECTIVES

Vascular anomalies are included in the 30 000 rare diseases worldwide affecting less than 5/10 000 people. Depending on their morphology and biological properties, they can cause varied disorders with organ involvement. Almost 60% of vascular anomalies have a predilection for the head and neck region in children. Clinical and scientific effort to establish interdisciplinary management concepts for vascular anomalies is increasing worldwide.

METHODS

Especially in the head and neck region, clinical impairment and organ dysfunction is associated with cosmetic issues that may represent a physical and psychological issue for the patient. Correct diagnosis, based on clinical presentation and symptoms, is a prerequisite for appropriate therapy, ranging from conservative management to a spectrum of minimally invasive treatment options. We searched PubMed for German and English language published data until December 2016 with focus on clinical studies, review articles and case reports on vascular anomalies with a focus on the head and neck region.

RESULTS

The last ISSVA update in 2014 has contributed to a better understanding of vascular anomalies, classifying them in vascular tumors and vascular malformations. The predominant representatives of vascular tumors are congenital and infantile hemangiomas. Infantile hemangiomas have the ability of spontaneous regression in more than 80%. Patients with symptomatic growing hemangiomas with ulcerations, bleeding complications and restriction of hearing, swallowing disorder, impairment of vision, or cosmetic dysfigurement require treatment. Therapies include oral propanolol, transcatheter embolization and surgery. Vascular malformations tend to progress with patientś age and are subdivided in slow flow and fast flow lesions. Symptomatic slow flow lesions, e.g. venous and lymphatic malformations, benefit from percutaneous sclerotherapy. Fast flow lesions, as arteriovenous malformations, are rare but undoubtedly therapeutically the most challenging vascular anomaly. Depending on location and size, they may require multiple transcatheter embolization procedures for successful occlusion of the AVM.

CONCLUSIONS

This review provides knowledge on the current ISSVA classification of vascular anomalies, their clinical presentation, diagnostic evaluation and minimally invasive therapy options to encourage the establishment of a comprehensive interdisciplinary management for head and neck vascular anomalies.

Factors associated with thrombotic complications in pediatric patients with vascular malformations

BACKGROUND AND OBJECTIVES

Thrombosis is an uncommon disorder in children. Patients with slowflow vascular malformations have higher risk of developing localized intravascular coagulation, which is closely related to the presence of thrombotic events. These episodes cause pain, can be recurrent and determine a clear deterioration in the quality of life. Moreover, serious complications such as pulmonary thromboembolism and eventually death have been described. The aim of the present study is to identify clinical and laboratory risk factors associated with thrombotic events in pediatric patients with vascular malformations.

METHODS

Case-Control study. Clinical records of patients who consulted the vascular anomalies study group (VASG). This group carries out interdisciplinary assessment of patients with vascular malformations. From June 2008 to December 2014, 110 patients were assessed of whom 46 patients met the inclusion criteria, with half of them presenting a thrombotic complication and the others not, these latter serving as controls. Statistical analysis included multivariate logistic regression analysis to determine major risk factors for thrombosis.

RESULTS

In the bivariate analysis we found a significant association between increased levels of Ddimer and thrombotic complications (OR 17.1 [95% CI 3.95-73.95; p<0.01]). In addition, a surface area≥10cm² (OR 6.18 [95% CI 1.59-23.99; p<0.01]) and the presence of palpable phleboliths (OR 20.17 [95% CI 2.32-165.77; p<0.01]) were associated with a significant higher risk of thrombosis. Multivariate analysis identified older age (OR 1.33; p=0.013), a surface area≥10cm² (OR 8.19; p=0.042) and palpable phleboliths (OR 85.29; p<0.01) as significant risk factors.

CONCLUSIONS

Our study suggests the existence of clinical factors associated with higher risk of thrombotic complications, such as the extent of the malformation, palpable phleboliths and increased age among children with vascular malformations.

Parkes Weber syndrome-Diagnostic and management paradigms: A systematic review

Objectives Parkes Weber syndrome is a congenital vascular malformation which consists of capillary malformation, venous malformation, lymphatic malformation, and arteriovenous malformation. Although Parkes Weber syndrome is a clinically distinctive entity with serious complications, it is still frequently misdiagnosed as Klippel-Trenaunay syndrome that consists of the triad capillary malformation, venous malformation, and lymphatic malformation. Methods We performed a systematic review investigating clinical, diagnostic, and treatment modalities of Parkes Weber syndrome (PubMed/MEDLINE, Embase, and Cochrane databases). Thirty-six publications (48 patients) fulfilled the eligibility criteria. Results The median age of patients was 23 years (IQR, 8-32), and 24 (50.0%) were males. Lower extremity was affected in 42 (87.5%) and upper extremity in 6 (12.5%) patients; 15 (31.3%) patients developed high-output heart failure; 12 (25.0%) patients had chronic venous ulcerations, whereas 4 (8.3%) manifested distal arterial ischemia. The spinal arteriovenous malformations were reported in six (12.5%) patients and coexistence of aneurysmatic disease in five (10.4%) patients. The most frequently utilized invasive treatments were embotherapy followed by amputation and surgical arteriovenous malformation resection, and occasionally stent-graft implantation. All modalities showed clinical improvement. However, long follow-up and outcome remained unclear. Conclusion A diagnosis of Parkes Weber syndrome should be made on the presence of capillary malformation, venous malformation, lymphatic malformation, and arteriovenous malformation (as main defect) in overgrowth extremity. Arteriovenous malformation presents the criterion for distinguishing Parkes Weber syndrome from Klippel-Trenaunay syndrome, which is substantial for treatment strategy. The primary management goal should be patient's quality of life improvement and complication reduction. Embolization alone/combined with surgical resection targeting occlusion or removal of arteriovenous malformation "nidus" reliably leads to clinical improvement.

Elevated Angiopoietin-2 Level in Patients With Continuous-Flow Left Ventricular Assist Devices Leads to Altered Angiogenesis and Is Associated With Higher Nonsurgical Bleeding

BACKGROUND

Nonsurgical bleeding is the most common adverse event in patients with continuous-flow left ventricular assist devices (LVADs) and is caused by arteriovenous malformations. We hypothesized that deregulation of an angiogenic factor, angiopoietin-2 (Ang-2), in patients with LVADs leads to increased angiogenesis and higher nonsurgical bleeding.

METHODS

Ang-2 and thrombin levels were measured by ELISA and Western blotting, respectively, in blood samples from 101 patients with heart failure, LVAD, or orthotopic heart transplantation. Ang-2 expression in endothelial biopsy was quantified by immunofluorescence. Angiogenesis was determined by in vitro tube formation from serum from each patient with or without Ang-2-blocking antibody. Ang-2 gene expression was measured by reverse transcription-polymerase chain reaction in endothelial cells incubated with plasma from each patient with or without the thrombin receptor blocker vorapaxar.

RESULTS

Compared with patients with heart failure or those with orthotopic heart transplantation, serum levels and endothelial expression of Ang-2 were higher in LVAD patients (P=0.001 and P<0.001, respectively). This corresponded to an increased angiogenic potential of serum from patients with LVADs (P<0.001), which was normalized with Ang-2 blockade. Furthermore, plasma from LVAD patients contained higher amounts of thrombin (P=0.003), which was associated with activation of the contact coagulation system. Plasma from LVAD patients induced more Ang-2 gene expression in endothelial cells (P<0.001), which was reduced with thrombin receptor blockade (P=0.013). LVAD patients with Ang-2 levels above the mean (12.32 ng/mL) had more nonsurgical bleeding events compared with patients with Ang-2 levels below the mean (P=0.003).

CONCLUSIONS

Our findings indicate that thrombin-induced Ang-2 expression in LVAD patients leads to increased angiogenesis in vitro and may be associated with higher nonsurgical bleeding events. Ang-2 therefore may contribute to arteriovenous malformation formation and subsequent bleeding in LVAD patients.

Common and specific effects of TIE2 mutations causing venous malformations

Venous malformations (VMs) are localized defects in vascular morphogenesis frequently caused by mutations in the gene for the endothelial tyrosine kinase receptor TIE2. Here, we report the analysis of a comprehensive collection of 22 TIE2 mutations identified in patients with VM, either as single amino acid substitutions or as double-mutations on the same allele. Using endothelial cell (EC) cultures, mouse models and ultrastructural analysis of tissue biopsies from patients, we demonstrate common as well as mutation-specific cellular and molecular features, on the basis of which mutations cluster into categories that correlate with data from genetic studies. Comparisons of double-mutants with their constituent single-mutant forms identified the pathogenic contributions of individual changes, and their compound effects. We find that defective receptor trafficking and subcellular localization of different TIE2 mutant forms occur via a variety of mechanisms, resulting in attenuated response to ligand. We also demonstrate, for the first time, that TIE2 mutations cause chronic activation of the MAPK pathway resulting in loss of normal EC monolayer due to extracellular matrix (ECM) fibronectin deficiency and leading to upregulation of plasminogen/plasmin proteolytic pathway. Corresponding EC and ECM irregularities are observed in affected tissues from mouse models and patients. Importantly, an imbalance between plasminogen activators versus inhibitors would also account for high d-dimer levels, a major feature of unknown cause that distinguishes VMs from other vascular anomalies.

Multidisciplinary treatment of extremity arteriovenous malformations

Congenital vascular malformations (CVMs) are a complex group of lesions that arise by embryologic dysmorphogenesis without increased endothelial proliferation that leads to structural and functional anomalies of the vascular system characterized by a wide range of presenting symptoms and often unpredictable clinical course. A recent advancement in the diagnostic and treatment modalities has resulted in a better understanding of the pathophysiology and natural history of CVMs and improved management of these lesions. The multidisciplinary approach and diagnostic algorithm used to distinguish high-flow (HFVM) from low-flow vascular malformations (LFVM) have been validated as clinically applicable for making an accurate anatomic and hemodynamic diagnosis of CVMs; they serve as a basis for proper treatment selection and significantly facilitate communication among different medical specialists. Dynamic contrast-enhanced magnetic resonance imaging is able to definitively distinguish HFVM from LFVM with accuracy of approximately 84%. In inconclusive cases, confirmatory angiography is required. Symptomatic, diffuse, extensive, macrocystic LFVMs and LFVMs that involve multiple tissue planes and vital structures are best treated with foam sclerotherapy. Primary surgical resection is the treatment of choice for localized, septated, and microcystic LFVMs. The management of HFVMs is characterized by multimodal treatment including preoperative embolization followed by complete surgical resection or sclerotherapy of the remaining venous component. Treatment of extensive CVMs is palliative and goal oriented. Implementation of the proposed diagnostic protocols and therapeutic algorithms in a multidisciplinary setting results in favorable outcomes with acceptable complication rates in this challenging patient population.

Early versus later presentations of venous malformations: where and why?

Venous malformations (VMs) are congenital anomalies of the venous vasculature, but not all are evident at birth. The factors that lead to presentation later in life are not well understood. The objective of this retrospective cohort study of patients with VMs evaluated at the University of California at San Francisco Birthmarks and Vascular Anomalies Center from 2005 to 2009 was to investigate the clinical presentation of VMs and correlate these features with different types of tissues (e.g., skin, subcutis, intramuscular). Main outcomes included the age at which lesions were first noticed, tissue type involved, presenting signs and symptoms, aggravating factors, and morbidities. A total of 115 subjects was included. The mean age when VM was first noted was 6.7 ± 0.9 years. Tissue types involved included skin/subcutaneous (46%); intramuscular (40%); and bone, tendon, or joint (14%). Presenting signs/symptoms included soft tissue swelling (44%), discrete mass (34%), pain (33%), and skin discoloration (26%). When compared with VMs limited to the skin or subcutis, those restricted to the intramuscular compartment were less likely to present at birth (27% vs 53%, p < 0.05) but were more frequently painful (79% vs 60%, p < 0.05) and contained more phleboliths (28% vs 11%, p < 0.05), and were associated with more exercise limitation (35% vs 16%, p < 0.05). VMs differ in age of onset, clinical features, and complications based on differing tissues and sites of involvement, with isolated intramuscular involvement associated with later presentation and greater morbidity.

Venous malformation-causative TIE2 mutations mediate an AKT-dependent decrease in PDGFB

Mutations in the endothelial cell (EC) tyrosine kinase receptor TIE2 cause inherited and sporadic forms of venous malformation. The recurrent somatic mutation L914F and common germline mutation R849W differ in terms of phosphorylation level, as well as sub-cellular localization and trafficking of the receptor. Previous studies have shed light on certain pathogenic properties of R849W, but the mechanisms of action of L914F are unknown. We used global gene expression profiling to study the effects of L914F on ECs. We found that L914F strongly dysregulates genes involved in vascular development, cell migration and extracellular matrix processing, while R849W has weak effects. We also demonstrate, for the first time, that TIE2-mutant ECs are deficient in the production of PDGFB, both in vitro and ex vivo in patient tissues. This defect is mediated by the chronic, ligand-independent activation of AKT by the mutant receptors. Inadequate secretion of the major mural cell attractant likely plays an important role in the development of abnormal vascular channels, contributing to the characteristic paucity of surrounding vascular smooth muscle cells.

Venous malformation and haemangioma: differential diagnosis, diagnosis, natural history and consequences

Venous malformation (VM) is the most common form of congenital vascular malformation (CVM). VM presents at birth as an inborn vascular defect and never disappears/regresses spontaneously through the rest of life; it will continue to grow slowly at a rate that is proportional to the growth rate of the body. Haemangioma is not a vascular malformation but one of the vascular tumours originating from the endothelial cells; it develops after birth mostly in the infantile/neonatal period with a distinctive growth cycle: a proliferation phase of early rapid growth followed by an involutional phase of slow regression. Although the vascular malformation and vascular tumour belong to the ‘vascular anomaly’ together, both conditions are fundamentally different not only in their anatomical, histological and pathophysiological findings but also in their clinical courses. Therefore, an appropriate differential diagnosis of the VM is mandated not only from other kinds of CVMs but also from ‘genuine’ haemangioma. Appropriate diagnosis and assessment of VMs can be made based on clinical presentation and a proper combination of basic non-invasive studies in general but the presence of a mixed lesion involving other types of CVM lesions and the type of VM lesion, extratruncular and truncular, will dictate the need for further work-up with additional non- to less-invasive study or angiography. Otherwise, angiography is usually reserved for therapeutic planning and treatment.

Natural course of venous malformation after conservative treatment

PURPOSE

To investigate the clinical course of patients with venous malformation (VM) treated conservatively.

METHODS

We reviewed retrospectively the database of our Congenital Vascular Malformation clinic and interviewed 207 patients with VM, who had been managed only conservatively. The questionnaires asked about changes in size (no change, increase in proportion to growth, increase greater than in proportion to growth, decrease) and changes in symptoms (markedly worse, moderately worse, no change, moderately improved, markedly much improved). Progression of VMs was defined as an increase greater than in proportion to growth or worsening symptoms.

RESULTS

Fifty patients (24 %) reported an increase in size greater than in proportion to growth and 25 patients (12 %) reported symptoms worsening from their initial symptoms. Overall, sixty-six (32 %) of the patients reported evidence of progression of their VM. A binary logistic regression model identified VM combined with capillary malformation (CM) or lymphatic malformation (LM) as an independent predictor of VM progression (OR 2.67, 95 % CI 1.29-5.53).

CONCLUSIONS

Based on responses to the questionnaire, the size and symptoms of VM progressed in 32 % of patients over the course of their life. VMs combined with CM or LM were the only independent predictor of progression of a VM after conservative management.

Diagnosis and management of extensive vascular malformations of the lower limb: part II. Systemic repercussions [corrected], diagnosis, and treatment

At least nine types of vascular malformations with specific clinical and radiologic characteristics must be distinguished in the lower limbs: Klippel-Trénaunay syndrome, port-wine stain with or without hypertrophy, cutis marmorata telangiectatica congenita, macrocephaly-capillary malformation, Parkes Weber syndrome, Stewart-Bluefarb syndrome, venous malformation, glomuvenous malformation, and lymphatic malformation. Extensive vascular malformations are often more complex than they appear and require a multidisciplinary therapeutic approach. Vascular malformations may be associated with underlying disease or systemic anomalies. Part II of this two-part series on the diagnosis and management of extensive vascular malformations of the lower limb highlights the systemic repercussions [corrected] (bone, articular, visceral, and hematologic involvement), diagnosis, and treatment of these lesions.