Special Considerations in Vascular Anomalies: Hematologic Management

Anticoagulation and vascular anomalies

A State of the Art lecture titled "Anticoagulation and Vascular Anomalies" was presented at the International Society on Thrombosis and Haemostasis (ISTH) Congress in 2023. Vascular anomalies have been classified by the International Society for the Study of Vascular Anomalies into vascular tumors and vascular malformations. Although some vascular tumors, such as tufted angioma and kaposiform hemangioendothelioma, and other vascular malformations can present with coagulation aberrancies, these are not generally managed with anticoagulation. A subclassification of vascular malformations includes slow-flow vascular malformations. It is this subgroup specifically that has a high risk of venous thromboembolism (VTE) and morbidity associated with coagulopathy that may be present. In these select cases, anticoagulation may be indicated to reduce the risk of VTE, treat VTE, or manage localized thrombosis in the malformation that causes significant pain and reduced quality of life. There are established risk factors for VTE in these patients that will be reviewed. Finally, we summarize relevant new data on this topic presented during the 2023 ISTH Congress.

Medical Management and Therapeutic Updates on Vascular Anomalies of the Head and Neck: Part 2

Discovery of inherited and somatic genetic mutations, along with advancements in clinical and scientific research, has improved understanding of vascular anomalies and changed the treatment paradigm. With aim of minimizing need for invasive procedures and improving disease outcomes, molecularly targeted medications and anti-angiogenesis agents have become important as both adjuncts to surgery, and increasingly, as the primary treatment of vascular anomalies. This article highlights the commonly used and emerging therapeutic medications for non-malignant vascular tumors and vascular malformations in addition to medical management of associated hematologic abnormalities.

Multiorgan Visceral Hemangiomas Presenting with Sequential Ruptures and Hemorrhage, Cardiac Thrombus, and Thromboembolic Phenomenon

Vascular anomalies can be seen in a disseminated or diffuse state to involve multiple superficial and deep sites. Large and diffuse lesions are known to induce a hemorrhagic tendency. The authors present, which they believe is the first case of multiorgan hemangiomas with rupture at multiple sites, along with hitherto unreported cardiac thrombus, with arterial and venous thromboembolic events, ultimately ending with the patient's demise.

How we approach localized vascular anomalies

Vascular anomalies are a group of disorders divided into two distinct subtypes: vascular tumors and vascular malformations. Vascular tumors are proliferative in nature, while malformations are nonproliferative. Simple, localized vascular malformations refer to a group of malformations that are localized to a single area of involvement. These simple malformations include capillary, lymphatic, venous, and arteriovenous malformations. The pediatric hematologists and oncologists are becoming increasingly involved in the diagnosis and management of these disorders. This review presents four cases as a means to discuss the diagnosis, clinical and imaging features, and management strategies of simple, localized vascular malformations.

How we approach the diagnosis and management of complex lymphatic anomalies

Complex lymphatic anomalies (CLA) are congenital diseases of the lymphatic circulation system that are associated with significant morbidity and early mortality. While guidelines for the comprehensive evaluation of the CLA were recently published, the diagnostic approach and medical management are not standardized. This article presents the clinical features of four CLA: Gorham-Stout disease, generalized lymphatic anomaly, kaposiform lymphangiomatosis, and central collecting lymphatic anomaly. We also offer three cases from the authors' practice and our views on diagnostic testing and disease management including supportive care, medical therapies, and other interventions.

Interventional Treatment Options in Children with Extracranial Vascular Malformations

Extracranial vascular malformations vary greatly and belong to the complex field of orphan diseases and can involve all segments of the vascular tree: arteries, capillaries, and veins, and similarly the lymphatic system. The classification according to the International Society for the Study of Vascular Anomalies (ISSVA) represents an important guidance for selecting appropriate therapy. Although many of the principles of endovascular treatment, including image-guided sclerotherapy and embolization, are similar in adult and pediatric practice, there are some distinct differences regarding the treatment of vascular malformations of children. Thus, it is crucial to involve longer-term plan about managing these chronic diseases and their impact on a growing child. This review provides a detailed overview over the clinical presentation of venous, lymphatic, and arteriovenous malformations in children and emphasizes the specifics of their interventional treatment options, including distinct pediatric dose limitations and procedure-related side effects.

Kaposiform Hemangioendothelioma with Kasabach-Merritt Phenomenon

A 3-y-3-mo old male child presented with massive hypertrophy and bluish-purple discoloration of the left upper limb and adjacent chest wall of 3 mo duration. There was no h/o fever, weight loss, painful large joint swelling, or any bleeding manifestations. He had spindle like nonprogressive, painless swelling of all fingers of the left hand since infancy. The child was moribund with microangiopathic hemolytic anemia, thrombocytopenia, and consumptive coagulopathy without sepsis. He received multiple transfusions of fresh frozen plasma (FFP), platelets, and packed RBC. Paradoxical worsening of symptoms with platelet transfusions and radiological evidences led to the diagnosis of a very rare congenital multifocal vascular tumor, kaposiform hemangioendothelioma (KHE) with Kasabach-Merritt phenomenon (KMP). The index case of KHE was multifocal with cutaneous lesions, osteolytic bony lesions of all phalanx and metacarpals of the left hand, and intrathoracic extension. It was successfully managed with a combination of steroid, vincristine and sirolimus.

Venous Malformations and Blood Coagulation in Children

Introduction: Venous malformations (VMs) are congenital low-flow lesions with a wide spectrum of clinical manifestations. An increasing number of studies link VMs to coagulation abnormalities, especially to elevated D-dimer and decreased fibrinogen. This condition, termed localized intravascular coagulopathy (LIC), may pose a risk for hemostatic complications. However, detailed data on the laboratory variables for coagulation and fibrinolytic activity in VM patients are limited. We addressed this question by systematically analyzing the coagulation parameters in pediatric VM patients. Methods: We included 62 patients (median age 11.9 years) with detailed laboratory tests for coagulation and fibrinolytic activity at a clinically steady phase. We assessed clinical and imaging features of VMs and their correlations with coagulation and fibrinolysis variables using patient records and MRI. Results: D-dimer was elevated in 39% and FXIII decreased in 20% of the patients, as a sign of LIC. Elevated D-dimer and decreased FXIII were associated with large size, deep location, and diffuse and multifocal VMs. FVIII was elevated in 17% of the patients and was associated with small VM size, superficial and confined location, discrete morphology, and less pain. Surprisingly, antithrombin was elevated in 55% of the patients but without associations with clinical or other laboratory variables. Conclusions: LIC was common in pediatric patients with VMs. Our results provide a basis for when evaluating the risks of hemostatic complications in children with VMs. Further research is warranted to explore the mechanisms behind coagulation disturbances and their relation to clinical complications.

A narrative review on the epidemiology, prevention, and treatment of venous thromboembolic events in the context of chronic venous disease

OBJECTIVE

Chronic venous disease (CVD) describes a spectrum of conditions associated with venous hypertension. The association between various CVD etiologies and the subsequent risk of venous thromboembolism (VTE), such as deep vein thrombosis or pulmonary embolism, is a topic of considerable clinical interest. The aims of the present review were to characterize the risk of VTE according to the CVD etiology and to determine the optimal anticoagulation strategy for the treatment or prevention of VTE in patients with CVD.

METHODS

An extensive search of the available surgical and medical data was conducted in PubMed and Google Scholar. We searched for the following terms and other related terms to identify relevant studies: CVD, chronic venous insufficiency, varicose veins, post-thrombotic syndrome (PTS), anticoagulation, venous thromboembolism, and venous disease scoring systems (eg, CEAP [clinical, etiology, anatomic, pathophysiology], Villalta, Ginsberg, venous clinical severity score). The identified studies included randomized control trials, retrospective and prospective observational studies, narrative and systematic reviews, case reports, and case series that contributed to the proposed aims. The ClinicalTrials.gov database was also queried to identify any relevant ongoing clinical trials.

RESULTS

Congenital CVD carries a heightened risk of VTE, although few higher level studies are available to inform on this topic or on the appropriate anticoagulation strategies for these patients. Noncongenital CVD seems to carry a heightened risk of VTE, although few studies have adequately differentiated between primary and secondary etiologies. Varicose veins are a risk factor for primary VTE but might not be associated with an increased risk of recurrent VTE. In the hospital setting, patients with varicosities should be provided thromboprophylaxis. In the setting of varicose vein intervention, high-risk patients should be identified using risk assessment models and receive thromboprophylaxis. The risk of recurrent VTE in the setting of PTS is unclear but indefinite anticoagulation is not currently indicated. For patients with PTS, residual vein thrombosis might be an indicator of when anticoagulation can be safely stopped, although practical limitations to its application exist.

CONCLUSIONS

CVD is associated with an increased risk of VTE. Few studies have differentiated between classes of CVD using a standardized method and have assessed the efficacy of anticoagulation prophylaxis against or treatment of VTE. Additional studies are needed to determine the optimal therapy for preventing and treating VTE in patients with active concurrent CVD.

Venous malformations: Coagulopathy control and treatment methods

Venous malformations (VMs) are ectatic channels which arise as a result of vascular dysmorphogenesis, commonly caused by activating mutations in the endothelial tyrosine kinase receptor (TIE2)/phosphatidylinositol 3-kinase (PI3Kinase) pathway. With a prevalence of 1% in the general population, and a diverse clinical presentation depending on site, size and tissue involvement, their treatment requires a personalised and multidisciplinary approach. Larger lesions are complicated by local intravascular coagulopathy (LIC) causing haemorrhagic and/or thrombotic complications which can progress to disseminated intravascular coagulopathy (DIC).

METHODS

We performed a literature review using a PubMed® search and identified 15 articles to include. References of these texts were examined to further expand the literature review.Principle findings: Several treatment options have been explored, including compression, sclerotherapy, laser therapy, cryoablation and surgery in addition to the management of LIC with low-molecular-weight-heparin (LMWH) and other anticoagulants. Targeted molecular therapies acting on the phosphatidylinositol 3-kinase (PI3Kinase)/Protein Kinase B (AKT)/mammalian target of rapamycin (mTOR) pathway are newly emerging.

CONCLUSION

Despite a wealth of literature, larger, multi-centric, randomised and prospective trails are required to offer further clarification on the therapeutic management of coagulopathy control and to provide symptomatic benefit to patients with VMs. There should be efforts to provide long term follow up and to use standardised risk stratification tools and quality of life (QOL) questionnaires to aid comparison of agents and treatment protocols.

Coagulation issues in vascular anomalies

Vascular anomalies, comprised of vascular tumors and malformations, are frequently associated with coagulopathy. Recognition of and familiarity with these vascular anomaly-associated hematologic abnormalities prior to surgery or interventional procedures is essential for pre-operative pre-operative planning. Complicated coagulopathies present within the framework of either Kasabach-Merritt phenomenon (KMP) or localized intravascular coagulopathy (LIC), and their management benefits from the expertise of a hematologist for optimal intra- and peri‑operative care. Furthermore, with the recent broadening of understanding of vascular anomalies and the addition of new classification sub-groups, distinctions of these two classic coagulopathy phenotypes have been recognized. This review summarizes the main features of these coagulopathies, described according to their vascular anomaly type, highlighting clinical aspects relevant to surgical management.

Retrospective study of hematologic complications in patients with slow-flow vascular malformations undergoing sclerotherapy

BACKGROUND

Slow-flow vascular malformations (SFVM) are associated with localized intravascular coagulopathy (LIC), which is characterized by elevated D-dimer and, when severe, hypofibrinogenemia. LIC results in intralesional clotting and hemorrhage and increases risk for significant thrombotic and bleeding complications. Sclerotherapy has been a suggested potential trigger for LIC worsening to disseminated intravascular coagulopathy. Hematologic complications of sclerotherapy in SFVM, along with low-molecular-weight heparin (LMWH) used to prevent worsening LIC, are largely unstudied.

PROCEDURE

Medical records of patients with SFVM and LIC who underwent sclerotherapy at Cincinnati Children's Hospital Medical Center from July 2008 to December 2016 were reviewed for periprocedural hematologic complications. LMWH dose, frequency, and course length were evaluated.

RESULTS

Fifty-nine patients with SFVM and LIC underwent 281 sclerotherapy procedures, of which 86% were in children. Eighty-five percent of patients received periprocedural LMWH, although at various doses and course lengths. No thrombotic complications occurred in children. One adult on LMWH developed pulmonary emboli after sclerotherapy. No major bleeding complications occurred postoperatively. In four patients, fibrinogen dropped below 100 mg/dL post-sclerotherapy, requiring cryoprecipitate. One patient required packed red blood cell (RBC) transfusion for sclerotherapy-induced hemolysis. No intraoperative bleeding or thrombotic events occurred.

CONCLUSION

LMWH use, at subtherapeutic dosing, was common in this patient population and did not appear to increase risk of significant bleeding before, during, or after sclerotherapy. In children with SFVM, bleeding and thrombotic complications after sclerotherapy appear rare. Although safe, prospective studies are needed to evaluate the efficacy of LMWH to prevent worsening coagulopathy with procedures.

Localized intravascular coagulation in venous malformations: A system review

Venous malformation is one of the slow-flow vascular malformations. Dysfunction of coagulation often occurs in most venous malformations, especially the diffuse and multifocal lesions, referred to as localized intravascular coagulopathy. It is characterized by the elevation of D-dimers and fibrin degradation products, low levels of fibrinogen, FV, FVIII, FXIII, and antithrombin III, and sometimes minor-to-moderate thrombocytopenia. Here we reviewed the clinical manifestations, pathogenesis, diagnosis, and treatment of localized intravascular coagulopathy in venous malformations.

Kaposiform hemangioendothelioma with Kasabach-Merritt phenomenon in an infant: Successful treatment with prednisolone, vincristine, and addition of sirolimus

A full-term newborn with kaposiform hemangioendothelioma (KHE) affecting the right thigh with thrombocytopenia due to Kasabach-Merritt phenomenon (KMP) was referred to our center. After biopsy, he rapidly evolved to severe thrombocytopenia and severe coagulopathy. Standard therapy was initiated with prednisolone and vincristine. His coagulopathy worsened to life-threatening hemorrhage necessitating aggressive blood products replacement. Sirolimus was added; he became transfusion independent with no further bleeding and reduction in tumor size. Addition of sirolimus to treatment of vascular anomalies with hemostatic complications should be considered as part of early treatment for patients with KMP/KHE.

Congenital Vascular Tumors

Vascular tumors are benign neoplasms, which result from proliferating endothelial cells. These lesions present during infancy or childhood, may affect any location, and exhibit postnatal growth. Local complications include bleeding, tissue destruction, and pain whereas systemic sequelae include thrombocytopenia, congestive heart failure, and death. Vascular tumors should be differentiated from vascular malformations, which present at birth, have a quiescent endothelium, and grow in proportion to the child. Together, vascular tumors and malformations comprise the field of vascular anomalies.

Venous Thromboembolism in Pediatric Vascular Anomalies

The presence of a vascular anomaly suggests that capillaries, veins, arteries, and/or lymphatic vessels have demonstrated abnormal development and growth. Often dilated and misshaped, these vessels augment normal flow of blood and lymphatic fluids that increases the overall risk to develop intralesional thrombosis. Abnormal endothelial and lymphoendothelial cells activate hemostasis and hyperfibrinolytic pathways through poorly understood mechanisms, which contribute to the development of localized intravascular coagulopathy. Vascular malformations, tumors, and complex combined syndromes demonstrate varying degrees of prothrombotic activity and consumptive coagulopathy depending on the vessels involved and the pattern and extent of abnormal growth. The clinical impact of venous thromboembolism in pediatric vascular anomalies varies from painful syndromes that disrupt quality of life to life-threatening embolic disease. There remains little literature on the study, evaluation, and treatment of thrombosis in pediatric vascular anomalies. However, there have been great advances in our ability to image complex lesions, to surgically and interventionally augment disease, and to provide enhanced supportive care including patient education, compression therapy, and strategic use of anticoagulation.

Kaposiform lymphangiomatosis: unifying features of a heterogeneous disorder

Kaposiform lymphangiomatosis (KLA) is a rare proliferation of abnormal lymphatic vessels often complicated by pleural/pericardial effusions and a consumptive coagulopathy that may lead to life threatening hemorrhage. Establishing the diagnosis is challenging due to the clinical heterogeneity and variable findings in laboratory values, radiographic features, and pathologic characteristics. We report three patients who had slowly progressive symptoms and presented with pleural or pericardial effusions, evidence of a consumptive coagulopathy and anemia. Despite being a rare and challenging diagnosis, KLA should be considered in patients presenting with non-specific indolent symptoms, pleural or pericardial effusions and laboratory evidence of a consumptive coagulopathy.

Perioperative care of the vascular anomaly patient

Patients with vascular anomalies present specific and unique challenges to providers of their postoperative care. Vascular anomalies can range from localized solitary lesions to diffuse lesions with vessel malformations and associated soft tissue, muscle, organ, and bone involvement. Perioperative issues for these patients can be complicated and include coagulopathies requiring anticoagulation, the need for postoperative surgical drains and specialized wound care, and the use of compression garments to maintain the desired postoperative result. This article will address these specific concerns for patients with vascular anomalies in order to create a framework for consistent and appropriate perioperative care.

Medical therapy for pediatric vascular anomalies

Vascular anomalies (VAs) comprise a large variety of individual diagnoses that in different phases of treatment require a diverse number of medical specialists to provide optimal care. Medical therapies include agents usually associated with cancer chemotherapy, such as vincristine, as well more immunomodulatory types of drugs, such as glucocorticoids and sirolimus. These immunomodulating drugs are being successfully applied in cases that are typically categorized as vascular tumors, including kaposiform hemangioendothelioma (KHE) and tufted angioma (TA), as well as some of the more invasive types of vascular malformations (i.e., microcystic lymphatic malformations and blue rubber bleb nevus syndrome (BRBNS). These therapies need to be combined with good supportive care, which often involves anticoagulation, antimicrobial prophylaxis, and comprehensive pain and symptom-relief strategies, as well as appropriate drug monitoring and management of side effects of medical treatment. The optimal care of these patients frequently involves close collaboration between surgeons, interventional and conventional radiologists, medical subspecialists, and nurses.

Vascular anomalies - a practical approach

Vascular anomalies are common clinical problems (around 4.5% of all patients) in pediatric dermatology. A correct diagnosis is possible on clinical grounds in around 90% of cases; the remaining patients may require radiologic evaluations (duplex ultrasonography, MRI scan) and, rarely, histology. Vascular anomalies are divided into tumors and vascular malformations. This clear division reflects the different biological behaviors of these two groups. The infantile hemangioma represents by far the most common vascular tumor and is characterized by a typical growth cycle consisting of rapid proliferation, plateau phase, and finally slow regression. The discovery in 2008 of the efficacy of beta blockers in this disease is a therapeutic milestone. Vascular malformations can affect all types of vessels (capillaries, veins, arteries and lymphatic vessels). They usually manifest at birth and grow proportionally with the affected child. Some show marked progression especially during puberty. Considerable progress has been made with innovative interventional therapies in recent years, but surgery remains an important option. Basic knowledge of these diseases is important to every dermatologist in order to be able to counsel and manage affected patients correctly.