Venous Anomalies in Overgrowth Syndromes

Overgrowth syndromes, particularly within the PIK3CA-related overgrowth syndrome (PROS) spectrum, are commonly associated with venous anomalies. The anomalies include spongiform venous malformations and persistent embryonic veins, such as the lateral marginal vein (of Servelle). The anomalous veins pose a significant risk of thromboembolic disease and should be occluded, preferably earlier in life. A thorough understanding of the conditions, anatomy, and interdisciplinary treatment of these complex anomalies is essential for optimal management. This review explores the clinical and imaging diagnosis of overgrowth syndromes and techniques for assessing and treating associated venous anomalies, particularly the endovenous closure of anomalous veins.

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.

Contemporary management of extracranial vascular malformations

Vascular malformations are congenital vascular anomalies that originate because of disorganized angiogenesis, most commonly from spontaneous somatic genetic mutations. The modern management of vascular malformations requires a multidisciplinary team that offers patients the gamut of medical, surgical, and percutaneous treatment options with supportive care. This manuscript discusses the standard and contemporary management strategies surrounding extracranial vascular malformations and overgrowth syndromes.

Structured magnetic resonance imaging-based characterization of the marginal vein reveals limits of the Weber-classification

Background: The marginal vein (MV) is a persisting embryonic vein located at the lateral aspect of the lower limb. The Weber-classification, which was developed on the basis of phlebography in the 1990s, is the only existing classification system for this rare disease. Aim of this study was the structured characterization of the lateral marginal vein (MV) using magnetic resonance imaging (MRI) and evaluation of the applicability of the Weber-classification. Patients and methods: Institutional Review Board approval was obtained for this retrospective, single-center study. All patients who underwent contrast-enhanced MRI (using a prospectively determined protocol) of the untreated MV were included. MV anatomy and associated findings were characterized in a structured way taking into account the criteria of the Weber-classification for MV: inflow, outflow and extension. If three criteria of the Weber-classification were fulfilled the MV was categorized as "classifiable according to Weber". The MV was categorized as "partially classifiable according to Weber", if two criteria were met and as "not classifiable according to Weber" if less than two criteria were applicable. Results: 56 imaging studies of 58 MV (7 thoracoabdominal, 51 lower extremities) were reviewed. 18/51 MV of the lower extremities were "classifiable" according to the Weber-classification. 33/51 lower extremity MV were not definitely categorized according to the Weber-classification: 19/51 MV were "partially classifiable" and 14/51 MV were "not classifiable". 30/51 MV presented with hypoplastic, 1/51 with aplastic deep venous system. 34/51 lower extremity and 6/7 thoracoabdominal MV were associated with an additional vascular malformation (VM). Conclusions: MRI is suitable for detailed anatomic characterization of the MV and reveals additional therapy relevant findings like associated VM. The Weber-classification was not applicable in most cases, reflecting its limits and the heterogeneity of this rare disease. Structured reports rather than an obsolete classification system should be preferred for MRI of the MV.

Die Marginalvene – nach wie vor eine seltene Entität: Fallserie von 16 Patienten

Hintergrund

Die Marginalvene (MV) ist eine angeborene, vorwiegend venöse Gefäßmalformation, die auf einer fehlenden Rückbildung des embryonalen Venensystems an den unteren Extremitäten beruht. Sie geht mit einer Vielzahl an Komplikationen einher. Bisher werden in der Literatur keine einheitlichen Therapieregime beschrieben.

Fragestellung

Welche Behandlungsstrategien und Ergebnisse gibt es bei Patienten mit MV?

Material und Methoden

Im Zeitraum 01.01.2008 bis 31.12.2020 wurden alle am Universitätsklinikum Augsburg behandelten Patienten mit Marginalvene retrospektiv aufgearbeitet.

Ergebnisse

Das mediane Alter zum Diagnosezeitpunkt lag bei 14,8 Jahren (3–42 Jahre). 12/16 Patienten hatten eine Beinlängendifferenz. 75 % der Patienten (12/16) hatten bereits zur Diagnosestellung MV eine chronisch-venöse Insuffizienz (CVI). Im untersuchten Kollektiv wurden 62,5 % (10/16) der Patienten zum Zeitpunkt der Diagnosestellung mittels Kompression konservativ behandelt. Bei weiteren 31,3 % (5/16) der Patienten erfolgte primär eine offen-chirurgische Entfernung der MV und bei 1/16 Patienten wurde die MV primär mittels endovenöser Lasertherapie (EVLT) verschlossen; 15/16 Patienten wurden sekundär therapiert. 2,6 ± 2,4 (MW ± SD) Sekundärprozeduren wurden pro Patient im Follow up durchgeführt. Das mittlere Follow-up lag bei 8,1 Jahren.

Diskussion

Zur Prävention/Vermeidung einer Progression einer CVI und Thrombembolieprophylaxe sollte nach Diagnosestellung die MV zeitnah verschlossen/entfernt werden. Die Anwendung chirurgisch-konventioneller Techniken zur Entfernung der MV scheint gegenüber der Behandlung mit minimal-invasiven Prozeduren hinsichtlich der Anzahl der erforderlichen Sekundäreingriffe von Vorteil.

How we approach coagulopathy with vascular anomalies

Some vascular anomalies can present with challenging hematologic aberrations. Kaposiform hemangioendothelioma (KHE) may be complicated with Kasabach-Merritt phenomenon (KMP) and stagnant blood flow in slow-flow malformations can promote activation and consumption of coagulation factors, which results in bleeding and clotting known as localized intravascular coagulopathy (LIC). These patients can experience significant morbidity secondary to pain due to thrombosis and are at higher risk of hematologic complications during surgical procedures. No standard of care has been established to prevent or manage these complications. This review focuses on the management of coagulopathy in children and adults with vascular anomalies.

Prevalence and inventory of venous anatomical abnormalities in the arms of patients with combined capillary, venous and lymphatic malformations (Klippel-Trénaunay syndrome)

OBJECTIVES

To investigate the prevalence of arm-involvement in Klippel-Trénaunay syndrome (KTS)-patients and to describe the venous anatomy and/or venous aberrations present in the arm, and if possible, their relationship to complaints (pain, congestion and thromboembolic events).

METHODS

A retrospective cohort-study was performed with data from medical records of a large KTS-cohort (n = 173) from a tertiary referral center. Within this cohort, a descriptive study (n = 12) was performed on the KTS-patients with arm involvement and who had been examined with Colour Duplex Ultrasonography (CDU).

RESULTS

Our KTS-cohort (n = 173) comprised 43 patients (24.9%) with arm-involvement; in nineteen patients (11.0%) the arm was the only affected limb. Of those KTS patients investigated with CDU, 9 out of 12 (75%) had an aberrant venous anatomy.

CONCLUSION

Future research needs to clarity whether the complaints of KTS-patients in general are caused by an aberrant venous anatomy, coagulation alterations and/or other factors. Herein, the KTS-arms may play an important role.

Mechanochemical Endovenous Ablation of Varicose Veins in Pediatric Patients with Klippel-Trénaunay Syndrome: Feasibility, Safety, and Initial Results

PURPOSE

To evaluate feasibility, safety, and results of endovenous mechanochemical ablation (MOCA) for treatment of persistent embryonic and dysplastic veins in pediatric patients with Klippel-Trénaunay syndrome (KTS).

MATERIALS AND METHODS

Thirteen MOCA procedures were performed in 11 patients (age range, 4-16 years) with KTS and symptomatic persistent embryonic or dysplastic veins during a 24-month period. All patients were evaluated with color Doppler (CD) ultrasound (US), contrast-enhanced MR imaging, and venography to assess the anatomy of the target vessels and patency of the deep venous system. All procedures were performed under general anesthesia with a ClariVein catheter and liquid sodium tetradecyl sulfate as the sclerosing agent. US and fluoroscopic guidance were used in all cases. Technical success rate, primary occlusion rate, adverse effects, and recanalization rates were evaluated. Clinical and radiological (CD US) controls were performed 1 day, 7 days, 1 month, and 6 months after the procedure and once a year thereafter, with a mean follow-up of 16 months (range, 6-25 months).

RESULTS

Technical success and primary occlusion were achieved in all patients with no adverse events. During the follow-up period, CD US demonstrated partial recanalization and symptom recurrence in 2 patients (18%), 14 and 18 months after the initial procedure. These 2 patients had a second ablation procedure with no recanalization or symptom recurrence during the subsequent follow-up period.

CONCLUSIONS

MOCA is feasible and appears to be a safe and effective technique for treatment of varicose veins in pediatric patients with KTS.

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.

Eine außergewöhnliche Therapie der Vena-iliaca-externa-Hypoplasie bei einer Patientin mit Klippel-Trénaunay-Syndrom – ein Fallbericht

Das Klippel-Trénaunay-Syndrom (KTS) ist eine seltene und komplexe Fehlbildung. Sie zeigt die typische Trias aus vaskulärer Malformation, Knochen- und Weichteilhypertrophie sowie venöser Varikosis. Die Systemmanifestationen werden in einem individuell variablen Muster beobachtet. Eine isolierte angeborene Hypoplasie des venösen Systems tritt jedoch in den seltensten Fällen auf. Aus diesem Grund spielt die Früherkennung eine wichtige Rolle für die weitere Behandlungsplanung. So können durch rechtzeitige Behandlung schwere Krankheitsverläufe oder Spätfolgen vermieden werden. Eine isolierte angeborene Hypoplasie ist extrem selten und prädisponiert insbesondere im jungen Erwachsenenalter für Becken- oder Beinvenenthrombosen. Bei dieser Krankheit wird selten eine chirurgische Rekonstruktion durchgeführt.

Wir beschreiben einen sehr seltenen Fall einer 60-jährigen Frau mit KTS, die vor 28 Jahren einen venösen Crossover-Bypass (Palma) mittels Vena saphena magna bei Hypoplasie der Vena iliaca externa rechts erhalten hat. Das Ziel des vorliegenden Berichts ist das klinische Erscheinungsbild, den diagnostischen Prozess und das Krankheitsmanagement vorzustellen sowie eine Literaturübersicht zum operativen Behandlungsverfahren darzustellen.

Congenital Limb Overgrowth Syndromes Associated with Vascular Anomalies

Congenital limb length discrepancy disorders are frequently associated with a variety of vascular anomalies and have unique genetic and phenotypic features. Many of these syndromes have been linked to sporadic somatic mosaicism involving mutations of the phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) pathway, which has an important role in tissue growth and angiogenesis. Radiologists who are aware of congenital limb length discrepancies can make specific diagnoses based on imaging findings. Although genetic confirmation is necessary for a definitive diagnosis, the radiologist serves as a central figure in the identification and treatment of these disorders. The clinical presentations, diagnostic and imaging workups, and treatment options available for patients with Klippel-Trenaunay syndrome, CLOVES (congenital lipomatous overgrowth, vascular anomalies, epidermal nevi, and scoliosis/spinal deformities) syndrome, fibroadipose vascular anomaly, phosphatase and tensin homolog mutation spectrum, Parkes-Weber syndrome, and Proteus syndrome are reviewed. ^©RSNA, 2019.

Evaluation and management of the lateral marginal vein in Klippel-Trénaunay and other PIK3CA-related overgrowth syndromes

The lateral marginal vein is an anomalous clinical entity found in association with Klippel-Trénaunay and other PIK3CA-related overgrowth syndromes. Although it is reported to affect <20% of patients with Klippel-Trénaunay syndrome, this venous anomaly has been associated with significant morbidity and mortality attributable to venous hypertension and potentially lethal thromboembolic events. Limited literature exists on the diagnosis and management of this rare anomaly, with most of the reports focusing on retrospective clinical experience at a few centers of excellence. Despite these limitations, a systematic approach to diagnosis and treatment of this anomaly is warranted and expounded on herein. When plausible, clinical recommendations based on best available literature are made.

Klippel-Trenaunay Syndrome

Klippel-Trenaunay syndrome or KTS is a complex vascular syndrome associated with overgrowth occurring as a result of somatic mutations in the PIK3CA gene. Patients are diagnosed on the basis of physical findings, sometimes with supportive imaging, of commonly a segmental anomaly with a cutaneous port-wine stain, lymphatic and venous malformations and overgrowth. The severity of the component vascular malformations and the degree of overgrowth varies from patient to patient which demands care given by a multi-professional team with regular follow-up in a specialist clinic. Some patients may present with acute life-threatening problems, often as a result of veno-thromboembolic events (VTEs) especially following surgical and invasive radiological procedures. Awareness of such problems is vital and prophylactic measures to reduce such risks are paramount. The interventional radiologist is vital to the care team as he/she can undertake procedures including endovascular closure of significant venous anomalies which predispose to such VTEs. Although these procedures can be lengthy and complex, they can now provide a minimally invasive means to reduce the risk from life-threatening and sometimes fatal VTEs. The results however from such interventions will require long-term studies which to date are unavailable.

Wound-Healing Problems Associated with Combined Vascular Malformations in Klippel-Trenaunay Syndrome

Significance: In Klippel-Trenaunay syndrome (KTS), management of a wound in the affected limb can be difficult because of the underlying vascular malformations present. This review describes the characteristics of KTS with wound complications in light of the genetic and molecular mechanisms of the disease. Recent Advances: KTS is a slow-flow combined vascular malformation characterized by the triad of capillary malformation, venous malformation with or without lymphatic malformation, and limb overgrowth. KTS is encompassed within the phosphatidylinositol-4,5-bisphosphate3-kinase catalytic subunit alpha (PIK3CA)-related overgrowth spectrum (PROS), having recently been linked to activating mutations in the PIK3CA gene. This clearly has implications for both molecular diagnosis and potential treatment strategies for the disease. Critical Issues: KTS should be distinguished from Parkes Weber syndrome, a fast-flow-type combined vascular malformation with limb overgrowth. Individualized management is needed for KTS and should be focused on the treatment of symptoms. Future Directions: Targeted therapies that inhibit the phosphoinositide 3-kinase signaling pathway are a potential treatment option for PROS.

Laser ablation of embryonic veins in children

BACKGROUND

Klippel-Trenaunay syndrome (KTS) and related overgrowth syndromes are rare conditions that often present to academic pediatric units and multidisciplinary vascular anomaly clinics. These conditions are commonly associated with abnormalities of the superficial and deep venous structures and carry an increased risk of venous thromboembolism.

METHODS

A retrospective chart review was completed of all patients treated at Johns Hopkins All Children's Hospital with endovenous laser ablation therapy (EVLT) for management of dilated embryonic veins in the setting of limb overgrowth.

RESULTS

Three patients with limb overgrowth underwent EVLT between 2015 and 2017. All patients had successful occlusion of the targeted veins on post-procedure imaging. One patient developed a cellulitis successfully treated with oral antibiotics.

CONCLUSIONS

Endovenous laser ablation therapy is a well-tolerated and safe procedure for prophylactic closure of abnormal superficial embryonic veins. This study supports the use of this technique in managing increased thromboembolic risk in this unique patient population and recognizes the need for a long-term study to determine its efficacy.

Septic superficial thrombophlebitis in Klippel-Trenaunay syndrome

This is a rare case of a young patient with Klippel-Trenaunay syndrome that presented with extensive septic superficial thrombophlebitis of the lower extremity. Treatment included intravenous antibiotics based on cultures, anticoagulant therapy as well as surgical removal of thrombi.

Diagnosis and management of the venous malformations of Klippel-Trénaunay syndrome

OBJECTIVE

A dearth of information exists in the literature regarding current practice in the management of Klippel-Trénaunay syndrome (KTS), a rare condition. We review and describe the etiology, diagnosis, and treatment of KTS.

METHODS

Relevant data were synthesized from a Medline review using a combination of the keyterms "Klippel" and "Trénaunay." The majority of hits described singular case reports and were subsequently excluded. The remaining papers were then reviewed and included on the basis of the quality of evidence and the authors' discretion.

CONCLUSIONS

KTS is characterized by a clinical triad of extremity varicosities, cutaneous vascular malformations, and hypertrophy of soft tissues and long bones. The diagnosis is clinically supplemented with magnetic resonance imaging and computed tomography. Although this syndrome is associated with significant comorbidities, such as pain, edema, ulcerations, and pruritus, it is rarely the cause of death. The backbone of treatment is nonoperative in nature but should be supplemented with minimally invasive, endovascular, and rarely open surgical procedures for refractory cases.

Female Pelvic Vascular Malformations

Vascular malformations are classified primarily according to their flow characteristics, slow flow (lymphatic and venous) or fast flow (arteriovenous). They can occur anywhere in the body but have a unique presentation when affecting the female pelvis. With a detailed clinical history and the proper imaging studies, the correct diagnosis can be made and the best treatment can be initiated. Lymphatic and venous malformations are often treated with sclerotherapy while arteriovenous malformations usually require embolization. At times, surgical intervention of vascular malformations or medical management of lymphatic malformations has been implemented in a multidisciplinary approach to patient care. This review presents an overview of vascular malformations of the female pelvis, their clinical course, diagnostic studies, and treatment options.

Localised intravascular coagulation complicating venous malformations in children: Associations and therapeutic options

Venous malformations are slow-flow congenital vascular malformations that enlarge as the child ages and may be associated with localised intravascular coagulation, a consumptive coagulopathy characterised by elevated D-dimer and decreased fibrinogen levels. The authors review the known correlations between localised intravascular coagulation and venous malformation number, size and planes involved, and call attention to the concept of the progression of localised intravascular coagulopathy as the child ages and their venous malformations enlarge. The authors also discuss the identified therapeutic options for its investigation, management and treatment, including compression garments, anti-coagulation therapy, sclerotherapy, endovascular laser, surgical excision and sirolimus (rapamycin). Evidence for protocol improvements that may be instigated for the optimal physical and medical therapy of venous malformations complicated by localised intravascular coagulopathy is reviewed.

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.