David J.E. Lord

Vascular Anomalies Classification: Recommendations From the International Society for the Study of Vascular Anomalies

Vascular anomalies represent a spectrum of disorders from a simple “birthmark” to life- threatening entities. Incorrect nomenclature and misdiagnoses are commonly experienced by patients with these anomalies. Accurate diagnosis is crucial for appropriate evaluation and management, often requiring multidisciplinary specialists. Classification schemes provide a consistent terminology and serve as a guide for pathologists, clinicians, and researchers. One of the goals of the International Society for the Study of Vascular Anomalies (ISSVA) is to achieve a uniform classification. The last classification (1997) stratified vascular lesions into vascular malformations and proliferative vascular lesions (tumors). However, additional disease entities have since been identified that are complex and less easily classified by generic headings, such as capillary malformation, venous malformation, lymphatic malformation, etc. We hereby present the updated official ISSVA classification of vascular anomalies. The general biological scheme of the classification is retained. The section on tumors has been expanded and lists the main recognized vascular tumors, classified as benign, locally aggressive or borderline, and malignant. A list of well-defined diseases is included under each generic heading in the “Simple Vascular Malformations” section. A short definition is added for eponyms. Two new sections were created: one dealing with the malformations of individually named vessels (previously referred to as “truncular” malformations); the second groups lesions of uncertain or debated nature (tumor versus malformation). The known genetic defects underlying vascular anomalies are included in an appendix. This classification is meant to be a framework, acknowledging that it will require modification as new scientific information becomes available.

Percutaneous Sclerotherapy of Lymphatic Malformations with Doxycycline

BACKGROUND Lymphatic malformations (LMs) can be effectively treated by percutaneous intralesional injection of a variety of sclerosant drugs. This study aims to evaluate the efficacy of doxycycline in the treatment of LMs. METHODS AND RESULTS We reviewed the medical records of all patients with LMs who underwent sclerotherapy with doxycycline between January 1, 2003 and September 1, 2004 at Childrens Hospital Boston. Follow-up imaging was performed to assess for change in lesion size. Surveys were sent to all study patients, to assess perceived improvements in symptoms and satisfaction with the results. Sixty sclerotherapy procedures were performed on 41 patients in the 20-month study period. The median age was 6.9 years (3 mo-31 y). The most common location was cervicofacial (66%), followed by truncal (19%) and extremity (15%). The most common lesion type was macrocystic (49%), followed by combined (44%) and microcystic (7%). The major and minor complication rates were 2% and 10%, respectively. The mean outcome score by imaging was 4.41/5 with a 95% CI of [4.13-4.68] corresponding to about an 83% reduction in lesion size, and by patient survey was 4.47/5 with a 95% CI of [4.15-4.79] corresponding to between a good to complete response. Higher complication rates were associated with microcystic and combined lesions (p = 0.03), and greater doxycycline dose (p = 0.05). CONCLUSIONS Doxycycline is a safe and effective sclerosant for LMs. Greater follow-up is necessary to quantify long-term outcomes and assess the risks of lesion recurrence.

RASA1 mutations and associated phenotypes in 68 families with capillary malformation-arteriovenous malformation

Capillary malformation–arteriovenous malformation (CM–AVM) is an autosomal‐dominant disorder, caused by heterozygous RASA1 mutations, and manifesting multifocal CMs and high risk for fast‐flow lesions. A limited number of patients have been reported, raising the question of the phenotypic borders. We identified new patients with a clinical diagnosis of CM–AVM, and patients with overlapping phenotypes. RASA1 was screened in 261 index patients with: CM–AVM (n = 100), common CM(s) (port‐wine stain; n = 100), Sturge–Weber syndrome (n = 37), or isolated AVM(s) (n = 24). Fifty‐eight distinct RASA1 mutations (43 novel) were identified in 68 index patients with CM–AVM and none in patients with other phenotypes. A novel clinical feature was identified: cutaneous zones of numerous small white pale halos with a central red spot. An additional question addressed in this study was the “second‐hit” hypothesis as a pathophysiological mechanism for CM–AVM. One tissue from a patient with a germline RASA1 mutation was available. The analysis of the tissue showed loss of the wild‐type RASA1 allele. In conclusion, mutations in RASA1 underscore the specific CM–AVM phenotype and the clinical diagnosis is based on identifying the characteristic CMs. The high incidence of fast‐flow lesions warrants careful clinical and radiologic examination, and regular follow‐up.

Pulmonary Embolism in Children

Unlike in adults, pulmonary embolism (PE) is an infrequent event in children. It has a marked bimodal distribution during the paediatric years, occurring predominantly in neonates and adolescents. The most important predisposing factors to PE in children are the presence of a central venous line (CVL), infection, and congenital heart disease. Clinical signs of PE are non-specific in children or can be masked by underlying conditions. Diagnostic testing is necessary in children, especially with the lack of clinical prediction rules. Recommendations for tests are derived from adult studies with ventilation/perfusion (V/Q) scintigraphy being well established. There exists an increasing role for computerised tomography pulmonary angiography (CTPA) and magnetic resonance pulmonary angiography (MRPA). Thrombotic events in children are initially treated with unfractionated heparin (UFH) or low molecular weight heparin (LMWH). For the extended anticoagulant therapy LMWH or vitamin K antagonists can be used with duration of treatment recommendations extrapolated from adult data. Mortality rates for PE in children are reported to be around 10%, with death usually related to the underlying disease processes. Exact data about recurrence risk in children is unknown. Because of the difference in aetiology, presentation, diagnostic methods and treatment between adults and children further research is necessary to assess the validity of recommendations for children.

Post-liver transplant mycotic aneurysm of the hepatic artery

BACKGROUND Mycotic aneurysm of the hepatic artery is a rare complication of liver transplantation, occurring in 0% to 3% of patients and having a mortality of around 30%. We present a unique report of mycotic aneurysms of the hepatic artery following liver transplantation in children. METHODS AND RESULTS A chart review of the 194 patients who underwent a liver transplantation over a 21-year period revealed 2 patients who developed a mycotic aneurysm of the hepatic artery. The first patient died due to rupture prior to diagnosis. The second patient was treated successfully using radiological coil embolization, followed by surgical excision with hepatic artery ligation and antibiotic therapy. CONCLUSIONS Early diagnosis and prompt multidisciplinary treatment is crucial to optimize treatment in this condition.

Embolization in Neonates and Infants

Several conditions presenting in the neonatal and infant period benefit from embolization, including hemangioma, vascular shunts, and tumors. The physiological delicacy and small size of newborns create distinct challenges. This paper discusses embolization of these patients and illustrates the techniques involved.

Biliary strictures and hepatic artery flow abnormalities in split liver transplants.

O’Loughlin EV, Stormon MO, Shun A, Verran D, Jermyn V, Wong C, Lord D. Biliary strictures and hepatic artery flow abnormalities in split liver transplants.
Pediatr Transplantation 2010: 14: 121–125.

Intensive care experience with sclerotherapy for cervicofacial lymphatic malformations.

Objective: To describe a cohort of patients needing intensive care support after sclerotherapy for cervicofacial lymphatic malformations. Design: Retrospective review of case records of patients undergoing sclerotherapy between January 2004 and November 2006. Setting: A tertiary, university-affiliated, pediatric teaching hospital. Patients: Five patients needing admission to a pediatric intensive care unit (PICU) following sclerotherapy with OK432. Interventions: None. Measurements and Main Results: Five patients needed a total of 13 PICU admissions. Ages ranged from 4 months to 19 months. All patients had extensive lesions that involved the airways, mediastinum, or floor of the mouth, documented by magnetic resonance imaging. Nine admissions involved elective intubation and ventilation following sclerotherapy due to the extent of lesions. There were four urgent admissions to the PICU with respiratory distress ranging from 3 to 18 days after sclerotherapy. The mean duration of admission was 7 days (total 93 days, range 2–22 days). Total ventilated hours were 1656 hrs with a range of 16.5–370 hrs per admission. Multiple procedures, such as drainage of cysts and further sclerotherapy procedures, were performed before extubation on the PICU. Conclusions: Children with extensive disease and airway involvement need multiple PICU admissions. The potential for life-threatening respiratory embarrassment is unpredictable following sclerotherapy. Consideration should be given to performing further sclerotherapy while the patients are intubated in the PICU. The PICU provides a safe and secure environment for such procedures.

The Practice of Pediatric Interventional Radiology

There is a stark contrast between adult and pediatric interventional radiology practice. The essential elements of this all relate to working with children, including a need for greater procedural sedation and anesthesia; the psychology of working with children and their families; a skill set based around smaller bodies; and technology for smaller and growing humans. Interventional radiology departments that cater to children need to accommodate these factors so that sick children can access minimally invasive image-guided therapy in a safe and nonthreatening environment.

Vein of Galen aneurysm

AV malformation of the vein of Galen, also known as vein of Galen aneurysm, is an intracranial anomaly characterised by a midline, high flow lesion with a complex vascular architecture. It compromises less than 1% of all cerebral arteriovenous malformations seen in adults and children. Timely diagnosis of the malformation is of importance particularly during the perinatal period due to the large systemic shunting within the fetal brain potentially leading to cardiac failure, hydrops and perinatal death.