Arteriovenous Malformations – Diagnosis and Treatment

Introduction

Vascular malformations (VM) remain one of the most difficult diagnostic and therapeutic enigmas in modern medicine due to their extremely variable clinical presentation, ranging from asymptomatic birthmarks to life-threatening conditions. The incidence of VM is 1.5% in the general population. These malformations are localized errors of angiogenic development. Most vascular malformations are mixed, and several are associated with developmental abnormalities (e.g., Klippel-Trenaunay syndrome and Parkes-Weber syndrome). The International Society for the Study of Vascular Anomalies recently adopted a classification scheme that clearly separated vascular tumors (hemangiomas of different types), which result from active cell proliferation, from vascular malformations, which are inborn defects in vascular morphogenesis. While the majority of VM are sporadic, autosomal dominance has been described (Table 1). These two types of lesions have different clinical behavior and require different diagnostic and therapeutic strategies. The majority of VM (approximately 65%) are predominantly related to venous malformations. The Hamburg Classification of vascular malformations uses criteria that take into account the underlying anatomical, histological, pathophysiological, and hemodynamic status of each malformation (Table 2). Venous malformations are differentiated into truncular and extratruncular forms, with the truncular forms (38%) being obstructions or dilations and the extratruncular forms (62%) being limited or infiltrating¹ The prevalence of deep venous anomalies associated with VM is approximately 47%.²