Estimate of the Prevalence of Vascular Malformations

Objectives:. To estimate the prevalence of vascular malformations using retrospective data collected from 1999 to 2020 in a specialty vascular anomalies service. Methods:. The vascular anomalies service associated with the Royal Children’s Hospital provides a reference service to both adults and children, covering the entire state of Victoria, Australia, which has a population of 6.7 million and around 70,000 births per year. A database of patients was interrogated to identify those treated by the service over the study period with a diagnosis of vascular malformation, excluding capillary malformations. A total of 1501 patients were identified, including 1233 with slow-flow malformations and 147 with arteriovenous malformations. Prevalence was calculated as the number of cases born per year who attended the service plus those estimated as yet to attend for assessment, divided by the average number of live births each year. This was calculated for a selected period comprising the years when the numbers were expected to be most stable. Results:. The prevalence of slow-flow malformations is estimated to be 1 case per thousand livebirths. Approximate estimates of cases per 100,000 births for individual lesions are: venous malformation 45, lymphatic malformation 35, intramuscular slow-flow malformation 10, complex malformations (Klippel-Trenaunay and CLOVES) 4, glomuvenous malformation 5, and verrucous venous malformation 2. The prevalence of extracranial arteriovenous malformation is estimated to be around one case per 10,000 population. Conclusions:. An updated estimate, more accurate than those previously published, of the prevalence of vascular malformations has been obtained.