Patients with airway vascular anomalies seen in the Vascular Anomalies Clinic, Seattle Children's Hospital, Seattle, Washington, between 2001 and 2008 were identified from the Vascular Anomaly Quality Improvement Database and Seattle Children's Hospital discharge data after approval from the institutional review board (No. 12699). The medical records of these patients were evaluated retrospectively by pediatric otolaryngologists (S.C.M., A.F.I., and J.A.P.). Vascular anomalies were classified as either airway IHs or airway VMs based on clinical presentation and endoscopic appearance. The clinical characteristics of airway IHs included rapid onset of respiratory distress in children younger than 1 year. The clinical characteristics, coupled with endoscopic findings of a red vascular lesion in the upper aerodigestive tract, led to the vascular lesion being classified as an airway IH. The clinical characteristics of airway VMs included chronic feeding symptoms without airway compromise or intermittent airway compromise. These symptoms, coupled with a bluish or compressible vascular mass in the upper aerodigestive tract, led to the lesion being classified as an airway VM. Lesions that were predominantly lymphatic malformations and involved the airway were excluded. The following data were collected: patient sex, patient age at presentation and diagnosis, presenting symptoms (eg, stridor, cyanosis, reflux, failure to thrive, dysphagia, hemoptysis), type of endoscopic evaluation, CTA appearance, endoscopic findings, histologic characteristics, and clinical outcome. Data were analyzed using descriptive statistics (Stata 8.0; Statacorp, College Station, Texas) and the Fisher exact test, as appropriate.