A Massive Arteriovenous Malformation arising from the Aorta causing Severe Pulmonary Hypertension

Aortic arteriovenous malformations (AVMs) are rare vascular anomalies where the aorta communicates with adjacent venous structures, bypassing the capillary system. We report a case of a neonate born at 34 weeks gestation who presented at 3 weeks of life in respiratory distress. Echocardiography demonstrated severe pulmonary hypertension with right ventricular dilatation but an otherwise structurally normal heart. Clinical examination revealed a pulsatile abdominal mass with an audible bruit. Abdominal ultrasound was performed and it demonstrated a large cystic mass arising from the inferior vena cava (IVC) with both arterial and venous vascular flow within it. Further evaluation with magnetic resonance angiography (MRA) showed a massive arteriovenous malformation from both left and right iliac arteries, and lumbar arteries communicating with the IVC. A decision was made with interventional radiology to attempt coiling of the vascular lesion. Following this procedure his pulmonary hypertension worsened in severity, culminating in acute heart failure and multi-organ dysfunction. A subsequent interventional radiology procedure found that there was no blood flow to his bowel or abdominal viscera. Cardiac arrest followed with an unsuccessful attempt at resuscitation. This case describes a presentation of severe pulmonary hypertension initially considered to be secondary to either congenital heart disease or intrinsic pulmonary disease, but which was found to be as a result of a very rarely occurring massive aortic AVM.