Embolisation therapy for pulmonary arteriovenous malformations

A pulmonary arteriovenous malformation is an abnormal connection between arteries and veins in the lung. It is known to cause serious complications such as stroke, brain abscess, bleeding in the lungs and exercise intolerance. Embolisation therapy is the mainstream treatment for pulmonary arteriovenous malformations. This comprises insertion of a catheter via the groin and eventual deployment of balloon, coil, or combinations of balloon and coil devices to occlude the pulmonary arteriovenous malformation. However, these pulmonary arteriovenous malformations can often be very small and be associated with multiple pulmonary arteriovenous malformations in other parts of the lungs. This means they are not amenable to either embolisation or surgery. In this systematic review of the literature, we did not identify any randomised controlled trials to support the use of embolisation treatments for pulmonary arteriovenous malformations. Neither did we find any comparison between embolisation therapy and surgery for pulmonary arteriovenous malformations. In view of the known benefits of embolisation, trials comparing embolisation to no treatment or to surgery are considered unethical. A more feasible study for future consideration will be to compare different embolisation devices. Currently, observational studies will require a standardised approach to reporting as well as long-term follow up through registry studies to strengthen the evidence base for embolisation therapy.