 Lung lesions , once identified , are usually treated to prevent episodes of bleeding and more importantly embolism to the brain . This is particularly done in lesions with a feeding blood vessel of 3 mm or larger , as these are the most likely to cause long @-@ term complications unless treated . The most effective current therapy is embolization with detachable metal coils . The procedure involves puncture of a large vein ( usually under a general anesthetic ) , followed by advancing of a catheter through the right ventricle and into the pulmonary artery , after which radiocontrast is injected to visualize the AVMs ( pulmonary angiography ) . Once the lesion has been identified , coils are deployed that obstruct the blood flow and allow the lesion to regress . In experienced hands , the procedure tends to be very effective and with limited side effects , but lesions may recur and further attempts may be required . CTA scans are repeated to monitor for recurrence . Surgical excision has now essentially been abandoned due to the success of embolotherapy . 
