RESULTS: The patient is a 54 year old female, with a history of COPD and severe aortic valve insufficiency, diagnosed via an echocardiogram at another facility, referred to cardiovascular surgery at our hospital. During pre-surgical evaluation, she was found to be hypoxic, with oxygen saturation in the 80%s on 2L of oxygen by nasal cannula and was admitted. Upon admission, her oxygen saturation was at 85% on a non re-breather mask. She denied any symptoms. Physical examination was unremarkable. Laboratory values showed hemoglobin of 17.3g/L and hematocrit of 48.9%. Chest X-Ray revealed a mass like density in the right lower lobe (RLL). CT scan of the thorax with contrast was negative for pulmonary embolus but 4 AVMs in RLL and 2 in right upper lobe were identified. Further questioning and workup was negative for Osler-Weber-Rendu syndrome or other underlying etiology. Resting echo showed an EF of 70% and a Bubble Echocardiogram revealed extensive right to left shunting. Bubbles entered from the pulmonary venous drainage into the left atrium consistent with AVMs. She had a pulmonary angiogram and AVMs of the RLL were embolizedx2 and an amplatzer vascular occlusion plug was deployedx2. After embolization, the patient's oxygen saturation was at 95% on 6L of oxygen. A Transesophageal Echo showed moderate aortic insufficiency and she decided to forego cardiac surgery.