SESSION TITLE: Lung Pathology 2 SESSION TYPE: Affiliate Case Report Poster PRESENTED ON: Tuesday, October 31, 2017 at 01:30 PM - 02:30 PM INTRODUCTION: Pulmonary arteriovenous malformations (PAVMs) are exceedingly rare, with an estimated prevalence of 38/10,000.1 Like intra-cardiac shunts, PAVMs can lead to paradoxical emboli and stroke, and their detection and management is therefore critical.2 We present a case of recurrent stroke secondary to a large AVM, discovered via saline-contrast echocardiography (SCE), with particular attention to bubble transit time. CASE PRESENTATION: A 77 year old female presented to the Emergency Room with dysarthria, right-sided weakness, and gait imbalance. MRI/MRA brain revealed sub-acute infarcts in the left pons, left superior cerebral peduncle, and right posterior cerebellum. Intra-cranial and intra-cervical arteries were patent. Telemetry monitoring did not reveal atrial fibrillation, and prior Holter monitoring did not reveal significant arrhythmia. Transthoracic echocardiogram (TTE) did not reveal any shunt. Aspirin was switched to clopidogrel and high-intensity statin was added. Two months later, she developed acute left-sided weakness. MRI brain revealed an acute infarct in the posterior right parietal lobe. SCE was positive for right to left shunt with delayed transit time. Chest X-ray showed an irregular opacity within the right middle lobe (RML). This appeared to be in the same location as a previously known PAVM on comparison to old imaging done 6 years prior. CT chest then revealed an enlarging PAVM in the RML, now with a diameter of >6 mm. She subsequently underwent coil embolization and is doing well. DISCUSSION: In a normal individual, peripherally injected saline bubbles are not observed in the left heart as lung capillaries act as filters.2 Their presence therefore indicates a right-to-left shunt, and transit time can help differentiate between intra-cardiac and intra-pulmonary shunts, both of which can lead to recurrent stroke.3 Delayed transit time of >6 beats is highly suggestive of intra-pulmonary shunting.3 Our case illustrates the need to differentiate between these two shunts, as PAVMs are indeed a rare cause of recurrent stroke. CONCLUSIONS: Though there is currently no role for PAVM screening in the work-up of stroke, routine SCE should be done for intra-cardiac shunt evaluation. As SCE also has a sensitivity of around 1.00 in the detection of PAVMs, one can therefore pick up more rare etiologies of stroke using this modality.3 Reference #1: Nakayama M, Nawa T, Chonan T, et al. Prevalence of pulmonary arteriovenous malformations as estimated by low-dose thoracic CT screening. Internal Medicine. 2012; 51(13): 1677-1681. Reference #2: Attaran, RR, Ata I, Kudithipudi V, et al. Protocol for optimal detection and exclusion of a patent foramen ovale using transthoracic echocardiography with agitated saline microbubbles. Echocardiography. 2006; 23(7): 616-622. Reference #3: Gazzaniga P, Buscarini E, Leandro G, et al. Contrast echocardiography for pulmonary arteriovenous malformations screening: does any bubble matter? European Journal of Echocardiography. 2009; 10: 513-518. DISCLOSURE: The following authors have nothing to disclose: Lydia Winnicka, Charumathi Raghu Subramanian, Amirahwaty Abdullah, Amirtha Dileepan, James Walsh No Product/Research Disclosure Information