ID:183 FC-D09-9 Extensive Intracardiac Thrombosis in a Patient on V-A ECMO Support with Insufficient LV Unloading

Clinical Course: A 29-year-old man with unremarkable past health developed out-of-hospital cardiac arrest. Peripheral V-A ECMO was successfully established with low-flow time of 60 minutes. V-A ECMO flow was maintained at 4L/min. Anticoagulation was initiated with unfractionated heparin. There was persistent lack of pulsatile arterial waveform following V-A-ECMO establishment. Transthoracic echocardiography showed absence of LV ejection and suspicious intracardiac thrombus. Transesophageal echocardiography was pursued for better delineation, which revealed significant left atrial (LA) thrombus (Figures 1A-C), with extension into right upper pulmonary vein (RUPV), right lower pulmonary vein (RLPV), and left upper pulmonary vein (LUPV) (Figure 1D-F). Thrombus was also seen in the left ventricle (LV), left ventricular outflow tract, aortic cusps, and ascending aorta (Figure 1G-H). Despite aggressive surgical clot evacuation, the patient expired due to multiorgan failure in the first post-operative day. Discussion: Intracardiac thrombosis is a well-recognized but rare complication associated with V-A ECMO support. Severely depressed LV systolic function and insufficient unloading are risk factors to intracardiac stasis and thrombus formation. Intracardiac thrombosis most commonly occur in the left ventricle, but involvement of the left atrium, aortic root, and pulmonary veins have been reported in isolated reports. This may occur despite on therapeutic anticoagulation and pertains to high mortality. Early recognition with echocardiography and timely LV unloading are key drivers to prevent this catastrophic complication.