Abstract 4372822: A Unique STEMI Etiology: Paradoxical Coronary Embolism

Paradoxical coronary embolism (CE) causes an estimated 4-13% of ST-segment-elevation myocardial infarction (STEMI) presentations. A thromboembolism can originate in the venous system and cross into systemic circulation via an intracardiac or intrapulmonary shunt, resulting in a variety of clinical presentations. Patent foramen ovale (PFO) is the most common intracardiac shunt, found in nearly 30% of the general population. A 72-year-old male with a history of prior pulmonary embolism and severe degenerative disc disease was admitted to the hospital for elective cervical laminectomy and decompression of C3-T1. His hospital course was complicated by aspiration pneumonia with resultant Streptococcus salivarius bacteremia and new onset atrial fibrillation and spontaneous conversion to sinus rhythm. Transthoracic echocardiogram and subsequent transesophageal echocardiogram after conversion to sinus rhythm demonstrated normal left ventricular systolic function, no evidence of endocarditis nor left atrial appendage thrombus, and a large PFO demonstrating bidirectional shunting. Later, he was noted to have new ST-segment elevations on telemetry, prompting an electrocardiogram which confirmed anterior and lateral ST-segment elevations. Emergent coronary angiography revealed mild coronary artery disease with no evidence of plaque rupture; however, thrombotic occlusions of the distal left anterior descending artery and distal second obtuse marginal artery were most consistent with a thromboembolic event. Bilateral upper and lower extremity duplexes revealed a superficial vein thrombosis in the right cephalic vein. Clinical suspicion was high for paradoxical CE related to his PFO; closure was pursued with transcatheter placement of an occluder device. Paradoxical CE is underdiagnosed, and subsequent evaluation for common culprits should include thrombus of aortic or mitral prosthetic valves, atrial fibrillation, endocarditis, PFO, neoplasm, and hypercoagulable disorders. The incidence of PFO related CE is unknown but suggested to be <4% of STEMI. Current guidelines give conditional recommendations for closure in paradoxical CE, owing to limited literature. As in our case, we would recommend closure of PFO once a paradoxical embolus occurs given risk for recurrent events and data suggesting a higher mortality rate despite lower cardiovascular risk.