Abstract Body (Do not enter title and authors here): An 84-year-old male with a history of prostate cancer not on chemotherapy presented to the ED with complaints of shortness of breath worse on exertion ongoing for 1 week accompanied by generalized malaise. On arrival, his troponins were elevated 373, elevated BNP 934. He was requiring supplemental oxygen and an initial bedside cardiac ultrasound was unremarkable. On day 3 of hospitalization, he experienced a syncopal episode and had acute worsening of hypoxemia that prompted a CT angiography of the chest which revealed bilateral, large clot burden pulmonary emboli with proximal thrombus in both the right and left main pulmonary arteries. He was administered a therapeutic dose of low-molecular weight heparin and transferred to the ICU. Despite his large clot burden, there was absence of obstructive shock.
Transthoracic Echocardiogram and bilateral duplex venous ultrasound were obtained to evaluate for right heart strain and clot burden. TTE showed a clot in transit between the right atrium and ventricle, a severely dilated RV with reduced RV systolic function. Extensive clot burden in bilateral lower extremities was visualized on ultrasound. Cardiology was consulted. The risk and benefits of catheter-based aspiration thrombectomy versus thrombolytics (peripheral versus catheter directed) versus surgical thrombectomy versus anticoagulation alone were discussed. Given his high risk of in-hospital mortality, age and frailty, shared-decision making to proceed with anticoagulation alone was decided. Unfortunately, on day 8 of hospitalization, he became bradycardic with no recordable blood pressures, and went into pulseless electrical activity soon after with an eventual demise.

In this clinical case, we discussed sub-massive pulmonary embolism (PE) complicated by a right heart clot-in-transit presenting insidiously. Acute sub-massive pulmonary embolism is defined as intermediate risk PE associated with right ventricular dysfunction without hemodynamic instability. Right heart clot in transit is a rare complication of PE and is associated with a high mortality rate of 20-30%. Anticoagulation is the 1st line treatment for sub-massive PE but definite therapy regarding the management of right heart clot in transit is still debated: CATHETER-BASED INTERVENTION versus SURGICAL THROMBECTOMY as none is thought to be superior. Indication for either therapy centers on hemodynamic compromise which is assessed on a case-by-case basis based on the clinician’s judgement.