(1174) When Clots Go Sightseeing: Clot-in-Transit Leading to Cardiac Arrest

Introduction: Clot in transit (CIT) is an unattached right heart thrombus that has detrimental sequelae such as pulmonary emboli (PE), obstructive shock and subsequent cardiac arrest. Point-of-care ultrasound (POCUS), albeit helpful in cardiac arrests, is limited to suboptimal views which in turn might lead to misdiagnosis.

Description: A healthy 52-year-old gentleman presenting with pelvic and rib fractures collapsed a few hours after admission. Resuscitation was initiated for pulseless electrical activity (PEA) cardiac arrest. Admission vital signs and laboratory markers were unremarkable. Cardiac POCUS was limited to the subxiphoid view due to active chest compressions but revealed a mildly dilated right ventricle. Remainder of the exam revealed poor lung sliding, prompting tube thoracostomy. Spontaneous circulation resumed 23 minutes later, however, he remained on maximal vasopressor support. A more comprehensive POCUS exam showed worsening right ventricular dilation with septal flattening, and a right atrial CIT traversing the tricuspid valve. Bilateral massive PE not amenable to surgical or percutaneous treatment were seen on CT angiography and he was emergently placed onto venoarterial extracorporeal membrane oxygenation (VA-ECMO) due to florid right ventricular failure. He made a miraculous recovery and was able to walk out of the hospital 17 days later.

Discussion: Patients with CIT often exhibit rapid decompensation compared to those who develop a PE without a discernible CIT, mortality rate is as high as 29% despite treatment [1]. Management is challenging due to the sparse and conflicting data, nevertheless, it remains similar to PE [2]. ECMO has been utilized to stabilize those with massive inoperable PE [3].

The use of POCUS has emerged during resuscitation of PEA cardiac arrests, nonetheless, its impact on clinical outcomes remains unclear. The goal of maintaining uninterrupted chest compressions makes the subxiphoid view the most feasibly obtained. However, satisfactory views have been reported in only 66% of patients [4].

The presence of rib fractures and findings of decreased lung sliding led to anchoring on tension pneumothorax leading to the cardiac arrest. With the gift of hindsight, the ultrasonographic findings were most likely due to pulmonary contusions.