Emergent percutaneous aspiration thrombectomy and VV-ECMO for a paradoxical clot-in-transit across a PFO in the setting of massive pulmonary embolism did not prevent fatal multiorgan failure.
Case Report (n=1)
This case highlights the extreme physiologic complexity and high mortality of paradoxical clot-in-transit with massive pulmonary embolism and refractory right ventricular failure, even when managed with advanced therapies like aspiration thrombectomy and VV-ECMO.
Abstract Background Clot-in-transit (CIT) across a patent foramen ovale (PFO) represents a rare but catastrophic presentation of pulmonary embolism (PE). In this scenario, acute right ventricular (RV) pressure overload opens the PFO, allowing right-to-left shunting, systemic embolization, and worsening hypoxemia. Acute RV failure remains the major determinant of mortality in massive PE, and despite recent advances, optimal management of paradoxical CIT remains controversial. Case A 62-year-old man with obesity, heart failure, tobacco use, and recent methamphetamine exposure presented with progressive dyspnea and orthopnea. CT pulmonary angiography revealed bilateral pulmonary emboli extending into segmental branches, bilateral pleural effusions, and a left upper-lobe cavitary lesion. Transthoracic echocardiography demonstrated a markedly dilated RV with McConnell’s sign and a mobile echogenic mass prolapsing through a PFO into the left atrium. Transesophageal echocardiography confirmed a large thrombus straddling the PFO. Given the high risk for paradoxical embolism, the patient underwent emergent percutaneous aspiration thrombectomy with cerebral embolic protection, successfully removing the thrombus. Post-procedure, he was managed in the cardiovascular ICU with anticoagulation, vasopressors, and inotropes. BNP was markedly elevated (2,895 pg/mL) while troponin remained negative, suggesting RV wall stretch without overt ischemia. Despite optimized preload reduction, ventilatory support, and empiric antibiotics for a suspected infectious cavitary lesion, he developed progressive RV failure and refractory shock. VV-ECMO with RV assist was initiated for oxygenation and partial unloading, but severe tricuspid regurgitation from cannula-related tethering developed. Anticoagulation was transitioned to bivalirudin for suspected heparin-induced thrombocytopenia. Despite maximal supportive therapy, he progressed to multiorgan failure and expired. Conclusion This case illustrates the physiologic complexity of paradoxical CIT across a PFO in the setting of massive PE. The right-to-left shunt can transiently decompress the RV yet worsen systemic hypoxemia, complicating management. Multidisciplinary coordination between cardiology, critical care, and interventional teams is essential. Even with advanced support such as VV-ECMO, refractory RV failure remains a major cause of mortality, underscoring the need for rapid recognition, individualized reperfusion strategies, and novel RV assist modalities to improve survival in this rare and devastating condition. This abstract is funded by: None
Janajrah et al. (Fri,) conducted a case report in Paradoxical clot-in-transit across a patent foramen ovale with massive pulmonary embolism and severe right ventricular failure (n=1). Percutaneous aspiration thrombectomy and VV-ECMO was evaluated. Emergent percutaneous aspiration thrombectomy and VV-ECMO for a paradoxical clot-in-transit across a PFO in the setting of massive pulmonary embolism did not prevent fatal multiorgan failure.