Pulmonary embolism with paradoxical embolization to right coronary artery in the presence of a large patent foramen ovale: a case report

Background Pulmonary embolism (PE) is the leading cause of in-hospital death and the third most frequent cause of cardiovascular death. The clinical presentation of PE is variable, and choosing the appropriate treatment for individual patients can be challenging. Case summary A 64-year-old man presented to hospital with acute chest pain, shortness of breath, and pulmonary oedema. Electrocardiogram revealed ST-elevation myocardial infarction. D-dimer was 18.8 mg/L fibrinogen equivalent units (FEU) (normal <0.64), and troponin was 25 (normal 5-14 ng/L). After systemic thrombolysis, respiratory failure persisted, and the arterial blood gas showed PaO2 of 6.0 kPa (normal 10.5-13.5 kPa), with 100% oxygen delivery via high-flow nasal cannula. A computed tomography diagnosed bilateral lobar PE, and coronary angiogram showed multiple thrombus in the right coronary artery. A bubble study with thoracic echocardiogram revealed a large right-left inter-atrial shunt. The patient denied treatment with extracorporeal membrane oxygenation and surgical thrombectomy. With no access to percutaneous catheter-directed thrombectomy, the patient received three separate thrombolysis treatments followed by a continued infusion for 22 h. After 6 weeks in hospital, the patient was discharged to rehab. Discussion For a long time, PE has been largely seen as a medical disease. Intra-cardiac shunts such as patent foramen ovale can complicate thrombo-venous disease and introduce paradoxical shunts leading to arterial emboli and persistent hypoxaemia. Over recent years, modern percutaneous catheter-directed thrombectomy has been developed for both high-risk and intermediate to high-risk PEs. Thrombectomy might improve right ventricular function and haemodynamics, but there is lacking evidence from randomized trials on efficacy, safety, and long-term outcome.