Traversing boundaries: thrombus in transit with paradoxical embolism

Anesthetic management and the role of TEE in the entrapment of a paradoxical embolus by a patent foramen ovale

Background

A paradoxical embolism arises when a venous thrombus passes through a cardiac right to left shunt and enters the arterial circulation. This can manifest as cardiovascular ischemia, cerebrovascular insults, increased right ventricular pressure, and/or volume overload leading to signs and symptoms of heart failure. While rare, paradoxical emboli carry high mortality and morbidity if diagnosis is missed and/or treatment is delayed. Transesophageal echocardiography can be diagnostic. Initial treatment revolves around anticoagulation and/or thrombolysis to prevent clot propagation. However, for clots in transit, emergent surgical removal is often necessary. Anesthetic induction can be tricky given the potential for rapid deterioration and the need to avoid increased right sided pressures and further clot migration.

Case presentation

In this report, we present a 72-year-old obese female with a history of hypertension, hyperlipidemia, gout, and diabetes found to have a paradoxical embolism caught in transit, trapped in a patent foramen ovale, and managed surgically. We describe the role of intraoperative transesophageal echocardiography in successfully treating this patient.

Conclusions

TEE plays an important role in the diagnosis and management of paradoxical PE. It can detect right and left heart thrombi and intracardiac shunts , can help in the successful closure of intracardiac shunts, and can impact intraoperative surgical decision making.

Wide-ranging clinical spectrum of paradoxical embolism

The purpose of this review is to raise the index of suspicion for paradoxical embolism among generalists. The review is based solely on anecdotal reports compiled from EMBASE, MEDLINE, Googlescholar and Pubmed. Search terms were 'paradoxical embolism', 'pulmonary embolism' and 'pulmonary arteriovenous malformations'. What emerged was that right-to-left paradoxical embolism could occur with or without concurrent pulmonary embolism, and also with and without proof of the presence of an 'embolus-in-transit'. Potential sites of single or multiple systemic involvement included the central nervous system, the coronary circulation, renal arterial circulation, splenic circulation, the mesenteric circulation and the limbs. In many cases, the deep veins of the lower limbs were the source of thromboembolism. In other cases, thrombi originated from an atrial septal aneurysm, from a central venous line, from a haemodialysis-related arterio-venous shunt, from a popliteal vein aneurysm, internal jugular vein, superior vena cava, from a pulmonary arteriovenous malformation, from tricuspid valve endocarditis (with and without pulmonary embolism) and from the right atrium, respectively. Stroke was by far the commonest systemic manifestation of paradoxical embolism. Some strokes were attributable to pulmonary arteriovenous malformations with or without coexistence of intracardiac shunts. Clinicians should have a high index of suspicion for paradoxical embolism because of its time-sensitive dimension when it occurs in the context of involvement of the intracranial circulation, coronary circulation, mesenteric circulation, and peripheral limb circulation.

Multiorgan paradoxical embolism in an elderly female with a patent foramen ovale: a case report

Paradoxical embolism is an uncommon cause of arterial occlusion with a high mortality burden. Current evidence suggests that patent foramen ovale is the most important etiological factor of paradoxical embolism, by acting as a pathway for a thromboembolic material originating from the peripheral veins, passing through the lungs and entering the systemic circulation. Here we present a case of paradoxical embolism in the mesenteric and renal arteries associated with pulmonary embolism and deep vein thrombosis in an elderly woman with no predisposing risk factor. A diagnosis of paradoxical embolism was considered and the presence of a patent foramen ovale was consequently confirmed with a transesophageal echocardiography. Urgent thrombolysis saved the life of the patient. Paradoxical embolism represents an emergency and therefore prompt diagnosis and initiation of therapy may prevent adverse outcomes.