Incidence of extracerebral paradoxical embolisms in patients with intracardiac shunts

Paradoxical Embolism Is an Unusual Etiology of Acute Limb Ischemia in Patients Suffering from COVID-19 Infection

Acute limb ischemia (ALI) is a large contributor to morbidity and mortality annually and can be managed either operatively or medically. ALI is most often caused by arterial embolism or in situ thrombosis and treatment is often dependent upon the severity. Anticoagulation is considered standard of care and first line therapy. However, more severe cases of ALI require surgical intervention.Paradoxical emboli are a rare and potentially under-appreciated cause of ALI. They arise when venous emboli, from a variety of sources, traverse a patent foramen ovale (PFO) to enter the arterial system, compromising blood flow to the affected end organ. In most cases, they can only be proven if the thrombus is identified as it crosses the cardiac defect, at which point it is an indication for surgery requiring PFO closure, management for the ischemia itself, and possible intervention for the embolism.In this report, we identify and discuss management of a series of cases where ALI was precipitated by PFOs that were discovered in the context of a pulmonary emboli that developed into paradoxical emboli. All patients had a confirmed diagnosis of COVID-19 which has been associated with a state of hypercoagulability and subsequent thrombus formation.

Systemic and venous thromboembolism: think about paradoxical embolism

Patent foramen ovale (PFO) is one of the most important causes of paradoxical embolism; it is found in about 25-30% of the population. In most patients, it is asymptomatic and diagnosis is usually made during routine echocardiography. In a small proportion of patients, PFO is diagnosed after paradoxical embolism is suspected. We present a case of a middle-aged smoker who was admitted with lower limb deep vein thrombosis and pulmonary embolism, who developed acute upper limb ischaemia during his inpatient stay. Since doctors might dismiss such cases as routine, this report highlights the importance of detailed history taking and examination in patients with venous thromboembolism. Paradoxical embolism should always be considered as a possible diagnosis when managing patients with concomitant venous and arterial embolism.

Percutaneous implantation of a second device in patients with residual right-to-left shunt after patent foramen ovale closure

INTRODUCTION

The management of patients with residual right-to-left shunt (rRLS) after percutaneous patent foramen ovale (PFO) closure is debated. The aim of this study was to define the incidence of moderate-to-large rRLS and to report the feasibility, safety and long-term clinical outcome of transcatheter closure of rRLS.

METHODS AND RESULTS

From June 2000 to March 2013, 322 subjects underwent percutaneous PFO closure. In 39 patients (12.1%) with moderate-to-large rRLS on transcranial Doppler (TCD) and/or transesophageal echocardiogram a second cardiac catheterization was performed with the aim of completing the closure. A second closure device was implanted in 21 patients (53.8%). In the remaining 18 (46.2%), a second device was not delivered for the following reasons: in 13 (72.2%) no residual passage could be crossed, in 5 (27.8%) the residual shunt was deemed to be negligible. No complications occurred. After the second procedure, complete closure was proved by TCD in 16/21 (76.2%) subjects. One patient received a third device. During follow-up (41 ± 19 months), no cerebrovascular ischemic accidents occurred.

CONCLUSION

A second percutaneous PFO occlusion device can be safely implanted in patients with significant rRLS. However, a moderate-to-large rRLS on TCD and/or TEE may not necessarily represent a significant risk of further paradoxical embolization.

[Which patent foramen ovale needs to be closed, and how?]

Patent Foramen Ovale (PFO) is a normal fetal communication between right and left atria that persists after birth by about 30% in adults. It is discussed to be associated to potential clinical events, asking rational of such closure. Its correction throughout venous access can be attempted on four different indications: (1) secondary prevention of stroke or transient ischemic attack, (2) decompression illness, (3) migraine with aura, and (4) platypnea-orthodeoxia. The PFO closure procedure implies the double control of X-rays and ultrasound, and is relatively simple to perform, using various prostheses. In France, the place of percutaneous closure procedure is nowadays unclear since the Haute Autorité de santé currently suspended recommendations about the management after stroke.

Prevention of Stroke in Patients with Patent Foramen Ovale

Patent foramen ovale is found in 24% of healthy adults and 38% of patients with cryptogenic stroke. This ratio and case reports indicate that patent foramen ovale and stroke are associated, probably because of paradoxical embolism. In healthy people with patent foramen ovale, embolic events are not more frequent than in controls, and therefore no primary prevention is needed. However, once ischaemic events occur, the risk of recurrence is substantial and prevention becomes an issue. Acetylsalicylic acid and warfarin reduce this risk to the same level as in patients without patent foramen ovale. Patent foramen ovale with a coinciding atrial septal aneurysm, spontaneous or large right-to-left shunt, or multiple ischaemic events potentiates the risk of recurrence. Transcatheter device closure has therefore become an intriguing addition to medical treatment, but its therapeutic value still needs to be confirmed by randomised-controlled trials.