The pivotal role of PFO in paradoxical embolism following venous sclerotherapy: a unique case report with pathological correlations.

Background  Vein sclerosing therapy for varicose veins remains an extremely popular procedure. Cerebrovascular accidents can be a serious complication. A patent foramen ovale (PFO) can act as a conduit to the arterial circulation, which could explain the adverse neurologic consequence of this procedure. This case provides pathologic evidence of this concept. Case summary  A 66-year-old female presented with syncope after undergoing varicose vein sclerotherapy. A computed tomography angiography of the head and neck in the emergency room revealed an occluded right distal M1 middle cerebral artery. Clot retrieval was performed with final pathology revealing amorphous material consistent with an exogenous agent, polidocanol foam, which was used for the patient's vein sclerotherapy. A transthoracic echocardiogram and transoesophageal echocardiogram showed a PFO, which was ultimately closed percutaneously. Discussion  In a quarter of the population, lack of closure of the intrauterine interatrial shunt leads to the existence of a PFO. This direct communication between the atria provides an anatomical conduit for paradoxical emboli and eventually infarction of affected tissues. While a paradoxical embolism is an uncommon cause of acute arterial occlusion, it can have catastrophic sequelae. Historically, the presence of an arterial thrombus from the venous circulation has been difficult to establish unless the thrombus is visualized in transit through a PFO. Complications from vein sclerotherapy have been reported in the literature and include transient ischaemic attacks and strokes, however, this is the first case to provide pathological proof of a paradoxical embolism, which ultimately resulted in percutaneous closure of the PFO.