Direct evidence of patent foramen ovale as a route for paradoxical embolism.

Analysis of the protective effect of topical sunscreens on the UVB-radiation induced suppression of the mixed-lymphocyte-reaction. Effect of topical sunscreens on the UV-radiation-induced suppression of the alloactivating capacity in human skin in vivo. A 83 year old woman was transferred from the departnent of surgery because of a syncopal attack with hypotension. Twenty days before she had had a palliative operation for gall bladder adenocarcinoma with hepatic invasion. Some days later she had had an ischaemic stroke in the middle cerebral artery territory, which was confirmed by computed tomography. Carotid ultrasonography showed no stenoses. Despite these clinical events and prolonged immobilisation, she could be treated only with low-dose subcutaneous heparin because of postoperative gastric Transthoracic echocardiogram (modified right ventricular inflow tract view, diastolic frame) showing the thrombus (THR, arrows) abutting the tricuspid valve (7T) and crossing the interatrial septum at the level offoramen ovale to impinge on the mitral valve haemorrhage which required blood transfusions. Transthoracic echocardiography (TTE) showed a thrombus abutting the tri-cuspid valve and crossing a patent foramen ovale to reach the left atrium and mitral valve (figure). A Doppler estimate of right ventricu-lar systolic pressure was about 75 mm Hg. A patent foramen ovale is a risk factor for ischaemic stroke'; indirect evidence of its role as a route for paradoxical embolism through a right-to-left shunt stems from case-control studies.2 A direct role is difficult to demonstrate ,4 because diagnosis of paradoxical embolism is based upon indirect criteria,5 and documentation of a patent foramen ovale itself usually requires transesophageal echo-cardiography, with intravenous saline contrast when necessary. This patient had several risk factors for deep vein thrombosis, such as old age, adeno-carcinoma, recent surgery, and prolonged immobilisation: but she also had contraindi-cations to antithrombotic therapy.6 The shape of the thrombus indicated a venous genesis. Pulmonary hypertension probably forced open the foramen ovale,5 leading to an interatrial shunt. The thrombus across the interatrial septum may explain the ischaemic stroke and confirm the role of patent foramen ovale in paradoxical embolism, especially in the presence of pulmonary hypertension. We thank Dr Antonio Giomi and Dr Maurizio Chiti for their help and advice in reviewing this case. ovale: a new risk factor for ischemic stroke.