PATENT FORAMEN OVALE SIZE AND EMBOLIC BRAIN IMAGING FINDINGS AMONG PATIENTS WITH ISCHEMIC STROKE

Background and Purpose-Although the cause of stroke among patients wit h patent foramen ovale (PFO) may be due to paradoxical cerebral emboli sm (PCE), this mechanism is often difficult to prove. The aim of our s tudy was to evaluate the association between brain imaging findings su ggestive of embolism and PFO among ischemic stroke patients. Methods-A s part of the Northern Manhattan Stroke Study, 95 patients with first ischemic stroke over age 39 underwent transesophageal echocardiography (TEE) for evaluation of a cardiac source of embolism. The stroke subt ype was determined by modified NINDS Stroke Data Bank criteria. Stroke subtype and MRI/CT imaging data were evaluated blind to the presence of a PFO. These findings were compared between two groups: patients wi th medium to large PFO (greater than or equal to 2 mm) and small (<2 m m) or no PFO, Results-Of the 95 patients who underwent TEE, 31 (33%) h ad a PFO, The frequency of PFO was significantly greater among patient s with cryptogenic infarcts (19 of 42; 45%) compared with patients wit h determined cause of stroke (12 of 53, 23%; P=0.02), Medium to large PFOs were found more often among cryptogenic strokes than among infarc ts of determined cause (26% versus 6%; P=0.04). Superficial infarcts o ccurred more often in the group with larger PFOs than in the group wit h small or no PFOs (50% versus 21%; P=0.02), Patients with medium or l arge PFOs more frequently had occipital and infratentorial strokes (57 % versus 27%; P=0.02), Conclusions-Stroke patients with larger PFOs sh ow more brain imaging features of embolic infarcts than those with sma ll PFOs. Larger PFOs may be more likely to cause paradoxical embolizat ion and may help explain the stroke mechanism among patients with no o ther definite cause.