Morphological and functional characteristics of patent foramen ovale and their embolic implications

Background and Purpose-Transesophageal echocardiography (TEE) has detected a high prevalence of patent foramen ovale (PFO) in stroke patients, but the clinical implications of the distinctive characteristics of this patency a re still a matter of debate, Methods-We studied 350 patients with acute ischemic stroke or transient isc hemic attack (TIA) within 1 week of admission. Of these, 101 (29%) were ide ntified by contrast TEE to have a PFO; 86 patients (25%) were cryptogenic s troke patients, and 163 were excluded because of the presence of a definite or possible arterial or clinical evidence of a source of emboli or small-v essel disease. Thirteen PFO subjects without a history of embolism were des ignated as the control soup, All PFO and cryptogenic stroke patients were f ollowed up by neurological visits. Results-Compared with controls, PFO patients with acute stroke or TIA more frequently presented with a right-to-left shunt at rest and a higher membra ne mobility (P<0.05). Patients with these characteristics evert considered to be at high risk. During a median follow-up period of 31 months (range, 4 to 58 months), 8 PFO and 18 cryptogenic stroke patients experienced recurr ent cerebrovascular events. The cumulative estimate of risk of cerebrovascu lar event recurrence at 3 years was 4.3% (95% confidence interval [CI], 0% to 10.2%) for "low-risk" PFO patients, 12.5% (95% CI, 0% to 26.1%) for "hig h-risk" PFO patients, and 16.3% (95% CI, 7.2% to 25.4%) for cryptogenic str oke patients (high-risk PFO versus low-risk PFO, P=0.05). Conclusions-The association of right-to-left shunting at rest and high memb rane mobility, as detected by contrast TEE, seems to identify PFO patients with cerebrovascular ischemic events who are at higher risk for recurrent b rain embolism.