Low cerebrovascular event rate in subjects with patent foramen ovale and different clinical presentations: results from a prospective non randomized study on a population including patients with and without patent foramen ovale closure.

Background: There are conflicting data on the role of a patent foramen ovale (PFO) in the pathogenesis of cryptogenic stroke. The aim of this study was to evaluate the incidence of cerebrovascular events associated with PFO in a large population of patients during mid-term follow-up.

Methods And Results: We prospectively investigated 446 consecutive patients (58% female, age 50 ± 14 years) in whom PFO was detected by contrast echocardiography following cryptogenic stroke (30.5%), transient ischemic attack (TIA, 23.7%), migraine(10.5%) or evaluation for other cardiac diseases(35%). Prevalence of other clinical conditions potentially associated with cerebral embolism, such as mitral valve disease, atrial fibrillation and aortic atherosclerosis were 31%, 12.5%, 11.2%, respectively; 99 out of 446 patients (22%, group 1) underwent PFO closure, shortly after diagnosis, while 347 (78%, group 2) received only medical therapy (antiplatelet drugs and vitamin K antagonists). During 54 months (range 12-96) of average follow-up few events had been observed: one fatal stroke (1%) in group 1 and 3 nonfatal strokes (0.86%) in group 2 (not significant); there were more TIAs in group 1 than in group 2 (5, 5% versus 3, 0.86%, p=0.02): 8/12 new cerebrovascular events occurred in patients with previous cerebral ischemia and in 7/12 there were other cardioembolic sources. Kaplan-Meier survival free from cerebrovascular events showed a slightly better prognosis in unclosed PFO patients compared to closed PFO ones, statistically significant (p=0.004).

Conclusions: New cerebrovascular events are rare in unselected subjects with PFO, even in those with previous cerebral ischemia and those who have not undergone PFO closure, with an event rate similar to that observed in the general population.