Background and purpose: Few studies have prospectively examined the risk of recurrent stroke associated with patent foramen ovale. We present the results of the Spanish right-to-left shunt (RLSh) multicenter study.
Methods: Four hundred eighty-six patients with cryptogenic stoke were included at 17 participating hospitals. Patients were examined by contrast transcranial Doppler methods at baseline. The magnitude of RLSh was quantified during the Valsalva maneuver. Transthoracic and/or transesophageal echocardiography, computed tomography scan, or magnetic resonance imaging was performed. Functional outcome and stroke recurrence were evaluated at 3 months and yearly thereafter. The independent relation between RLSh magnitude and stroke recurrence was analyzed by logistic-regression analysis in the whole group and in the younger subgroup (<55 years).
Results: Massive RLSh was detected in 200 patients (41.2%). The mean follow-up was 729+/-411 days. Stroke recurrence was low (5.8%, n=28) and similar in patients with massive RLSh, with nonmassive RLSh, and with no RLSh, in both the younger group (3.4% vs 2.3% vs 4.5%, respectively; P=0.75) and in the whole population (5.0% vs 6.2% vs 6.3%, respectively; P=0.58). Regression analysis found no association between massive RLSh and recurrent stroke in either group (in the whole population, odds ratio=0.94; 95% CI, 0.36 to 2.40; P=0.89; in the younger population, odds ratio=0.93; 95% CI, 0.18 to 4.91; P=0.93). These results were similar when concurrent atrial septal aneurysm and massive RLSh were analyzed and when antithrombotic treatment and concomitant stroke risk factors were included.
Conclusions: These results suggest that neither massive RLSh nor massive RLSh with concurrent atrial septal aneurysm is an independent risk factor for recurrent stroke, in either the general or younger stroke populations.