Abstract only Background and purpose: Recurrent ischemic stroke in patients with CS and PFO has been proposed as a marker of increased risk for paradoxical embolism. It is unclear, whether the excess risk is driven by specific features of the PFO (right-to-left shunt (RLS) size, RLS at rest, associated atrial septum aneurysm (ASA)) or the presence of vascular risk factors (vRF). We compare the prevalence of vRF, TEE features, and baseline medications in PFO patients with first-ever versus multiple CS. Methods: From September 2008 to March 2013, the International PFO Consortium enrolled 993 patients with ischemic stroke or transient ischemic attack (TIA) and newly diagnosed PFO. In this analysis of baseline data, we included 386 patients with first-ever CS and no radiological evidence of prior cerebral ischemia (first-ever CS group, mean age, 52y) as well as 71 patients with recurrent CS and multiple ischemic lesions on CT and/or MRI (multiple CS group, mean age, 59y). Patients with TIA as index event, those with first-ever CS but additional “silent” ischemic lesions on imaging as well as those with recurrent CS without radiological findings of prior cerebral ischemia were excluded. We used nonparametric tests for independent samples and the Bonferroni correction for multiple comparisons. Results: Age > 55y (63% vs. 44%, P=0.001), hypertension (52% vs. 30%, P=0.001), hyperlipidemia (64% vs. 44%, P=0.003), and coronary artery disease (15% vs. 3%, P=0.001) were significantly more frequent in the multiple CS than in the first-ever CS group. The frequencies of male gender, current smoking, diabetes, migraine with or without aura, associated ASA, RLS size, and RLS at rest did not differ between groups. At baseline, patients with multiple CS were more likely to be on antiplatelets (50% vs. 18%), antihypertensive (51% vs. 22%) or lipid lowering drugs (44% vs. 10%, P=0.001 for each comparison) than patients with first-ever CS. The frequency of anticoagulant treatment did not differ between groups. Conclusions: In patients with CS, vRF but not specific PFO features were associated with recurrent cerebral ischemic events. The ongoing prospective part of the International PFO Consortium will likely shed light upon the role of vRF control for secondary stroke prevention in patients with PFO.