G1691A factor V and G20210A FII mutations, acute ischemic stroke of unknown cause, and patent foramen ovale.

Background: Genetic polymorphisms of haemostatic factors such as G1691A factor V (FV Leiden) and G20210A prothrombin (FII) may be involved in the onset of patent foramen ovale (PFO)-related cerebral ischaemia. We assessed the possible association between such inherited thrombophilic alterations and right-to-left shunt in patients with stroke.

Methods: We investigated the presence of G20210A FII and FV Leiden mutations in 340 Caucasian patients consecutively evaluated by our Angiology Unit for stroke of unknown cause. PFO was assessed in all patients with Transcranial Doppler with intravenous injection of agitated saline. Stroke patients were divided into two groups: patients with PFO (n=136), and patients without PFO (n=204). As control group, we studied 272 subjects with early venous insufficiency.

Results: The prevalence of FII G20210A mutation was significantly higher in patients with PFO vs. controls (OR: 2.90; 95% CI: 1.19-7.07) and in patients without PFO vs. controls (OR: 2.88; 95% CI: 1.25-6.60) but was similar in patients with and without PFO (OR: 1.11; 95% CI: 0.51-2.44). The frequency of FV Leiden mutation was similar in the three groups. Across the population the presence of the FII G20210A mutation (OR: 2.97;95% CI: 1.32-6.69), a history of DVT (OR: 1.04; 95% CI: 1.02-1.06), and oestrogen-containing contraceptive therapy (OR: 1.14; 95% CI: 1.09-1.18) were all associated with stroke of unknown cause after adjustment for other risk factors, This was not the case with PFO.

Conclusions: Our data do not support the assumption that these inherited thrombophilic alterations are associated with PFO in patients with cryptogenic stroke. FII G20210A mutation may be associated with cryptogenic stroke irrespective of the presence of PFO.