Approximately 40% of strokes are classified as cryptogenic or as having no identifiable cause. Some of these cryptogenic strokes may be due to an embolus from the venous circulation crossing into the systemic circulation through a patent foramen ovale (PFO). While PFOs are certainly common in the general population – with a prevalence of around 25% – they do appear to be more common in patients with cryptogenic stroke, with some series reporting the prevalence to be as high as 56%. Closure with a percutaneous device is often recommended, but it is not known whether this intervention reduces the risk of recurrent stroke as compared with standard medical therapy alone.
In the multicentre, randomized, open-label, CLOSURE I study, these two strategies were compared in 909 patients between 18 and 60 years of age who presented with a cryptogenic stroke or transient ischemic attack (TIA) and had evidence of a PFO. The primary end point was a composite of stroke or transient ischemic attack during 2 years of follow-up, death from any cause during the first 30 days, or death from neurologic causes between 31 days and 2 years. Using a STARflex closure device, the rate of effective closure were 86%. However,the results demonstrated no benefit for intervention with a cumulative incidence of the primary end point of 5.5% in the closure group as compared with 6.8% with medical-therapy (HR, 0.78; 95% CI, 0.45 to 1.35; P=0.37). The respective rates for stroke were 2.9% and 3.1% (P=0.79) and 3.1% and 4.1% for TIA (P=0.44). Periprocedural major vascular complications occurred in 3.2% of patients in the closure group and within 6 months left atrial thrombus was found in 1.1% of patients, 50% of whom went on to have a second stroke.
In this well-conducted and adequately powered study, patients with cryptogenic stroke or TIA who had a PFO accrued no extra benefit from device closure than with medical therapy alone for the prevention of recurrent stroke or TIA.
- Furlan AJ, Reisman M, Massaro J, Mauri L, Adams H, Albers GW, Felberg R, Herrmann H, Kar S, Landzberg M, Raizner A and Wechsler L. Closure or medical therapy for cryptogenic stroke with patent foramen ovale. N Engl J Med. 2012 Mar 15;366(11):991-9.