Some Closure for the Issue of PFO Closure

This week, 2 articles examine the possible benefit of closing a patent foramen ovale (PFO), the vestige congenital hole between the left and right atria. Individuals with isolated PFO are typically asymptomatic, but longstanding reason has dictated that PFO, as a conduit for cardiac emboli, increases the risk of stroke and is a prominent cause of brain infarction in young adults. At least 2 studies indicated that the prevalence of PFO is increased (up to 45%) in patients with cryptogenic stroke.

However, a meta-analysis of 4 trials (N = 1081), published in this week's Neurology, indicates that the pooled relative risk (RR) of recurrent ischemic stroke or TIA in patients with PFO (vs those without) is only 1.1 (P = .149). The pooled RR for ischemic stroke alone in patients with PFO is 0.8 (P = .666).* Post-event treatments in these studies included antiplatelet therapy, warfarin, and/or surgical closure (the latter in 28% of patients with PFO), but the authors advise against using their meta-analysis data—which cannot be adjusted for important study differences—to assess therapeutic efficacies.

In this week's JAMA, a second study, performed at the Cleveland Clinic, assessed the effects of closing an incidental PFO—which was seen in 2277 of 13,092 (17%) surgical patients. Surgical closure was performed in 639 patients (28%) with PFO. The investigators calculated similar rates of in-hospital death (3.4% vs 2.6%) and stroke (2.3% vs 2.3%) in matched PFO groups. But patients with a repaired PFO were significantly more likely to experience a longer-term postoperative stroke than patients whose PFO was not repaired (2.8% vs 1.2%; P = .04). Surgical closure was statistically more likely in younger patients, in patients undergoing atrial valve surgery, or in those with a history of stroke or TIA. Long-term survival was not affected by PFO closure.

Currently there are no completed randomized trials comparing medical therapy with surgery in patients with cryptogenic stroke and PFO. The NIH database indicates that at least 1 US-based controlled trial is active but not recruiting.

In 2004, the American Academy of Neurology concluded that PFO does not increase the risk of subsequent stroke or death in medically treated patients. However, the combination of PFO and an atrial septal aneurysm possibly increases the risk of recurrent stroke (but not death) in medically treated patients who are younger than 55 years of age.

TIA = transient ischemic attack.

* In patients with PFO, the pooled absolute rate of recurrent stroke or TIA is 4 events per 100 person-years; the pooled absolute rate of recurrent stroke is 1.6 events per 100 person-years. The authors write that this rate is similar to the annual rate of major bleeding with warfarin therapy for cryptogenic stroke.

Mini-graphic of atrial septal defect (ASD) attributed to the NIH.