Patent Foramen Ovale Characteristics May Predict Benefits of PFO Closure

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Patients with cryptogenic stroke were randomly assigned to either medication only or patent foramen ovale closure.
Patients with cryptogenic stroke were randomly assigned to either medication only or patent foramen ovale closure.

Patent foramen ovale (PFO) closure in patients with high-risk PFO characteristics resulted in lower rates of stroke, vascular death, or Thrombolysis in Myocardial Infarction (TIMI)-defined major bleeding, according to a study presented at the American College of Cardiology 67th Annual Scientific Session and Expo held March 10-12, 2018 in Orlando, Florida, and simultaneously published in the Journal of the American College of Cardiology

Pil Hyung Lee, MD, and colleagues from the Asan Medical Center in Seoul, Korea, conducted a multicenter randomized open-label superiority trial (DEFENSE-PFO; ClinicalTrials.gov Identifier: NCT01550588) to evaluate whether the benefits of PFO closure with the Amplatzer™ PFO occluder device (Abbott) could be determined based on PFO characteristics as assessed by transesophageal echocardiography (TEE). High-risk PFO was defined as PFO with atrial septum aneurysm, hypermobility, or PFO size ≥2 mm.

The researchers evaluated 450 patients who were diagnosed with cryptogenic stroke with PFO. The frequency of high-risk PFO was 38.9% (175 of 450 patients). The primary end point included a lower rate of stroke, vascular death, or TIMI-defined major bleeding during the 2 years of follow up. The secondary end point was asymptomatic ischemic stroke on a follow-up MRI 6 months after random assignment to either PFO closure or medication only.

Of the 450 eligible patients, 120 patients (mean age, 51.8 years) were randomly assigned to PFO closure or medication only with an even distribution between the two groups. Both groups had similar PFO size, septal aneurysm frequency (13.3% vs 8.3%; P =.56), and hypermobility (45.0% vs 46.7%; P >.99).

All PFO closures were successful and no event of the primary end point occurred in the PFO closure group compared with 6 of 60 patients in the medication-only group (2-year event rate, 12.9%; log-rank P =.013; 2-year rate of ischemic stroke, 10.5%; 95% CI, 1.68-19.23; P =.023). In the medication-only group, 5 patients had an ischemic stroke, 1 had a cerebral hemorrhage, 2 had TIMI-defined major bleeding, and 1 had a transient ischemic attack. 

“[W]e have confirmed that the morphologic characteristics of PFO and the adjacent atrial septum as evaluated by TEE are important determinants of the clinical benefit of percutaneous device closure of PFO in patients with cryptogenic stroke,” the researchers wrote.

There were several study limitations, including the early termination of the trial due to patient safety issues, which meant a hazard ratio could not be provided as a result of underpowering, and there may have been a selection bias because the trial was conducted in only 2 centers.

Reference

Lee PH, Song JK, Kim JS, et al. Cryptogenic stroke and high-risk patient foramen ovale: the DEFENSE-PFO trial [published online March 12, 2018]. J Am Coll Cardiol. doi:10.1016/j.jacc.2018.02.046

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