Study Supports Device Closure of PFO in Patients After Cryptogenic Stroke
March 12, 2018—Two-year data from the DEFENSE-PFO trial comparing device closure of patent foramen ovale (PFO) versus medical therapy for secondary prevention in cryptogenic stroke patients with high-risk PFO were presented by Jae Kwan Song, MD, in a Late Breaking Trial session at the American College of Cardiology's (ACC) 67th annual scientific session held March 10–12 in Orlando, Florida. The study was simultaneously published online in Journal of the American College of Cardiology.
The investigators found that patients who underwent closure treatment with the Amplatzer PFO occluder device (Abbott Structural Heart) fared better than those receiving medications alone, which supports results of several similar trials in recent years and suggests patients with a high-risk PFO are likely to benefit most from device closure. Also, the new findings add to a growing body of evidence that closing the PFO after cryptogenic stroke can help prevent subsequent strokes and related problems, particularly in those with a high-risk PFO.
The ACC announcement noted that trial enrollment was stopped early after investigators determined that based on the results of several recent trials, it would be unethical to continue assigning some patients to not receive the PFO closure device in light of mounting evidence of its clear benefits. Despite the smaller-than-expected number of participants, the investigators advised that the new trial helps clarify which patients are likely to benefit most from the medical device based on the physical characteristics of their PFO.
Dr. Song commented in the conference press release, "Considering the high prevalence of PFO in the general population and cryptogenic stroke patients, the key to appropriate use of this medical device is determining how to select optimal candidates for the procedure. Our study showed that the potential benefit from closure can be determined on the basis of the size of the PFO and the movement of the heart wall around the PFO."
As summarized in the ACC announcement, the trial enrolled 120 patients at two centers in South Korea. All patients had recently experienced a cryptogenic stroke and were found to have a high-risk PFO-defined as either a PFO sized ≥ 2 mm across or PFO accompanied by an outgrowth of tissue protruding into one of the heart's chambers.
All patients received medications such as anticoagulants or antiplatelet drugs. The specific type of medication was determined by each patient's physician, although no direct oral anticoagulants were used in the study. Half of the patients were randomly assigned to receive a PFO closure device, while the other half received medications alone. Investigators followed patient outcomes for 2 years.
The study's primary endpoint was a composite of stroke, major bleeding events, and death from vascular causes. There were no endpoint events in the 60 patients who underwent PFO closure. However, among the 60 patients receiving medications alone, six patients had a stroke and one had a transient ischemic attack. These results suggest that treating 10 PFOs with a closure device would be expected to prevent, on average, about one stroke after 2 years.
Dr. Song concluded, "We believe that PFO closure should be done in selected patients with cryptogenic stroke and PFO. With our study and other recent trials, the criteria for selecting patients for the procedure are becoming clearer; in particular, the results suggest that closure is beneficial for those with high-risk PFO." He noted that additional studies are needed to clarify the potential benefits of different medications when used after a stroke in patients with PFO.