BY ED SUSMAN
HOUSTON—A long-term analysis shows that patients who are diagnosed with cryptogenic strokes that are believed to be associated with patent foramen ovale (PFO) appear to reduce their risk of subsequent strokes by PFO closure devices, researchers reported here Wednesday at the 2017 International Stroke Conference sponsored by the American Heart Association/American Stroke Association.
After more than 10 years of follow-up, in the intention-to-treat population, 18 strokes occurred among patients who were implanted with the Amplatzer PFO Occluder device compared with 28 strokes among patients who were treated medically, a difference that achieved statistical significance (p=0.046), reported David Thaler, MD, PhD, chief of neurology at Tufts University Medical Center in Boston.
In the RESPECT (Randomized Evaluation of Recurrent Stroke Comparing PFO Closure to Established Current Standard of Care Treatment) study, 499 patients who had experienced so-called cryptogenic strokes were assigned to the PFO closure device and 481 patients to medical management in attempts to prevent a second brain attack. The device was successfully implanted in 465 patients; two stroke events occurred among the 34 patients in the intention-to-treat population that never had the device implanted.
"In the RESPECT trial, PFO closure with the Amplatzer device was more beneficial than medical management alone in the intention-to-treat population for the primary outcome," Dr. Thaler said. "The treatment effect was magnified in populations that account for treatment crossover and that include the age range in which recurrent stokes are predominantly cryptogenic."
The new data covers the period from August 2003 to May 2016. Patients were enrolled within nine months of being diagnosed with a cryptogenic stroke and having a confirmed PFO. The researchers excluded those who had strokes that were determined to have been caused by large vessel atherosclerosis, atrial fibrillation, lacunar infarcts, and other etiologies. Median follow-up was 5.9 years. The mean age of the patients at entry into the study was 45.9 years. The study population was limited to adults 60 years of age or younger.
Commenting on the study, James C. Grotta, MD, FAAN, director of stroke research at the Clinical Institute for Research and Innovation at Memorial Hermann-Texas Medical Center in Houston, said: "Current guidelines do not recommend PFO closure, based on several randomized trials, including the RESPECT trial." The problem with the trials, he said, was that the prevalence of stroke attributed to PFO is very low, and there weren't enough events during the timeframe of the trials to have a positive outcome.
Dr. Grotta, who serves on the editorial advisory board of Neurology Today, said that ithe RESPECT trial showed a strong trend to a positive result when it was first presented. It failed to reach statistical significance in the intention-to-treat analysis, thought it did show a positive result in the per-protocol analysis.
"This report was a 10-year follow-up and when you follow patients for 10 years, significance with the closure device emerges," he said.
Dr. Grotta said that people who have strokes that may be caused by having a PFO are likely to have a higher risk of deep vein thrombosis whether a PFO closure device is used or if they are treated medically, and those patients must be monitored closely for the possibility of recurrent deep vein thromboses.
"They have to be followed for the rest of their lives with a high index of suspicion for deep vein thromboses," he suggested.
"Now that the FDA has approved the Amplatzer device for selected patients, I now feel justified in having the PFO closed," he said.
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