NASHVILLE, TENN. – Device closure of a patent foramen ovale didn’t reduce the composite risk of death, stroke, or transient ischemic attack when compared against medical therapy alone in a pooled analysis of three trials.
Device intervention, did, however, reduce the individual risk of recurrent stroke, although the absolute reduction seemed modest, Dr. David M. Kent said at the International Stroke Conference, sponsored by the American Heart Association.
Overall device closure conferred about a 30% annual risk reduction of recurrent stroke upon those with patent foramen ovale (PFO) who had experienced a prior cryptogenic stroke. About 30 patients would have to be treated to prevent one stroke over 5 years, said Dr. Kent of Tufts University, Boston.
“It’s not a huge benefit – it’s not like thrombectomy. But it’s comparable to the benefit of high-dose statins seen in the SPARCL [Stroke Prevention by Aggressive Reduction in Cholesterol Levels] trial.”
Altogether, the pooled analysis comprised about 2,300 patients. Of these, 440 were lost to 5-year follow-up; their outcomes were imputed into an intent-to-treat analysis based on last-known clinical status.
Dr. Kent and his colleagues also conducted a subanalysis of only the two Amplatzer device trials, which comprised 1,400 patients.
The primary outcome for each analysis was a composite of recurrent stroke, transient ischemic attack (TIA), and early death. The secondary outcome was recurrent stroke alone.
The patients were a mean of 45 years old. About a third had dyslipidemia, and a third had hypertension. The PFO was considered large in 60%.
During the 5-year follow-up period, there were 58 strokes and 54 TIAs. Four patients died during the trial – two in the device arms and two in the medical therapy arms.
When all three trials were analyzed together, PFO closure was not significantly better than medical therapy in the composite endpoint (1.5% vs. 2.3%). The difference in recurrent stroke rate alone was significant (0.7% vs. 1.3%), although Dr. Kent did note that the event rate was very low in both groups.
In the two Amplatzer trials, the device also did not significantly reduce the risk of the composite endpoint. It did confer significant benefit on the stroke-only outcome (hazard ratio, 0.41; 0.4% vs. 1.1%). Again, Dr. Kent said, the event rate was very low for both intervention groups.
There was no significantly increased risk of bleeding with PFO closure in the analysis of all three trials or in the two Amplatzer device trials alone, although both did find a significantly increased risk of atrial fibrillation. In the three-trial analysis, rates of atrial fibrillation were 1.5% vs. 0.48%; in the Amplatzer-only analysis, rates were 0.87% vs. 0.47%. The investigators weren’t able to identify any factors that might predispose to a safety event.
The analyses were sponsored by the National Institutes of Health. Dr. Kent had no financial disclosures, although several coauthors had ties with multiple pharmaceutical companies, or were investigators on the original trials, which were sponsored by the device manufacturers.
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