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Meta-Analysis Shows Mixed Results for Percutaneous PFO Closure
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A meta-analysis has found that percutaneous closure of patent foramen ovale in patients with cryptogenic stroke is not superior to medical therapy and is associated with an increased incidence of atrial fibrillation. However, there also were signals pointing toward a potential benefit with the therapy.
Researchers of the analysis looked at randomized controlled trials and nonrandomized observational studies through May 2013 that compared percutaneous PFO closure with best medical therapy.
Three randomized controlled trials and 11 nonrandomized observational studies were identified, including 4,335 patients with cryptogenic stroke. Randomized controlled trials showed no significant treatment effect of PFO closure regarding stroke (RR=0.66; 95% CI, 0.37-1.19). However, observational studies showed that stroke was reduced after PFO closure (RR=0.37; 95% CI, 0.2-0.67).
A time-to-event analysis for strokes that combined the three randomized controlled trials with two observational studies that applied strict multivariate adjustments showed a borderline significant risk reduction after PFO closure (HR=0.58; 95% CI, 0.33-0.99). Although neither risk of bleeding nor mortality differed significantly between the groups, there was a higher incidence of new onset AF in the closure group (RR=3.5; 95% CI, 1.47-8.35).
According to the researchers, the high incidence of post-procedure AF could be related to the PFO closure device triggering arrhythmias or that AF has been under-diagnosed and many of these patients had paroxysmal AF from the start. However, there also were signals pointing toward a potential benefit when they considered data from observational studies or from trials that used the Amplatzer PFO Occluder (AGA Medical Corp).
Pascal Meier
“We feel that the higher rate of AF in the closure group is concerning and defeats the purpose of the procedure intending to prevent strokes since AF is probably the much stronger risk factor than a PFO. However, this association is not necessarily causal or, if so, probably device specific,” Pascal Meier, MD, researcher with The Heart Hospital, London, told Cardiology Today’s Intervention. “The Amplatzer device may be somewhat less ‘arrhythmogenic,’ which means that these devices need further modifications to make them safer. So this story should not end here, but we should encourage device redesign and additional trials.”
Disclosure: Researchers report no relevant financial disclosures.Perspective
Back to TopStefan Bertog, MD
It should be pointed out that studies with a number of different closure devices were included in this meta-analysis. Such an approach assumes that all examined devices are equivalent regarding their efficacy in stroke prevention and incidence of device-associated adverse events. However, there are important differences in closure rates and adverse event rates between different devices. For example, the closure rate may be lower and the incidence of atrial fibrillation and device-associated thrombus formation higher after CardioSEAL STARFlex implantation than after Amplatzer device implantation. The higher incidence of device-related thrombus formation and atrial fibrillation may offset the potential benefits of PFO closure. In this context, the incidence of device-associated thrombus formation, AF and the recurrent event rate after CardioSEAL STARFlex implantation has been reported to be higher compared with the Amplatzer PFO occluder (Hornung M. Abstract #771. Presented at: TCT 2012; and Krumsdorf U. J Am Coll Cardiol. 2004;43:203-209). Therefore, instead of assuming equivalency among devices, it would be important to determine the device-specific efficacy of PFO closure. For example, given concerns with the CardioSEAL STARFlex device, when analyzing randomized controlled trial data, only the PC and RESPECT trial should be included (only Amplatzer devices were used in these trials whereas the CardioSEAL STARFlex device was used exclusively in the CLOSURE I trial). In this case, the as-treated analysis would be as important as the intention-to-treat analysis.
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