Two controversial trials testing PFO closure with the Amplatzer PFO Occluder (St. Jude Medical) in patients with cryptogenic stroke, first presented last fall at the TCT meeting, have now been published in the New England Journal of Medicine. Both trials missed their primary endpoints but contained suggestions of possible benefit. The results appear unlikely to resolve the ongoing controversy over the value, or lack of value, of this procedure, but, as an accompanying editorial states, both advocates and critics of PFO closure will find source material for their arguments in these papers.
In the accompanying editorial, Steven Messé and David Kent write that both trials suffered from slow enrollment, “which was probably due to widespread off-label use of atrial septal closure devices.” They note that RESPECT and PC, like the only other randomized trial in the field, CLOSURE 1, did not show significant benefits in the main intention-to-treat analysis, but did present some evidence of possible benefit.
…we are left for the moment to make decisions under conditions of uncertainty. In such circumstances, evidentiary standards vary among decision makers — patients, clinicians, authors of practice guidelines, and regulatory authorities — depending not only on the interpretation of the results, but also on the potential consequences of their decisions. Some of them may interpret the data as supporting closure of a patent foramen ovale as a viable therapeutic option, even while conceding the failure of trials to show the superiority of closure over medical therapy. Yet given the prevalence of patent foramen ovale in the general population, the enormous potential for overuse of percutaneous closure of a patent foramen ovale, and the relatively low risk of stroke in patients who are treated medically, the routine use of this therapy seems unwise without a clearer view of who, if anyone, is likely to benefit…. Randomized studies of closure may come to an end, however, if the Amplatzer device is approved. Thus, all eyes will be on the regulatory agencies to see how they will interpret these results in light of their own evidentiary standards.