Drug-Eluting Stents: The Position of the FDA.
As a regulatory agency, the FDA (Food & Drugs Administration) has been closely monitoring the outcomes in terms of safety and effectiveness. In accordance with the methodological designs, the first outcomes were closely related to the procedure and the evolution during the first year. The emergence of recent data on follow-ups was cautiously received with view to its approval in 2003.
Nevertheless, in recent scientific meetings, evidence related to two specific aspects of the device long-term results was presented. This evidence suggested a slight increase (statistically significant) of events such as mortality and myocardial infarction, possibly related to late stent thrombosis and an increase of non-cardiac mortality. The systematic revision of the evidence presented shows as a first element of consideration the fact that the trials carried out implied the stent implantation with a lower clopidogrel use rate (due to the design of the trials), lower to what it would be considered standard practise nowadays. Somehow, this plays down the reported findings. The direct consequence involves two options: wait for the report of new outcomes so as to confirm or rule out this new evidence or use the most recent reports on emerging outcomes coming from registries in order to find out its real scope.
The characterization of risks, chronology and impact of late thrombosis of bare-metal stents has been the reason why a series of debates were carried out with a panel of FDA experts (Circulatory System Devices Advisory Panel) on December 7th-8th of this year.
The most relevant conclusions of this meeting were:
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The use of drug-eluting stents in accordance with the FDA recommendations has shown an increase of late stent thrombosis. Nevertheless, it is difficult to assess at the moment the real dimension of this risk and the presentation of new evidence is still pending.
In the evidence accepted by the industry, there was no increased risk of mortality or myocardial infarction. Due to the lower in-stent restenosis, which significantly reduces the need of new revascularizations, the relative increase of events would not be evident.
This panel also suggested that the outcomes should not underestimate its beneficial result when the devices are used under these recommendations, particularly stressing the incorporation of the products to the presentation, the concepts of percutaneous angioplasty of the ACC/AHA/SCAI guidelines in regard to the duration of the antiplatelet treatment.
Lastly, in those cases where its use goes beyond the recommendations, an antiplatelet treatment for no less than 12 months was suggested. |
As shown, the FDA has been extremely cautious when evaluating the recently presented evidence and suggested to wait for emerging long-term results.
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