Original title: Lack of association between dual antiplatelet therapy use and stent thrombosis between 1 and 12 months following Resolute zotarolimus-eluting stent implantation. Reference: Silber S, Kirtane AJ, Belardi JA, et al. Eur Heart J. 2014; Epub ahead of print.

Dual antiplatelet aggregation optimal time after implantation of a new generation drug-eluting stent (DES) is still discussed. This sub-study evaluated the association between discontinuation of dual anti-aggregation and stent thrombosis chance, cardiac death and infarction related to the vessel in 4896 patients receiving the zotarolimus-eluting stent. Discontinuation of dual anti aggregation was defined as any disruption of aspirin and / or thienopyridine greater than one-day and prolonged interruption if this was longer than 14 days. Out of the total 1069 (21.8 %) patients, discontinued treatment, of which 166 were within the first month and 903 between the first month and the year. 

Among the 166 patients who discontinued before the first month (all were long interruptions) 6 definite / probable thrombosis (3.61 %) were observed unlike the 903 patients who stopped among the first month and the year (60 % within the first 6 months) in this group. Only one definite / probable (0.11 %) thrombosis was observed. 32 definite / probable thrombosis were observed among patients who met the full year of double anti-aggregation (0.84 %). The rate of cardiac death and infarction related to the vessel was 6.84 % among those suspended within the first month, 1.41 % for those suspended among the month and one year and 4.08 % among those who met the full year of double anti-aggregation. In 2309 patients it was possible to gather information about bleeding complications, 34 bleedings (1.79 %) were observed in those who complete the year of dual anti-aggregation (n = 1896) as opposed to 2 bleeding events only ( 0.56 %), among those suspended between the month and year and none among those who discontinued prior month.

Conclusion

In this retrospective analysis of patients receiving drug-eluting zotarolimus stent, a high incidence of adverse events among patients who discontinued the double anti-aggregation a month before stent implantation was observed. Moreover, the suspension between the month and year was associated with a low incidence of stent thrombosis and adverse cardiac events.

Editorial comment

While other studies have suggested that 6 months or even 3 months of dual anti-aggregation are in off, there is not enough information and in fact have not changed the guidelines. Keep in mind that this is a retrospective analysis of pooled patients of 4 studies evaluating the Resolute stent.

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