In a recent meta-analysis published in the Journal, El-Hayek et al analyzed the use of short-term (3 to 6 months) dual antiplatelet therapy (DAPT) with long-term (12 to 24 months) DAPT after drug-eluting stent (DES) placement. The investigators were measured in their conclusions regarding stent thrombosis (ST) in their landmark analysis stating, “Although there was no significant difference in ST using this analysis, there was a near twofold greater rate of ST in the group of patients assigned to a short course of DAPT. These findings raise concerns regarding the safety of shorter DAPT and certainly merit further evaluation with a larger data set of patients, especially to identify those who may be at high risk for ST from the short DAPT.”
The 2 groups compared within this meta-analysis, although well matched in most regards (Table 2 of El-Hayek et al ), had significantly different proportions of patients receiving first-generation stents: 10.5% and 19.8% in the short-term and prolonged groups, respectively (p <0.001). This difference is as a result of the REal Safety and Efficacy of 3-month dual antiplatelet Therapy following Endeavor zotarolimus-eluting stent implantation (RESET) trial, in which there were 383 patients receiving first-generation stents in the prolonged DAPT group and none in the short-term DAPT group. Therefore, any comparison between the 2 groups in the analysis is bias by differences between stent generations. In particular, as noted by the investigators, there is evidence that the rate of late ST is higher in first-generation DESs. If the RESET trial is removed from the landmark analysis of ST, there is a borderline significant difference (p = 0.05), with a 2.66-fold (95% confidence interval 0.99 to 7.12) increased risk of ST in the short-term DAPT group ( Figure 1 ).
