Less may be more: Insights on dual antiplatelet therapy duration after drug‐eluting stent implantation from the MATRIX registry

Dual antiplatelet therapy (DAPT) is the principal measure for preventing stent thrombosis. The risk for stent thrombosis after bare metal stents is very low after >1 month post-implantation, hence the recommended DAPT duration is 1 month. However, since stent thrombosis can occur after many months or years after drug-eluting stent (DES) implantation, prolonged DAPT duration is recommended. The current ACC/ AHA percutaneous coronary intervention guidelines recommend 12-month DAPT administration post DES [1]. This recommendation, however, is not based on solid data, but on the DAPT duration used in some of the early DES studies. Why should every patient receive the same duration of DAPT? We now know that the risk for stent thrombosis varies widely between patient to patient and vessel to vessel. It depends on factors related to the target lesion (thrombus, calcification, and bifurcation), the technical result (optimal stent expansion and apposition), the type of stent used [2], the patient (platelet reactivity, systemic inflammation, renal failure, need for noncardiac surgery), and, of course, the type and duration of DAPT [3,4]. Wouldn’t it make sense to customize DAPT duration to each patient, each lesion, and each DES stent type? Especially, since prolonged DAPT carries a small, but significant increase in the risk for bleeding and high cost? In May 2012, the everolimus-eluting stent received Conformité Européene (CE) mark for 3-month DAPT duration based on no stent thrombosis among patients who discontinued DAPT at 3 months. In the Prolonging Dual Antiplatelet Treatment after Grading Stentinduced Intimal Hyperplasia (PRODIGY) Study, compared to 24 months, 6 months DAPT duration was associated with similar incidence of ischemic events, and less risk for bleeding [5]. Similar results were seen in the Multicentre registry with Antiplatelet TReatment two–sIX (MATRIX) study published in this issue of the Journal: among 572 patients who received the Janus Flex stent (a polymer free, tacrolimus-eluting stent that elutes drug on the abluminal side only and is manufactured by the Carbostent and Implantable Devices—CID, Saluggia, Italy), the incidence of major adverse events and stent thrombosis was very low and similar with 2 vs. 6 months of DAPT post-stenting. Although the MATRIX findings appear to support <12 month DAPT duration post DES, they should be interpreted with caution. First, the outcomes after implantation of the Janus Flex stent have been variable, with one study showing no difference from a similar bare metal stent [6] and another study showing an exceedingly high rate of major adverse events [7] (Table I). Moreover, although comparisons between studies are always fraud with limitations, the 12.7% incidence of major adverse cardiac events in MATRIX is double than the 6% rate observed in the COMPARE trial of the everolimus-eluting stent [13]. Second, the study was underpowered: when relatively rare events are examined, such as stent thrombosis, many thousands of patients are needed to derive strong conclusions. Third, any final decisions about DAPT duration post DES should await the completion of the ongoing