P2Y12 inhibition after thrombotic thrombocytopenic purpura remission.

To the Editor,

We read the article entitled “Ticagrelor-associated thrombotic thrombocytopenic purpura” by Doğan et al. (1), which was recently published in the Anatolian Journal of Cardiology, with great interest. It is well known that patients with acute coronary syndrome (ACS) who visit the emergency department have increased rates of recurrent ischemic events. Dual antiplatelet therapy (DAPT) is of importance to reduce these rates; further, DAPT duration after drug-eluting stent (DES) implantation is one the most significant determinant for reducing recurrent ischemic events, including stent thrombosis (2). In your case, DAPT was discontinued 5 weeks after ACS because of ticagrelor-associated thrombotic thrombocytopenic purpura (TTP), and aspirin was used as the only antiplatelet therapy for 6 months. According to the guidelines, DAPT should be administered for at least 12 months after ACS is treated with DES implantation (2). Further, retreatment with P2Y12 after TTP complete remission in ACS can be considered necessary. Reportedly, it is possible to encounter rechallenge with the same P2Y12 inhibitors, leading to TTP after remission. It was indicated that this approach does not induce relapse (3). In addition, in one case, ticlopidine was used instead of clopidogrel because of clopidogrel-linked TTP after TTP complete remission, and no relapse occurred after ticlopidine usage (4). Considering the foregoing data, a group of P2Y12 inhibitors different from ticagrelor could have been used with aspirin after TTP remission in your patient. Thienopyridines have action mechanisms different from those of ticagrelor and can be administered after ticagrelor-linked TTP.

On the other hand, the stent type is also crucial in case of recurrent ischemic events. In addition, DAPT duration can differ according to the first- and second-generation DES. DAPT duration can be shorter in second-generation DES than in first-generation DES (5). It will be beneficial to know which generation of stent was used in your case, which could have led to a better outcome of DAPT discontinuation.