The main findings of our study are as follows: the usage rate of newer generation P2Y12 inhibitors in STEMI patients referred to primary PCI in Poland is still low. In addition, there are significant differences between networks in the proportion of ticagrelor/prasugrel and clopidogrel (from zero to almost half of patients) use. The main newer generation P2Y12 inhibitor is ticagrelor, the rate of periprocedural escalate switching (from clopidogrel to ticagrelor/prasugrel) is up to 12% in top newer generation P2Y12 inhibitor centers, the precathlab administration of P2Y12 inhibitors is relatively high but heterogeneous in terms of clopidogrel to ticagrelor/prasugrel proportions.
According to guidelines, newer generation P2Y
12 inhibitors (ticagrelor and prasugrel) are preferred over clopidogrel in patients with STEMI [
1]. However, many reports shows that clopidogrel is still frequently used despite lack of contraindications to ticagrelor and prasugrel. In the GRAPE Study (data based on year 2012 registry; acute coronary syndromes (ACS) patients with 53% of STEMI), the initial choice of clopidogrel was present in about 70% of patients. However, at discharged this number was significantly lower (less than 40%) what may suggest a conservative approach in the acute phase (clopidogrel) following in-hospital treatment escalate to newer generation oral P2Y
12 inhibitors [
2]. Those proportions are different in recently published data. In the rapport from four centers from Austria (data from year 2015) clopidogrel was administered initially in 29% of patients with ACS (22% of STEMI patients) and 27% at discharge (STEMI 18.7%), confirming that majority of patients were treated with newer generation P2Y
12 inhibitors [
3]. In EYESHOT Study from Italy (data collected in years 2013/2014) clopidogrel at discharge was prescribed in more than half of patients with ACS (32% in STEMI patients treated with primary PCI) [
4]. In APATHY Registry (also data from Italy, year 2014) clopidogrel was administered in 52% of patients [
5]. The report from the US based registry on ACS patients enrolled from 2011 to 2014 have shown clopidogrel usage in 77.6%. However, the penetration of newer generation P2Y
12 inhibitors was higher in STEMI (clopidogrel usage in less than 60% of patients) [
6]. In our report (data from years 2015/2016) the rate of ticagrelor and prasugrel usage was low and there were large differences between centers in Poland (from zero to almost half of STEMI patients). It should be underlined that newer generation P2Y
12 inhibitors are not reimbursed in Poland. Low prasugrel availability on Polish market may explain a large discrepancy between ticagrelor and prasugrel usage. Moreover, the reason for high usage of clopidogrel is not clear and the presence of contraindications may not explain it. In above-mentioned registry from Austria, about 55% of patients discharged on clopidogrel had no absolute contraindications to newer generation P2Y
12 inhibitors [
3]. In GRAPE registry, the selection of clopidogrel at discharge was less preferred in about 75% of patients [
2]. In APATHY Registry only 48% of patients received antiplatelet therapy according to guidelines [
5]. Data from registries showed that “typical” patient for newer generation P2Y
12 inhibitors administration is relatively young male, undergone PCI for STEMI and without COPD and without a need for oral anticoagulation, with low bleeding risk. In our study, it was not possible to analyze all factors to assess current adherence to guidelines but we also observed that newer generation P2Y
12 inhibitors were more often administered to young male patients with a lower rate of COPD. During hospitalization, the rate of switching from and to clopidogrel was different in different reports. In GRAPE registry one-third of patients initially treated with clopidogrel was switched to ticagrelor or prasugrel during hospitalization [
2]. On the contrary, in EYESHOT Registry the escalate switch occurred only in 3.6% during the procedure and 14.2% of patients at discharge among patients receiving revascularization [
4]. Similarly, Tscharre et al. showed a low rate of in-hospital switching between clopidogrel and newer generation P2Y
12 inhibitors [
3]. The SCOPE Registry was focused on the incidence of oral P2Y
12 inhibitors switching in ACS patients treated with PCI and on the 30-day outcomes. About 40% of patients were initially treated with clopidogrel. The switching rate was 9.6% (2.3% in cathlab, 3.3% at discharge, and 5.1% at follow-up). The de-escalate switching (from newer generation to old P2Y
12 inhibitors) in an early phase of ACS was an independent predictor of net adverse events [
12]. On the other hand results of recently published TOPIC Trial suggests that the “late” switch to clopidogrel (after 1 month from PCI in ACS) may reduce the rate of bleeding events without increasing the risk of ischemic events [
13]. In TROPICAL-ACS Trial platelet function testing guided de-escalation of antiplatelet treatment was non-inferior to standard treatment with prasugrel at 1 year after (net clinical benefit) [
14]. In our study, the rate of periprocedural escalate switch was about 2%. However, in top centers it was six times higher. The reason for significant differences in escalate switching rate between centers is not clear. In some networks old approach with a high rate of prehospital clopidogrel administration may be the reason (despite lack of contraindications for ticagrelor to be administered on top of clopidogrel) [
15]. In top 10 centers in Poland (according to newer generation P2Y
12 inhibitors usage rate), the rate of prehospital clopidogrel administration was lower than in general cohort. This is along to concept proposed in 2011 by experts in Poland to postpone the decision of P2Y
12 inhibitor administration until cathlab hospital admission [
16]. It should be underlined that when this concept was born, ticagrelor and prasugrel were available only in cathlab hospitals. Before introducing of newer generation oral P2Y
12 inhibitors, clopidogrel was available and widely used in many networks in ambulance [
17]. Currently, ticagrelor is also available in growing number of ambulances based on new regulations. So in top 10 centers we observed less clopidogrel administered early and more ticagrelor administered both early as well as during procedure. Also, the periprocedural escalate switching in those centers was about 12% showing that antiplatelet treatment strategy was reassessed during the procedure. Data on the effectiveness of the strategy of early (prehospital) P2Y
12 inhibitors administration in STEMI patients is not clear. ATLANTIC trial has shown no clear benefit of early ticagrelor administration but the time from loading dose administration to the procedure was relatively short [
8]. On the other hand, in many European centers such approach is a part of daily practice in STEMI treatment showing some clinical benefit [
9]. All those data on type, time of administration and eventual switch between P2Y
12 suggest the need for tailored rather than systematic approach, what will be the future challenge in the treatment of patients with ACS.