Vol.:(0123456789) 1 3 Heart and Vessels https://doi.org/10.1007/s00380-018-1167-8 ORIGINAL ARTICLE The relationship between timing of prasugrel pretreatment and in‑stent thrombus immediately after percutaneous coronary intervention for acute coronary syndrome: an optical coherence tomography study Yosuke Katayama 1  · Takashi Kubo 1  · Yasushi Ino 1  · Takeyoshi Kameyama 1  · Yoshiki Matsuo 1  · Hironori Kitabata 1  · Kosei Terada 1  · Hiroki Emori 1  · Hiroshi Aoki 1  · Akira Taruya 1  · Kunihiro Shimamura 1  · Shingo Ota 1  · Atsushi Tanaka 1  · Takeshi Hozumi 1  · Takashi Akasaka 1 Received: 30 October 2017 / Accepted: 20 April 2018 © Springer Japan KK, part of Springer Nature 2018 Abstract The optimal timing of pretreatment with prasugrel in percutaneous coronary intervention (PCI) for acute coronary syn- drome (ACS) is unclear. We used optical coherence tomography (OCT) to compare in-stent thrombus volume immediately after PCI between the administration of low-dose prasugrel (20 mg loading dose) at the time of diagnosis of ACS (early prasugrel: n = 34) and the administration of low-dose prasugrel immediately after diagnostic angiography prior to PCI for ACS (late prasugrel: n = 56). The durations between the administration of prasugrel and OCT in the early prasugrel group and late prasugrel group were 5.1 ± 6.5 and 0.9 ± 0.7 h, respectively (p < 0.001). OCT detected thrombus/plaque protrusion in all stented segments. In-stent thrombus/plaque protrusion volume (2.92 ± 1.96 vs. 6.48 ± 4.97 mm 3 , p < 0.001), mean in-stent thrombus/plaque protrusion area (0.13 ± 0.07 vs. 0.29 ± 0.23 mm 2 , p < 0.001) and maximum in-stent thrombus/ plaque protrusion area (0.70 ± 0.36 vs. 1.06 ± 0.56 mm 2 , p < 0.001) were signifcantly smaller in the early prasugrel group as compared with the late prasugrel group. The administration of prasugrel at the time of diagnosis of ACS was associated with signifcantly reduced in-stent thrombus/plaque protrusion immediately after PCI as compared with the administration of prasugrel after the coronary angiography prior to PCI. Keywords Acute coronary syndrome · Optical coherence tomography · Prasugrel · Stent · Thrombus Introduction Pretreatment with thienopyridine in addition to aspirin for patients undergoing percutaneous coronary intervention (PCI) is efective for preventing in-stent thrombosis [1]. In acute coronary syndrome (ACS), the risk of in-stent throm- bosis increases in the period immediately after PCI because platelets are highly activated in the acute phase of ACS [2]. Therefore, pretreatment with thienopyridine aims at achiev- ing a maximal level of inhibition of platelet aggregation at the time of PCI. Prasugrel is a new-generation thienopyridine antiplatelet agent, which is converted to its active metabolite with less infuence of the cytochrome P450 (CYP) genotype. Prasug- rel provides more prompt and potent platelet inhibition than clopidogrel [3]. However, in the pretreatment with prasug- rel for PCI in ACS, the optimal timing of administration of prasugrel—at the time of diagnosis of ACS or immediately after diagnostic angiography—is unclear. Some studies have examined the clinical efcacy and safety of low-dose prasugrel, because the TRITON-TIMI 38 (Trial to Assess Improvement in Therapeutic Outcomes by Optimizing Platelet Inhibition with prasugrel Throm- bolysis in Myocardial Infarction) trial showed that stand- ard-dose prasugrel (60 mg loading dose/10 mg mainte- nance dose) increased major bleeding events as compared with clopidogrel [ 1]. The PRASFIT-ACS (PRASugrel compared with clopidogrel For Japanese patIenTs with * Takashi Kubo takakubo@wakayama-med.ac.jp 1 Department of Cardiovascular Medicine, Wakayama Medical University, 811-1 Kimiidera, Wakayama 641-8510, Japan