Inhibitory mechanisms of very low-dose rivaroxaban in non-ST-elevation myocardial infarction

Abstract

Very low-dose (VLD) factor Xa (FXa) inhibition, in combination with acetylsalicylic acid (ASA) and clopidogrel, is associated with improved outcomes in patients with acute coronary syndrome (ACS) with a tolerable bleeding risk profile. To date, there are no data documenting platelet inhibition and the anticoagulatory effects of VLD FXa inhibition on top of guideline-adherent dual-antiplatelet therapy (DAPT) in patients with ACS. Patients with non-ST-elevation myocardial infarction (NSTEMI) receiving oral DAPT (ASA + clopidogrel, n = 20; or ASA + ticagrelor, n = 20) were prospectively enrolled in a nonrandomized study. Coagulation- and platelet-dependent thrombin generation (TG), measured by means of the calibrated automated thrombogram, were significantly decreased after in vitro and in vivo addition of rivaroxaban. As shown by a total thrombus-formation analysis approach, rivaroxaban treatment led to a significantly decreased coagulation-dependent (AR-chip) thrombus formation in patients treated with ASA plus P2Y12 inhibitor (clopidogrel/ticagrelor), whereas the pure platelet-dependent (PL-chip) thrombus formation was not affected at all. Adjunctive rivaroxaban therapy was not associated with significant differences in platelet aggregation assessed by light-transmission aggregometry (LTA). Nevertheless, according to fluorescence-activated cell sorter analysis, VLD rivaroxaban treatment resulted in a significantly reduced expression of platelet HMGB-1, whereas P-selectin exposure was not affected. Furthermore, an enhanced effect of rivaroxaban on total thrombus formation and TG was observed in particular in clopidogrel nonresponder patients defined as adenosine 5'-diphosphate-induced LTA ≥40%. VLD rivaroxaban reduces thrombus formation and platelet-dependent TG in patients with ACS receiving DAPT, which can be of potential ischemic benefit. This trial was registered at www.clinicaltrials.gov as #NCT01417884.

Conflict of interest statement

Conflict-of-interest disclosure: O.B. received research grants and personal fees from Bayer Healthcare. S.H. is an employee of Bayer AG. R.F.S. reports receiving institutional research grants/support from AstraZeneca and PlaqueTec; consultancy fees from Actelion, AstraZeneca, Avacta, Bayer, Bristol-Myers Squibb/Pfizer, Novartis, PlaqueTec, and The Medicines Company; and honoraria from AstraZeneca. D.J.A. reports receiving payments as an individual for a consulting fee or honorarium from Amgen, Aralez, AstraZeneca, Bayer, Biosensors, Bristol-Myers Squibb, Chiesi, Daiich-Sankyo, Eli Lilly, Janssen, Merck, PLx Pharma, Pfizer, Sanofi, and The Medicines Company; for participation in review activities from CeloNova and St. Jude Medical; and receiving institutional payments for grants from Amgen, AstraZeneca, Bayer, Biosensors, CeloNova, CSL Behring, Daiichi-Sankyo, Eisai, Eli Lilly, Gilead, Janssen, Matsutani Chemical Industry Co., Merck, Novartis, Osprey Medical, and Renal Guard Solutions. B.R. received institutional research grants from the Italian Medicines Agency, consultancy fees from Bayer AG, and speaker fees from Amgen, Celgene, Daiichi Sankyo Italia, Novartis Farma, and Sanofi. H.T.C. is a consultant to Stago; received research support from Bayer, Boehringer, and Pfizer/BMS; serves on the advisory boards for Bayer and Daiichi Sankyo; and is the chair of the board for the Dutch Federation of Anticoagulation clinics (unpaid). T.G. received personal fees from AstraZeneca, Boehringer Ingelheim, Pfizer, and MSD; grants and personal fees from Bayer Healthcare, Bristol-Myers Squibb, Daiichi Sankyo, Eli Lilly, and The Medicines Company; and grants from Siemens Healthcare and Spartan Bioscience, outside of the submitted work. The remaining authors declare no competing financial interests.

© 2018 by The American Society of Hematology.

Figures

Graphical abstract

Figure 1.

Flowchart of REVEAL study.

Figure 2.

TG in PPP of patients with NSTEMI treated with ticagrelor in the presence or absence of VLD rivaroxaban. (A) Representative tracings and (B) arithmetic means ± SEM (n = 20) of lag time, TTP, peak (thrombin), and velocity of TG in PPP of patients with NSTEMI before (baseline) and after medication with ticagrelor + ASA for 1 and 2 days (d1 and d2) in the absence (DMSO) or presence of 40 ng/mL rivaroxaban (in vitro). **P < .01 and ***P < .001 indicate statistically significant differences from solvent control at the indicated time point. #P < .05, ##P < .01, and ###P < .001 indicate significant differences from baseline.

Figure 3.

TG in PPP of patients with NSTEMI treated with clopidogrel in the presence or absence of VLD rivaroxaban. (A) Representative tracings and (B) arithmetic means ± SEM (n = 20) of lag time, TTP, peak (thrombin), and velocity of TG in PPP of patients with NSTEMI before (baseline) and after medication with clopidogrel + ASA at d1 in the absence (DMSO) or presence of 40 ng/mL rivaroxaban (in vitro) as well as following medication with clopidogrel + ASA and 2.5 mg rivaroxaban twice daily at d2 (in vivo). ***P < .001 indicates statistically significant differences from solvent control at the indicated time point. ##P < .01 and ###P < .001 indicate significant differences from baseline.

Figure 4.

TG in PRP of patients with NSTEMI treated with ticagrelor in the presence or absence of VLD rivaroxaban. (A). Representative tracings of TG in PRP of patients with NSTEMI before (baseline) and after medication with ticagrelor + ASA for 1 and 2 days (d1 and d2) in the absence (DMSO) or presence of 40 ng/mL rivaroxaban (in vitro) with resting platelets and (C) with 10 µg/ml CRP-stimulated platelets. (B) Arithmetic means ± SEM (n = 20) of lag time, TTP, peak (thrombin), and velocity of TG in PRP of patients with NSTEMI before (baseline) and after treatment with ticagrelor for 1 and 2 days (d1 and d2) in the absence (DMSO) and presence of 40 ng/mL rivaroxaban (in vitro) with resting platelets and (D) with 10 µg/mL CRP stimulated platelets. *P < .05, **P < .01, and ***P < .001 indicate statistically significant differences from solvent control at the indicated time point. #P < .05 and ###P < .001 indicate significant differences from baseline.

Figure 4.

TG in PRP of patients with NSTEMI treated with ticagrelor in the presence or absence of VLD rivaroxaban. (A). Representative tracings of TG in PRP of patients with NSTEMI before (baseline) and after medication with ticagrelor + ASA for 1 and 2 days (d1 and d2) in the absence (DMSO) or presence of 40 ng/mL rivaroxaban (in vitro) with resting platelets and (C) with 10 µg/ml CRP-stimulated platelets. (B) Arithmetic means ± SEM (n = 20) of lag time, TTP, peak (thrombin), and velocity of TG in PRP of patients with NSTEMI before (baseline) and after treatment with ticagrelor for 1 and 2 days (d1 and d2) in the absence (DMSO) and presence of 40 ng/mL rivaroxaban (in vitro) with resting platelets and (D) with 10 µg/mL CRP stimulated platelets. *P < .05, **P < .01, and ***P < .001 indicate statistically significant differences from solvent control at the indicated time point. #P < .05 and ###P < .001 indicate significant differences from baseline.

Figure 5.

TG in PRP of patients with NSTEMI treated with clopidogrel in the presence or absence of VLD rivaroxaban. (A) Representative tracings of TG in PRP of patients with NSTEMI before (baseline) and after medication with clopidogrel + ASA at d1 in the absence (DMSO) or presence of 40 ng/mL rivaroxaban (in vitro), as well as after medication with clopidogrel + ASA and 2.5 mg rivaroxaban twice daily at d2 (in vivo) with resting platelets and (C) with 10 µg/mL CRP-stimulated platelets. (B) Arithmetic means ± SEM (n = 20) of lag time, TTP, peak (thrombin), and velocity of TG in PRP of patients with NSTEMI before (baseline) and after medication with clopidogrel + ASA at d1 in the absence (DMSO) or presence of 40 ng/mL rivaroxaban (in vitro) as well as after medication with clopidogrel + ASA and 2.5 mg rivaroxaban twice daily at d2 (in vivo) with resting platelets and (D) with 10 µg/mL CRP-stimulated platelets. *P < .05, **P < .01, and ***P < .001 indicate statistically significant differences from solvent control at the indicated time point. #P < .05 and ###P < .001 indicate significant differences from baseline.

Figure 5.

TG in PRP of patients with NSTEMI treated with clopidogrel in the presence or absence of VLD rivaroxaban. (A) Representative tracings of TG in PRP of patients with NSTEMI before (baseline) and after medication with clopidogrel + ASA at d1 in the absence (DMSO) or presence of 40 ng/mL rivaroxaban (in vitro), as well as after medication with clopidogrel + ASA and 2.5 mg rivaroxaban twice daily at d2 (in vivo) with resting platelets and (C) with 10 µg/mL CRP-stimulated platelets. (B) Arithmetic means ± SEM (n = 20) of lag time, TTP, peak (thrombin), and velocity of TG in PRP of patients with NSTEMI before (baseline) and after medication with clopidogrel + ASA at d1 in the absence (DMSO) or presence of 40 ng/mL rivaroxaban (in vitro) as well as after medication with clopidogrel + ASA and 2.5 mg rivaroxaban twice daily at d2 (in vivo) with resting platelets and (D) with 10 µg/mL CRP-stimulated platelets. *P < .05, **P < .01, and ***P < .001 indicate statistically significant differences from solvent control at the indicated time point. #P < .05 and ###P < .001 indicate significant differences from baseline.

Figure 6.

Total thrombus formation of patients with NSTEMI treated with ticagrelor in the presence or absence of VLD rivaroxaban. (A) Representative tracings and (B) arithmetic means ± SEM (n = 12) of occlusion start time (T10), AUC and OT of total thrombus formation on a collagen and tissue factor coated (AR) chip in recalcified citrated whole blood from patients with NSTEMI before (baseline) and after medication with ticagrelor + ASA for 1 and 2 days (d1 and d2) in the absence (DMSO) or presence of 40 ng/mL rivaroxaban (in vitro). #P < .05 indicates significant differences from baseline.

Figure 7.

Total thrombus formation of patients with NSTEMI treated with clopidogrel in the presence or absence of VLD rivaroxaban. (A) Representative tracings and (B) arithmetic means ± SEM (n = 14) of occlusion start time (T10), AUC, and OT of total thrombus formation on a collagen- and tissue factor-coated (AR) chip in recalcified citrated whole blood from patients with NSTEMI before (baseline) and after medication with clopidogrel + ASA at d1 in the absence (DMSO) or presence of 40 ng/mL rivaroxaban (in vitro), as well as after medication with clopidogrel + ASA and 2.5 mg rivaroxaban twice daily at d2 (in vivo). *P < .05, **P < .01, and ***P < .001 indicate statistically significant differences from solvent control at the indicated time point. #P < .05 and ##P < .01 indicate significant differences from baseline.