(P045) TICAGRELOR VS RIVAROXABAN: EFFECTS ON HEMOSTASIS, THROMBOTIC AND INFLAMMATORY BIOMARKERS

Background: Acute coronary syndrome (ACS) usually results from thrombotic occlusion of one of the coronary arteries. Dual antiplatelet therapy (DAPT) with aspirin and a P2Y12 inhibitor is usually recommended for 12 months. Beyond that, patients continue aspirin monotherapy. However, amongst those who survive the first year, ~20% die or suffer a major ischemic event within the first 3 yrs. Additional antithrombotic therapy with either ticagrelor (60 mg BID) or rivaroxaban (2.5 mg BID) resulted in a significant reduction in major cardiovascular events. Both, however, increased the risk of major bleeding events. In this study we aimed to compare the effects of rivaroxaban (2.5 mg BID) and ticagrelor (60 mg PO BID) on hemostasis, thrombotic and inflammatory biomarkers in high-risk patients with history of ACS.

METHODS AND RESULTS: This is a prospective crossover randomized clinical trial. 20 patients with history of ACS (> 1 yr) and at least one additional risk factor were randomized to either one week of rivaroxaban 2.5 mg BID or ticagrelor 60 mg BID (Fig 1). The first week was followed with a 2-3 wk washout period before starting the second treatment week. All patients were on background aspirin therapy. The study is powered to detect a 25% reduction in bleeding with rivaroxaban as compared to ticagrelor. Fibrin clot lysis time will also be analyzed in citrated-plasma samples. White cell count and CRP were used assess differential effects on inflammation. ANOVA with Tukey’s multiple comparison test was used to compare the effects of ticagrelor and rivaroxaban on all outcome measures.

Bleeding time significantly increased with rivaroxaban from baseline (314 ± 109 secs vs. 440 ± 184 secs; P = 0.0095). Ticagrelor also increased bleeding time (279 ± 60 secs vs. 897 ± 482 secs; P < 0.0001) but the effects were greater when compared to rivaroxaban (P = 0.0004) (Fig 2). There was no effect on either white cell count or CRP with both agents. Fibrin clot lysis time should be available by time of presentation.

Conclusion: Ticagrelor appears to have greater impact on hemostasis as compared to rivaroxaban. We expect rivaroxaban to positively modulate fibrin clot making them more amenable to lysis. These differences may imply more bleeding risk with ticagrelor, but larger trials are needed to provide head-to-head comparison between the two treatment strategies.