Differential Inhibition of Platelet Reactivity by Dual Therapy With Aspirin and Low-Dose Rivaroxaban in Peripheral Arterial Disease: A Pilot Study

Patients with peripheral arterial disease (PAD) benefit from combination therapy with acetylsalicylic acid (ASA, 100 mg, one time per day) plus low-dose rivaroxaban (2.5 mg, two times per day) compared to ASA monotherapy. In particular, major adverse cardiac and limb events were significantly reduced after peripheral endovascular revascularization (EVR). In this pilot study, the platelet activation status in vivo and platelet reactivity in vitro were longitudinally analyzed by flow cytometric assays and calibrated automated thrombography in platelet-rich plasma (PRP) from 10 patients with PAD receiving ASA (100 mg, one time per day) before EVR, ASA plus clopidogrel (75 mg, one time per day) after EVR, and ASA plus rivaroxaban (2.5 mg, two times per day) during a long-term follow-up. Platelet responsiveness to clopidogrel was compared to additional 10 patients with stable PAD and clopidogrel (75 mg, one time per day) monotherapy. ASA plus rivaroxaban treatment resulted in a significantly decreased thrombin peak in PRP for two triggers, namely, low concentration of tissue factor (TF) and thrombin, compared to ASA monotherapy. TF-controlled thrombin generation was additionally characterized by a significantly prolonged lag time in PRP and platelet-free plasma during ASA plus rivaroxaban combination therapy. In comparison, ASA plus clopidogrel treatment presented a significant reduction of the thrombin peak in PRP, which was less pronounced than during subsequent ASA plus rivaroxaban therapy. Platelet responsiveness to clopidogrel was observed for 60% of patients receiving ASA plus clopidogrel and clopidogrel monotherapy, respectively. Blocking of CD36 on the platelet surface further reduced the thrombin peak in PRP induced by TF for all three therapy regimes. Platelet activation in vivo and in response to the GPVI-agonist convulxin or thrombin in vitro was similar, whereas integrin αIIbβ3 activation and α-granule release induced by the PAR-1 activating peptide TRAP-6 were significantly diminished during ASA plus rivaroxaban treatment compared to ASA monotherapy. In conclusion, the data of this pilot study indicate an inhibitory effect of rivaroxaban on the thrombin propagation phase of CD36-sensitive platelet thrombin formation in patients with PAD treated with ASA plus rivaroxaban combination therapy, which is associated with decreased PAR-1 but not thrombin-mediated platelet activation.

Antithrombotic therapy in peripheral arterial disease

Background

Patients with peripheral arterial disease (PAD) are at increased risk for major adverse cardiovascular events (MACE) such as cardiovascular death, myocardial infarction, and stroke as well as major adverse limb events (MALE) such as amputation and acute limb ischemia. Therefore, prevention of thrombotic events is crucial to improve the prognosis of PAD patients. This review article concludes current evidence and guideline recommendations about antithrombotic therapy in PAD patients.Antithrombotic therapy is highly effective to reduce MACE and MALE events in PAD patients. Recently, the concept of dual pathway inhibition (low-dose rivaroxaban plus acetylic salicylic acid (ASA) has been tested in the COMPASS and VOYAGER-PAD trial. Compared to ASA alone dual pathway inhibition was superior to prevent MACE and MALE. After peripheral revascularization, in particular the risk for acute limb ischemia was reduced. In contrast, the risk for major bleeding is increased. Therefore, current guidelines recommend the combination of low-dose rivaroxaban and ASA in PAD patients with low bleeding risk. In patients with high bleeding risk, a single antiplatelet drug (preferable clopidogrel) is indicated. In patients with atherosclerotic vascular disease and indication for oral anticoagulation, no additional antiplatelet drug is necessary, as this would increase the risk of bleeding without improving the prognosis.

Conclusion

Antithrombotic treatment reduces MACE and MALE and is recommended in all patients with PAD. Individual bleeding risk should always be considered based on the current data situation and an individual benefit-risk assessment must be carried out.

[Conservative treatment of peripheral arterial disease]

Patients with peripheral arterial disease (PAD) often have polyvascular atherosclerosis and are at increased risk of major adverse cardiovascular events (MACE), such as cardiovascular death, myocardial infarction or stroke, and major adverse limb events (MALE), such as amputation and acute limb ischemia. Therefore, the aim of conservative treatment is the reduction of MACE and MALE. In patients with intermittent claudication, the aim is also to extend walking distance. Management of risk factors includes smoking cessation, statin therapy, reduction of low-density lipoprotein cholesterol (target < 55 mg/dL and reduction to at least 50% of baseline value), normalization of blood glucose and treatment of arterial hypertension (target < 140/90 mm Hg). Moreover, antithrombotic treatment should include antiplatelet therapy (acetyl salicylic acid 100 mg and clopidogrel 75 mg), and in patients at high thrombotic risk and low bleeding risk rivaroxaban 2 × 2.5 mg should be added. In patients with intermittent claudication exercise therapy is highly recommended. Despite the high risk, in particular patients with PAD are often undertreated in clinical practice.