Vorapaxar, combination antiplatelet therapy, and stroke

Role for Thrombin Receptor Antagonism With Vorapaxar in Secondary Prevention of Atherothrombotic Events: From Bench to Bedside

In spite of treatment with the current standard of care antiplatelet regimens including dual antiplatelet therapy, recurrence rates of ischemic events remain elevated for high-risk patients with atherosclerotic disease. This may be in part attributed to the fact that other key platelet activation pathways remain uninhibited and can thus continue to trigger platelet activation and lead to thrombotic complications. Thrombin is a powerful inducer of platelet activation and mediates its effects directly on platelets through protease activator receptors (PARs), particularly the PAR-1 subtype, making PAR-1 inhibition an attractive approach for reducing atherothrombotic events. These observations have led to the development of several PAR-1 antagonists. Vorapaxar is a direct inhibitor of PAR-1 and the only agent of this class approved for the prevention of recurrent ischemic events in patients with prior myocardial infarction or peripheral artery disease. In the present manuscript, we present a review of the pathophysiologic role of thrombin on thrombotic complications, the impact of vorapaxar on outcomes, including the most recent updates deriving from clinical trials, as well as future perspectives in the field.

Antithrombotic therapy for secondary prevention of atherothrombotic events in cerebrovascular disease

Atherothrombosis is the common underlying process for numerous progressive manifestations of cardiovascular disease, including coronary artery disease (CAD) and cerebrovascular disease (CVD). Antiplatelet therapy is the cornerstone of pharmacological management in patients with atherothrombosis. Over the past 20 years, major advances in antiplatelet pharmacotherapy have been made, particularly for the treatment of patients with CAD. The treatment of patients with concomitant CAD and CVD is complex, owing to their increased risk of both ischaemia and bleeding. When CVD arises from large artery atherosclerosis, antithrombotic therapies are essential to prevent stroke or transient ischaemic attack (TIA). However, the use of antithrombotic medications in patients with CVD can put them at high risk of intracranial haemorrhage. As such, the risk-benefit profile of various combinations of antiplatelet agents in patients with both CAD and CVD is uncertain. This Review provides a state-of-the-art account of the available evidence on antithrombotic therapies for the secondary prevention of atherothrombotic events in patients with concomitant CAD and CVD, particularly those with a history of noncardioembolic stroke or TIA.

Antithrombotic therapy for secondary prevention of atherothrombotic events in cerebrovascular disease

Atherothrombosis is the common underlying process for numerous progressive manifestations of cardiovascular disease, including coronary artery disease (CAD) and cerebrovascular disease (CVD). Antiplatelet therapy is the cornerstone of pharmacological management in patients with atherothrombosis. Over the past 20 years, major advances in antiplatelet pharmacotherapy have been made, particularly for the treatment of patients with CAD. The treatment of patients with concomitant CAD and CVD is complex, owing to their increased risk of both ischaemia and bleeding. When CVD arises from large artery atherosclerosis, antithrombotic therapies are essential to prevent stroke or transient ischaemic attack (TIA). However, the use of antithrombotic medications in patients with CVD can put them at high risk of intracranial haemorrhage. As such, the risk-benefit profile of various combinations of antiplatelet agents in patients with both CAD and CVD is uncertain. This Review provides a state-of-the-art account of the available evidence on antithrombotic therapies for the secondary prevention of atherothrombotic events in patients with concomitant CAD and CVD, particularly those with a history of noncardioembolic stroke or TIA.

Vorapaxar for secondary stroke prevention: perspectives and obstacles

Vorapaxar, a novel antiplatelet thrombin protease-activated receptor 1 (PAR-1) inhibitor, has been evaluated in the successful TRA2P trial and failed TRACER trial. The drug is currently approved for post myocardial infarction and peripheral artery disease indications on top of clopidogrel and/or aspirin. The stroke data after vorapaxar are mixed, dominated with heavy excess of intracranial bleeding risks and slightly worsened second stroke rates, but show less primary ischemic strokes. Fortunately, these conflicting data do not belong purely to vorapaxar per se but rather, reflect unreasonably aggressive strategies, including predominantly triple antiplatelet therapy, utilized in both Trial to Assess the Effects of SCH 530348 in Preventing Heart Attack and Stroke in Patients with Arteriosclerosis (TRA2P) and especially in Thrombin-Receptor Antagonist Vorapaxar in Acute Coronary Syndromes (TRACER). The FDA-confirmed evidence strongly suggests that unique pharmacokinetics and a very mild "comfort zone" antiplatelet profile makes vorapaxar a good candidate for improved secondary stroke prevention. The outcome-driven, randomized trial should test head-to-head monotherapy with vorapaxar (Zontivity®) versus clopidogrel (Plavix®) and versus dipyridamole with very low dose aspirin (Aggrenox®). The advantages and potential pitfalls of such a trial are discussed in this article.