ACS: a Worldwide Killer

Acute Coronary Syndrome (ACS) is a major public health concern and claims millions of lives worldwide each year. In the United States, ACS will affect approximately 1.5 million people annually¹ and almost a quarter of a million deaths occur annually in the EU as a result of coronary artery disease.² Emergency room doctors, physicians and cardiologists will see countless cases of ACS in their respective careers, and according to the latest statistics published by the American Heart Association, ACS was responsible for over a million hospital admissions in the U.S. in 2009.¹

The Unmet Need In ACS (Residual Risk)

Of significant concern, are the high incidence and mortality rates of a subsequent cardiovascular

event occurring after leaving the hospital. According to data from the GRACE registry, 68-97% of deaths in ACS patients occur after hospital discharge.³

Antiplatelet therapy has been the mainstay of secondary prevention in ACS for the last 2 decades. The Antiplatelet Trialists Collaboration conducted a review of antiplatelet therapy in 1994.⁴ It was shown that antiplatelet therapy reduced vascular events by approximately 25%. However, the percentage of patients on ASA alone going on to suffer a vascular event was still fairly high. Almost ten years later, the Antithrombotic Trialists Collaboration conducted a larger review of 287 antiplatelet studies.⁵ Again, antiplatelet therapy reduced the outcome of vascular events by approximately one quarter, but the amount of►

patients on antiplatelet therapy experiencing vascular events was still substantial, at approximately 15%.

These days, therapy for ACS prevention most commonly consists of dual antiplatelet therapy with ASA and clopidogrel.⁶ However, the rate of subsequent events remains high. Most recently, the field has witnessed the development of novel antiplatelet agents that may replace clopidogrel. Two recent trials analysed the overall rate of major cardiovascular events for patients on ASA and clopidogrel compared to novel antiplatelet agents.^{7, 8} The results showed the overall rate for ASA plus clopidogrel was approximately 12%. Despite improved outcomes with the newer agents, the number of serious vascular events was approximately 10%.

This illustrates that residual risk for CV events remains high in such patients.

Thus, while antiplatelet therapy is the cornerstone of treatment to prevent recurrent ACS events, overall approximately 1 in 10 patients with ACS will have another major cardiovascular incident within one year after the index event.^{4, 5, 7, 8} Due to the fact that ACS is such a significant public health issue, and the rates of subsequent events remains fairly high despite current treatment strategies, additional approaches to further reduce complications and enhance secondary prevention efforts are needed.