TRIAGE Study Shows Risk Algorithm Helps Identify Patients Who May Benefit From More Intensive Antiplatelet Medication

May 8, 2015—The Society for Cardiovascular Angiography and Interventions (SCAI) announced that a risk assessment algorithm combining clinical risk factors and platelet function test results may help interventional cardiologists better identify patients who stand to benefit from intensive antiplatelet medication after percutaneous coronary intervention (PCI). 

These findings from the TRIAGE study were presented by Jaya Chandrasekhar, MD, as a late-breaking clinical trial at the SCAI 2015 scientific sessions being held May 6–9 in San Diego, California.

The background of the study is that patients may respond to one antiplatelet medication differently than another and heart disease patients who do not respond well to their antiplatelet therapy after receiving a stent may be at higher risk for adverse events, including blood clots, heart attack, and death. In recent years, new platelet function tests have been developed to help physicians assess how patients respond to antiplatelet medication but the use of these tests alone has not proven to be advantageous in randomized trials. This study seeks to evaluate the role of a combined approach of clinical risks and platelet function tests for the selection of the optimal antiplatelet regimen by interventional cardiologists. 

In the SCAI announcement, Dr. Chandrasekha commented, “Patients receiving a stent are typically prescribed antiplatelet medications for up to 1 year, but we know some patients may not respond adequately, which places them at greater risk of developing a blood clot, heart attack and even death. While intensive antiplatelet regimens may alleviate this risk, there is the cost of increased bleeding. It is important that we attempt to identify high-risk patients early so we can optimize their antiplatelet medication.” Dr. Chandrasekhar is from the Icahn School of Medicine at Mount Sinai in New York, New York.

According to SCAI, the TRIAGE investigators developed an algorithm combining clinical risk factors (including PCI indication, high angiographic-risk PCI, high ischemic- or bleeding-risk scores) with platelet function test results to determine high on-treatment platelet reactivity (HTPR) or patients likely to still have highly reactive platelets even after taking antiplatelet medication. Platelet function was tested immediately before PCI using the VerifyNow assay (Accriva Diagnostics; formerly, Accumetrics, Inc.).

Suitable patients whose assessment indicated HTPR received the antiplatelet drug prasugrel (Effient; Eli Lilly and Company and Daiichi Sankyo Company, Ltd), and patients with low on-treatment platelet reactivity (LTPR) received clopidogrel. Compared to clopidogrel, prasugrel has been shown to reduce the risk of adverse events in heart disease patients undergoing PCI, but is associated with increased bleeding, noted the press release.

Of the 318 patients assessed in the study, 228 patients (72%) received clopidogrel after PCI. The remaining 90 patients (28%) received prasugrel.

The investigators found that after 1 year, HTPR patients who received prasugrel had similar rates of major adverse cardiovascular events (death, spontaneous myocardial infarction, or thrombosis in the stent) compared to patients receiving clopidogrel (4.4% vs 3.5%; P = .7). There were no significant differences in death (4.4% vs 1.8%), blood clot (0% vs 0.4%), spontaneous heart attack (1.1% vs 2.2%), or need for repeat stenting in the treated coronary artery (6.7% vs 7%) between the two groups of patients (P > .05). Importantly, patients receiving prasugrel did not experience increased bleeding. These results indicate that the clinical risk algorithm may be useful in determining which patients might benefit from using prasugrel versus continuing on clopidogrel after PCI, reported SCAI. 

Dr. Chandrasekhar concluded in the SCAI press release, “We found that combining clinical risk with platelet function testing is potentially an effective way to help interventional cardiologists in the real world determine whether a patient should continue on clopidogrel or be switched to prasugrel after PCI. Using this intuitive risk-assessment algorithm can help us tailor antiplatelet medication to the individual patient, to better ensure they receive optimal therapy following their procedure, without undue risk of bleeding. Further trials with adequate patient numbers are warranted to demonstrate a definitive long-term reduction in adverse events with such an approach.”