May 18, 2015 — 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). This assessment is according to results of the TRIAGE study, presented as a late-breaking clinical trial at the Society for Cardiovascular Angiography and Interventions (SCAI) 2015 Scientific Sessions in San Diego.
Patients may respond to one antiplatelet medication differently than another. 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. While the use of these tests alone has not proven to be advantageous in randomized trials, the role of a combined approach of clinical risks and platelet function tests for the selection of the optimal antiplatelet regimen by interventional cardiologists has not been investigated until now.
“Patients receiving a stent are typically prescribed antiplatelet medications for up to one 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,” said Jaya Chandrasekhar, MBBS, of the Icahn School of Medicine at Mount Sinai in New York, and the study’s presenter. “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.”
For the new trial, researchers 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 prior to PCI using the VerifyNow assay.
Suitable patients whose assessment indicated HTPR received antiplatelet drug prasugrel (Effient), while 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.
A total of 318 patients were assessed, and of these 228 (72 percent) received clopidogrel following PCI, while the remaining 90 (28 percent) received prasugrel. After one year, HTPR patients who received prasugrel had similar rates of major adverse cardiovascular events (death, spontaneous heart attack or blood clot in the stent) compared to patients receiving clopidogrel (4.4 percent vs. 3.5 percent, p=0.7). There were no significant differences in death (4.4 percent vs. 1.8 percent), blood clot (0 percent vs. 0.4 percent), spontaneous heart attack (1.1 percent vs. 2.2 percent) or need for repeat stenting in the treated coronary artery (6.7 percent vs. 7.0 percent) between the two groups of patients (p>0.05). Importantly, patients receiving prasugrel did not experience increased bleeding.
The 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.
“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,” said Chandrasekhar. “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.”
Chandrasekhar reported no disclosures.
For more information: www.scai.org