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Updated: Jul 16, 2025

Microfluidics in Assessing Platelet Function
Published on: November 8, 2024
Differential inhibition of platelet function by cilostazol in combination with clopidogrel
Masako Yamazaki1,2, Yuka Shirai3, Tomoko Ohnishi4
1Department of Neurology, Tokyo Women's Medical University, 8-1, Kawada-cho, Shinjuku-ku, Tokyo, 162-8666, Japan. masako.yamazaki@chiba-u.jp.
Insights
Adding cilostazol to clopidogrel (dual antiplatelet therapy) enhanced antiplatelet effects in patients with ischemic stroke. VerifyNow % inhibition and vasodilator-stimulated phosphoprotein (PRI) showed greater inhibition with dual therapy.
Area of Science:
- Cardiovascular Medicine
- Pharmacology
- Clinical Trials
Background:
- The study investigated the antiplatelet effects of cilostazol in patients with ischemic stroke.
- This research was a substudy of the CSPS.com trial, registered retrospectively.
Purpose of the Study:
- To clinically assess the antiplatelet effect of cilostazol when combined with clopidogrel.
- To compare the impact of dual antiplatelet therapy (DAPT) versus single antiplatelet therapy (SAPT) on platelet function tests.
Main Methods:
- Patients with ischemic stroke receiving clopidogrel underwent baseline platelet function tests.
- Participants were randomized to receive either clopidogrel plus cilostazol (DAPT) or clopidogrel alone (SAPT) for 6 months.
- Platelet function was reassessed after 6 months, comparing changes within and between groups.
Main Results:
- In the DAPT group, adenosine diphosphate- and collagen-induced aggregation, VerifyNow P2Y12 reaction units, vasodilator-stimulated phosphoprotein (PRI), and plasma p-selectin were significantly reduced.
- VerifyNow % inhibition significantly increased in the DAPT group compared to baseline.
- The rate of decrease in PRI and the rate of increase in VerifyNow % inhibition were significantly greater in the DAPT group than in the SAPT group.
Conclusions:
- Adjunctive cilostazol to clopidogrel demonstrated varied inhibitory effects on platelet function depending on the test used.
- VerifyNow % inhibition and PRI were identified as more sensitive indicators of platelet inhibition by dual therapy.
Purpose:
To assess the antiplatelet effect of cilostazol clinically, we compared the effects of cilostazol in combination with clopidogrel on various platelet function tests.
Methods:
We recruited patients with ischemic stroke at high risk of recurrence who were treated with clopidogrel alone within 180 days after stroke onset. Subjects underwent baseline platelet function tests, and were then randomly assigned to receive dual antiplatelet therapy (DAPT) comprising clopidogrel and cilostazol or clopidogrel monotherapy (SAPT). After 6 months, platelet function was measured again and compared to that at baseline in each group, and the rate of change was compared between groups.
Results:
Thirty-four patients were enrolled, but 4 patients were excluded for various reasons. In total, 30 subjects (13 in DAPT and 17 in SAPT group) were analyzed. Adenosine diphosphate- and collagen-induced aggregation, VerifyNow P2Y12 reaction units, vasodilator-stimulated phosphoprotein (platelet reactivity index: PRI) and plasma p-selectin concentration were significantly lower (P = 0.004, 0.042, 0.049, 0.003 and 0.006 respectively), while VerifyNow % inhibition was significantly higher at 6 months compared to baseline (P = 0.003) in the DAPT group only. Comparison of the rate of change in each parameter from baseline to 6 months showed that while PRI decreased at a greater rate (P = 0.012), VerifyNow % inhibition increased at a greater rate (P = 0.003) in the DAPT group than the SAPT group.
Conclusions:
The inhibitory effects of adjunctive cilostazol added to clopidogrel on platelet function differed by type of platelet function test. VerifyNow % inhibition and PRI were more inhibited than the other platelet function tests.
Trial Registration:
CSPS.com substudy in TWMU (UMIN000026672), registered on April 1, 2017. This study was performed as a substudy of CSPS.com (UMIN000012180, registered on October 31, 2013) and was retrospectively registered.
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