Author + information
- Michael Joseph Lipinski1,
- Michael A. Gaglia1,
- Thibault Lhermusier1,
- Arie Steinvil1,
- Sarkis Kiramijyan1,
- Rebecca Torguson1,
- Johanna Kim1,
- Nina Chandra1,
- Dominick J. Angiolillo2,
- Lars Wallentin3,
- Robert F. Storey4 and
- Ron Waksman1
Little is known regarding the ability of ticagrelor to inhibit platelet reactivity in African Americans (AA) with acute coronary syndrome (ACS). Thus, we performed pharmacodynamic studies of platelet reactivity following treatment with ticagrelor in AA with ACS.
We prospectively enrolled AA with ACS who did not have contraindication to ticagrelor. Blood samples were collected 1, 4, and 8 hours following loading with ticagrelor and again at 30 days. Platelet reactivity was assessed with maximal platelet aggregation (MPA) to 20 or 5 μM adenosine diphosphate (ADP) on light transmission aggregometry, VerifyNow P2Y12 reaction units (PRU), and platelet reactivity index vasodilator-stimulated phosphoprotein phosphorylation (PRI-VASP).
We enrolled 24 AA patients with a mean age of 67±13 and 54% were men. Twenty-one were admitted for NSTEMI, 1 for STEMI, 2 patients for UA, and 58% of patients received clopidogrel before ticagrelor. Platelet reactivity was significantly inhibited after loading with ticagrelor and remained inhibited on maintenance therapy (Figure). Platelet inhibition was significantly greater at 4 and 8 hours compared with 1 hour for all tests (p<0.05). Importantly, patients that received clopidogrel prior to ticagrelor had significantly greater platelet inhibition at 1 hour than patients who did not receive clopidogrel (PRU 201±72 vs 70±69, p<0.001; PRI 63±19 vs 14±24, p<0.001). However, there was no difference in PRU values by 4 hours (PRU 33±44 vs 31±33). The degree of platelet inhibition following loading with ticagrelor and on maintenance therapy appears comparable to that seen in Caucasian patients enrolled in the PLATO trial.
Ticagrelor significantly inhibits platelet reactivity measured by LTA, VerifyNow PRU, and VASP in AA with ACS.
|1 Hour||4 Hours||8 Hours||30 Days|
|MPA (%) to 20 μM ADP||26±21||9±8||8±8||17±11|
|MPA (%) to 5 μM ADP||17±16||3±4||4±5||8±7|