ACS patients treated with antiplatelet drugs who require CABG surgery have to wait 5-7 days
for the effects of the drugs to wean off. This treatment-devoid period leaves the patient
vulnerable, therefore any means to shorten this period could be useful. The present study
aims to investigate the possibility of reversing the antiplatelet effects of ticagrelor with
the help of fresh donor platelets. Fresh platelets will be added to blood samples of treated
patients in varying concentrations at specific timepoints to determine the time and amount
of fresh platelets needed to normalize platelet reactivity in the treated samples.
The current ACC/AHA guidelines for ACS patients requiring CABG surgery after treatment with
dual antiplatelet therapy recommend delaying surgery for 5-7 days after discontinuation of
therapy, to allow for the dissipation of its antiplatelet effects. This treatment-devoid
waiting period puts the ACS patients at risk for further cardiovascular events. Any means to
shorten this vulnerable period would be of critical value. One possibility to speed up the
recovery of the inhibited platelets is to administer infusions of fresh platelets. In fact,
platelet transfusions are frequently administered to patients during surgery who had
received prior antiplatelet therapy. However, the degree to which these transfusions restore
platelet function in the recipient subjects' blood and the time from dosing when they are
most effective are unknown. The timing is critical in scenarios where urgent surgery is
required because infusion of platelets too soon after antiplatelet dosing could render them
useless by the residual drug in circulation.
The aim of the present study is to investigate the restoration of platelet function of
ticagrelor-treated subjects by adding donor platelets to their blood. The study would have 2
arms mimicking different clinical scenarios:
1. Clinical Scenario 1 - Patient given a loading dose (LD) of ticagrelor in the emergency
room, requires surgery: A single (180 mg) LD of ticagrelor with aspirin 325 mg will be
given to study subjects and platelet testing will be performed after addition of fresh
platelets to their blood ex vivo. Donor platelets will be added at 4-, 6-, 24- and
48-hours post-dose, to assess the time required for normalizing subject's platelet
function after a LD of ticagrelor.
2. Clinical Scenario 2 - Patient on maintenance dosing (MD) of ticagrelor, requires
surgery: Subjects will receive 3-7 days of ticagrelor (90 mg BID) with aspirin (81 mg
OD). After the last dose, platelet testing will be performed after addition of fresh
platelets to their blood ex vivo, at 4-, 6-, 24- and 48-hours post-dose to assess the
time required for normalizing subject's platelet function after a LD of ticagrelor
Platelet testing will be carried out using the following methodologies:
1. Platelet Aggregation - VerifyNow P2Y12 assay.
2. Platelet Aggregation - Multiplate Analyzer.
- Male or female volunteer between 18 and 75 years old.
- History of stable (i.e. non-acute) cardiovascular disease or the presence of risk
factors for cardiovascular disease (i.e. hypertension, diabetes, hyperlipidemia, high
calcium score and abnormal findings on angiography or stress test).
- Conditions associated with hemorrhagic risk, e.g., frequent epistaxis,
gastrointestinal ulcer, hemorrhagic vascular lesions, recent surgery.
- Allergy or hypersensitivity to aspirin or ticagrelor.
- Loss of >400 mL blood or blood donation within past 3 months.
- Positive serology for hepatitis B (HBs Ag) or hepatitis C.
- History of drug abuse or alcohol abuse.
- Positive pregnancy test.
- Evidence of unstable or acute cardiovascular disease (e.g., unstable angina, recent
myocardial infarction, congestive heart failure).
- History of clinically relevant pulmonary, hepatic, gastrointestinal, renal,
metabolic, hematologic, neurologic, respiratory or psychiatric disease, bleeding,
acute infectious disease or signs of acute illness.