This is a forward-looking, open, one-arm, and real clinical trial world. The researchers plan to recruit at least 50 qualified patients. The main purpose of this study is to establish a population pharmacokinetic model of ticagrelor , explore the correlation between its blood concentration and the events of ischemia and the adverse effects of hemorrhage, and evaluate the effectiveness and safety of ticagrelor in the treatment of ischemic cerebrovascular disease.

Ischemic stroke and transient ischemic attack are the most common types of ischemic cerebrovascular disease. Patients will suffer from physiological function damage, even mental symptoms, social function and other obstacles, seriously affecting the quality of life, and bringing heavy burden to families and society.

Ticagelor is a new P2Y12 receptor antagonist. Compared with clopidogrel, ticagelor has stronger and more lasting platelet inhibition, and can reduce the recurrence of ischemic events in patients with acute coronary syndrome .

Therefore, at least 50 patients with ischemic cerebrovascular disease using ticagelor will be included. Before and after treatment, the laboratory examination data, NIHSS, mRS, combined medication and adverse events, and ischemic events of the patients will be collected. The population pharmacokinetics model of Ticagelor was established to evaluate its effectiveness and safety.

Inclusion Criteria:

1. Female or male aged ≥ 18 years.
2. Clinically diagnosed as ischemic cerebrovascular disease.
3. Take ticagelor for antiplatelet therapy.
4. Provision of informed consent.

Exclusion Criteria:

1. Head CT or MRI suggests the presence of intracranial hemorrhagic disease.
2. People with tumors and other serious systemic diseases.
3. Allergy to ticagelor.

Patients with ischemic cerebrovascular disease must sign written informed consent before collecting blood samples