Any platelet function tests have not been widely used in the clinical practice of acute cerebrovascular disease because of the concerns in repeatability, economic performance, and simplicity. Soluble C-type lectin-like receptor 2 (sCLEC-2) is a new marker for platelet activation, which can be easily measured by usual blood collection in routine clinical practice. We planned the sCLEC-2 in Stroke (CLECSTRO), which is a prospective cohort study in patients with acute ischemic stroke (AIS) and transient ischemic attack (TIA). We planned the sCLEC-2 in Stroke (CLECSTRO), which is a prospective cohort study in patients with acute ischemic stroke (AIS) and transient ischemic attack (TIA).

The purpose of this study is to evaluate the clinical utility of sCLEC-2 as a biomarker for pathophysiology, differential diagnosis, prediction of prognosis, and monitoring of antiplatelet therapy in patients with AIS and TIA. Subjects are patients with AIS or TIA and control patients required for differentiation from AIS or TIA. The target population is 600 including the patients and the controls. The outcomes include difference in plasma sCLEC-2 level between patients with AIS or TIA and patient controls, correlation between sCLEC-2 after antithrombotic therapy and recurrence or worsening of stroke, difference in sCLEC-2/D-dimer ratio between non-cardioembolic and cardioembolic AIS or TIA, and correlation between baseline sCLEC-2 and outcome (modified Rankin scale score) after 3 months. sCLEC-2 could be a widely useful biomarker to contribute to the progress of precision medicine in clinical practice of AIS and TIA.

The study design is a multicenter prospective cohort study across Japan including 8 stroke centers. Patients are male or female at age of 20 years or older. The inclusion criteria are (1) AIS within 24 hours of onset and mRS 0 to 2, (2) TIA without MRI positivity within 7 days of onset, and (3) contemporary patients with neurological symptoms, who are required for differentiation from AIS or TIA (served as controls). The main exclusion criteria are (1) platelet or coagulation abnormalities, (2) hemorrhagic stroke, head or other trauma, post-surgery, and hemorrhagic tendency, (3) severe infection, (4) inappropriate patients who were judged by doctors, and (5) poor status of blood samples. The target population is 600 in total (AIS 400, TIA 100 and control 100).

The plasma levels of sCLEC-2 are measured with D-dimer, soluble fibrin, and thrombin-antithrombin complex. sCLEC-2 is determined before starting treatment on admission. The modified Rankin Scale (mRS) and NIH Stroke Scale (NIHSS) are evaluated at registration as baseline data. sCLEC-2 as well as mRS and NIHSS are measured at Day 7 or at discharge. mRS is finally evaluated at 3 months. In the controls, plasma levels of sCLEC-2 and the baseline data are collected at entry.

The sCLEC-2 levels are measured for the difference between patients with AIS or TIA and controls, correlation with severity of stroke, correlation with size of infarct, correlation with Age, Blood pressure, Clinical feature, Diabetes, Duration of symptoms (ABCD2) score in TIA, relationship between treatment effect and worsening or recurrence, difference in the sCLEC-2/D-dimer ratio between cardiogenic and non-cardiogenic etiologies, and difference between TOAST subtypes of ischemic stroke. The study protocol has been approved in each ethical committee at stroke centers.

Inclusion Criteria:

1. Ischemic stroke within 24 hours of onset and modified Rankin Scale 0 to 2
2. Transient ischemic attack without MRI positivity within 7 days of onset
3. Contemporary patients required for differentiation from ischemic stroke or transient ischemic attack

Exclusion Criteria:

1. Platelet or coagulation abnormalities
2. Hemorrhagic stroke, head or other trauma, post-surgery, and hemorrhagic tendency
3. Severe infection
4. Inappropriate patients who were judged by doctors
5. Poor status of blood samples

Patients who visit to the department specialized for stroke