2.1 Trial Design

We aimed to evaluate the role of ticagrelor versus clopidogrel in patients with first-ever noncardioembolic moderate and moderate-to-severe ischemic stroke in Egypt.

We got an acceptance from the ethical committee of the faculty of medicine at Kafr el-Sheikh University.

We evaluated all participants who had their first-ever noncardioembolic moderate or moderate to severe ischemic stroke and came to Kafr-Elsheikh University Hospital, Nasr City Insurance Hospital, and Ain Shams University Hospital between 1 July 2022 and 20 March 2024; we included the last participant in our study on 10 December 2023.

Randomization occurred at admission, and all participants received the antiplatelet treatment during the first 24 h after the onset of symptoms. Patients randomly administered ticagrelor or clopidogrel in a 1:1 ratio, upon a computer-based, fixed-randomization plan with a four-block size. We utilized an internet-based response system to detect the medication assignments in every center.

In our trial, we regularly followed up with our patients for 3 months via twice-weekly telephone calls and a monthly interview in our clinic. When one of our participants suffered from any manifestations of recurrent stroke during the follow-up calls, then we directed him to come to our hospital to perform brain computed tomography (CT) and brain magnetic resonance imaging (MRI) using stroke protocol to evaluate his neurological condition.

Our trial was registered in ClinicalTrials.gov (NCT05553613), 23/09/2022.

2.2 Participants

Our study had two parallel groups: the (A) group, which involved 450 patients who received ticagrelor, and the (B) group, which involved 450 patients who received clopidogrel.

2.3 Eligibility Criteria

Inclusion criteria: Our study encompassed males and females, aged between 18 and 75 years, who were diagnosed with acute first-ever non-cardioembolic moderate or moderate-to-severe ischemic stroke, we defined moderate stroke as stroke with National institute of Health Stroke Scale (NIHSS) 5–15 and moderate-to-severe stroke as stroke with NIHSS 16–20 [15, 16], and started antiplatelet treatment within the first 24 h post-stroke onset; we limited the age to 75 years old to minimize the possibility of atrial fibrillation (AF), which increased with age [17]. We did not exclude patients who had previous TIA.

Exclusion criteria: We ruled out patients who had been administered alteplase, anticoagulant, or antiplatelet therapy within the 3 days before randomization to avoid clouding our drug safety assessment [18]. Additionally, patients with NIHSS less than 4 or more than 25 and patients with a known history of persistent or recurrent central nervous system (CNS) pathology (e.g., epilepsy, multiple sclerosis, history of head trauma with a residual neurological deficit) were excluded.

We excluded patients who underwent carotid, cerebrovascular, or coronary revascularization during the first seven days of the study.

We ruled out participants who regularly administered medication influencing clopidogrel metabolism, such as proton pump inhibitors, statins, ketoconazole, dihydropyridine calcium channel blockers, and rifampin [19].

We excluded patients who had a cardioembolic stroke. We diagnosed cardioembolic strokes when the participant had major or minor risk factors of a potential cardiac source of emboli such as mechanical cardiac valves, atrial fibrillation (AF), mitral valve prolapse, aortic valve stenosis or calcification, and patent foramen ovale [20, 21]. We diagnosed clinical atrial fibrillation (AF) if we had a minimum of 30 s of cardiac rhythm, showing the absence of P waves and irregular RR intervals (when atrioventricular conduction is not impaired) in a conventional 12-lead electrocardiogram (ECG) recording [22].

We ruled out patients exhibiting any major organ failure such as renal failure and liver cell failure, active malignancies, or an acute myocardial infarction within the previous 6 weeks and patients with active peptic ulcer bleeding history within the last year.

Patients who suffered from recurrent ischemic stroke based on appropriate clinical history, examination, and/or MRI brain findings were excluded. Moreover, patients with a known allergy to the study drugs and those with INR > 1.4 or PT>18 seconds or Platelets < 100,000 platelets per microliter were excluded from our trial.

We ruled out pregnant and lactating patients, those with stroke due to venous thrombosis, and those with stroke following cardiac arrest.

2.4 Interventions

Our study had two parallel groups: the (A) group, which involved 450 patients who were administered a 180-mg loading dose of ticagrelor during the first 24 h of stroke onset, followed by 90 mg twice daily (b.i.d.) from the 2nd to the 90th day; and the (B) group which involved 450 patients who were administered a 300 mg loading dose of clopidogrel during the first 24 h of stroke onset followed by 75 mg once daily from the 2nd day to the 90th day.

We evaluated the personal history precisely, stroke details, and co-morbid conditions.

We used a combination of clinical history and examination, brain CT, and brain MRI using stroke protocol: T1W, T2W, FLAIR, DWI, T2 Echo Gradient, annd CTA or MRA (if CTA was contraindicated) of all intracerebral vessels to diagnose ischemic stroke and exclude intracranial haemorrhage.

All the participants who were evaluated for eligibility underwent transthoracic echocardiography (TTE) and a 12-lead routine ECG to diagnose AF and valvular heart disease before enrolment in the trial.

After randomization and receiving at least a single dose of antiplatelet, each patient underwent 24-h cardiac rhythm monitoring. We found that six patients in the ticagrelor group and seven patients in the clopidogrel group had atrial fibrillation, so we stopped the antiplatelet treatment and started anticoagulant therapy [23]; the 13 patients were included in the intention-to-treat analysis as patients with permeant premature drug discontinuation.

After enrolment in the trial, every patient had some laboratory investigations such as fasting and postprandial blood glucose levels, lipid profiles, liver functions, coagulation profiles, complete blood counts, and HbA1. In addition, each patient underwent a 24-h cardiac rhythm monitoring, carotid duplex, and blood pressure assessment; also, a patient was classified as hypertensive when his systolic blood pressure was higher than 130 mmHg and/or diastolic blood pressure was higher than 85 mm/Hg in at least three different measurements [24].

We evaluated lipid profile and diagnosed hyperlipidemia if serum cholesterol was higher than 200 mg/dL, low-density lipoprotein (LDL) cholesterol was higher than100 mg/dL, triglycerides were higher than150mg/dL, and/or high-density lipoprotein (HDL) cholesterol was lower than 40 mg/dL [25, 26]. We managed impaired lipid profile as follows: patients received 20 mg daily of rosuvastatin and 10 mg of ezetimibe to achieve LDL cholesterol < 70 mg/dL, and we used rosuvastatin as simvastatin. Lovastatin and atorvastatin are metabolized by cytochrome P450 3A4 (CYP3A4) and had many drug–drug interactions with clopidogrel; however, rosuvastatin has few drug–drug interactions with clopidogrel [27]. We did fasting lipid profile after 1–3 months of using antihyperlipidemia medications [28].

The patient was classified as having diabetes when his fasting blood glucose level was higher than 126 mg/dL, and/or casual plasma glucose was more than 200 mg/dL, and/or HbA1C was more than 6.5 [24].

2.5 Outcomes2.5.1 The Primary Outcomes

We defined our primary efficacy outcome as the occurrence of any new stroke (whether hemorrhagic or ischemic) during the 3-month follow-up period [29] and defined our primary safety outcome as the percentage of patients who developed any medication-related haemorrhagic complications classified according to the PLATO bleeding definition, which had three categories: major, minor, and minimal bleeding [30].

We utilized a follow-up CT brain after 2 days and 7 days or discharge to diagnose the hemorrhagic transformation of brain infarction which was classified according to the European Cooperative Acute Stroke Study (ECASS) classification [31].

2.5.2 The Secondary Outcomes

We defined our secondary efficacy outcomes as the percentage of patients who experienced a composite of myocardial infarction, new stroke, and death due to vascular events during the 3-month follow-up period, and the percentage of patients who had an unfavorable outcome in the form of a modified Rankin scale (mRS) greater than two [12, 32] after 1 week and 3 months, while our secondary safety outcome was the percentage of patients who experienced medication-related side effects which were evaluated using a follow-up questionnaire.

2.6 Sample Size

We utilized the Power Analysis and Sample Size System (PASS, V12), NCSS) to calculate our sample size and found that 842 patients would provide 85% power to detect a relative risk reduction of 40% in new stroke (primary outcome) among patients who received ticagrelor when compared with those who received clopidogrel, with final two-sided significance level of 95%, alpha error of 5%, assuming an incidence of new stroke of 14.1% [33] in patients who received clopidogrel and a dropout rate of 5%. We estimated our final sample size to be 900 patients, with 450 in each arm.

2.7 Randomization and Blinding

We obtained the signed informed agreement from the participants or their siblings before they were allocated to one of our study's two arms.

Our trial was single-blinded to the investigators; an independent statistician developed a computer-based randomization chart with a four-block size; our patients were randomly allocated in a one-to-one ratio to administer either ticagrelor or clopidogrel by a specially trained and qualified nurse. None of our investigators knew about the allocation of patients. We arranged consecutively numbered opaque closed envelopes and 900 labels for each drug labeled drug A or B. We utilized our randomization plan to sort the labels into envelopes numbered 1 to 900. The enrollment numbers assigned to patients began with 1 and were documented in their medical records. Next, we opened the files that matched the patient enrollment number, and according to the randomization, the patient was allocated to receive either medication A or B. Drug A involved ticagrelor 90 mg tablets, while drug B had clopidogrel 75 mg tablets. An unbiased statistician who was unaware of the treatment plans of groups A and B conducted the statistical analysis. We did not use placebos in our trial because of a lack of funding and financial support. Instead, patients were instructed not to inform the examining neurologist about their medications but to inform the nurse. The nurse would inform the physician if participants suffered from any medication-related side effects. A consultant neurologist conducted the follow-up interviews, and a specially trained nurse handled the follow-up calls. Patients were advised to visit the hospital if they experienced any clinical deterioration.

2.8 Statistical Analysis of the Data

Our efficacy and safety analyses were based on the intention-to-treat principle, and we analyzed our data using the IBM SPSS software package, version 20.0 (Armonk, NY: IBM Corp.). There were independent statistical evaluations of the primary and secondary outcomes. We expressed numerical data as means and standard deviation (SD) or median and interquartile range (IQR) based on their distribution, which was evaluated by the Shapiro–Wilk test. We also used percentages and numbers to report categorical data. We compared the abnormally distributed data using the Mann–Whitney U test. For categorical data, we used Pearson’s chi-squared test. Every piece of information was considered in our study. Differences were deemed statistically significant when the P value was less than 0.05, and all statistical analyses were two-sided. We utilized correction for multiple comparisons to ensure that our analysis of secondary efficacy outcomes did not involve type 1 statistical error, and differences in these outcomes were deemed statistically significant when the adjusted P value was less than 0.0167. We executed a survival analysis using the Kaplan–Meier test and the log-rank technique to examine the impact of antiplatelet on the occurrence of outcomes over the 3-month follow-up period. At a 95% confidence interval (CI), the hazard ratio (HR) was calculated using the Cox regression method. HR was considered significant when one does not lie between lower and upper CI, and we adjusted the following confounding factors in the Cox regression model: age, history of hypertension, smoking, dyslipidemia, diabetes mellites, ischemic heart disease, TOAST classification of stroke, previous TIA, number of prior antiplatelet, number of prior statins, gender, and type of circulation affected.