Objective: In daily clinical practice, we encounter ST segment elevation myocardial infarction (STEMI) patients loaded with clopidogrel upon
admission to primary angioplasty. These patients are loaded with ticagrelor, if there is no contraindication. This study aimed to compare the
level of injury between STEMI patients who were first loaded with clopidogrel and the ones first loaded with ticagrelor. Although patients were
switched from clopidogrel to ticagrelor at the first hour of angioplasty, antiplatelet action may still be lower than the others.
Methods: This study included STEMI patients with angina onset of ≤3 h and who had primary angioplasty to proximal segment of one coronary
artery. All patients had total thrombotic occlusion at the proximal segment. Δtroponin level (6th-hour troponin–admission troponin) was calculated to compare the level of myocardial injury.
Results: A total of 105 patients were included; 52 were loaded with ticagrelor and 53 with clopidogrel first and switched to ticagrelor. Baseline
characteristics were similar in the two groups, except from type B2 lesions being more common in the ticagrelor-loaded group. Δtroponin levels
were significantly higher in the clopidogrel-loaded group compared with the ticagrelor-loaded group (p=0.013). Major bleeding and in-hospital
MACE rates were similar in both groups.
Conclusion: In STEMI patients, the degree of troponin rise was more prominent in clopidogrel-loaded patients, despite the switch to ticagrelor in
the first hour of intervention. Clopidogrel is slow and modest, and variable platelet inhibition may continue to be a negative factor for protection
from myocardial injury, even after switching to ticagrelor.