Bagai A, et al. - Researchers analyzed if the clinical benefit with pre-hospital ticagrelor varied by ischemic duration in patients with ST-segment elevation myocardial infarction (STEMI). When given early within 3 hours after symptom onset, the effect of pre-hospital ticagrelor to reduce stent thrombosis was most evident, displaying a delay in the ticagrelor administration after symptom onset linked with a higher rate of stent thrombosis. These results stressed on the necessity for early ticagrelor administration in primary PCI treated STEMI patients.

Methods

• A comparison was pursued of the absence of ST-segment resolution post-PCI and stent thrombosis at 30 days between randomized treatment groups (pre- vs in-hospital ticagrelor), in a post hoc analysis.
• Data was stratified by symptom onset to first medical contact (FMC) duration [≤1 hr. (n = 773), >1 to ≤3 hrs (n = 772), and >3 hrs (n = 311)].
• Researchers contemplated the interaction between randomized treatment strategy and duration of symptom onset to FMC for each outcome.

Results

• Herein, the patients presenting later after symptom onset were older, exhibiting a greater tendency of being female, and displaying a higher baseline risk.
• Patients with symptom onset to FMC >3 hrs illustrated the greatest improvement in post-PCI ST-segment elevation resolution with pre- vs in-hospital ticagrelor (absolute risk difference: ≤1 hr., 2.9% vs. >1 to ≤3 hrs, 3.6% vs. >3 hrs, 12.2%; adjusted p for interaction=0.13).
• On the other hand, patients with shorter duration of ischemia demonstrated greater improvement in stent thrombosis at 30 days with pre- vs in-hospital ticagrelor (absolute risk difference: ≤1 hr., 1.3% vs. >1 hr. to ≤3 hrs, 0.7% vs. >3 hrs, 0.4%; adjusted p for interaction=0.55).
• An independent correlation was revealed between the symptom onset to active ticagrelor administration with stent thrombosis at 30 days (adjusted OR 1.89 per 100 minute delay, 95%CI 1.20-2.97, P < .01), but not post-PCI ST-segment resolution (P=.41).