Clinical Impact of Dyspnea after Ticagrelor Treatment and the Effect of Switching to Clopidogrel in Patients with Myocardial Infarction.

Background:  Dyspnea is frequent during ticagrelor-based dual antiplatelet therapy (DAPT) for acute myocardial infarction (AMI). However, its clinical characteristics or management strategy remains uncertain.

Methods:  The study assessed 2,617 AMI patients from the Ticagrelor versus Clopidogrel in Stabilized Patients with AMI (TALOS-AMI) trial. Dyspnea during 1-month ticagrelor-based DAPT and following DAPT strategies with continued ticagrelor or de-escalation to clopidogrel from 1 to 12 months were evaluated for drug adherence, subsequent dyspnea, major adverse cardiovascular events (MACE), and bleeding events.

Results:  Dyspnea was reported by 538 patients (20.6%) during 1 month of ticagrelor-based DAPT. Adherence to allocated DAPT over the study period was lower in the continued ticagrelor arm than the de-escalation to clopidogrel, particularly among the dyspneic population (81.1% vs. 91.5%,  < 0.001). Among ticagrelor-treated patients with dyspnea, those switched to clopidogrel at 1 month had a lower frequency of dyspnea at 3 months (34.3% vs. 51.7%,  < 0.001) and 6 months (25.5% vs. 38.4%,  = 0.002) than those continued with ticagrelor. In patients with dyspnea in their 1-month ticagrelor-based DAPT, de-escalation was not associated with increased MACE (1.3% vs. 3.9%, hazard ratio [HR]: 0.31, 95% confidence interval [CI]: 0.08-1.11,  = 0.07) or clinically relevant bleeding (3.2% vs. 6.2%, HR: 0.51, 95% CI: 0.22-1.19,  = 0.12) at 1 year.

Conclusion:  Dyspnea is a common side effect among ticagrelor-based DAPTs in AMI patients. Switching from ticagrelor to clopidogrel after 1 month in AMI patients may provide a reasonable option to alleviate subsequent dyspnea in ticagrelor-relevant dyspneic patients, without increasing the risk of ischemic events (NCT02018055).