No cardiac, pulmonary dysfunction found in ticagrelor-induced dyspnea
MedWire News: Ticagrelor therapy can cause a transient and reversible dyspnea in patients free from active lung disease without affecting their cardiac or pulmonary function, researchers suggest.
The findings, reported in the Journal of the American College of Cardiology, support those of the Platelet Inhibition and Patient Outcomes (PLATO) study, which suggested an increased risk for dyspnea with ticagrelor therapy compared with clopidogrel.
However, as Robert Storey (University of Sheffield, UK) and colleagues report: "The reversible nature of ticagrelor-related dyspnea and the lack of any evidence of cardiac or pulmonary pathology associated with this provide preliminary reassurance about the nature of this side effect."
They explain that "although the mechanism for dyspnea is unproven" adenosine may play an important role as previous studies have shown "that intravenous infusion of adenosine to healthy volunteers can induce dyspnea without any associated bronchoconstriction."
The researchers observed 123 patients with coronary artery disease and background aspirin therapy (75-100 mg daily). All patients were randomly allocated to receive ticagrelor (n=57), clopidogrel (n=54), or placebo therapy (n=12).
Cardiac and pulmonary functions were assessed via electrocardiography, echocardiography, serum N-terminal pro-brain natriuretic peptide, and pulmonary function tests at baseline or 6 weeks. Patients developing dyspnea before 6 weeks were additionally assessed at onset of dyspnea.
In all, 38.6%, 9.3%, and 8.3% of patients reported dyspnea in the ticagrelor, clopidogrel, and placebo group, respectively (p<0.001). The majority (n=24) of the 28 reported cases of dyspnea were described as mild, and 22 of the cases resolved upon cessation of ticagrelor, clopidogrel, or placebo.
The researchers found no obvious changes between baseline and 6-week cardiac and pulmonary function parameters in any of the treatment groups, even in the patients reporting dyspnea.
Of note, no evidence of transient bronchospasm or metabolic acidosis was indicated in the spirometry and biochemical test results of any patient.
Storey et al acknowledge that the small study size and the selection of patients free of active lung disease are limitations.
They conclude: "Further studies of ticagrelor in patients with active lung disease are now warranted."
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By Lauretta Ihonor