Double Antiplatelet Therapy After Drug-Eluting Stent Implantation: Risk Associated With Discontinuation Within the First Year
What is the time-dependent cardiovascular risk associated with discontinuation of double antiplatelet therapy (DAT) within the first year of implantation of a drug-eluting stent (DES)?
This was a prospective multicenter cohort study conducted in Spain, of 1,622 consecutive patients who underwent DES implantation. Through phone interviews and review of clinical records, patients were followed up at 3, 6, 9, and 12 months to record the rate and duration of antiplatelet therapy discontinuation (ATD), along with the antiplatelet drug (clopidogrel, aspirin, or both) that was discontinued. Incident acute coronary syndrome (ACS) and death were the primary outcomes of interest. Extended Cox regression modeling with a time-dependent covariate was used to evaluate the continuous risk of ATD.
Overall, ATD was not infrequent, with 172 (10.6%) patients interrupting at least one antiplatelet drug during the first year after DES implantation. Only one interruption was noted during the first month. Most interruptions were temporary (n = 111, 64.5%) and 55 involved both drugs (53 temporarily). Among those in whom interruption was temporary, the median number of days without DAT was 7. ACS occurred in seven patients with ATD (4.1%; 95% confidence interval [CI], 1.7-8.2), similar to the rate observed in those without ATD (n = 80, 5.5%; 95% CI, 4.4-6.8; p = 0.23).
In this prospective study, ATD within 1 year of DES implantation was not infrequent, and was not associated with major cardiovascular risk.
Though DAT is generally recommended for at least 6-12 months following DES implantation, the risk of ATD beyond the first month is not well defined. This study suggests that temporary ATD after the first month of DES implantation may be safe and not associated with clinically meaningful cardiovascular risk. While this study may give some confidence to temporary ATD, the results warrant further confirmation, as the study may have lacked sufficient power to detect statistically significant associations.
Keywords: Acute Coronary Syndrome, Pyridinolcarbamate, Platelet Aggregation Inhibitors, Drug-Eluting Stents, Cardiology, Spain, Cardiovascular Diseases, Risk Factors, Coronary Thrombosis, Angioplasty
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