Clopidogrel discontinuation within the first year after coronary drug-eluting stent implantation: an observational study

BMC Cardiovascular Disorders, Aug 2014

Background The impact of adherence to the recommended duration of dual antiplatelet therapy after first generation drug-eluting stent implantation is difficult to assess in real-world settings and limited data are available. Methods We followed 4,154 patients treated with coronary drug-eluting stents in Western Denmark for 1 year and obtained data on redeemed clopidogrel prescriptions and major adverse cardiovascular events (MACE, i.e., cardiac death, myocardial infarction, or stent thrombosis) from medical databases. Results Discontinuation of clopidogrel within the first 3 months after stent implantation was associated with a significantly increased rate of MACE at 1-year follow-up (hazard ratio (HR) 2.06; 95% confidence interval (CI): 1.08-3.93). Discontinuation 3-6 months (HR 1.29; 95% CI: 0.70-2.41) and 6-12 months (HR 1.29; 95% CI: 0.54-3.07) after stent implantation were associated with smaller, not statistically significant, increases in MACE rates. Among patients who discontinued clopidogrel, MACE rates were highest within the first 2 months after discontinuation. Conclusions Discontinuation of clopidogrel was associated with an increased rate of MACE among patients treated with drug-eluting stents. The increase was statistically significant within the first 3 months after drug-eluting stent implantation but not after 3 to 12 months.

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Clopidogrel discontinuation within the first year after coronary drug-eluting stent implantation: an observational study

BMC Cardiovascular Disorders Clopidogrel discontinuation within the first year after coronary drug-eluting stent implantation: an observational study Troels Thim 0 Martin Berg Johansen 2 Gro Egholm Chisholm 0 Morten Schmidt 2 Anne Kaltoft 0 Henrik Toft Srensen 2 Leif Thuesen 0 Steen Dalby Kristensen 0 Hans Erik Btker 2 Lars Romer Krusell 0 Jens Flensted Lassen 0 Per Thayssen 1 Lisette Okkels Jensen 1 Hans-Henrik Tilsted 3 Michael Maeng 0 0 Department of Cardiology, Aarhus University Hospital , Aarhus , Denmark 1 Department of Cardiology, Odense University Hospital , Odense , Denmark 2 Department of Clinical Epidemiology, Aarhus University Hospital , Brendstrupgaardsvej 100, Aarhus, N 8200 , Denmark 3 Department of Cardiology, Aalborg University Hospital , Aalborg , Denmark Background: The impact of adherence to the recommended duration of dual antiplatelet therapy after first generation drug-eluting stent implantation is difficult to assess in real-world settings and limited data are available. Methods: We followed 4,154 patients treated with coronary drug-eluting stents in Western Denmark for 1 year and obtained data on redeemed clopidogrel prescriptions and major adverse cardiovascular events (MACE, i.e., cardiac death, myocardial infarction, or stent thrombosis) from medical databases. Results: Discontinuation of clopidogrel within the first 3 months after stent implantation was associated with a significantly increased rate of MACE at 1-year follow-up (hazard ratio (HR) 2.06; 95% confidence interval (CI): 1.08-3.93). Discontinuation 3-6 months (HR 1.29; 95% CI: 0.70-2.41) and 6-12 months (HR 1.29; 95% CI: 0.54-3.07) after stent implantation were associated with smaller, not statistically significant, increases in MACE rates. Among patients who discontinued clopidogrel, MACE rates were highest within the first 2 months after discontinuation. Conclusions: Discontinuation of clopidogrel was associated with an increased rate of MACE among patients treated with drug-eluting stents. The increase was statistically significant within the first 3 months after drug-eluting stent implantation but not after 3 to 12 months. Percutaneous coronary intervention; Dual antiplatelet therapy; Drug-eluting stent; Clopidogrel - Background Dual antiplatelet therapy (DAPT), i.e., aspirin in combination with a P2Y12 antagonist, has been shown to reduce occurrence of ischemic events after coronary stent implantation in randomized clinical trials [1,2]. In real-world settings, however, the level of adherence to recommended DAPT is difficult to assess and its influence on outcomes is less well known. Moreover, the optimal duration of DAPT after coronary stent implantation is disputed [3]. Twelve months of DAPT after percutaneous coronary intervention (PCI) with coronary stent implantation has been recommended in Denmark since November 2002. This recommendation is based on interpretation of results of existing randomized clinical trials [1,2]. In such trials, we expect adherence to treatment to be high owing to patient selection, trial-related follow-up, and cost-free provision of the platelet inhibitor. Adherence to DAPT in real-world settings is most likely lower than in these randomized trials. Assessment of adherence levels and risks associated with discontinuation of DAPT within the first year after coronary stent implantation is needed in real-world settings. Danish medical registries allow validated monitoring of coronary interventions, prescription redemption, and clinical outcomes [4-9]. Based on data from these registries, we report rates of discontinuation of clopidogrel treatment after coronary drug-eluting stent (DES) implantation and assess the risk of associated adverse events. Methods According to the Central Denmark Region Committees on Health Research Ethics, this study could be conducted without an approval from the Committees. Setting We conducted this population-based cohort study, retrospectively, using medical registries in Western Denmark, which has approximately three million inhabitants (55% of the Danish population). The Danish National Health Service provides universal tax-supported health care, guaranteeing unfettered access to general practitioners and hospitals. Costs of prescription medications, including clopidogrel, are partially reimbursed. Accurate and unambiguous linkage of data from all registries at the individual level is possible in Denmark using the unique central personal registry number assigned to every Danish citizen at birth or upon immigration [9]. Patients and procedures We used the Western Denmark Heart Registry (WDHR) [10] to identify all PCI procedures performed between 1 January 2003 and 30 June 2005 [11-13]. For each patient, the first PCI procedure with implantation of one or more coronary DES during the inclusion period was defined as the index PCI procedure and the date of that procedure as the index date. Patients treated with balloon angioplasty without stenting o (...truncated)


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Troels Thim, Martin Johansen, Gro Chisholm, Morten Schmidt, Anne Kaltoft, Henrik Sørensen, Leif Thuesen, Steen Kristensen, Hans Bøtker, Lars Krusell, Jens Lassen, Per Thayssen, Lisette Jensen, Hans-Henrik Tilsted, Michael Maeng. Clopidogrel discontinuation within the first year after coronary drug-eluting stent implantation: an observational study, BMC Cardiovascular Disorders, 2014, pp. 100, 14, DOI: 10.1186/1471-2261-14-100