Registry of Clopidogrel Use and Long-Term Clinical Outcomes After Drug-Eluting Stent Implantation - Registry of Clopidogrel Use and Long-Term Clinical Outcomes After Drug-Eluting Stent Implantation
The goal of the observational study was to evaluate late clinical outcomes associated with drug-eluting stent (DES) use compared with bare-metal stents (BMS) with and without long-term clopidogrel use.
Patients Enrolled: 3,609
Mean Follow Up: Up to 24 months
Mean Patient Age: Median age 61 years
Underwent PCI with stenting at the Duke Heart Center during the specified time period
Consecutive patients at the Duke Heart Center undergoing percutaneous coronary intervention (PCI) with stenting were evaluated for late clinical events. Patients were categorized into four groups: 1) DES with clopidogrel, 2) DES without clopidogrel, 3) BMS with clopidogrel, and 4) BMS without clopidogrel.
Time points that clopidogrel use was evaluated were 6 and 12 months. Only patients without prior events were evaluated for events subsequent to the 6- and 12-month time points (landmark analysis). Data were included for BMS procedures done during the period of January 1, 2000 to July 31, 2005, and for DES procedures performed from April 1, 2003 to July 31, 2005.
At baseline, the BMS groups had higher rates of prior myocardial infarction (MI) than the DES groups. History of diabetes was lowest in BMS patients without clopidogrel use at 6 months (22.7%). History of CHF was highest in DES patients without clopidogrel use at 6 months (14.5%). Single-vessel disease was more common in the BMS groups.
In an analysis adjusting for propensity score for each of the four groups, mortality in the subsequent 18 months occurred in 5.3% of the DES without clopidogrel use at 6-month group, 2.0% of the DES with clopidogrel group, 4.5% of the BMS without clopidogrel group, and 3.7% of the BMS with clopidogrel group (p = 0.054; p = 0.03 for the comparison of DES with vs. without clopidogrel; p = 0.50 for the comparison of BMS with vs. without clopidogrel).
For nonfatal MI, the adjusted rates were 2.6%, 1.3%, 1.6%, and 1.7%, respectively (p = 0.24 for the comparison of DES with vs. without clopidogrel). Death or MI occurred in 7.2%, 3.1%, 6.0%, and 5.5%, respectively (p = 0.02 for the comparison of DES with vs. without clopidogrel).
For events subsequent to evaluation of clopidogrel use at 12 months, the sample size was greatly reduced in the DES groups (n = 276 without clopidogrel and n = 252 with clopidogrel). Mortality in the subsequent 12 months occurred in 3.5% of the DES without clopidogrel use at 12-month group, 0% of the DES with clopidogrel group, 2.7% of the BMS without clopidogrel group, and 3.3% of the BMS with clopidogrel group (p < 0.001; p = 0.004 for the comparison of DES with vs. without clopidogrel).
For nonfatal MI, the adjusted rates were 1.0%, 0%, 0.9%, and 1.4%, respectively (p = 0.047 for the comparison of DES with vs. without clopidogrel). Death or MI occurred in 4.5%, 0%, 3.6%, and 4.7%, respectively, in the following 12 months (p < 0.001 for the comparison of DES with vs. without clopidogrel).
Among patients undergoing PCI with stenting in this observational registry, longer-term clopidogrel use was associated with lower rates of death or MI in patients receiving a DES, but clopidogrel use was not associated with a difference in death or MI in patients implanted with a BMS.
Recent reports have shown increases in late stent thrombosis and possibly death or MI associated with DES compared with BMS. The BASKET LATE study suggested this increase may occur following clopidogrel discontinuation. Clopidogrel is currently recommended to be used through 3-6 months following DES placement.
These data, along with other recent registry data, suggest that longer-term clopidogrel use may be needed for DES-treated patients given the higher rate of late stent thrombosis and mortality. However, it should be noted that there are no randomized trial data evaluating different durations of clopidogrel use in the setting of DES. Additionally, despite adjustments in the analysis, selection bias cannot be fully accounted for in any registry analysis.
Many questions remain unanswered, including whether PCI is being overused compared with medical therapy or bypass surgery; whether DES is needed if PCI is performed; if DES is used, how long clopidogrel should be continued; and what are the risks associated with long-term clopidogrel use, including the possible increased risk of bleeding.
Eisenstein EL, Anstrom KJ, Kong DF, et al. Clopidogrel use and long-term clinical outcomes after drug-eluting stent implantation. JAMA 2007;297 159-168.
Keywords: Myocardial Infarction, Propensity Score, Platelet Aggregation Inhibitors, Metals, Drug-Eluting Stents, Selection Bias, Ticlopidine, Coronary Thrombosis, Angioplasty, Balloon, Coronary, Diabetes Mellitus, Purinergic P2Y Receptor Antagonists
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