The DAPT study concluded that continued thienopyridine plus aspirin beyond a year after coronary angioplasty is associated with a decrease in the rate of stent thrombosis and major cardiovascular events. In contrast, there is a significant increase in moderate to severe bleeding when compared with continued aspirin alone.
Based on the outcomes of this and other studies, in 2016, the American College of Cardiology (ACC)/American Heart Association (AHA) guidelines recommended at least 6 months of dual antiplatelet therapy after angioplasty with a drug-eluting stent. Guidelines also emphasized the importance of individualizing time according to the risk for thrombosis compared with the risk for bleeding.
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Procedural complexity, number of treated vessels, caliber, stent-covered artery length, etc., are known thrombosis factors, which means that they might be factors that should be taken into account when deciding the duration of dual antiplatelet therapy.
This study compared 30 months versus 12 months of dual antiplatelet therapy after angioplasty based on the presence or absence of anatomically-complex lesions.
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The criterion for complex lesions was any of the following characteristics: unprotected left main artery, >2 lesions per vessel, stent length ≥30 mm, bifurcation lesion with side branch ≥2.5 mm, vein graft, or thrombus-containing lesion.
The study enrolled 25,416 patients; subjects with more complex lesions had higher rates of infarction and stent thrombosis during the first 12 months after the procedure (3.9% vs. 2.4%; p < 0.001).
In patients who were event-free at 12 months, continued dual antiplatelet therapy up to 30 months offered the same benefit in terms of ischemic events and the same risk for bleeding, regardless of anatomical complexity.
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The greatest reduction in the rates of infarction and stent thrombosis was observed in patients with complex anatomy and dual antiplatelet therapy (DAPT) scores ≥2, which continued up to 30 months (3.0% vs. 6.1%; p < 0.001), unlike patients with scores <2, for whom the difference was non-significant (1.7% vs. 2.3%; p = 0.42).
Conclusion
Complex target-lesion anatomy is associated with increased ischemic events, particularly within the first year after angioplasty. Patients without events within the first year who continued dual antiplatelet therapy up to 30 months benefited from a reduction in the rates of infarction and stent thrombosis, but this benefit was independent from target-lesion complexity.
Editorial
These findings suggest that anatomical complexity can be useful for the determination of a dual antiplatelet therapy duration of a year, not less. However, beyond a year, the DAPT score is much better than anatomical complexity for the identification of patients who benefit from this therapy.
Original title: Lesion Complexity and Outcomes of Extended Dual Antiplatelet Therapy After Percutaneous Coronary Intervention.
Reference: Robert W. Yeh et al. J Am Coll Cardiol 2017;70:2213-23.
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