短期間の抗血小板薬2剤併用療法は長期にわたり有効性を保つ(Abstract 3831)
NIPPON：薬剤溶出性ステント留置後、抗血小板薬2剤併用療法（DAPT）を受けた患者の3年間の追跡において、短期間のDAPTが長期療法と同等に有益性が持続することが示された。3年間の追跡期間中3,307人の患者が対象とされ、6か月の治療と18か月の治療とで安全性および有効性のエンドポイントは2群間で統計学的に有意差はなかったが、長期DAPT群においてアウトカムが良好な率が高かった（p=0.17）。このNIPPONスタディの長期追跡の結果は、2017 ESC Congress で発表された。
Three-year follow-up of patients who received dual antiplatelet therapy (DAPT) after placement of a drug-eluting stent (DES) shows that a short course of the therapy continues to be as beneficial as a longer course.
The long-term follow-up of patients in the NIPPON (NoborI dual antiplatelet therapy as aPPrOpriate DuratioN) study was presented at ESC Congress 2017.
"These findings support and strengthen the evidence for short-term DAPT after DES deployment, and may help confirm that clinical benefits of extended DAPT are reduced in patients with newer generation DES," said Prof Masato Nakamura MD, PhD, from the Division of Cardiovascular Medicine at Toho University Ohashi Medical Center, in Tokyo Japan.
"The findings are important because shorter duration of therapy is less expensive and could theoretically reduce the risk of side-effects," noted Prof Nakamura.
Initial results of NIPPON, presented last year at ESC Congress, showed no significant differences in rates of a composite efficacy and safety endpoint in patients randomized to either 6 or 18-month durations of DAPT.
"For the long-term follow-up we wanted to evaluate efficacy and safety individually," said Prof Nakamura explaining that efficacy endpoints included cardiac death, myocardial infarction, stroke, and definite or probable stent thrombosis, while the safety endpoint was major bleeding.
Among the 3,307 patients included in the 3-year follow-up, there were no statistically significant differences between those treated for 6 versus 18 months in either safety or efficacy endpoints, although there was a numerically higher rate of better outcomes in the long-term DAPT group (HR: 1.53, 95%CI: 0.81-2.87, p=0.17), he reported.
To explore this trend, the researchers did subgroup analyses to see if any particular groups fared better with longer therapy. They discovered that in patients aged 70-77 years with either diabetes or more severe coronary artery disease (based on a SYNTAX score above 23.3) the rate of efficacy events was zero percent in those on long-term therapy, but 18.8 percent in those on short-term therapy. These patients "represent a high-risk population for ischemic events who might be good candidates for prolonged DAPT," they concluded.
"In real-world practice, it is not easy to find the balance between risks and benefits of DAPT duration, and consensus criteria for individualization therapy have not been established," said Prof Nakamura. "The present findings may provide some assistance, although it is essential to obtain confirmation by further investigation."
The study was sponsored by the Association for Establishment of Evidence in Interventions.
Dr. Nakamura disclosed research expert witness payment from Terumo Corporation, grant support from Daiichi Sankyo and Sanofi, and honoraria from Terumo Corporation, Daiichi Sankyo, and Sanofi.
