title: The Importance of the Mean Platelet Aggregation Degree in Long-term Dual Antiplatelet Therapy Following Drug-Eluting Stent Implantation.
abstract: BACKGROUND
  The dual antiplatelet therapy (DAPT) and the response of clopidogrel were two pivotal issues in drug-eluting stent (DES) era.
  
  
  OBJECTIVE
  To analyze the combined impacts of DAPT and the response to clopidogrel to evaluate their long-term effect on patients undergoing DES implantation.
  
  
  METHODS
  Platelet aggregation was serially measured by light transmission aggregometry in all eligible patients during the course of treatment with DAPT, and the mean platelet aggregation degree of each participant was calculated. Based on the duration of DAPT and the mean platelet aggregation degree, all the enrolled patients were then divided into four groups. The primary endpoint was a composite of major adverse cardiovascular events.
  
  
  RESULTS
  We analyzed 1245 suitable patients in this study. They were divided into four groups: Group A (12-month DAPT & low platelet aggregation degree) with 233 subjects, Group B (12-month DAPT & high platelet aggregation degree) with 260 subjects, Group C (>12-month DAPT & low platelet aggregation degree) with 374 subjects, and Group D (>12-month DAPT & high platelet aggregation degree) with 378 subjects. Group C was associated with a decreased incidence of primary endpoints [HR 0.512, 95%CI (0.27-0.97); P = 0.040]. The Cox proportional hazard model was further analyzed with Groups A and B combined as the reference category [HR for Group C vs. Group A, 0.84, 95%CI (0.33-2.15); P = 0.719; HR for Group C vs. Group B, 0.45, 95%CI (0.21-0.98); P = 0.043]. Their respective multivariate Cox proportional hazard regressions confirmed these trends.
  
  
  CONCLUSIONS
  The mean platelet aggregation degree is of importance in long-term use of DAPT; extension of DAPT beyond 1 year should be implemented cautiously in patients implanted with DESs.
authors.affiliation: Department of Cardiology, Beijing Anzhen Hospital, Capital Medical University and Beijing Institute of Heart Lung and Blood Vessel Disease, Beijing, China.
authors.forename: Quan
authors.initials: Q
authors.lastname: Li
authors.affiliation: Department of Cardiology, Beijing Anzhen Hospital, Capital Medical University and Beijing Institute of Heart Lung and Blood Vessel Disease, Beijing, China.
authors.forename: Xuejun
authors.initials: X
authors.lastname: Ren
authors.affiliation: Department of Cardiology, Beijing Anzhen Hospital, Capital Medical University and Beijing Institute of Heart Lung and Blood Vessel Disease, Beijing, China.
authors.forename: Xianpeng
authors.initials: X
authors.lastname: Yu
authors.affiliation: Department of Cardiology, Beijing Anzhen Hospital, Capital Medical University and Beijing Institute of Heart Lung and Blood Vessel Disease, Beijing, China.
authors.forename: Jiqiang
authors.initials: J
authors.lastname: He
authors.affiliation: Department of Cardiology, Beijing Anzhen Hospital, Capital Medical University and Beijing Institute of Heart Lung and Blood Vessel Disease, Beijing, China.
authors.forename: Yuechun
authors.initials: Y
authors.lastname: Gao
authors.affiliation: Department of Cardiology, Beijing Anzhen Hospital, Capital Medical University and Beijing Institute of Heart Lung and Blood Vessel Disease, Beijing, China.
authors.forename: Xiaoling
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Department of Cardiology, Beijing Anzhen Hospital, Capital Medical University and Beijing Institute of Heart Lung and Blood Vessel Disease, Beijing, China.
authors.forename: Changyan
authors.initials: C
authors.lastname: Wu
authors.affiliation: Department of Cardiology, Beijing Anzhen Hospital, Capital Medical University and Beijing Institute of Heart Lung and Blood Vessel Disease, Beijing, China.
authors.forename: Yawei
authors.initials: Y
authors.lastname: Luo
authors.affiliation: Department of Cardiology, Beijing Anzhen Hospital, Capital Medical University and Beijing Institute of Heart Lung and Blood Vessel Disease, Beijing, China.
authors.forename: Yuchen
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Cardiology, Beijing Anzhen Hospital, Capital Medical University and Beijing Institute of Heart Lung and Blood Vessel Disease, Beijing, China.
authors.forename: Fang
authors.initials: F
authors.lastname: Chen
mesh_terms: D000368:Aged; D001241:Aspirin / Q000008:administration & dosage* / Q000009:adverse effects; D016009:Chi-Square Distribution; D000077144:Clopidogrel; D004334:Drug Administration Schedule; D004359:Drug Therapy, Combination; D054855:Drug-Eluting Stents; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D062645:Percutaneous Coronary Intervention / Q000009:adverse effects / Q000295:instrumentation*; D010974:Platelet Aggregation / Q000187:drug effects*; D010975:Platelet Aggregation Inhibitors / Q000008:administration & dosage* / Q000009:adverse effects; D010979:Platelet Function Tests; D016016:Proportional Hazards Models; D012042:Registries; D012189:Retrospective Studies; D012307:Risk Factors; D013988:Ticlopidine / Q000008:administration & dosage / Q000009:adverse effects / Q000031:analogs & derivatives*; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D010975:Platelet Aggregation Inhibitors; D000077144:Clopidogrel; D013988:Ticlopidine; D001241:Aspirin
keywords: Clopidogrel; Coronary artery disease; Dual antiplatelet therapy; Prognosis