title: Standard vs Modified Antiplatelet Preparation for Preventing Thromboembolic Events in Patients With High On-Treatment Platelet Reactivity Undergoing Coil Embolization for an Unruptured Intracranial Aneurysm: A Randomized Clinical Trial.
abstract: OBJECTIVE
  Thromboembolism is the most common complication in coiling for an unruptured aneurysm and is frequent in patients with high on-treatment platelet reactivity (HTPR) who are prescribed a standard antiplatelet preparation for its prevention.
  
  
  OBJECTIVE
  To evaluate the effect of a modified antiplatelet preparation compared with a standard preparation in patients with HTPR undergoing coiling.
  
  
  METHODS
  A prospective randomized open-label active-control trial with blinded outcome assessment at the Seoul National University Bundang Hospital from May 27, 2013, to April 7, 2014. Patients with HTPR were randomly assigned (1 to 1) to the standard or modified preparation group. Patients without HTPR were assigned to the non-HTPR group. A total of 228 patients undergoing coiling for unruptured aneurysms were enrolled and allocated to the study, 126 in the HTPR group (63 to the standard preparation group and 63 to the modified preparation group) and 102 to the non-HTPR group. Intent-to-treat analysis was performed.
  
  
  METHODS
  The modified preparation (HTPR to aspirin, 300 mg of aspirin and 75 mg of clopidogrel bisulfate; and HTPR to clopidogrel, 200 mg of cilostazol added to the standard regimen) was performed before coiling in the modified preparation group. Standard preparation (100 mg of aspirin and 75 mg of clopidogrel) was maintained in the standard preparation and non-HTPR groups.
  
  
  METHODS
  The primary outcome was a thromboembolic event defined as thromboembolism during coiling and a transient ischemic attack or ischemic stroke within 7 days after coiling. The principal secondary outcome was a bleeding complication according to Thrombolysis in Myocardial Infarction bleeding criteria within 30 days after coil embolization.
  
  
  RESULTS
  The thromboembolic event rate was low in the modified preparation group (1 of 63 [1.6%]) compared with the standard preparation group (7 of 63 [11.1%]; adjusted risk difference, -11.7% [95% CI, -21.3% to -2.0%]; P = .02), which had a higher thromboembolic risk than the non-HTPR group (1 of 102 [1.0%]; adjusted risk difference, 8.6% [95% CI, 1.0% to 16.3%]; P = .03). All bleeding complications were of minimal grade according to Thrombolysis in Myocardial Infarction bleeding criteria. The bleeding rate was not different between the modified (6 of 63 [9.5%]) and standard (4 of 63 [6.3%]) preparation groups (adjusted risk difference, 5.6% [95% CI, -4.2% to 15.4%]; P = .26).
  
  
  CONCLUSIONS
  Modified antiplatelet preparation for patients with HTPR compared with standard antiplatelet preparation reduced the thromboembolic event rate in coiling for an unruptured aneurysm without increasing bleeding.
  
  
  BACKGROUND
  Clinical Research Information Service Identifier: KCT0000804.
authors.affiliation: Regional Cardiocerebrovascular Center, Department of Neurosurgery, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: Gyojun
authors.initials: G
authors.lastname: Hwang
authors.affiliation: Department of Neurosurgery, Pohang SM Christianity Hospital, Pohang, Korea.
authors.forename: Won
authors.initials: W
authors.lastname: Huh
authors.affiliation: Department of Neurosurgery, Pohang SM Christianity Hospital, Pohang, Korea.
authors.forename: Jin Soo
authors.initials: JS
authors.lastname: Lee
authors.affiliation: Section of Neurosurgery, Department of Neuroscience, Makati Medical Center, Makati, Philippines.
authors.forename: Jay Bautista
authors.initials: JB
authors.lastname: Villavicencio
authors.affiliation: Department of Neurosurgery, Vicente Sotto Memorial Medical Center, Cebu, Philippines.
authors.forename: Reynaldo Benedict V
authors.initials: RB
authors.lastname: Villamor
authors.affiliation: Regional Cardiocerebrovascular Center, Department of Neurosurgery, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: Seong Yeol
authors.initials: SY
authors.lastname: Ahn
authors.affiliation: Regional Cardiocerebrovascular Center, Department of Neurosurgery, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: Junhak
authors.initials: J
authors.lastname: Kim
authors.affiliation: Regional Cardiocerebrovascular Center, Department of Neurology, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: Jun Young
authors.initials: JY
authors.lastname: Chang
authors.affiliation: Regional Cardiocerebrovascular Center, Department of Neurosurgery, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: Soo Joo
authors.initials: SJ
authors.lastname: Park
authors.affiliation: Regional Cardiocerebrovascular Center, Department of Neurosurgery, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: Nam-Mi
authors.initials: NM
authors.lastname: Park
authors.affiliation: Regional Cardiocerebrovascular Center, Department of Neurosurgery, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: Eun-A
authors.initials: EA
authors.lastname: Jeong
authors.affiliation: Regional Cardiocerebrovascular Center, Department of Neurosurgery, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: O-Ki
authors.initials: OK
authors.lastname: Kwon
mesh_terms: D000368:Aged; D001792:Blood Platelets / Q000187:drug effects* / Q000378:metabolism; D004621:Embolization, Therapeutic / Q000379:methods / Q000592:standards*; D005260:Female; D006801:Humans; D002532:Intracranial Aneurysm / Q000175:diagnosis / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D015539:Platelet Activation / Q000187:drug effects* / Q000502:physiology; D010975:Platelet Aggregation Inhibitors / Q000008:administration & dosage*; D011446:Prospective Studies; D013923:Thromboembolism / Q000175:diagnosis / Q000517:prevention & control*; D016896:Treatment Outcome
chemical_list: D010975:Platelet Aggregation Inhibitors