Delayed ischemic stroke after stent-assisted coil placement in cerebral aneurysm: characteristics and optimal duration of preventative dual antiplatelet therapy

Radiology. 2014 Oct;273(1):194-201. doi: 10.1148/radiol.14140070. Epub 2014 Jun 11.


Purpose: To evaluate characteristics of delayed ischemic stroke after stent-assisted coil placement in cerebral aneurysms and to determine the optimal duration of dual antiplatelet therapy for its prevention.

Materials and methods: This retrospective study was approved by the institutional review board, and the requirement to obtain written informed consent was waived. Of 1579 patients with 1661 aneurysms, 395 patients (25.0%) with 403 aneurysms (24.3%) treated with stent-assisted coil placement were included and assigned to groups stratified as early (126 patients [31.9%]; 3 months of coil placement), midterm (160 patients [40.5%]; 6 months), or late (109 patients [27.6%]; ≥ 9 months), according to the time points of switching dual antiplatelet therapy to monotherapy from coil placement. Cumulative rates of delayed ischemic stroke in each group were calculated by using Kaplan-Meier estimates that were compared with log-rank tests. Risk factors of delayed ischemic stroke were identified by using Cox proportional hazard analysis.

Results: Delayed ischemic stroke occurred in 3.5% of all cases (embolism, 3.0%; thrombotic occlusion, 0.5%) within 2 months following the switch. Late switch yielded no delayed ischemic stroke, unlike early (seven of 126 patients [5.6%]; P = .013) or midterm (seven of 160 patients [4.4%]; P = .028) switch. Incomplete occlusion (hazard ratio, 6.68 [95% confidence interval: 1.490, 29.900]) was identified as a risk factor.

Conclusion: Delayed ischemic stroke after stent-assisted coil placement is caused by embolism from or thrombotic occlusion of stent-containing vessels after switching from dual antiplatelet therapy to monotherapy. The stent-containing vessel with incomplete aneurysm occlusion presents as a long-term thromboembolic source. Therefore, dual antiplatelet therapy for more than 9 months and late switch to monotherapy are recommended for its prevention.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aspirin / administration & dosage*
  • Clopidogrel
  • Embolization, Therapeutic / adverse effects*
  • Female
  • Humans
  • Intracranial Aneurysm / therapy*
  • Male
  • Middle Aged
  • Platelet Aggregation Inhibitors / administration & dosage*
  • Registries
  • Retrospective Studies
  • Stents / adverse effects*
  • Stroke / etiology*
  • Stroke / prevention & control
  • Ticlopidine / administration & dosage
  • Ticlopidine / analogs & derivatives*
  • Treatment Outcome


  • Platelet Aggregation Inhibitors
  • Clopidogrel
  • Ticlopidine
  • Aspirin