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Original research
Antiplatelet therapy for prevention of thromboembolic complications in coiling-only procedures for unruptured brain aneurysms
  1. Mohammed A Almekhlafi1,2,3,
  2. Abdulaziz S Al Sultan1,3,
  3. Andrea M Kuczynski1,
  4. Waleed Brinjikji4,
  5. Bijoy K Menon1,2,3,
  6. Michael D Hill1,2,3,
  7. Mayank Goyal1,2
  1. 1Department of Clinical Neurosciences, Calgary Stroke Program, and Hotchkiss Brain Institute, University of Calgary Cumming School of Medicine, Calgary, Alberta, Canada
  2. 2Department of Radiology, University of Calgary, Calgary, Alberta, Canada
  3. 3Department of Community Health Sciences, and O’Brien Institute for Public Health​ , University of Calgary, Calgary, Alberta, Canada
  4. 4Department of Neurosurgery, and Radiology, Mayo Clinic, Rochester, MN, USA
  1. Correspondence to Dr Mohammed A Almekhlafi; mohammed.almekhlafi1{at}


Background and purpose Thromboembolic events are recognized complications of aneurysm coiling.

Objective To identify any protective effects of antiplatelet therapy use before coiling of unruptured aneurysms.

Methods We conducted a meta-analysis of clinical studies published up to February 2019. We included studies reporting symptomatic thromboembolic events (defined as clinical stroke or transient ischemic attacks) in patients who received antiplatelet therapy before coiling of unruptured aneurysms using unassisted coiling, balloon assistance, or multiple microcatheters. We excluded ruptured aneurysms and those treated with stent coiling or flow diverters.

Results We identified 14 studies (2486 patients). All were single-center studies and four were prospective. In three studies with a control (no treatment) arm, the pooled risk ratio for symptomatic thromboembolic events with versus without antiplatelet therapy was 0.33 (95% CI 0.17 to 0.92, p= 0.035). The cumulative risk of symptomatic thromboembolic events with single antiplatelet agents was 5.0% ‘56/1122’ (95% CI 1.6% to 8.4%, I183.63%), and with dual or multiple agents 2.7% ‘33/1237’ (95% CI 1.0% to 3.0%, I139.9%). The incidence of diffusion lesions was reported in seven studies. It was 50.5% ‘96/190’ (95% CI 7.3% to 93.9%, I194.4%) with single agents compared with 43.9% ‘196/446’ (95% CI 25.9% to 61.9%, I173.4%) with dual or multiple agents.

Conclusion Periprocedural antiplatelet therapy was associated with a low symptomatic thromboembolic event after coiling-only for unruptured aneurysms. However, available evidence is of limited quality with significant heterogeneity, requiring evidence from randomized controlled trials.

  • aneurysm
  • embolic
  • coil

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  • Contributors MAA, MG had the idea for the article. AMK, ASA performed the literature search, screened thearticles for inclusion, and extracted the data. MAA performed the analyses andwrote the article. BKM, MDH, MG, WB critically reviewed the manuscript and madeimportant revisions. MAA is the guarantor.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests MAA and MG are theprincipal investigators of a randomized controlled trial comparing acetyl salicylicacid with placebo in preventing thromboembolic complications in patients undergoing coiling-only procedures for unruptured brain aneurysms.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data sharing statement All data related to this work are presented in the manuscript or the supplementary files.