Evaluation of aspirin resistance and the presence of unstable carotid plaque in patients undergoing carotid endarterectomy

Kardiol Pol. 2015;73(4):255-60. doi: 10.5603/KP.a2014.0237. Epub 2015 Jan 7.


Background: Antiplatelet therapy using low dose acetylsalicylic acid (ASA) is routinely recommended in patients undergoing surgical or endovascular treatment of carotid artery disease. Despite this treatment, a significant proportion of postoperative complications may result from inadequate response to antiplatelet therapy which may contribute to the development of unstable plaques.

Aim: Assessment of correlation between ASA resistance and the presence of unstable carotid plaque in patients after carotid endarterectomy.

Methods: We studied 66 patients (27 women and 39 men) aged 41-80 years who were operated for carotid stenosis. All patients received ASA (75 mg once daily) in the pre- and perioperative period. Measurements of platelet reactivity were performed using the PFA-100 platelet analyser at the second day after the operation. Plaque stability was evaluated using a computer analysis system based on the greyscale median method. The patients were divided into two groups, showing good response to ASA or ASA-resistant.

Results: ASA resistance was identified in 19 (32%) patients. In multivariate logistic regression analysis, unstable plaque showed a borderline correlation with ASA resistance (p = 0.051).

Conclusions: 1. Prevalence of increased platelet reactivity despite ASA treatment (ASA resistance) in patients treated surgically for carotid artery disease is high, suggesting a possibility of ineffective antiplatelet therapy. 2. A modest correlation between abnormal platelet response during treatment with ASA and the presence of unstable plaques suggests that these two phenomena may coexist but we were unable to show a clear association between them.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Aspirin / therapeutic use*
  • Blood Platelets / drug effects
  • Carotid Stenosis / surgery*
  • Endarterectomy, Carotid / adverse effects*
  • Female
  • Humans
  • Male
  • Middle Aged
  • Perioperative Period
  • Plaque, Atherosclerotic / drug therapy
  • Plaque, Atherosclerotic / etiology*
  • Plaque, Atherosclerotic / prevention & control
  • Platelet Aggregation Inhibitors / therapeutic use
  • Treatment Outcome


  • Platelet Aggregation Inhibitors
  • Aspirin