Abstract

Background: Thromboembolic complications are the most frequent risk in endovascular treatment of intracranial pathology. To prevent this, unfractionated heparin (UFH) is used. The effect of heparin is difficult to predict. Therefore, bedside monitoring is necessary by measuring activated clotting time (ACT).

Objectives: The aim of this study is to explore which factors are contributing to the variability in ACT values and to assess if a more individualized approach is potentially beneficial.

Design: A retrospective, single-center study at Ghent University Hospital.

Methods: All patients who underwent an elective interventional neuroradiologic procedure with the administration of heparin between January 2018 and December 2023 were enrolled. A baseline measurement of ACT was done before heparin administration. A second measurement was taken five minutes after administration. A retrospective analysis was conducted to identify potential predictors of ACT levels and their association with heparin dosing.

Results: 285 patients (193 males, age 55 ± 12 years) were included. Patients with higher weight (p < 0.001), higher body mass index (BMI) (p < 0.001) and patients already taking acetylsalicylic acid (p < 0.001) and thienopyridines (p < 0.001) received higher doses of heparin. In univariate analysis gender, height, weight, BMI, use of acetylsalicylic acid or thienopyridines, creatinine, AST, aPTT, baseline ACT and heparin dose (p: <0.001, 0.004, <0.001, 0.004, <0.001, <0.001, 0.019, 0.038, 0.003, <0.001, <0.001 resp.) were associated with ACT values. In multivariate analysis baseline ACT, heparin dose, weight and use of thienopyridine (p: <0.001, <0.001, <0.001, <0.001 resp.) were retained as significant independent predictors.

Conclusion: Significant interindividual variability exists in ACT response after a loading dose of heparin. A more accurate estimation of the appropriate dose may be possible by considering other influencing factors, such as weight, baseline ACT and preoperative use of antiplatelet therapy. Nevertheless, some level of unpredictability is likely to persist.