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A Methodological Approach to Non-invasive Assessments of Vascular Function and Morphology
Published on: February 7, 2015
Coagulation activation and ultrasound characteristics in patients with carotid artery disease
Tilo Kölbel1, Isabel Goncalves, Nuno Dias
1Vascular Center, Malmö University Hospital, Malmö, Sweden. tilokoelbel@gmail.com
Insights
Activated Protein C-Protein C Inhibitor (APC-PCI) complex levels are elevated in patients with carotid artery stenosis, especially those with echogenic plaques. This finding highlights APC-PCI as a marker for thrombin generation in carotid artery disease.
Area of Science:
- Vascular Biology
- Thrombosis and Hemostasis
Background:
- Elevated thrombin activation markers correlate with plaque echogenicity and stenosis severity in carotid artery disease.
- The Activated Protein C-Protein C Inhibitor (APC-PCI) complex indicates Protein C system activation and measures thrombin generation.
Purpose of the Study:
- To investigate APC-PCI complex levels in patients undergoing carotid endarterectomy.
- To correlate APC-PCI levels with clinical characteristics and ultrasound-determined plaque morphology.
Main Methods:
- Blood samples from 125 carotid artery stenosis patients (Sept 2005-May 2007) were analyzed for APC-PCI complex using a sandwich immunofluorometric assay.
- Patient data included clinical characteristics, routine labs, and ultrasound findings, compared to age- and sex-matched healthy controls.
- Univariate and multivariate analyses were employed to assess relationships between APC-PCI levels and patient/plaque characteristics.
Main Results:
- APC-PCI complex concentrations were significantly higher in carotid artery stenosis patients (median 0.21 µg/L) versus healthy controls (median 0.19 µg/L; P=.009).
- Patients with minor stroke showed higher APC-PCI levels (median 0.27 µg/L) compared to those with amaurosis fugax or transient ischemic attack (P=.016).
- Echogenic plaques were associated with significantly higher APC-PCI concentrations (0.24 µg/L) than echolucent plaques (0.20 µg/L; P=.043).
Conclusions:
- Carotid artery disease patients exhibit elevated APC-PCI concentrations compared to healthy individuals.
- Higher APC-PCI levels are particularly noted in patients with echogenic plaques, suggesting a link between plaque composition and thrombin generation.
- APC-PCI may serve as a biomarker for thrombotic risk in carotid artery disease.
Introduction:
Elevated levels of markers for thrombin activation are associated with plaque echogenicity and degree of stenosis in patients with carotid artery stenosis. The Activated Protein C-Protein C Inhibitor (APC-PCI) complex reflects activation of the Protein C system and is a measure of thrombin generation. The aim of the present study was to examine APC-PCI complex in patients undergoing thrombendartherectomy for carotid artery stenosis, and to relate the findings to clinical characteristics and plaque morphology as determined by ultrasound.
Materials And Methods:
Blood was obtained from 125 patients (39 female, median age 71 years) with carotid artery stenosis admitted from September 2005 to May 2007. The APC-PCI complex was measured using a sandwich immunofluorometric method and compared to an age- and sex-matched healthy control-group. Clinical and demographic characteristics, routine laboratory markers and ultrasound characteristics were analysed using univariate and multivariate analysis.
Results:
APC-PCI complex concentration was significantly increased in patients with carotid artery stenosis (median 0.21 microg/L; 10th to 90th percentile 0.15-0.36) compared to a healthy control-group (0.19 microg/L; 0.11-0.31; P=.009). There was no significant difference in APC-PCI-values between asymptomatic (n=48) and symptomatic (n=77) patients with carotid artery stenosis (0.22 vs. 0.20 microg/L; p=0.626). Patients with minor stroke (n=31) had a higher median APC-PCI-concentration (0.27 microg/L; 0.15-0.63) than patients with amaurosis fugax (0.19 microg/L; 0.15-0.36) or transient ischemic attack (0.21 microg/L; 0.12-0.36) (p=0.016). No association was found between APC-PCI-values and the degrees of carotid artery stenosis or the time from the latest neurological symptoms to blood sampling. Patients with echolucent plaques had significantly lower APC-PCI concentrations (0.20 microg/L; 0.14-0.35 vs. 0.24 microg/L; 0.15-0.60; p=0.043), according to the Gray-Weale classification.
Conclusions:
Patients with carotid artery disease exhibit increased concentrations of APC-PCI compared to a healthy control-group, particularly those patients with echogenic plaques, who have significantly higher APC-PCI levels than patients with echolucent plaques.
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