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Coagulation factors and the increased risk of stroke in nonvalvular atrial fibrillation
C Gustafsson1, M Blombäck, M Britton
1Department of Medicine, Danderyd Hospital, Sweden.
Insights
Hemostatic abnormalities, including elevated clotting factors and platelet markers, are linked to stroke risk in nonvalvular atrial fibrillation patients. No differences were found between patients with or without prior strokes.
Area of Science:
- Cardiovascular Medicine
- Hematology
- Neurology
Background:
- Nonvalvular atrial fibrillation (NVAF) is a significant risk factor for ischemic stroke.
- The precise mechanisms linking NVAF to stroke, beyond traditional risk factors, require further elucidation.
- Hemostatic system alterations are implicated in thrombotic events.
Purpose of the Study:
- To investigate the role of hemostatic abnormalities in the increased stroke risk associated with NVAF.
- To compare hemostatic function in NVAF patients with and without a history of ischemic stroke.
- To differentiate hemostatic profiles between NVAF patients and stroke patients in sinus rhythm.
Main Methods:
- Four age-matched groups were studied: NVAF with prior stroke, NVAF without prior stroke, stroke patients in sinus rhythm, and healthy controls.
- Comprehensive analysis of hemostatic function, including specific markers like von Willebrand factor, factor VIII:C, fibrinogen, D-dimer, beta-thromboglobulin, and platelet factor 4.
- Assessment of fibrinogen/antithrombin ratio, spontaneous amidolytic activity, prekallikrein, and fibrinopeptide A levels.
Main Results:
- Both NVAF groups exhibited significantly higher levels of von Willebrand factor, factor VIII:C, fibrinogen, D-dimer, beta-thromboglobulin, and platelet factor 4 compared to healthy controls.
- Elevated fibrinogen/antithrombin ratio and spontaneous amidolytic activity were observed in NVAF groups.
- Prekallikrein levels were significantly lower in NVAF patients, while stroke patients in sinus rhythm showed largely normal hemostatic function.
Conclusions:
- Alterations in hemostatic function, characterized by prothrombotic and procoagulant changes, are present in patients with NVAF.
- These hemostatic abnormalities may contribute to the heightened risk of stroke in NVAF.
- No significant differences in hemostatic function were detected between NVAF patients with and without a history of ischemic stroke, suggesting a general prothrombotic state in NVAF.
Abstract:
We studied whether hemostatic abnormalities contribute to the increased risk of stroke in patients with nonvalvular atrial fibrillation. Hemostatic function was studied in four age-matched groups: 20 patients with nonvalvular atrial fibrillation and a previous ischemic stroke, 20 patients with nonvalvular atrial fibrillation without a previous stroke, 20 stroke patients with sinus rhythm, and 40 healthy controls. Both groups with nonvalvular atrial fibrillation had significantly higher concentrations of von Willebrand factor, factor VIII:C, fibrinogen, D-dimer (a fibrinolytic product), beta-thromboglobulin, and platelet factor 4; a significantly higher fibrinogen/antithrombin ratio; and significantly higher spontaneous amidolytic activity than the healthy controls. Prekallikrein levels were significantly lower in both groups with nonvalvular atrial fibrillation. Stroke patients with sinus rhythm had normal hemostatic function, normal concentrations of platelet-related factors, and a slightly increased concentration of fibrinopeptide A compared with the healthy controls. Both groups with nonvalvular atrial fibrillation differed from the stroke patients with sinus rhythm as they did from the healthy controls. No difference in hemostatic function was seen between the nonvalvular atrial fibrillation patients with and without a previous ischemic stroke. Thus, alterations in hemostatic function may contribute to the increased risk of stroke in patients with nonvalvular atrial fibrillation.