Factor XI Levels in Acute Ischemic Stroke
| Status: | Archived |
|---|---|
| Conditions: | Peripheral Vascular Disease, Neurology |
| Therapuetic Areas: | Cardiology / Vascular Diseases, Neurology |
| Healthy: | No |
| Age Range: | Any |
| Updated: | 7/1/2011 |
| Start Date: | May 2009 |
| End Date: | May 2011 |
The purpose of this study is to evaluate the utility of measuring coagulation factor
activities in the setting of acute ischemic stroke, as potential markers of inherited
thrombotic risk. The investigators will determine if relationships exist between
coagulation factors, including factor VIII, factor IX, and factor XI and clinical diagnosis,
classification, and outcome. The investigators will determine if any significant elevations
of these factor activities are independent thrombotic risk factors.
Null Hypothesis: There is no statistical difference between coagulation factors, including
factors VIII, IX, or XI activity levels in patients having acute ischemic stroke as
compared to acute stroke mimics.
Increased factor XI levels have been associated with venous thromboembolic disease and acute
myocardial infarction. However, checking factor XI levels is not currently indicated to
assess individual thromboembolic risk. Factor XI is an important protease that links the
extrinsic arm of the coagulation cascade with the intrinsic arm through dual activation by
both factor XII and thrombin. Since thrombin is a downstream product of factor XI, a
feedback loop is created that amplifies thrombin production and ultimately results formation
of a stable fibrin clot. Sufficient thrombin generation via this pathway also contributes
to activation of the Thrombin-Activatable Fibrinolysis Inhibitor (TAFI). Activated TAFI
downregulates fibrinolysis and has been implicated as part of the association between
elevated factor XI levels and venous thromboembolic disease. One study found that functional
TAFI levels of > 120% increased the risk of ischemic stroke approximately 6-fold, however,
the association between Factor XI and ischemic stroke has yet to be firmly established. We
recently performed a preliminary retrospective analysis of 78 patients with stroke or
transient ischemic attack (TIA) and found that patients with factor XI activity levels above
the 95th percentile of an age and sex matched reference population had a relative risk of
5.3 for stroke or TIA. Factor XI measurements may be able to help identify thromboembolic
disease, aiding in the determination of stroke etiology.
We found this trial at
1
site
Click here to add this to my saved trials
