The overall purpose of this study is to evaluate how effective Thromboelastography (TEG) is on identifying ischemic and hemorrhagic stroke patients at increased risk for bleeding after receiving tissue plasminogen activator (tPA), as well as on differentiating between patients in whom optimal thrombolysis has been achieved, and those whom it has not.
Thromboelastography (TEG), a computerized analysis that has been used since the 1940s, is the only stand alone test that can provide integrated information on the balance between the two separate but simultaneously occuring components of coagulation, thrombosis and lysis. It measures the coagulation process from initial clotting cascade to clot strength.
TEG may be used to assess the coagulation status of patients with acute stroke, whether ischemic or hemorrhagic. TEG might also be a useful way to predict and assess the degree of fibrinolysis that is achieved by tissue plasminogen activator (tPA). Currently tPA is given as a standard dose determined by the patient's body weight, thus given the variability in patient outcome after tPA, this dose could sometimes be too small or too large, leading to thrombolysis or bleeding, respectively. One of the purposes of this observational study is to evaluate how effective TEG is on predicting and assessing the degree of thrombolysis following tPA therapy, by producing a range of TEG values correlated with optimal thrombolysis.
The results of the recent FAST trial demonstrated the need to identify patients with spontaneous intracerebral hemorrhage (ICH) who are at increased risk for hematoma enlargement. Such identified patients, could benefit from a therapeutic advantage of activated factor VII or other hemostatic agents may be more clearly studied. Therefore, another purpose of this study is to evaluate how effective TEG is on predicting further bleeding for patients with spontaneous ICH.
The study will consist of 208 ischemic patients and 80 hemorrhagic patients, whom which are approached from all stroke patients admitted to Memorial Hermann Hospital Emergency Department receiving a confirmatory CT or MRI scan. Patients who agree to participate will have blood drawn the day of hospital arrival, will then be followed for 36 +/- 12 hours after the stroke, and 90 +/- 30 days after the stroke, all during which two more blood samples will be obtained.
Normal controls will be age and sex matched to the investigators' research population. A one-time blood draw will be obtained and information collected will be age, sex and TEG values.
- Thromboelastography Biological
Intervention Desc: TEG (Thrombelastography) measurements include: Split Point (SP) is the time elapsed for the clot to initially form fibrin when the blood is first placed in the TEG machine. Reaction Time (R) is the time elapsed from its initial fibrin formation until the clot reaches 2mm. K is the time measured from R until the level of clot firmness reaches 20mm, measuring the speed of clot strengthening. These are measured in minutes. Delta measures if the formation of the clot has been suppressed; measured as the difference between R and SP. Angle reflects the speed at which clots form by forming the slope of the TEG tracing at R from the horizontal line. Maximum Amplitude (MA) in mm is the measure of maximum strength of the clot, true platelet function. G is the measure of the clot firmness; measured by a formula (G=(5000*MA)/(100-MA) in dynes/cm2). LY30 is a measure of clot lysis at 30 minutes after MA is reached. ARM 1: Kind: Experimental Label: Ischemic Stroke Description: Ischemic stroke patients who have had blood analyzed using thromboelastography (TEG) ARM 2: Kind: Experimental Label: Healthy Controls Description: Healthy controls who have had their blood analyzed using thromboelastography (TEG) ARM 3: Kind: Experimental Label: Hemorrhagic Stroke Description: Intracerebral hemorrhage patients who have had their blood analyzed by thromboelastography (TEG)
- Observation: Case Control
- Perspective: Prospective
- Sampling: Non-Probability Sample
All stroke patients admitted to Memorial Hermann Hospital Emergency Department receiving a confirmatory CT or MRI scan.
|Type||Measure||Time Frame||Safety Issue|
|Primary||Baseline TEG in patients with spontaneous ICH vs age matched controls||TEG obtained within 6 hours of last seen normal in patients with spontaneous ICH||No|
|Secondary||Rapid clinical improvement after tPA (8 or greater point improvement on NIHSS score or total NIHSS 0 or 1)||Change in NIHSS score from baseline (prior to IV tPA within 4.5 hours of last seen normal) to NIHSS 36 +/- 12 hours after last seen normal.||No|