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Query: UMLS:C0038454 (stroke)
 147,016 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Ischemic optic neuropathy and retinal arterial occlusion are 2 forms of arterial occlusive disease affecting the eye. Reports in the literature suggest platelet hyperactivity in acute arterial occlusive diseases affecting other organ systems. Therefore, 14 patients with ischemic optic neuropathy and 17 patients with central or branch retinal artery occlusion were studied to determine whether platelets have a role in the pathogenesis of these vascular occlusive disorders. The results of the following investigations were no different in these patients compared with those in 18 control patients with non-vascular eye diseases: prothrombin times, partial thromboplastin times, plasma fibrinogen, factor V, factor VIII, platelet counts and threshold concentrations of ADP, epinephrine and collagen resulting in secondary platelet aggregation and serotonin release. In contrast, platelet coagulant activities concerned with the early stages of intrinsic coagulation were significantly increased in patients with retinal artery occlusion without hypertension or type IV hyperlipoproteinemia, but generally normal in patients with ischemic optic neuropathy and in patients with retinal artery occlusion associated with hypertension, type IV hyperlipoproteinemia, diabetes mellitus and generalized atherosclerosis. These results are consistent with a platelet contribution to retinal arterial occlusive disease in patients without other known contributing factors such as hypertension, serum lipid abnormalities, diabetes mellitus and generalized atherosclerosis and may have implications regarding prophylaxis.
Stroke
PMID:Platelet coagulant activities in arterial occlusive disease of the eye. 50 1

Studies of 11 patients with haemorrhagic stroke revealed no significant change in kaolin cephalin clotting time, prothrombin time, thrombin time, PF 3 availability, platelet count and factor V and VIII during the first week. Plasma fibrinogen was significantly increased while factors VII + X were decreased (borderline significance). Prolongation of plasma recalcification time and decrease in heparin tolerance reached borderline significance. There was moderate, but significant, increase in serum antithrombin activity and plasma (euglobulin fraction) fibrinolytic activity.
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PMID:Blood coagulation and fibrinolysis in haemorrhagic stroke. 58 May 8

Fifteen Marine recruits with acute heat stroke were examined for (1) predisposing factors, (2) blood coagulation disturbances, (3) renal function abnormalities, and (4) blood composition alterations. Epidemiologic data identified the following risk factors; previous residence in a temperate climate, first phase of training, fatigue, and strenuous exercise in hot, humid conditions. Results of blood coagulation studies disclosed an increase in prothrombin and partial thromboplastin times, with a decrease in platelet count, probably indicating a transient, low-grade consumptive process. Blood urea nitrogen and creatinine levels and creatinine clearance were normal. Only mild elevations of SGOT, SGPT, and lactic dehydrogenase levels were noted, and in combination with clinical observations, they argued against significant muscle damage. No deaths or instances of renal failure occurred.
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PMID:Acute heat stroke. Epidemiologic, biochemical, renal, and coagulation studies. 124 74

The paper is concerned with the results of studying risk factors correlations in patients who suffered minor brain stroke (MBS) associated with different forms of arterial hypertension (AH). As regards their importance in the pathogenesis of MBS, risk factors may be distributed into the two categories: atherogenic, coagulant and vascular alterations and ++cardio-cerebral ones characterizing the status of heart pump function. The atherogenic and coagulant risk factors (perivascular and intravascular lesions, agglutination of the capillaries by formed elements of the blood, aggregation of red blood cells, a high level of TH and beta-lipoproteins, fibrinogen and prothrombin) are significantly marked more widely and intensely among persons suffering from stable AH, with a history of MBS. Risk factors characterizing a decrease of heart pump function (myocardial contractility, ejection fractions) were demonstrable without significant differences among persons who suffered MBS associated with stable and labile AH. As to further studies, of the main interest is the pathogenesis of MBS in persons suffering from mild, episodic AH, since the data obtained may cast doubt on the thrombocoagulant mechanism thereof.
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PMID:[Study of atherogenic, coagulant and cardio-cerebral risk factors in the pathogenesis of minor strokes in arterial hypertension]. 165 96

The use of oral anticoagulants and antiplatelet agents for the prevention of strokes in elderly patients with atrial fibrillation is controversial. Recent studies suggest that warfarin and aspirin can be safe and effective in selected patients. To determine attitudes toward this subject, we sent a questionnaire to 480 attending physicians at two major university-affiliated medical centers. Among the 251 responses (52.3%), 46 respondents (18.3%) used warfarin in atrial fibrillation of any cause, 175 (69.7%) used it in atrial fibrillation with transient ischemic attacks, 161 (64.1%) used it in patients with cerebrovascular accidents, and 196 (78.0%) used it in patients with mitral valve disease. One hundred twenty-nine (51.4%) believed that the risk of hemorrhage associated with warfarin outweighs the benefit, 61 (24.3%) were not convinced that warfarin prevents strokes in atrial fibrillation, and 42 (16.7%) believed it was difficult to monitor prothrombin time in the elderly because of poor compliance. Aspirin was used by 91 physicians (36.2%) in atrial fibrillation of any cause, 161 (64.1%) in patients with transient ischemic attacks, 140 (55.7%) in patients with cerebrovascular accidents, and 48 (19.1%) when patients were in sinus rhythm. We concluded that physicians are still hesitant to use oral anticoagulants and antiplatelet agents for the prevention of strokes in their elderly patients with atrial fibrillation. These agents are used most frequently after an ischemic episode (transient ischemic attack or cerebrovascular accident) has occurred or in patients with mitral valve disease.
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PMID:Physicians' attitudes toward oral anticoagulants and antiplatelet agents for stroke prevention in elderly patients with atrial fibrillation. 192 82

A 55-year-old woman was transferred to our institution from another hospital. The history of her present illness began 17 days earlier with a right-sided cerebral vascular accident (CVA). Three days later she had a superior mesenteric artery (SMA) embolus with infarcted bowel. Her small bowel was resected leaving about 20-25 centimeters of small bowel. A cardiac echo on hospital day 6 documented the presence of a left ventricular embolus, which was considered to be the cause of her CVA and SMA embolus. The cardiologists recommended lifelong anticoagulation, preferably with warfarin when technically feasible. After one month of warfarin therapy, with doses as high as 25 mg/d, the patient's prothrombin times (PTs) were not changed from baseline; however, this was probably due to concomitant therapy with vitamin K. Heparin was incorporated into her total parenteral nutrition (TPN) in preparation for her discharge. Because the TPN was cycled, she required subcutaneous heparin twice daily while off TPN. This patient's clinical course while she was maintained on heparin therapy was complicated by bleeding episodes and extensive thigh and abdominal hematomas, which led to erratic heparin absorption and widely fluctuating partial thromboplastin times. Ten months after the initiation of anticoagulation the patient was again tried on an oral warfarin regimen. She was successfully titrated to achieve the desired PT ratio. This case led to a review of the literature of patients with short-bowel syndrome requiring anticoagulation.
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PMID:Oral anticoagulation in patients with short-bowel syndrome. 211 45

Ten clinically healthy subjects (5 men and 5 women), 31 +/- 11 yrs of age, were studied at six timepoints (0800, 1200, 1600, 2000, 0000, 0400) distributed over a 1-week span. Circadian rhythms in platelet aggregation in response to adenosine diphosphate (ADP) and adrenalin (A), platelet adhesiveness measured as retention in a glass bead column, prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time (TT), fibrinogen, Factor VIII activity and alpha-1-antitrypsin antigen showed circadian rhythms. The plasma concentrations of plasminogen, alpha-2-macroglobulin, and antithrombin III (AT III) antigen, Factor V and fibrinogen degradation products showed no circadian rhythm by ANOVA or cosinor analysis. The phase relations of the rhythms of different coagulation parameters are of interest in the physiology and pathobiology of the coagulation-fibrinolytic system. The extent of the circadian rhythm (range of change) described is not of a magnitude to lead to diagnostic problems in the clinical laboratory. The timing of these rhythms, however, may determine transient risk states for thromboembolic phenomena, including myocardial infarction and stroke. Several but not all coagulation parameters suggest a transient state of hypercoagulability during the morning hours. The recognition of these rhythmic, and thus in the time of the occurrence predictable temporary risk states for thromboembolic phenomena, may lead to timed treatment and/or effective prevention.
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PMID:Circadian variations in blood coagulation parameters, alpha-antitrypsin antigen and platelet aggregation and retention in clinically healthy subjects. 212 46

Individuals with nonvalvular atrial fibrillation are at increased risk of stroke. The Stroke Prevention in Atrial Fibrillation Study is a 15-center randomized clinical trial examining the risks and benefits of low-intensity warfarin (prothrombin time of 1.3-1.8 times control) and aspirin (325 mg/day) in patients with constant or intermittent atrial fibrillation. Candidates for anticoagulation (group I) are randomized to receive warfarin in an open-label fashion, aspirin, or placebo; the last two treatments are given in a double-blind fashion. Warfarin-ineligible patients (group II) are randomized to receive aspirin or placebo in a double-blind fashion. Primary end points are ischemic stroke and systemic embolism. Secondary end points are death, transient ischemic attack, myocardial infarction, and unstable angina pectoris. Analysis is based on the intention-to-treat principle. The anticipated rate of primary end points in patients receiving placebo is 6%/yr. The sample size of 1,644 patients is based on a projected reduction in the rate of primary end points of 50% by warfarin and of 33% by aspirin (beta = 0.2, alpha = 0.05). Patient entry commenced in June 1987 and will continue for 3 years, with an additional year of follow-up. High-risk subsamples identified by clinical and echocardiographic criteria are sought prospectively.
Stroke 1990 Apr
PMID:Design of a multicenter randomized trial for the Stroke Prevention in Atrial Fibrillation Study. The Stroke Prevention in Atrial Fibrillation Investigators. 218 5

Using two-dimensional echocardiography, we studied the pathophysiology of intracardiac thrombus regression accompanied by anticoagulant therapy in 82 consecutive patients with acute cardiogenic cerebral embolism. We noted intracardiac thrombus in 15 patients; nine of the 15 were started on anticoagulant therapy with warfarin potassium to maintain the prothrombin time between 2.5 and 3.5 (international normalized ratio). Serial two-dimensional echocardiograms were obtained for these nine patients before and after anticoagulation, with the plasma levels of fibrinopeptide A, fibrinopeptide B beta 15-42, and D-dimer measured at the same time. In eight of the nine patients the intracardiac thrombi gradually decreased in size while the plasma level of fibrinopeptide A fell to within the normal range and the plasma levels of fibrinopeptide B beta 15-42 and D-dimer remained above the normal ranges. In the other patient the thrombus disappeared, with embolization to the right arm immediately after starting anticoagulant therapy. Mobile or small thrombi regressed earlier than nonmobile or large ones. We conclude that regression of intracardiac thrombi after anticoagulation may be based on the relative predominance of plasma fibrinolytic activity over anticoagulation-inhibited thrombin activity.
Stroke 1990 Nov
PMID:Regression of intracardiac thrombus after embolic stroke. 223 46

The coagulability of plasmas from 63 patients with acute ischemic stroke (cerebral thrombosis and cerebral embolism) was analyzed by an automated method for prothrombin time using a fluorogenic peptide substrate. The fluorogenic prothrombin time (FPT) of patients' plasmas collected within 48 hr after onset, as expressed as percent of control plasma, was significantly higher in cerebral thrombosis than in an age-matched control group (p less than 0.01). The high values of FPT in cerebral thrombosis patients were observed until the 30th day after onset. On the other hand, FPT values in cerebral embolism patients were not significantly different than that of the control group. Factor VII activity levels in cerebral thrombosis patients were significantly higher than those of the control group and cerebral embolism patients, while levels of factor X activity were not significantly different among these groups. Although FPT and factor VII activity in these stroke patients did not significantly correlate, factor VII activity did correlate well with factor VII antigen. Decreased levels of antithrombin III and elevated levels of FDP and alpha 2-antiplasmin-plasmin complexes were observed only in cerebral embolism patients. Our findings strongly suggest that patients with cerebral thrombosis have been in a hypercoagulable state before the onset of symptoms, which was caused in part by an increase of factor VII activity/antigen, and in part by other unknown mechanisms. In contrast, patients with cerebral embolism were in a low grade consumptive coagulopathy.
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PMID:Hypercoagulability in acute ischemic stroke: analysis of the extrinsic coagulation reactions in plasma by a highly sensitive automated method. 236 33


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