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

Transient ischemic attacks (TIAs) constitute the most specific and powerful warnings of impending stroke. They are defined as brief, focal neurological events of sudden onset. Their proper recognition and treatment rank second only to the modification of risk factors in importance for stroke prevention. Carotid endarterectomy, although widely used to treat TIAs, remains unproven; randomized clinical trials are attempting to define its role. Anticoagulant therapy appears worth while for suspected cardiac embolism and possibly for disabling TIAs. Acetylsalicylic acid is the only agent that has been found to be effective in controlled trials, but questions persist about its dosage, its efficacy in women and its use after stroke. Another platelet inhibitor, ticlopidine hydrochloride, is being investigated and may prove to be an effective alternative.
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PMID:Transient ischemic attacks and stroke. 328 85

Derivatives of arachidonic acid may be involved in atherosclerosis and its clinical complications. There is much interest in pharmacologically manipulating the arachidonic acid cascade as a means of preventing cardiovascular disease. The development of atherosclerosis has been intensively studied and the consequences of cardiovascular or cerebrovascular vessel occlusion are too familiar. Many factors are probably involved, but the role of plasma lipoproteins and the interactions between various constituents of blood and blood vessel walls have received particular attention. The risk of cardiovascular disease associated with high plasma concentrations of the low density lipoproteins and the possible protective effects of high density lipoproteins have been well documented. Much is now known about lipoprotein biochemistry, and the importance of controlling the quantity and quality of dietary lipids has been demonstrated in epidemiological studies. In studies of patients with transient ischaemic attacks, aspirin reduced the risk of stroke and death in males, although these benefits were not as convincingly demonstrated in women. The majority of patients were given aspirin 1300 mg daily, but the optimum dosage was not properly evaluated. Administering aspirin in combination with another antiplatelet drug did not appear to offer any therapeutic advantage in these patients. Aspirin showed a positive, but non-significant trend towards reduced numbers of cardiac events, non-fatal infarcts and total mortality in patients who had experienced at least one myocardial infarction. In contrast, statistically significant beneficial effects were recorded when patients with unstable angina were administered aspirin. The risks of myocardial infarction or coronary death were reduced by 51% in 2 large studies.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:The role of arachidonic acid metabolites in cardiovascular homeostasis. Biochemical, histological and clinical cardiovascular effects of non-steroidal anti-inflammatory drugs and their interactions with cardiovascular drugs. 329 23

Aspirin inhibits platelet function by acetylating platelet cyclo-oxygenase. When aspirin is administered in doses as low as 40-160 mg per day, it inhibits platelet cyclo-oxygenase activity by more than 80%. The effect of aspirin on platelet function is maintained for the life-span of the platelet and there is evidence that aspirin also acetylates platelets before they are released in the circulation and while they are still within megakaryocytes. Aspirin also inhibits the synthesis of PGI2 by vascular wall cells but compared to the platelet, this vessel wall effect is relatively short-lived and requires slightly larger doses of aspirin. In vivo studies in rabbits indicate that very high doses of aspirin are thrombogenic. However, there is no evidence that aspirin is thrombogenic in man even when administered in high therapeutic doses. The optimal antithrombotic dose of aspirin has not yet been determined. Clinically, impressive results have been obtained with low doses of aspirin (ranging from 100 to 300 mg per day) in preventing aorta coronary bypass thrombosis, in patients undergoing hemodialysis, and in patients with unstable angina. Aspirin is also effective in preventing stroke and death in patients with cerebral ischemia when administered in doses of approximately 1 gram per day. There are trends suggesting that aspirin is effective when administered in doses between 300 mg per day and 1500 mg per day in patients who have survived myocardial infarction. The side-effects of aspirin are mainly gastrointestinal and are dose-related. Generalized bleeding is very uncommon and limited mainly to patients with other hemostatic abnormalities or due to the concomitant use of anticoagulant therapy.
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PMID:Effect of aspirin on hemostasis and thrombosis. 330 53

In the past 20 years treatment appears to have had a major impact on all forms of cerebral vascular disease. Morbidity and mortality from strokes have declined nearly 50% in developed countries. Modern imaging techniques, methodology, and biostatistics have identified risk factors and refined clinical trials such that we question all previous studies of stroke management. Control of moderate and severe hypertension has significantly lowered stroke rates. In borderline and mild hypertension the decision to treat is influenced by other stroke risk factors including diabetes mellitus, cigarette smoking, ischaemic heart disease, plasma lipid levels, gout, haematocrit, and body weight. Current data indicate that anticoagulants are of no value, or hazardous, in atherothrombotic strokes; of unknown value in transient ischaemic attacks; of dubious value in evolving strokes; and beneficial in cardiac embolism. The cardiac causes, including mural thrombus, unstable arrhythmias, and mitral valve prolapse should be actively sought. Aspirin, as the prototype anti-platelet agent, holds promise in transient ischemic attacks and minor strokes at both small and moderate dosages. Ticlopine is now being critically evaluated in America. Use of cerebral vasodilators should be abandoned. Enthusiasm in the use of streptokinase and urokinase has been dampened by the conversion of ischemic infarcts into haemorrhagic infarcts. In subarachnoid haemorrhage epsilon-aminocaprioc acid is useful although hazardous, in preventing rebleeding. Certain calcium ion channel blockers are promising in the reduction of vasopasm. Since the November 1985 article in the new England Journal of Medicine on the failure of external-to-internal carotid arterial bypass to reduce the risk of ischemic stroke, the swing is back to conservative management.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Advances in the medical management of cerebral vascular disease. 331 47

A total of 243 patients who had reversible ischemic attacks (RIA) were submitted to clinical trial to determine whether dipyridamole (400 mg/day) (D) or aspirin (100 mg/48 hours) + dipyridamole (300 mg/day) (ASA + D) would produce significant reduction in the subsequent occurrence of RIA and completed stroke. One hundred and fifteen were selected for Group ASA + D and 71 were treated with dipyridamole only. The treatment groups were similar in relation to age, sex, risk factors, duration and presumed vascular territory of RIA, incidence of alterations of arterial supra-aortic trunks, cerebral infarct (CT scan), and platelet function. Patients were followed for a mean time of 21 months. At the end of the study, 21.7% of the ASA + D group and 19.7% in the D group had suffered new episodes of RIA or completed stroke (p = 0.88). Frequency of stroke (reversible ischemic neurologic deficit or completed stroke) was 7.8% in the ASA + D patients and 9.8% in the D patients (p = 0.83). Subgroup analysis did not show significant differences either. It is concluded that ASA + D has no significantly greater beneficial effect than that observed with D alone in the secondary prevention of atherothrombotic cerebral ischemia. However, a statistical Type II error cannot be excluded by the reduced number of recurrences.
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PMID:Low-dose acetylsalicylic acid (ASA) plus dipyridamole versus dipyridamole alone in the prevention of stroke in patients with reversible ischemic attacks. 332 18

Aspirin is of proven value as an antithrombotic drug. In unstable angina it reduces the risk of death and myocardial infarction by half. After a myocardial infarction it reduces the risk of death by about 10% and of coronary incidence (coronary death or definite myocardial infarction) by about 25%. These effects appear to be additive with those of beta-blocking drugs. Aspirin also reduces the risk of occlusion of aortocoronary saphenous vein grafts by about half. In transient cerebral ischaemia, aspirin may reduce the risk of stroke and death by 50%. In most clinical trials to date the daily dose of aspirin ranges from 325 mg to 1400 mg. Interest in very low doses of aspirin (less than 60 mg daily) is considerable but has yet to be translated into proven clinical benefit. Dipyridamole has not been shown to be effective as an antithrombotic when used alone. Its antiplatelet action ex vivo may be enhanced by combination with aspirin but clinical trials have shown relatively little advantage of the combination over aspirin alone. Sulphinpyrazone has not become established as a first line antithrombotic drug. Epoprostenol is useful in extracorporeal circulations to prevent platelet consumption and possibly in severe inoperable peripheral vascular disease.
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PMID:Aspirin and other antiplatelet drugs in the prophylaxis of thrombosis. 333 89

Cardiopulmonary baroreceptors located primarily on the low-pressure side of the circulation sense slight reductions in cardiac filling pressures and elicit sustained peripheral vasoconstriction. Because most inhalation and many intravenous anesthetics attenuate arterial baroreflex function, the low-pressure baroreflex may serve a major role in maintaining blood pressure during intraoperative hypovolemia. To activate the low-pressure baroreflex, progressive nonhypotensive reductions in central venous pressure were produced with graded applications of lower body negative pressure (LBNP, -5, -10, -15 mm Hg) in 18 ASA class I patients before elective surgery. This produced linear reductions in stroke volume as determined by impedance cardiography and cardiac output. Cardiopulmonary baroreflex-mediated increases in total and forearm vascular resistance assisted in maintaining stable blood pressure. After ten patients were anesthetized with fentanyl (12.5 micrograms/kg) and diazepam (0.25 mg/kg) and an additional eight received these agents plus supplemental N2O (70%), reflex vasoconstrictor responses to LBNP were not attenuated and, therefore, blood pressure continued to be well maintained despite substantial reductions in cardiac filling pressures. Thus, these anesthetic regimens preserved vasoconstrictor responses mediated by cardiopulmonary baroreflexes. This promoted cardiovascular stability that may be particularly beneficial in patients with cerebral, cardiovascular, or renal disease undergoing surgical procedures with potential for rapid blood loss.
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PMID:Fentanyl-diazepam anesthesia with or without N2O does not attenuate cardiopulmonary baroreflex-mediated vasoconstrictor responses to controlled hypovolemia in humans. 337 9

The cardiovascular effects of midazolam as induction agent in A.S.A. class 2 surgical patients (N = 6) were compared with a similar group of patients (N = 6) receiving flunitrazepam. An induction-sized dose of midazolam was 0.17 +/- 0.03 mg/kg and the dose of flunitrazepam was 0.036 +/- 0.0039 mg/kg. The induction-sized dose of midazolam produced a moderate cardiovascular depression, similar to flunitrazepam. Cardiac index, left ventricular stroke work index and mean pulmonary pressure were decreased significantly after injection of midazolam and mean arterial pressure, cardiac index and left ventricular stroke work index were decreased significantly after administration of flunitrazepam. Following the administration of midazolam, there were decreasing tendency of mean pulmonary pressure and pulmonary artery occluded pressure, and no change of central venous pressure, while increasing tendency of central venous pressure with flunitrazepam. Unlike flunitrazepam, midazolam may act capacitance vessels. However in this study, statistical significant differences between the hemodynamic effects of midazolam and those of flunitrazepam were not obtained.
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PMID:[Comparative hemodynamic effects of midazolam and flunitrazepam as induction agents]. 338 93

The European Stroke Prevention Study showed: 1. That the association Persantin-Aspirin reduces stroke and vascular death risks with 36,5% in a population of 2500 patients. Risk reduction persisted during the two years follow-up and was the same for men and women. 2. That this reduction is higher than the reduction obtained in all other studies with anti-aggregation prevention. 3. That studies with less than 600 patients cannot lead to significant differences.
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PMID:European stroke prevention study. 338 69

Aspirin has been convincingly shown to reduce stroke and death in men with transient ischemic attacks (it may possibly be beneficial to women also), myocardial infarction and death in patients with unstable angina, thromboembolic complications associated with artificial heart valves in patients receiving oral anticoagulants (although gastrointestinal bleeding is prohibitive with this combination), and thrombotic occlusion of silicone rubber arteriovenous cannulae in uremic patients undergoing hemodialysis. In addition, aspirin may possibly decrease occlusion of saphenous vein aortocoronary grafts and venous thrombosis in men after hip replacement, although these reports require confirmation. Aspirin is ineffective in the secondary prevention of stroke and has unproven benefit in the secondary prevention of myocardial infarction. Dipyridamole in combination with oral anticoagulation decreases the thromboembolic complications associated with mechanical heart valves. The combination of aspirin and dipyridamole prevents both early and late occlusion of saphenous vein aortocoronary bypass grafts and protects renal function in patients with membranoproliferative glomerulonephritis. The relative importance of combining aspirin and dipyridamole compared with either agent used singly remains to be established. Sulfinpyrazone reduces the thrombotic occlusion of arteriovenous cannulae and early occlusion of saphenous vein aortocoronary grafts. The reported benefit in the secondary prevention of myocardial infarction is controversial.
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PMID:Clinical trials evaluating platelet-modifying drugs in patients with atherosclerotic cardiovascular disease and thrombosis. 351 Jul 60


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