Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0038454 (stroke)
 147,016 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The Stroke Prevention in Atrial Fibrillation Study recently found and reported (SPAF Investigators, N Engl J Med, 1990;322:863-868) a beneficial effect of both warfarin and aspirin compared with placebo in the primary prevention of ischemic stroke and systemic embolism in patients with nonvalvular atrial fibrillation. Among warfarin-eligible patients, the event rates were 1.6%/yr for those receiving active antithrombotic therapy (warfarin or aspirin) and 8.3%/yr for those receiving placebo (p less than 0.00005) (risk reduction 81%, 95% confidence interval 56-91). Ironically, we did not find a beneficial effect of aspirin in warfarin-ineligible patients. On the basis of these results, the study has been reshaped to directly compare these two antithrombotic agents. Insight into the apparent aspirin unresponsiveness noted in some patients also is being sought. Interpretation of the preliminary results and the reshaping of the study have been made more complex by the continued blinding of the investigators to certain portions of the data. Presented is an account of the study from its inception through its recent redesign.
Stroke 1990 Nov
PMID:Progress report of the Stroke Prevention in Atrial Fibrillation Study. 223 68

Unlike what happened regarding rheumatic atrial fibrillation, there was no consensus until few years ago about the indication for antithrombotic therapy in nonrheumatic atrial fibrillation. Nevertheless, as it was noticed a high prevalence of stroke in this last situation, several clinical trials were accomplished to clarify the role of those drugs. It was reviewed the five initial big trials, which in spite of having different dimensions, endpoints and design, were remarkably consistent in their results, showing in those patients taking varfarine a 60% reduction in ischemic stroke and systemic embolism. Those results were obtained with an acceptable risk of hemorrhage, which was related to anticoagulation intensity. An European trial showed similar results in secondary prevention, in patients with higher risk, all of them with a previous minor stroke. In some of those trials antiplatelet therapy was also evaluated but only one (SPAF I), showed a significant reduction of stroke with aspirin; the reductions of risk was meanwhile much smaller than with varfarine. As there were a high number of patients with indication for anticoagulants one tried to find thromboembolic risk factors, to identify the population potentially more prone to benefit from that therapy. It was possible in SPAF I trial to find some clinical and echocardiographic risk factors. SPAF II trial directly compare aspirine with varfarine, showing the superiority of the last one but also its greater haemorrhagic risk. That study permitted a better understanding of the indications of those two therapies, according to embolic and haemorrhagic risk of each patient.
 ...
PMID:[Atrial fibrillation: anticoagulation or antiaggregation. Is there still a controversy?]. 761 83

Warfarin is an established treatment for prevention of ischaemic stroke in patients with atrial fibrillation, but the value of this agent relative to aspirin in unclear. In the first Stroke Prevention in Atrial Fibrillation (SPAF-I) study, direct comparison of warfarin with aspirin was limited by the small number of thromboembolic events. SPAF-II aims to address this issue and also to assess the differential effects of the two treatments according to age. We compared warfarin (prothrombin time ratio 1.3-1.8, international normalised ratio 2.0-4.5) with aspirin 325 mg daily for prevention of ischaemic stroke and systemic embolism (primary events) in two parallel randomised trials involving 715 patients aged 75 years or less and 385 patients older than 75; we sought reductions in the absolute rate of primary events by warfarin compared with aspirin of 2% per year and 4% per year, respectively. In the younger patients, warfarin decreased the absolute rate of primary events by 0.7% per year (95% CI-0.4 to 1.7). The primary event rate per year was 1.3% with warfarin and 1.9% with aspirin (relative risk [RR] 0.67, p = 0.24). The absolute rate of primary events in low-risk younger patients (without hypertension, recent heart failure, or previous thromboembolism) on aspirin was 0.5% per year (95% CI 0.1 to 1.9). Among older patients, warfarin decreased the absolute rate of primary events by 1.2% per year (95% CI-1.7 to 4.1). The primary event rate per year was 3.6% with warfarin and 4.8% with aspirin (RR 0.73, p = 0.39). In this older group, the rate of all stroke with residual deficit (ischaemic or haemorrhagic) was 4.3% per year with aspirin and 4.6% per year with warfarin (RR 1.1). Warfarin may be more effective than aspirin for prevention of ischaemic stroke in patients with atrial fibrillation, but the absolute reduction in stroke rate by warfarin is small. Younger patients without risk factors had a low rate of stroke when treated with aspirin. In older patients the rate of stroke (ischaemic and haemorrhagic) was substantial, irrespective of which agent was given. Patient age and the inherent risk of thromboembolism should be considered in the choice of antithrombotic prophylaxis for patients with atrial fibrillation.
 ...
PMID:Warfarin versus aspirin for prevention of thromboembolism in atrial fibrillation: Stroke Prevention in Atrial Fibrillation II Study. 791 Dec 13

When atrial fibrillation (AF) complicates rheumatic heart disease, the risk of stroke is 17 times that of patients in sinus rhythm and full anticoagulation is mandatory. Non-rheumatic AF carries a lower risk--5% per annum, a 5-fold increase. Four major trials (SPAF, AFASAK, BAATAF, CAFA) have lately examined thromboembolic prophylaxis in this group of patients. These randomized prospective open studies showed a 56-86% reduction in stroke and systemic embolism in patients receiving full anticoagulation compared with placebo. In older people, the BAATAF trial of low-dose warfarin (INR = 1.5-2.7) showed an 86% reduction in stroke and a significant reduction in mortality. In all 4 studies the incidence of hemorrhagic complication was very low (0.5%). In SPAF trial, aspirin, 325 mg/day was found to be effective, but this was not the case in AFASAK, which used 75 mg/day and had an older population. In a double-blind randomized trial indobufene, 100 mg bid, was found effective in the 67% reduction of stroke, systemic and pulmonary embolism in patients with various cardiac diseases in AF or in sinus rhythm. Consequently, a reasonable policy would be to give full or low-dose anticoagulation to those patients with chronic AF who have structural heart disease or are over 65 years old; to consider low-dose anticoagulation or aspirin or indobufene in younger patients with chronic lone AF; and to give indobufene or aspirin or nothing to those with episodes of paroxysmal AF lasting hours only. In borderline cases, the use of transesophageal echocardiography to exclude left atrial thrombus and spontaneous echo contrast may aid decision-making.
 ...
PMID:[Atrial fibrillation: embolic risk and prevention]. 802 31

There is a demonstrated statistical association between atrial fibrillation, rheumatic valvular disease, and embolic stroke. This article assesses the results of 6 major clinical trials (AFASAK, BAATAF, SPINAF, SPAF [parts I and II], CAFA and EAFTA--see text for trial names). Multivariate analysis revealed 4 independent clinical features that identified patients with atrial fibrillation at an increased risk for stroke: hypertension, increasing age, previous transient ischemic attack, and diabetes mellitus. Without anticoagulation therapy, patients with any of these risk factors had a 4% annual risk of stroke. Patients with cardiac disorders such as congestive heart failure and coronary artery disease have a stroke rate 3 times higher than patients without any risk factors; patients with atrial fibrillation but no concomitant risk factors or structural heart disease seemed to have little concomitant risk for stroke. Meta-analysis revealed a 64% reduction of risk for stroke in patients treated with warfarin, as compared with placebo. The value of warfarin therapy in patients > 75 years old is less clear because of a high risk of hemorrhagic complications.
 ...
PMID:Atrial fibrillation, anticoagulation, and stroke. 860 90

Anticoagulants should be used more widely in patients with atrial fibrillation. Legitimate concerns exist about the risk/benefit ratio in younger patients with no risk factors and in patients over the age of 75 years. Use of lower doses of anticoagulation (potential target range INR of 1.5-2.5) than used heretofore is probably the solution to most of the problems associated with anticoagulation, but conclusive proof of the efficacy of this strategy is needed. Although aspirin may reduce the risk of stroke the effect may be no more than among patients with a similar level of cardiovascular risk factors and in sinus rhythm. As such, aspirin is a valid alternative for patients with atrial fibrillation at a low risk of stroke but should not be used as an excuse to withhold anticoagulants in patients at greater risk. Several larger studies investigating the effects of different intensities of anticoagulation and the use of aspirin-warfarin combinations are underway. Indeed SPAF-III, comparing a combination of low dose warfarin and aspirin with formal anticoagulation has been stopped and reported in March 1996. A summary of the results will appear in the July issue. Identification of the minimum effective dose of warfarin and effective monitoring systems remain a priority.
 ...
PMID:Should all patients with atrial fibrillation receive warfarin? Evidence from randomized clinical trials. 873 97

Nonvalvular atrial fibrillation is associated with an overall risk of stroke of 4.5% per year. Advancing age, prior stroke or transcient cerebral ischemia, diabetes and hypertension are known risk factors. Ischemic stroke in patients with atrial fibrillation are generally more severe than ischemic stroke in patients with sinus rhythm. Warfarin is effective for primary and secondary prevention of ischemic stroke, reducing the risk by 68%. The effect of aspirin is still controversial, reducing the risk by 18-44%. Recent clinical trials have investigated the effect of warfarin given at a very low intensity either alone or combined with aspirin. The results from the SPAF III study demonstrated that a combination of mini-intensity warfarin plus aspirin was insufficient for stroke prevention in atrial fibrillation. Other trials now indicate, that oral anticoagulation at INR-values below 2.0 is not effective for stroke prevention in these patients. It is recommended that patients at high risk of stroke are treated with warfarin at an intensity of INR 2.0-3.0. Patients younger than 65 without other risk factors can be given aspirin 325 mg/day. The present clinical challenge is to ensure effective and safe oral anticoagulation to patients with atrial fibrillation at high risk of stroke.
 ...
PMID:Prevention of thromboembolic events in atrial fibrillation. 919 82

Atrial fibrillation belongs to the group of cardiovascular diseases that most frequently predispose to arterial thromboembolic events. Within the last years, the AFASAK, BAATAF, SPAF I, SPINAF, and CAFA trials have consistently demonstrated a significant, approximately 70%, risk reduction for stroke on oral anticoagulation in patients with nonrheumatic atrial fibrillation. This benefit by far outweighed the slight increase in annual major hemorrhage. Recently, additional trials (SPAF II, EAFT, SPAF III, and others) have shed further light on important questions concerning risk factors, secondary prophylaxis, the optimal intensity of anticoagulation, and the role of aspirin and other antiplatelet drugs. The main results of these studies are discussed in this review. The majority of patients with atrial fibrillation are > 65 years of age and have other clinical or echocardiographic risk factors. In these patients, adjusted-dose warfarin with target international normalized ratios (INRs) 2.0 to 3.0 is effective and safe. The risk of stroke rises with INR values < 2.0, whereas INR values > 3.0 result in an increase in intracerebral hemorrhages, especially in the very elderly. In contrast, no anticoagulation seems warranted in younger atrial fibrillation patients < 60 years of age without any clinical or echocardiographic risk factor. An overview of all randomized trials that compared aspirin with placebo and/or adjusted-dose warfarin indicates that adjusted-dose warfarin is approximately 50% more effective than aspirin for primary and secondary prevention of stroke, at least in patients with atrial fibrillation who have clinical risk factors. Therefore, oral anticoagulation clearly is the therapy of choice for prevention of thromboembolism in patients with atrial fibrillation.
 ...
PMID:Role of anticoagulant therapy in atrial fibrillation. 972 82

Nonvalvular atrial fibrillation (AF) is the most common cardiac disorder causing stroke and systemic emboli. Recent clinical trials have clearly demonstrated the effects of antithrombotic treatment in preventing these devastating complications of AF. This review summarizes the salient findings of the first 5 published studies the Atrial Fibrillation, Aspirin, Anticoagulation Study (AFASAK) from Copenhagen, Denmark; the Boston Area Anticoagulation Trial for Atrial Fibrillation (BATAFF); the Canadian Atrial Fibrillation Anticoagulation study (CAFA); the Stroke Prevention in Non-rheumatic Atrial Fibrillation (SPINAF) study; and the Stroke Prevention in Atrial Fibrillation study (SPAF I) from the United States. These trials emphasize the unequivocal benefits of warfarin therapy compared with no treatment. SPAF II showed that aspirin is quite effective in younger patients (<75 years) who have no risk factors. The European Atrial Fibrillation Trial (EAFT) and SPAF III demonstrated that in older patients (>75 years) who had associated risk factors, warfarin therapy at the target international normalized ratio (INR) of 2-3, is the best treatment; however, a combination of low intensity fixed-dose warfarin and aspirin is ineffective. Thus, the guidelines recommended by the American College of Chest Physicians should be followed in treating patients with AF.
 ...
PMID:Long-term antithrombotic treatment for atrial fibrillation. 980 99

Atrial fibrillation, which has age-dependent exponentially rising high prevalence, is now well known to frequently predispose to systemic thromboembolism. In the past decade, several large-scale clinical randomized trials for prevention of thromboembolism in nonrheumatic atrial fibrillation have been performed for its primary and secondary preventions. The first five major trials (AFASAK, BAATAF, SPAF-I, CAFA, SPINAF) for primary prevention of stroke have demonstrated a significant risk reduction (68%) for stroke on oral anticoagulation without any significant increase in major hemorrhage. On the other hand, although AFASAK and SPAF I showed controversial results for comparison of aspirin and control, the collaborative analysis revealed a significant risk reduction (36%). In their analysis of risk factors for stroke, prior stroke, diabetes mellitus, and hypertension have been stressed as high risk factors. Recently, some additional trials have been done concerning secondary prophylaxis, primary prevention in high risk patients, the optimal dose of warfarin, the role of aspirin and so on. In EAFT, a secondary prevention trial, warfarin has reduced (66%) stroke from 12%/yr to 4%/yr, while aspirin alone to 10%/yr. In SPAF III, it has been reported that adjusted-dose warfarin with target INR2.0 to 3.0 is effective and safe in high risk patients. However, SPAF II showed that warfarin was not useful in elder patients (75yr <) because of an increase in hemorrhage. That may be why warfarin was still underused (40% >). Anyway, it is of importance to think about the strategy for prevention on the individual level of patients with atrial fibrillation, taking into consideration echocardiographical and hematological data besides clinical risk factors.
 ...
PMID:[Frontiers in prevention of thromboembolism in nonvalvular atrial fibrillation]. 1034 39


1 2 Next >>