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

Persistent coagulation activity after an acute myocardial infarction may increase the risk of reinfarction. We prospectively investigated the effects on plasma coagulation of a low, fixed dose of warfarin in combination with aspirin after myocardial infarction. We also evaluated the influence of coagulation activity on clinical outcome. Plasma samples from 97 patients, randomised to 1.25 mg of warfarin daily in combination with 75 mg of aspirin or aspirin alone were drawn 4 days, 1 month, and 6 months after myocardial infarction. Patients receiving warfarin had a greater reduction in factor VII coagulation activity (FVII:C) after 6 months: 0.18 vs. 0.06 U/mL,(95% CI, 0.02-0.22), whereas no differences were seen in levels of protein C, protein S, or prothrombin fragment 1+2. In the acute phase, the level of free protein S was lower than after 6 months in both groups: 25.6 vs. 28.8% (95% CI, 4.19--2.35). Cardiovascular mortality, reinfarction, and stroke were evaluated after 4 years (median). In a survival analysis, every 0.1 U/mL increase in the level of FVII:C1 month after myocardial infarction was associated with an 15% increase in risk of cardiovascular events (95% C1, 1.01-1.30). Warfarin at 1.25 mg daily reduces FVII:C but not systemic thrombin generation measured as prothrombin fragment 1 +2. Low levels of the anticoagulant protein S may contribute to a procoagulant state.
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PMID:Changes in levels of factor VII and protein S after acute myocardial infarction: effects of low-dose warfarin. 1058 63

Evidence-based medicine is currently a fashionable term. The evidence that warfarin is safe, effective, and cost beneficial in preventing stroke in AF, DVT treatment, and DVT prophylaxis is mounting. However, the evidence that warfarin remains underutilized in these conditions is also mounting. There is new evidence that supports conservative management of overanticoagulation without bleeding. The amount of time, if any, that patients are off warfarin for various procedures is being reduced. Warfarin interactions with other agents continue to be reported so that practitioners can avoid or treat them. Even the contraindication of warfarin in pregnancy is being reexamined. Those with expertise in anticoagulation therapy have an imperative to inform colleagues about the evidence in favor of warfarin.
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PMID:Warfarin therapy: a review of the literature since the Fifth American College of Chest Physicians' Consensus Conference on Antithrombotic Therapy. 1072 12

In the Coumadin Aspirin Reinfarction Study (CARS), the primary (efficacy) endpoint was time to the first occurrence of reinfarction, ischemic stroke, or cardiovascular death. Study events likely to be a component of the primary endpoint were reviewed by a blinded Events Classification Committee (ECC). To accommodate the inherent delay imposed by the adjudication process, we used the results of prior adjudication to predict classifications for selected unadjudicated study events in order to conduct "up-to-date" interim analyses for the Data and Safety Monitoring Committee (DSMC). Rates at which previously adjudicated study events were confirmed as primary event components were used to adjust the Kaplan-Meier estimates of survival and the log-rank statistics. Multiple events for a given subject were weighted according to the probability that prior events would be confirmed. Once all study events were adjudicated, final analyses confirmed the results of the adjusted interim analysis. For monitoring clinical trials with adjudicated endpoint events, models based on prior adjudication histories can be reliably used to predict event classifications for unadjudicated events and support accurate, contemporary interim analyses.
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PMID:Adjusting survival analysis for the presence of unadjudicated study events. 1082 19

Atrial fibrillation(AF) is a common arrhythmia that is an important independent risk factor for stroke. The overall risk of stroke in AF patients averages about 5%/y, but with wide variation depending on the presence of coexistent thromboembolic risk factors, which include increasing age, history of hypertension, previous stroke or transient ischemic attack(TIA), and diabetes. AF patients with prior stroke or TIA are at highest risk(about 12%/y). Adjusted-dose warfarin(target INR 2.0-3.0) is highly efficacious for preventing stroke in AF patients, and is safe for selected patients. Aspirin has a modest effect on reducing stroke. Warfarin is recommended for high-risk AF patients who can safely receive it. Aspirin may be indicated for those with a low stroke risk and for those who cannot receive warfarin.
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PMID:[Antithrombotic therapy for stroke prevention in patients with atrial fibrillation]. 1087 60

The anticoagulant effect of warfarin should be kept at an international normalised ratio (INR) of about 2.5 (desirable range, 2.0-3.0), although a higher level may be better in a few clinical conditions. The risk of bleeding increases exponentially with INR and becomes clinically unacceptable once the INR exceeds 5.0. Warfarin therapy should be continued for around six weeks for symptomatic calf vein thrombosis, and for 3-6 months after proximal deep vein thrombosis (DVT) that occurs after surgery or limited medical illness. Therapy for six months or longer could be considered for DVT occurring without an obvious precipitating factor, proven recurrent venous thromboembolism (VTE), or if there are continuing risk factors. Oral anticoagulants prevent ischaemic stroke in atrial fibrillation (AF). Maximum efficacy requires an INR > 2.0, but some benefit remains at an INR of 1.5-1.9. Patients aged over 75 years are at greatest risk of intracranial bleeding during warfarin therapy for AF, and the target INR may be reduced to 2.0-2.5, or perhaps as low as 1.5-2.0, in such patients. Warfarin should be withheld if it is more likely to cause major bleeding than to protect from stroke (e.g., in young people with isolated AF where the annual baseline risk of stroke is < 1%). In patients with AF, aspirin is less effective than warfarin (much less effective after such patients have had a stroke or transient cerebral ischaemia). In people with prosthetic heart valves, an INR of 2.5-3.5 is probably sufficient for bileaflet or tilting disc valves, but a higher target INR is necessary for caged ball or caged disc valves. The addition of aspirin (100 mg/day) further decreases the risk of embolism but increases the risk of gastrointestinal bleeding.
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PMID:Consensus guidelines for warfarin therapy. Recommendations from the Australasian Society of Thrombosis and Haemostasis. 1091 7

Heart valve calcifications are rarely recognized as a potential source for cerebral embolism. Previous studies have identified mitral, but not aortic, valve calcifications to be risk factors for stroke. Based on these studies, heart surgery is unlikely to be indicated in patients who present with a stroke and an 'incidental' aortic valve calcification. We report a case of a 46-year-old man presenting with acute onset of left-sided weakness and numbness. A previous smoking history was the only cardiovascular risk factor found. Head CT scan revealed a right middle cerebral artery territory infarct and an adjacent high-density lesion. CT angiography demonstrated the presence of calcific embolic material in the middle cerebral artery. A search for embolic sources revealed a calcific aortic stenosis (CAS). Initially placed on coumadin, the patient developed silent myocardial infarction 2 months later, presumed to be also embolic in origin from the CAS. After aortic valve replacement, the patient has been symptom-free during a 2-year follow-up. In conclusion, CT angiography may be the method of choice for detecting calcific cerebral emboli, and demonstration of a causal relationship between CAS and an embolic stroke by CT angiography may be an important adjunct in surgical decision-making.
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PMID:Stroke as the first manifestation of calcific aortic stenosis. 1097 Oct 29

Nonvalvular atrial fibrillation (AF) is an independent risk factor for stroke. The overall risk of ischemic stroke in patients experiencing AF without prior stroke averages about 5% per year, but varies depending on the presence of coexistent thromboembolic risk factors. Patients with AF with low (about 1% per year), moderate (2%-4% per year) and high (> or = 6% per year) stroke risks have been identified, but the generalizability of available risk stratification schemes to clinical practice has not been defined. Adjusted-dose warfarin (target International Normalized Ratio 2-3) is highly efficacious for prevention of stroke in patients with AF (about 60% reduction) and is relatively safe for selected patients, if carefully monitored. Aspirin has a modest effect on reducing stroke (about 20% reduction). The role of transesophageal echocardiography is routine management of AF remains unsettled. Warfarin therapy should be considered for patients with AF predicted to have a high risk of stroke and who can safely receive it. Aspirin may be indicated for patients with AF at low risk for stroke and for those who cannot safely receive adjusted-dose warfarin. For those with moderate stroke risk, individual bleeding risks during anticoagulation and patient preferences should guide antithrombotic therapy.
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PMID:Stroke prevention in atrial fibrillation. 1098 Aug 72

Atrial fibrillation (AF) affects 5% of people older than 65 years. Among patients with AF, the risk of stroke averages about 5% per year. The risk of stroke increases cumulatively with increasing age, previous transient ischaemic attack or stroke, hypertension, diabetes, impaired left ventricular function and a large left atrium. Management aims to identify and treat the underlying cause, control the ventricular rate, restore and maintain sinus rhythm, and minimise the risk of stroke. Warfarin reduces the risk of stroke by about two-thirds, and aspirin by about one-fifth. The risk of anticoagulant-associated haemorrhage increases with serious concomitant disease, and with poorly controlled hypertension and poorly controlled anticoagulation. All patients with chronic AF should be considered for oral anticoagulant therapy, and the decision based on the balance between the risks of thromboembolism and bleeding. The recommended INR (international normalised ratio) is 2.0-3.0. Treating 1,000 "average" AF patients (ie, those with a 5% per year risk of stroke) with warfarin prevents about 30 strokes and causes at least two episodes of major haemorrhage each year. Treating 1,000
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PMID:Non-valvular atrial fibrillation and stroke prevention. National Blood Pressure Advisory Committee of the National Heart Foundation. 1128 Jun 95

In the Clopidogrel versus Aspirin in Patients at Risk of Ischaemic Events (CAPRIE) trial, clopidogrel showed a statistically significant superiority over aspirin in the prevention of ischaemic stroke, myocardial infarction and vascular death in patients with symptomatic atherosclerosis. More recently, post-hoc analysis of the data also showed that repeat hospitalization for ischaemic or bleeding events was decreased with clopidogrel compared with aspirin. Complementary analyses show that the benefit of clopidogrel over aspirin is amplified in a large population at very high risk of further atherothrombotic events (diabetics, patients with high cholesterol, and patients with previous manifestations of atherothrombosis). A potential clinically useful advantage of clopidogrel is its low propensity for adverse interaction with angiotensin-converting enzyme (ACE) inhibitors, contrary to what may be seen with aspirin, as observed in a post-hoc CAPRIE analysis. The putative aspirin-ACE inhibitor interaction is being tested prospectively in the Warfarin and Antiplatelet Therapy in Chronic Heart Failure (WATCH) trial - a randomized comparison of warfarin, clopidogrel and aspirin in patients with chronic heart failure. The good gastrointestinal tolerance of clopidogrel seen in CAPRIE has been further demonstrated in a study in healthy volunteers where there was a markedly lower gastroduodenal erosion score after 8 days' administration of clopidogrel 75 mg/day compared with aspirin 325 mg/day (p < 0.001). Following the positive findings obtained with clopidogrel plus aspirin in the Clopidogrel Aspirin Stent International Cooperative Study (CLASSICS) trial, other studies of clopidogrel plus aspirin have been initiated or are planned. These include Management of Atherothrombosis with Clopidogrel in High-risk patients (MATCH), a randomized comparison of clopidogrel plus aspirin versus clopidogrel in high-risk patients with recent stroke or transient ischaemic attack.
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PMID:Benefit of ADP receptor antagonists in atherothrombotic patients: new evidence. 1131 16

Atrial fibrillation, the most common chronic arrhythmia, results in an increased risk of stroke. Anticoagulation therapy can reduce this risk, but appears to be underused. The objective of this study was to examine the use of warfarin and prevalence of stroke in patients with rheumatic, nonrheumatic valvular and nonvalvular atrial fibrillation. Between January 1993 and December 1998, 457 chronic atrial fibrillation patients with continuous follow-up in our hospital were identified as having rheumatic heart disease (n = 114): nonrheumatic valvular disease (n = 65); or nonvalvular disease (n = 278). Warfarin was used less often in patients with nonrheumatic valvular (16.7%) and nonvalvular diseases (20.1%) than in those with rheumatic heart disease (81.6%, p < 0.001). In contrast, the prevalence of stroke among patients with nonvalvular disease was 40.3% which was similar to the 33.3% found in patients with rheumatic heart disease but significantly higher than the 24.6% found in patients with nonrheumatic valvular disease (p < 0.05). A history of stroke did not alter the trend of use of warfarin among the three groups of patients. Only 20.6% of patients on warfarin received monthly monitoring of prothrombin time. In conclusion, the anticoagulation therapy in our patients with chronic atrial fibrillation, regardless of their associated valvular diseases, is significantly underutilized. This underuse could account for a high prevalence of stroke. This risk of stroke, however, is less in patients with nonrheumatic valvular discase than in those with nonvalvular atrial fibrillation.
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PMID:Underutilization of anticoagulation therapy in chronic atrial fibrillation. 1132 7


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