Aspirin dosage and thromboxane synthesis in patients with vascular disease.

Study Objective: To determine whether urinary 11-dehydrothromboxane B2 (d-TXB2) is a marker of aspirin resistance and define the relationship between aspirin dosage and concentrations of this thromboxane metabolite.

Design: Randomized, crossover study.

Setting: Two outpatient clinical centers.

Markers of thrombin and platelet activity in patients with atrial fibrillation: correlation with stroke among 1531 participants in the stroke prevention in atrial fibrillation III study.

Background And Purpose: Markers of thrombin generation and platelet activation are often elevated in patients with nonvalvular atrial fibrillation, but it is unclear whether such markers usefully predict stroke. Therefore, we undertook the present study to assess the relationship between prothrombin fragment F1.2 (F1.

Clinically significant differences in the International Normalized Ratio measured with reagents of different sensitivities. SPAF Investigators. Stroke Prevention in Atrial Fibrillation.

The International Normalized Ratio (INR) system was introduced a decade ago as a way of standardizing the results of prothrombin time testing for patients taking oral anticoagulants. A strong emphasis has been placed upon using thromboplastin reagents that are very sensitive to the effects of oral anticoagulants upon the prothrombin time [i.e.

Plasmin-alpha2-antiplasmin complex in patients with atrial fibrillation. Stroke Prevention in Atrial Fibrillation Investigators.

Plasmin-alpha2-antiplasmin complex (PAP) is an index of recent fibrinolytic activity. We examined PAP levels in patients with atrial fibrillation (AF) to determine whether these levels are correlated with clinical characteristics associated with stroke risk. We obtained blood for measurement of PAP in a non-random sample of 586 patients with AF on entering the Stroke Prevention in Atrial Fibrillation III Study.

Stroke risk in an elderly population with atrial fibrillation.

Patients with nonvalvular atrial fibrillation (AF) have an increased risk of stroke, but the absolute rate of stroke varies widely depending on coexistent vascular disease. We assessed the stroke rate and predictive value of two published schemes for stroke risk stratification in a population-derived cohort of 259 elderly people with nonvalvular AF followed for a median of 5.3 years.

Anticoagulation for prevention of stroke.

One of the important recent advances in stroke prevention is the demonstration that warfarin can substantially reduce the risk for stroke in patients with atrial fibrillation (AF). On average, patients with AF have a stroke risk of 4.5% per year.

Behavioral issues in the efficacy versus effectiveness of pharmacologic agents in the prevention of cardiovascular disease.

A number of pharmacologic interventions are now recommended for the prevention of cardiovascular disease, based on the results of randomized controlled trials. These include antihypertensive drugs, lipid-lowering agents, antiplatelet and anticoagulant drugs, estrogen replacement therapy, beta-blockers, and angiotensin converting enzyme (ACE) inhibitors. It is likely that additional pharmacologic interactions will soon be proven efficacious.

Relationship between prothrombin activation fragment F1.2 and international normalized ratio in patients with atrial fibrillation. Stroke Prevention in Atrial Fibrillation Investigators.

Background And Purpose: The prothrombin time (expressed as the international normalized ratio [INR]) is the standard method of monitoring warfarin therapy in patients with atrial fibrillation. Prothrombin activation fragment F1.2 provides an index of in vivo thrombin generation and might provide a better index of the effective intensity of anticoagulation.

Status of lipids as a risk factor for stroke.

There is mounting epidemiologic evidence to support the relationship of lipids as a risk factor for ischemic stroke. We review epidemiologic and pathophysiologic evidence for such a link. Treatment of hyperlipidemia is addressed within the context of overall cardiovascular disease risk but also for stroke prevention.

Hemostatic markers in acute ischemic stroke. Association with stroke type, severity, and outcome.

Background And Purpose: Hemostatic markers can identify activation of the coagulation system in stroke patients. We evaluated whether the levels of these markers at the time of stroke are correlated with stroke severity, type, or mortality.

Methods: We measured fibrinopeptide A, cross-linked D-dimer, and beta-thromboglobulin in 70 patients within 1 week of stroke.

Comparison of centralized versus "site-based" measurement of angiographic stenosis for eligibility in the asymptomatic carotid atherosclerosis study.

Rationale And Objectives: The authors determine the reliability of centralized versus noncentralized (site-based) measurement of angiographic stenosis of patients enrolled into the multicenter, prospective, Asymptomatic Carotid Atherosclerosis Study by angiographic studies.

Methods: Percent agreements and correlations of 244 masked and prospectively interpreted angiograms were calculated for comparison of centralized and noncentralized readers measuring the percent carotid stenosis from the same angiographic studies. Univariate summary statistics for differences in percent stenoses were calculated for these readings.

The relative contributions of carotid duplex scanning, magnetic resonance angiography, and cerebral arteriography to clinical decisionmaking: a prospective study in patients with carotid occlusive disease.

Purpose: Recent reports suggest that 80% to 90% of patients can safely undergo carotid endarterectomy on the basis of duplex scanning alone without cerebral angiography. Other investigators have recommended that a complementary imaging study such as magnetic resonance angiography (MRA) also be obtained.

Methods: We prospectively evaluated 103 consecutive patients with carotid occlusive disease.

Primary and secondary stroke prevention.

Recent clinical trials have demonstrated that we can prevent stroke with appropriate medical and surgical therapy. Treatment of stroke risk factors, antiplatelet therapy, anticoagulant therapy, and carotid endarterectomy have all proven to be effective if applied in appropriate clinical circumstances. This review will highlight the areas in which we have clinical trial evidence to guide us, and will point out those circumstances in which uncertainty remains.

Differential effect of aspirin versus warfarin on clinical stroke types in patients with atrial fibrillation. Stroke Prevention in Atrial Fibrillation Investigators.

The Stroke Prevention in Atrial Fibrillation II study compared the efficacy and safety of aspirin and warfarin in patients with atrial fibrillation. Three neurologists, blinded to patient therapy, categorized the pathophysiology of ischemic strokes that occurred in the trial based on predetermined clinical criteria. Upon analyzing the patients being treated with these two drugs, warfarin proved significantly more effective than aspirin in preventing cardioembolic strokes (p = 0.

What's new in stroke?

More than 30,000 strokes occur each year in Texas, even though most strokes can be prevented by currently available and well-tolerated therapies. Antiplatelet therapy with aspirin or ticlopidine reduces stroke by about 25% in many patients with transient ischemic attack or initial stroke. Warfarin should not be used routinely for primary cerebrovascular disease but is useful to prevent cardioembolic stroke.

Prevalence, age distribution, and gender of patients with atrial fibrillation. Analysis and implications.

The prevalence of atrial fibrillation (AF) is related to age. Anticoagulation is highly effective in preventing stroke in patients with AF, but the risk of hemorrhage may be increased in older patients. We reviewed the available epidemiologic data to define the age and sex distribution of people with AF.