Transesophageal echocardiography risk factors for stroke in nonvalvular atrial fibrillation.

Atrial fibrillation is a common arrhythmia, particularly in the older age groups. It confers an increased risk of thromboembolism to these patients, and multiple clinical risk factors have been identified to be useful in predicting the risks of thromboembolic events. Recent studies have evaluated the role of transesophageal echocardiography (TEE) in the evaluation of patients with atrial fibrillation. The purpose of this review is to evaluate the significance of transesophageal echocardiographic findings in the prediction of thromboembolic events, particularly stroke, in patients with nonvalvular atrial fibrillation, with an emphasis on recently reported prospective studies. Aortic plaque and left atrial appendage abnormalities are identified as independent predictors of thromboembolic events. Although they are associated with clinical events, they also have independent incremental prognostic values. Other transesophageal echocardiographic findings, such as patent foramen ovale and atrial septal aneurysm, have not been found to be predictors of thromboembolic events in this patient group. Thus, TEE is a useful tool in stratifying patients with nonvalvular atrial fibrillation into different risk groups in terms of thromboembolic events, and it will likely play an important role in future studies to assess new treatment strategies in high-risk patients with atrial fibrillation.

Hydrophilic, semipermeable membranes fabricated with poly(ethylene oxide)-polysulfone block copolymer.

Semipermeable membranes may be fabricated from mixtures of poly(ethylene oxide)/polysulfone block copolymer (PEO-b-PSF) and polysulfone. Membranes fabricated with PEO-b-PSF possess a hydrophilic surface. PEO-b-PSF segregates to the membrane surface during phase inversion fabrication of the membrane rendering the surface hydrophilic. Changes in surface hydrophilicity were demonstrated by a dramatic reduction in the dynamic contact angle in water. With regard to the similar microporous hollow fiber membranes, a PEO-b-PSF membrane had a dynamic water contact angle of 33 degrees +/- 2 compared to a 111 degrees +/- 3 for a polysulfone membrane. Studies on porcine platelet-rich plasma in vitro demonstrated that the hydrophilic PEO-b-PSF membrane was resistant to platelet adhesion compared to a polysulfone membrane. An order of magnitude fewer adherent platelets were observed on a PEO-b-PSF membrane compared to a polysulfone membrane. The hydrophilicity of PEO-b-PSF makes it a unique material for the fabrication of membranes for medical devices.

Neuropsychological importance of subcortical white matter hyperintensity.

Subcortical hyperintensity on magnetic resonance imaging is a common incidental finding in healthy elderly subjects. The relationship of such changes to cognitive functioning remains unclear, however, because only a small number of studies have examined this issue with conflicting results. We therefore assessed 66 healthy adult volunteers (mean [+/- SD] age, 61.8 +/- 15.8 years) with magnetic resonance imaging scans rated for subcortical hyperintensity, and with two neuropsychological instruments selected a priori on the basis of previous reports in the literature. Findings were highly significant for both the Benton Facial Recognition Test and the Wechsler Adult Intelligence Scale-Revised Digit Symbol. However, in both cases, the majority of variance was accounted for by age and educational level. Effects of subcortical hyperintensity were not significant. We conclude that subcortical hyperintensity in healthy adults does not relate to cognitive functioning, at least with these two instruments.