Association Between Apelin and Atrial Fibrillation in Patients With High Risk of Ischemic Stroke.

Background: Atrial fibrillation (AF) is associated with high risk of stroke preventable by timely initiation of anticoagulation. Currently available screening tools based on ECG are not optimal due to inconvenience and high costs. Aim of this study was to study the diagnostic value of apelin for AF in patients with high risk of stroke. Methods: We designed a multicenter, matched-cohort study. The population consisted of three study groups: a healthy control group (34 patients) and two matched groups of 60 patients with high risk of stroke (AF and non-AF group). Apelin levels were examined from peripheral blood. Results: Apelin was significantly lower in AF group compared to non-AF group (0.694 ± 0.148 vs. 0.975 ± 0.458 ng/ml, p = 0.001) and control group (0.982 ± 0.060 ng/ml, p < 0.001), respectively. Receiver operating characteristic (ROC) analysis of apelin as a predictor of AF scored area under the curve (AUC) of 0.658. Apelin's concentration of 0.969 [ng/ml] had sensitivity = 0.966 and specificity = 0.467. Logistic regression based on manual feature selection showed that only apelin and NT-proBNP were independent predictors of AF. Logistic regression based on selection from bivariate analysis showed that only apelin was an independent predictor of AF. A logistic regression model using repeated stratified K-Fold cross-validation strategy scored an AUC of 0.725 ± 0.131. Conclusions: Our results suggest that apelin might be used to rule out AF in patients with high risk of stroke.

Oxidative stress and antioxidant defense systems in patients after heart transplantation.

Heart transplantation ranks among those surgical interventions associated with ischemia-reperfusion injury to the donor heart as well as to the recipient. These events are connected with increased production of reactive oxygen species which evoke metabolic, structural and functional disturbances. Twenty-four transplant patients were investigated for oxidative stress (plasma levels of thiobarbituric acid reactive substances, TBARS) and antioxidant capacity (plasma total antioxidant status, TAS), and for activities of erythrocyte superoxide dismutase (SOD) and glutathione peroxidase (GPx) during the first year after heart transplantation. The post-transplant period was characterized by progressive decrease of plasma TAS, indicating a significant long-term drop of antioxidant reserves in patients after successful heart transplantation. The decrease in plasma TAS is accompanied by long-lasting increase of TBARS levels, which may represent oxidative stress of the organism. We conclude that additional therapy with antioxidant substances should be an important component of the complex therapeutic programme of patients after heart transplantation.