BACKGROUND/AIM: Brachial artery flow-mediated dilation (FMD) is extensively used for non-invasive assessment of endothelial function. Traditionally, FMD is calculated as a percent change of arterial diameter from the baseline value at an arbitrary time point after cuff deflation (usually 60 seconds). Considerable individual differences in brachial artery temporal response to hyperemic stimulus have been observed, potentially influenced by the presence of atherosclerotic risk factors (RF). The importance of such differences for the evaluation of endothelial function has not been well established. The aim of the study was to determine the time course of maximal brachial artery endothelium-dependent dilation in healthy adults with and without RF, to explore the correlation of RF with brachial artery temporal response and to evaluate the importance of individual differences in temporal response for the assessment of endothelial function. METHODS: A total of 115 healthy volunteers were included in the study. Out of them, 58 had no RF (26 men, mean age 44 +/-14 years) and 57 had at least one RF (29 men, mean age 45 +/-14 years). High-resolution color Doppler vascular ultrasound was used for brachial artery imaging. To determine maximal arterial diameter after cuff deflation and the time-point of maximal vasodilation off-line sequential measurements were performed every 10 seconds from 0 to 240 seconds after cuff release. True maximal FMD value was calculated as a percent change of the true maximal diameter from the baseline, and compared with FMD value calculated assuming that every participant reached maximal dilation at 60 seconds post cuff deflation (FMD60). Correlation of different RF with brachial artery temporal response was assessed. RESULTS: A maximal brachial artery endothelium-dependent vasodilation occurred from 30-120 seconds after cuff release, and the mean time of endothelium-dependent dilation was 68 +/-20 seconds. Individuals without RF had faster endothelium-dependent dilation (mean time 62 +/-17 seconds), and a shorter time-span (30 to 100 seconds), than participants with RF (mean time 75 +/-21 seconds, time-span 40 to 120 seconds) (p < 0.001). Time when the maximal endothelium-dependent dilation occurred was independently associated with age, serum lipid fractions (total cholesterol, LDL and HDL cholesterol), smoking, physical activity and C-reactive protein. True maximal FMD value in the whole group (6.7 +/-3.0%) was significantly higher (p < 0.001) than FMD60 (5.2 +/-3.5%). The same results were demonstrated for individuals with RF (4.9 +/- 1.7% vs 3.1 +/- 2.3%, p < 0.001) and without RF (8.4 +/- 2.9% vs 7.2 +/- 3.2%, p < 0.05). CONCLUSION: The temporal response of endothelium-dependent dilation is influenced by the presence of coronary FR and individually heterogeneous. When calculated according to the commonly used approach, i.e. 60 seconds after cuff deflation, FMD is significantly lower than the true maximal FMD. The routinely used measurement time-points for FMD assessment may not be adequate for the detection of true peak vasodilation in individual persons. More precise evaluation of endothelial function can be achieved with sequential measurement of arterial diameter after hyperemic stimulus.

Discontinuation of antiepileptic therapy presents a challenge for physicians and patient. Many parameters play a role, and the doctor has to assess the relationship between benefits and any possible damages caused by this act. The final decision should be made with the parents and the patient. In this study, we assessed the role of various factors on the possibility of relapse of epileptic seizures after discontinuation off antiepileptic therapy. We studied a cohort of children with partial epilepsy. Discontinuation was performed from 2001-2007. The study included 93 children divided into groups according to age of diagnosis and the introduction of antiepileptic therapy, the type of seizures, etiology, neurological and psychological status, the results neuroimaging studies, family history, history of febrile seizures, antiepileptic therapy, EEG registration before discontinuation of the treatment, speed of tapering therapy. Multivariable analysis was made, binary logistic regression. Factors that showed statistical significance were: age at the diagnosis, duration of active epilepsy, neurological and psychological status, EEG registration before discontinuation of therapy, the length of the period without seizures before discontinuation of the therapy and length of tapering the therapy.It is necessary to pay attention to the factors affecting increased risk of relapse of epileptic seizures when discontinuing the antiepileptic therapy in patients with partial epilepsies. This should be discussed with parents and patients, and consensus has to be reached. Doctor and patient must be aware that the risk of recurrence of epileptic seizures is high.