Aortic elastic properties and left ventricular diastolic dysfunction in patients with obstructive sleep apnea

Although the responsible mechanisms are not yet fully known, obstructive sleep apnea is associated with an increased risk for cardiovascular disease and events. The aorta is not only a conduit delivering blood to the tissues but is also an important modulator of the entire cardiovascular system, its elastic properties also affecting left ventricular function and coronary blood flow. The aim of this study was to determine left ventricular diastolic function and aortic elastic properties in patients with obstructive sleep apnea syndrome. Fourteen male patients with obstructive sleep apnea and 14 age- and body mass index-matched healthy male controls took part in the study as a control group. All subjects underwent echocardiographic examination; left ventricular cavity dimension, standard and tissue Doppler parameters, and aortic diameter (3cm above aortic valve) at systole and diastole were measured. While the aortic stiffness index in patients with obstructive sleep apnea was significantly higher than that of the control group (4.5 +/- 0.3 vs 2.1 +/- 0.1, P = 0.001), the aortic distensibility index was found to be lower in this group compared with controls (2.4 +/- 1.2 vs 3.9 +/- 1.5cm(2)dyne(-1)10(-6) P = 0.009). Furthermore, peak velocity of myocardial systolic wave and peak velocities of myocardial diastolic waves in sleep apnea patients were lower than in controls. There was an association between aortic stiffness and the apnea hypopnea index (coefficient = 0.49, P = 0.002). We also found an inverse correlation between peak velocity of myocardial diastolic wave and aortic stiffness (coefficient = -0.43, P = 0.003), using multiple linear regression. Increased aortic stiffness that is associated with the severity of disease in patients with obstructive sleep apnea may lead to diastolic dysfunction of the left ventricle

Discrimination between physiologic and pathologic left ventricular dilatation

The identification of certain cardiovascular disease in athletes may constitute the basis for disqualification from competition in an effort to minimize the risk of sudden cardiac death. The aim of this study was to assess diastolic and systolic parameters measured by tissue Doppler imaging in endurance veteran athletes who had prominent cardiac dilatation and patients with idiopathic dilated cardiomyopathy in order to determine whether these variables might differentiate each other. (c) 2005 Elsevier Ireland Ltd. All rights reserved

Endothelial flow-mediated dilatation and exercise capacity in highly trained endurance athletes

Brachial artery ultrasound during reactive hyperemia is a noninvasive method of assessing peripheral endothelium-dependent vasodilatation. Aerobic exercise has the potential to improve local endothelial function. We sought to analyze the effects of regular aerobic training on brachial artery endothelial function in endurance athletes. We studied diameter and blood flow of the brachial artery in 32 endurance male athletes and 30 healthy male subjects. In the same subjects flow-mediated dilatation of the brachial artery was recorded by inducing an ischemia through a forearm arterial occluding cuff. Maximal oxygen consumption was significantly higher in the athletes group than in the controls (61.24 +/- 5.43 vs 44.49 +/- 2.68 ml/kg/min, p < 0.001). Flow-mediated dilatation of the brachial artery induced by forearm arterial occlusion in athletes was also higher than that of the control subjects (17.1 +/- 2.3 vs 11.2 +/- 1.7, p = 0.002). Furthermore, there was an association between flow-mediated dilatation and VO2max (r = 0.69, p < 0.001). Baseline measurements of the diameter and the blood flow volume of the brachial artery were similar in both groups. During reactive hyperemia period, the percent of the changes of endothelial diameters and flow were significantly higher in athletes than in controls. Higher flow-mediated dilatation levels in athletes reflect better vascular adaptation to habitual aerobic exercise. - endothelium; athlete; exercise; nitric oxide (C) 2005 Tohoku University Medical Press

The Transeurope Footrace Project: longitudinal data acquisition in a cluster randomized mobile MRI observational cohort study on 44 endurance runners at a 64-stage 4,486km transcontinental ultramarathon

BACKGROUND: The TransEurope FootRace 2009 (TEFR09) was one of the longest transcontinental ultramarathons with an extreme endurance physical load of running nearly 4,500 km in 64 days. The aim of this study was to assess the wide spectrum of adaptive responses in humans regarding the different tissues, organs and functional systems being exposed to such chronic physical endurance load with limited time for regeneration and resulting negative energy balance. A detailed description of the TEFR project and its implemented measuring methods in relation to the hypotheses are presented. METHODS: The most important research tool was a 1.5 Tesla magnetic resonance imaging (MRI) scanner mounted on a mobile unit following the ultra runners from stage to stage each day. Forty-four study volunteers (67% of the participants) were cluster randomized into two groups for MRI measurements (22 subjects each) according to the project protocol with its different research modules: musculoskeletal system, brain and pain perception, cardiovascular system, body composition, and oxidative stress and inflammation. Complementary to the diverse daily mobile MR-measurements on different topics (muscle and joint MRI, T2*-mapping of cartilage, MR-spectroscopy of muscles, functional MRI of the brain, cardiac and vascular cine MRI, whole body MRI) other methods were also used: ice-water pain test, psychometric questionnaires, bioelectrical impedance analysis (BIA), skinfold thickness and limb circumference measurements, daily urine samples, periodic blood samples and electrocardiograms (ECG). RESULTS: Thirty volunteers (68%) reached the finish line at North Cape. The mean total race speed was 8.35 km/hour. Finishers invested 552 hours in total. The completion rate for planned MRI investigations was more than 95%: 741 MR-examinations with 2,637 MRI sequences (more than 200,000 picture data), 5,720 urine samples, 244 blood samples, 205 ECG, 1,018 BIA, 539 anthropological measurements and 150 psychological questionnaires. CONCLUSIONS: This study demonstrates the feasibility of conducting a trial based centrally on mobile MR-measurements which were performed during ten weeks while crossing an entire continent. This article is the reference for contemporary result reports on the different scientific topics of the TEFR project, which may reveal additional new knowledge on the physiological and pathological processes of the functional systems on the organ, cellular and sub-cellular level at the limits of stress and strain of the human body.Please see related articles: http://www.biomedcentral.com/1741-7015/10/76 and http://www.biomedcentral.com/1741-7015/10/77