View clinical trials related to Vascular Stiffness.
Filter by:Arterial hypotension during induction of general anesthesia is a risk factor for developing postoperative cardiovascular complications. After induction of general anesthesia patients have a high risk of developing arterial hypotension due to anesthetic drugs who can depress cardiac contractility and determine vasodilatation. Previous studies have shown that even short periods of hypotension with a mean arterial pressure of less than 55 mmHg during surgery is associated with an increased incidence of cardiac injury and acute kidney injury in the postoperative period. The volemic status of the patients in the preoperative period is very difficult to quantify and can vary due to comorbidities of the patient, chronic treatment, preoperative fasting. Bioimpedance is recognized by over 30 years as a simple and non invasive technique to determine the volemic status especially in the hemodialysed patients. A new device BCM- Body Composition Monitoring (Fresenius Medical Care) offers a simple method to determine extracellular water and total body water. These volumes are determined by measuring impedance at 50 different frequencies thru electrodes placed at the ankle and wrist. BCM can also determine lean tissue mass and adipose tissue mass. Increasing arterial stiffness is the main characteristic of arterial aging; this increase determines the increase of the afterload, left ventricular hypertrophy, the decrease of coronary and tissue perfusion. Arterial applanation tonometry is a non-invasive technique that has been shown to reliably provide indices of arterial stiffness. In this study investigators wish to determine if there is a correlation between the hidric status determined by BCM, carotid-femural pulse wave velocity determined with SphygmoCor system and the development of hypotension during induction of general anesthesia. The measurements will be obtained before induction of general anesthesia in the pre-surgical area. During induction of general anesthesia with standard induction agents and Bispectral index monitoring, brachial blood pressure will be measured by a cuff every minute after the loss of verbal contact with the patient up to ten minutes after tracheal intubation. A hypotensive response to anesthesia will be defined as a drop in mean arterial pressure below 55mmHg or a drop in mean arterial pressure with more than 40% than the base line value of the patient before the surgery. Measurement of the hidric status and aortic stiffness may represent a valid indicator of the risk of hypotension during anesthesia induction.
The conduit arteries exhibit a viscoelastic behavior. Visco-elasticity is partially regulated by endothelium and contributes to the optimization of the heart-vessel coupling. Aging or high resting heart rate (HR) could alter visco-elastic properties leading to increase stiffness of the conduit arteries, an independent cardiovascular risk factor, and degradation of heart-vessel coupling. Lowering HR with ivabradine could reduce these effects. The objective of this study is to assess the effect of HR reduction by repeated administration of ivabradine on visco-elastic properties, vascular geometry and function of common carotid artery, and on cardiovascular hemodynamic in healthy subject. The influence of aging on ivabradine effects are studied too. 30 healthy volunteers aged between 25 and 65 years old, with a HR ≥ 70 bpm, will receive ivabradine or placebo during 8 days in a single center, randomized, cross-group, double blinded, placebo-controlled study. Each period of treatment will be separate by 12 to 16 days of wash-out. Each subject will participate in an exploration visit, including evaluation of visco-elastic properties, vascular geometry and function of common carotid artery, and cardiovascular hemodynamic, before and after ivabradine or placebo taking.
The current study proposes to investigate the effects of chronic snus use on the blood vessels. Several cardiovascular endpoints are measured using various methods in healthy daily snus users as well as in healthy matched controls.