Approach of the peripheral circulation in heart failure

Peripheral vascular abnormalities make a major contribution to the circulatory disturbances in the chronic heart failure syndrome. These vascular changes have been identified in the past by calculating systemic vascular resistance as the ratio of the mean arterial pressure and cardiac output. This calculated parameter is inadequate for an accurate assessment of the different parts of the vascular system. Arterial compliance is usually determined at a certain site or segment of the arterial system. It differs along the arterial tree, because of differences in wave travelling properties (distensibility) and differences in arterial diameter. Systemic arterial compliance gives an overall index of compliance in the whole arterial system and is an important factor in determining cardiac afterload. Vascular compliance measurements are becoming an attractive way of detecting abnormalities of the conduit arteries and monitoring the vascular response by physiological and pharmacological interventions. Arterial blood flow can be measured at the forearm and calf (mainly representative for muscle circulation) or at the finger (mainly representative for skin circulation) at rest and during reactive hyperemia by venous occlusion plethysmography. In several studies muscle blood flow has also been determined during different types of exercise. Furthermore the influence of the endothelial function can be assessed by measuring local blood flow during intra-arterial local administration of acetylcholine or L-arginin. The microcirculation plays a crucial role in the nutritional exchange process of the different tissues. Morphological and functional changes at the level of the capillaries can be examined noninvasively by capillaroscopy and the determination of capillary blood cell velocity. Venous compliance of the peripheral circulation can be determined by venous occlusion plethysmography. It may contribute to the cardiac preload. The approach of the different parts of the peripheral circulation in the chronic heart failure syndrome can help us in the better understanding of the pathophysiologic process as well as in the evaluation of the therapeutical choice.