Circulatory abnormalities in cirrhosis with focus on neurohumoral aspects.

Patients with cirrhosis exhibit characteristic hemodynamic changes with a hyperkinetic circulation and an abnormal distribution of the blood volume and neurohumoral regulation. Their plasma and noncentral blood volumes are increased, and the central and arterial blood volume and systemic vascular resistance are decreased. A peripheral arterial vasodilatation may be of pathogenic importance to the low systemic vascular resistance as it directly correlates to the degree of central hypovolemia. It may therefore be an important element in the development of the low arterial blood pressure and hyperkinetic circulation in cirrhosis. Various vasodilators such as atrial natriurectic peptide, calcitonin gene-related peptide, adrenomedullin, and nitric oxide are among potential candidates in the arterial vasodilatation in cirrhosis. Besides enhanced sympathetic nervous activity, activation of the renin-angiotensin-aldosterone system, and elevated circulating vasopressin, endothelin-1 may also be implicated in the hemodynamic counter-regulation in cirrhosis. Recent research has focused on the assertion that the hemodynamic and neurohumoral abnormalities in cirrhosis are part of a general circulatory dysfunction influencing the course of the disease.