Systemic hypertension and the right-sided cardiovascular system: a review of the available evidence

Abnormal vasoconstriction of the lesser circulation characterizes a subset of patients with essential hypertension, a possible effect of mechanisms, such as enhanced sympathetic tone, increased delivery of blood-borne vasoconstrictor substances or abnormal local release of vasoactive factors, acting on both sides of the circulation or to backward transmission of increased pressure due to stiffer left ventricles with more advanced diastolic dysfunction. Elevated systemic pressure also associates with thickening of the right ventricle, a central element of the low-pressure system. Right ventricular remodelling develops in parallel with a similar process occurring at the left side, likely as a result of ventricular interdependence under the influence of trophic factors targeting both ventricles, though other mechanisms, including increased pulmonary afterload, may also be operative. By and large independent of the extent of structural remodelling of both ventricles, systemic hypertension also conditions an impaired filling rate of the right ventricle that accompanies a similar phenomenon at the left side. Thus, quite in contrast with the common and simplistic assumption of a separate behaviour of the two ventricles, the right-sided cardiovascular system is not immune to the effect of systemic hypertension, a concept whose clinical and pathophysiological implications require further studies.