Venous tone regulatory mechanisms: what's new?

The mechanisms regulating venous tone have an important effect on whether a patient develops the complication on post operative venous thrombosis. In animal studies, venous endothelial damage has been demonstrated in veins remote from the operative wound, and correlated with the amount of operative venodilation. In human studies, operative venodilation has been directly correlated with venographically proven postoperative deep venous thrombosis. Interestingly, operative venodilation and post operative deep venous thrombosis can be avoided with venotonic agents. The mechanisms responsible for the maintenance of venous tone are complex. The venous response is likely a result of a complex interaction of circulating biologically active substances, the endothelium-vascular smooth muscle interaction as well as humoral-endothelial-neurotransmitter balance.