Role of vasopressinergic V₁ receptor agonists in the treatment of perioperative catecholamine-refractory arterial hypotension

Three pathways are critically involved in blood pressure regulation during anaesthesia, i.e. the sympathetic nervous system, the renin angiotensin system (RAS), and the vasopressinergic system. The fact that anaesthetic agents typically blunt the regulatory role of the adrenergic system emphasises the importance of the remaining compensatory mechanisms. In patients chronically treated with RAS antagonists, such as angiotensin converting enzyme inhibitors and angiotensin II receptor antagonists, however, this mechanism is also blunted, possibly resulting in absolute dependency of blood pressure regulation on the vasopressinergic system. To date, several small-scale clinical trials demonstrated the efficacy of V₁ receptor agonists in reversing perioperative catecholamine-refractory hypotension in patients with chronic RAS blockade. Therefore, perioperative administration of a V₁ agonist, such as terlipressin, may be a rational approach to treat severe hypotension non-responsive to conventional treatment strategies. In the absence of catecholamine resistance and RAS blockade, administration of V₁ agonists may contribute to a dose-dependent reduction in regional splanchnic vasoconstriction. Likewise, bolus infusion may result in coronary vasospasm and is thus not recommended for routine clinical use. Future large-scale randomized, controlled clinical trials are warranted to evaluate the role of V₁ agonists in the treatment of perioperative hypotension in more detail.

Key words: angiotensin converting enzyme inhibitors, angiotensin II receptor antagonists, blood pressure regulation, vasopressin, terlipressin