Mechanistic Assessment of Norepinephrine Therapy versus Angiotensin-II in Septic Shock (MANTRA): Study Protocol for a multicenter randomized trial

Introduction: Norepinephrine remains first-line vasopressor therapy for septic shock despite its association at high doses with undesirable cardiovascular, kidney, and immune effects. Angiotensin-II (Ang-II) is a non-catecholamine vasopressor of the renin-angiotensin-aldosterone system (RAAS) now approved to increase blood pressure in vasodilatory shock. RAAS dysregulation is common in septic shock and may represent a treatable trait. However, few prospective investigations evaluate the effect of early Ang-II use in septic shock on dysfunctional RAAS biology, host-response, or clinical outcomes. Therefore, we designed a mechanistic clinical trial to test the hypothesis that early Ang-II therapy in septic shock normalizes systemic RAAS abnormalities and modulates innate immune responses.