(1481) Impact of Angiotensin II on Mortality in Septic Shock

Introduction: Septic shock is the most common type of distributive shock with an associated mortality rate of 30-40%. When hypotension persists despite adequate treatment, vasoactive agents are used to improve a patient’s hemodynamics. Studies have shown mortality increases as vasopressor requirements increase; often defined as greater than 0.5 mcg/kg/min norepinephrine equivalents (NEE). Angiotensin II (Ang2) is a non-catecholamine vasopressor which is an agonist of angiotensin type 1 receptors on vascular smooth muscle cells. The goal of this study is to evaluate the difference in in-hospital mortality between patients who were initiated on Ang2 before total vasopressor requirement was greater than 0.5 mcg/kg/min NEE compared to those who did not receive Ang2.

Methods: This study is a single-institution, retrospective cohort of adult patients admitted for septic shock between January 1, 2019 and July 31, 2022 who received vasopressor therapy for at least one hour at a NEE dose of 0.28 mcg/kg/min or greater. Patients included in the Ang2 cohort received Ang2 when their NEE was greater than or equal to 0.28 mcg/kg/min but not greater than 0.5 mcg/kg/min. The control group received greater than or equal to 0.28 mcg/kg/min NEE and did not receive Ang2. Initial MAP goals had to be greater than 65 mmHg and the patient had to receive hydrocortisone within 24 hours of admission. The primary outcome is the difference in in-hospital mortality.

Results: 46 patients were included in analysis (n=31 Ang2; n=15 control). The primary outcome occurred in 22 (71%) patients in the Ang2 cohort and 12 (80%) patients in the control group. ICU mortality was 64.5% in the Ang-2 cohort and 60% in the control group. Ang2 patients had a shorter ICU length of stay by an average of 4.9 days and a shorter hospital length of stay by an average of 3.8 days. Time to resolution of shock was shorter in the Ang2 cohort compared to control (92.6 + 122.3 hr vs 207.9 + 204.8 hr). Time to achieve lactic acid clearance was also shorter in the Ang2 cohort compared to control (68.6 + 80.7 hr vs 72 + 70.7 hr).

Conclusions: The study did not meet power to determine significance. Patients who received Ang2 had a lower in-hospital mortality and shorter ICU and hospital lengths of stay. Larger studies are necessary to determine statistical significance.