(1485) RAAS Therapy and Catecholamine Dose in Propensity Score-Weighted Septic Shock Patients

Introduction: Angiotensin II (Ang II) is used with catecholamines and vasopressin (Conventional Therapy) in patients with septic shock. Literature suggests benefit of early use of Ang II, at low background catecholamine doses. We sought to evaluate whether Ang II, when added to Conventional Therapy at different background catecholamine doses, was associated with differences in mortality in a large analysis of propensity-score weighted septic shock patients.

Methods: We performed a retrospective chart review of 1149 patients who received vasopressors for septic shock. Age/gender, sequential organ failure assessment (SOFA) score, serum lactate, and Charlson Comorbidity Index (CCI) were calculated at initiation of Ang II (Ang II cohort) or at the time it would have been initiated (Conventional Therapy cohort) based on a previously published protocol. We stratified patients by a catecholamine dose of 0.40 mcg/kg/min and used multivariable logistic regression to compare the two cohorts with regard to 30-day mortality.

Results: In both the high and low catecholamine strata, the Ang II and Conventional Therapy cohorts were well distributed by age and gender but differed by SOFA, CCI, and lactate (all p values < 0.001). For patients with catecholamine doses above 0.40 mcg/kg/min (n=426), 30-day mortality was higher in the Ang II cohort than in the Conventional Therapy Cohort (OR 1.98, 95% CI: 1.20-3.27, p=0.008). However, for those below 0.40 mcg/kg/min (n=708), 30-day mortality was no different between the two cohorts (OR 0.95, 95% CI: 0.64-1.42, p=0.808). After propensity-score weighting, all variables were well-balanced, and the odds ratio for 30-day mortality in patients with high background catecholamines fell to 1.54 (95% CI: 1.00-2.38, p=0.049). Likewise, for those below 0.40 mcg/kg/min, the odds ratio for 30-day mortality fell to 0.84 (95% CI: 0.59-1.18, p=0.310).

Conclusions: Patients who receive Ang II at catecholamine doses above 0.40 mcg/kg/min are at higher risk of death, while those who receive Ang II at low catecholamine doses are not. These findings are preserved when adjusting for severity of illness and comorbidity using propensity score weighting. A dose of 0.40 mcg/kg/min, commonly considered a threshold of high versus low catecholamine dose, may help guide clinicians when considering Ang II.