Bellomo R, Wunderink RG, Szerlip H, et al. - Among participants enrolled in the Angiotensin II for the Treatment of High-Output Shock (ATHOS-3) study, experiencing catecholamine-resistant vasodilatory shock (CRVS), researchers evaluated the epidemiology and outcome links of plasma angiotensin I (ANG I) and angiotensin II (ANG II) levels and their ratio in these protocol prespecified and subsequent post hoc analyses. They determined ANG I and ANG II concentrations at baseline, computed their ratio, and contrasted these outcomes to values from healthy volunteers (controls). Relative to healthy controls, patients with CRVS exhibited high ANG I levels and ANG I/II ratios. Greater norepinephrine demands related to a high ANG I/II ratio was evident in these patients. A high ANG I/II ratio was identified as an independent predictor of death in such patients, therefore, affording a biological rationale for interventions directed at its correction.