Study to Explore the Association of the Renin-Angiotensin System and Right Ventricular Function in Mechanically Ventilated Patients.

Background: Right ventricular () dysfunction is associated with pulmonary vasoconstriction in mechanically ventilated patients. Enhancing the activity of angiotensin-converting enzyme 2 (2), a key enzyme of the renin-angiotensin system (), using recombinant human 2 (2) could alleviate -mediated vasoconstriction and vascular remodeling.

Methods: This prospective observational study investigated the association between concentrations of peptides (Ang II or Ang(1-7)) and markers of function, as assessed by echocardiography (ratio of to left ventricular end-diastolic area, interventricular septal motion, and pulmonary arterial systolic pressure ()).

Results: Fifty-seven mechanically ventilated patients were enrolled. Incidence rates of acute cor pulmonale () and pulmonary circulatory dysfunction () were consistent with previous studies. In the 45 evaluable participants, no notable or consistent changes in peptides concentration were observed over the observation period, and there was no correlation between Ang II concentration and either or size. The model of the predicted posterior distributions for the pre- and post-dose values of Ang II demonstrated no change in the likelihood of after hypothetical dosing with 2, thus meeting the futility criteria. Similar results were observed with the other peptides evaluated.

Conclusions: Pre-defined success criteria for an association between and the plasma peptides were not met in the mechanically ventilated unselected patients.