Pulmonary arterial compliance and pulmonary hemodynamic effects of Serelaxin in a sheep model.

Background: The influence of the recombinant form of human relaxin-2 (serelaxin) on pulmonary hemodynamics under physiologic conditions have not been the subject of studies in an animal model up until now.

Methods: We therefore utilised the large animal model sheep, convenient in its similar cardiovascular physiology, to investigate said influence. All animals underwent right heart catheterization, a safe and reliable invasive procedure for the assessment of pulmonary hemodynamics, and then received either 30μg/kg serelaxin (n = 11) or saline (n = 13). Systolic, diastolic and mean values of both pulmonary artery pressure (respectively, PAPs, PAPd, PAPm) and pulmonary capillary wedge pressure (respectively, PCWs, PCWd, PCWm) blood gases, heart rate (HR) and both peripheral and pulmonary arterial oxygen saturation were obtained. Cardiac output (CO), pulmonary vascular resistance (PVR), pulmonary arterial compliance (PAcompl) and systemic vascular resistance (SVR) were calculated.

Results: The key findings of the current study are that 20 min after serelaxin injection a rapid decrease of the PAPm, PCWPm, SVR and an decrease of the PAcompl was observed (P < 0.01).

Conclusion: These findings suggest that serelaxin might be suitable to improve pulmonary hemodynamics in clinically relevant scenarios, like acute heart failure or pulmonary hypertension.