Impact of residual stretch and remodeling on collagen engagement in healthy and pulmonary hypertensive calf pulmonary arteries at physiological pressures.

Understanding the mechanical behavior of proximal pulmonary arteries (PAs) is crucial to evaluating pulmonary vascular function and right ventricular afterload. Early and current efforts focus on these arteries' histological changes, in vivo pressure-diameter behavior and mechanical properties under in vitro mechanical testing. However, the in vivo stretch and stress states remain poorly characterized.

In vivo measurement of proximal pulmonary artery elastic modulus in the neonatal calf model of pulmonary hypertension: development and ex vivo validation.

Developing clinical work suggests that vascular stiffening plays a role in the progression of pulmonary hypertension (PH), while recent studies in animal models of hypoxic PH have found significant proximal vascular stiffening in the diseased population. Here, we develop and validate a minimally invasive, clinically realizable method to estimate the local elastic modulus of the proximal pulmonary arteries from pressure-diameter (PD) data. PD measurements were made in the main pulmonary arteries of 16 calves; lumen diameter was assessed using color M-mode tissue Doppler imaging ultrasound, while pressure was measured via catheter.