Catheterization of pulmonary and carotid arteries for concurrent measurement of mean pulmonary arterial (mPAP) and systemic arterial pressure (mSAP) in PAH rats

Pulmonary hypertension (PH) is a group of pulmonary vascular disorders in which mean pulmonary arterial pressure (mPAP) becomes abnormally high because of various pathological conditions, including remodeling of the pulmonary arteries, lung and heart disorders, or congenital conditions. Various animal models, including mouse and rat models, have been used to recapitulate elevated mPAP observed in PH patients. However, the measurement and recording of mPAP and mean systemic arterial pressure (mSAP) in small animals require microsurgical procedures and a sophisticated data acquisition system. In this paper, we described the surgical procedures for right heart catheterizations (RHC) to measure mPAP in rats. We also explained the catheterization of the carotid artery for simultaneous measurement of mPAP and mSAP using the PowerLab Data Acquisition system. We enumerated the surgical steps involved in exposing the jugular vein and the carotid artery for catheterizing these two blood vessels. We listed the tools used for microsurgery in rats, described the methods for preparing catheters, and illustrated the process for inserting the catheters in the pulmonary and carotid arteries. Finally, we delineated the steps involved in the calibration and setup of the PowerLab system for recording both mPAP and mSAP. This is the first protocol wherein we meticulously explained the surgical procedures for RHC in rats and the recording of mPAP and mSAP. We believe this protocol would be essential for PH research. Investigators with little training in animal handling can reproduce this microsurgical procedure for RHC in rats and measure mPAP and mSAP in rat models of PH. Further, this protocol is likely to help master RHC in rats that are performed for other conditions such as heart failure, congenital heart disease, heart valve disorders, and heart transplantation.