Relationship between pulmonary artery pressure and structure of pulmonary artery in puppies with pulmonary artery hypertension

Objective\ To explore the relationship between pulmonary artery pressure (PAP) and structure of pulmonary artery (PA) in pulmonary hypertension (PH). Methods\ Fifteen experimental puppies were divided into 2 groups: shunted group ( n =12) and normal control group ( n =3). The pathologic examination of PA was done after hemodynamic changes were measured and recorded on the 90th day. Results\ (1) The pressure (PLLPA), resistance (LLPVR) and the blood glow (PBF) of the lower left pulmonary artery were elevated from 1.36 to 11.13 kPa (1 kPa=0.75 mm Hg), 5.65 to 14.31 Wood's U and 1.8 to 5.83 L/min , respectively ( P 0.01). The pressure of right pulmonary artery (PRPA) was also increased, but not so remarkable as PLLPA. (2) The structure of lower left pulmonary artery was changed observably, and the smooth muscle cells (SMC) proliferated and extended to the distance. The muscle artery (MA) and partially muscle artery (PMA) were increased in arterioles. The intima and media were proliferous and hypertrophic, and the occlusion and the plexiform were observed in some arterioles.However, the changes of right PA in shunt dogs were much milder than those of lower left PA and only observed in media. Conclusion\ The elevation of PAP resulted in the remodeling of PA. The different degrees of PH caused the different remodeling of PA, and the pathologic changes of PA led to a further elevation of PAP to form a vicious cycle.\;