Application of superior vena cava Doppler spectra in evaluation of the therapeutic effects of hypobaric hypoxia-induced pulmonary hypertension in rats

Abstract

Objective To explore the value of superior vena cava (SVC) Doppler spectrum in evaluation of the therapeutic effects of intermittent hypobaric hypoxia (HBHO)-induced pulmonary hypertension (PH) in rats and establish a new method for assessing pulmonary hypertension.Methods Fifty male SD rats were included.Forty of them were developed HBHO-PH and randomly divided into four groups with different manipulations:beraprost treatment group,sildenafil treatment group,placebo group and model group,with 10 rats in each group.The rest of 10 rats served as controls.Cardiac structure,pulmonary peak velocity (PAVmax),tricuspid peak velocity (TVEmax) and SVC Doppler ultrasound were performed in all rats before and after treatment for 2 weeks.Pulmonary arterial pressure was determined by the right heart catheterization.The relationship of the parameters with the pulmonary arterial pressure was analyzed.HE staining was done in lung tissues.Results Right heart catheterization showed that pulmonary artery systolic pressure (PASP) of the treatment groups were lower than that of the model group,the difference was significant(P ＜0.01).Pulmonary artery pressure decreased in varying degrees both after placed in a normal environment and after 2 weeks of treatment.PASP of the beraprost treatment group and the sildenafil treatment group decreased significantly and showed no statistical significant difference with the control group.In contrast,PASP of the placebo group was significant higher than that of control group(P ＜ 0.05).No statistically significant difference was found between the non-placebo treatment groups in PASP.Compared with the control group,the right ventricle/body weight ratio of the model group was statistically significant increased in all other groups(P ＜0.01).Right SVC AR/S ratio was well correlated with PASP (r =0.603,P =0.001).Right SVC AR/S ratio was statistically significant lower in treatment groups compared with the model group (P ＜0.01).All groups except the control group demonstrated various degrees of pulmonary arterial wall thickening.Conclusions The right SVC spectrum of AR/S correlates well with PASP and can be used to evaluate the pharmacological therapeutic effect of rats with HBHO-PH,in particular with moderate to severe PH. Key words: Ultrasonography; Vena cava, superior; Hemodynamics; Hypertension, pulmonary; Hypobaric hypoxia