BACKGROUND: A left-to-right shunting animal model is needed to study chronic pulmonary vascular remodeling of congenital heart attachment disease in adult.OBJECTIVE: To observe the characteristics of chronic pulmonary arterial hypertension in rat models subjected to left-to-right shunting.DESIGN, TIME AND SETTING: Randomized controlled animal modeling observation was performed in Experimental Animal Center, Xinqiao Hospital, the Third Military Medical University of Chinese PLA from April 2008 to April 2009.MATERIALS: A total of 80 male inbred line healthy SD rats of specified-pathogens free class, 4 weeks old, weighing 95-110 g, were randomly assigned into control group (n=40) and shunt operation group (n=40). A shrinking polyethylene blood vessel connector (proximal part inner diameter was 0.6 mm and outer diameter was 0.8 mm, while distal part's was 0.8 mm and 1.0 mm, respectively, 1.6 mm long), was applied.METHODS: Shunt operation group underwent left-to-right shunting through right common carotid artery and external jugular vein connected by shrinking polyethylene blood vessel connector. Control group underwent sham operation. At 4, 8, 12 and 16 weeks postoperation, ten models were determined with a series in procedures: hemodynamics detection, pathological sample preparation, hematoxylin-eosin staining, imaging analysis and so on.MAIN OUTCOME MEASURES: Changes in right ventricular systolic pressure, right ventricular hypertrophy index of right ventricle to left ventricle plus interventricular septum, and relative medial wall thickness in moderate sized pulmonary arteries in rats of shunt group and control group.RESULTS: All animal were survived. The pulmonary blood flow in shunt group was significantly higher than control groups (P<0.01). Compared with control group, right ventricular systolic pressure elevated obviously and right ventricular hypertrophy index were significantly higher in shunt group at 12 and 16 weeks (P<0.01). Compared with control group, the relative medial wall thickness in pulmonary arteries also elevated obviously in shunt group at 12 and 16 weeks (P<0.01).CONCLUSION: Left-to-right continuous low-flow shunt in rats can induced right ventricle accommodated with the change of right ventricular systolic pressure and promote chronic pulmonary arterial remodeling continuously. The procedure of establishing left-to-right shunting models with common carotid artery and external jugular vein connection, is a stable tool for studying chronic pulmonary arterial hypertension induced by low flow.