Experimental Study Of The Operative Indication Of The Pulmonary Arterial Stenosis

OBJECTIVE To assess the critical degree of pulmonary stenosis for operative treatment on canine models experimentally created by constricting the pulmonary artery(PA) to various degrees and observing the changes of pressure in right ventricle, arterial blood gas analyses and biochemical products. METHOD 18 dogs were divided into 4 groups at random. PA constriction was 35% in group A(n=5), 50% in group B(n=5) and 65%in group C(n=5). Group D(n~3) served as control. Right ventricular pressure(RVP) was measured before and after the constriction ,Arterial blood gas analyses and biochemical products including serum lactic acid(LA) lipoperoxide(LPO) ,creatine phosphokinase(CPK) and lactic dehydrogenase( LDH), were determined prior to constriction and 1 6h, 40h and I 68h after the constriction. The histology of myocardial specimens taken before and after the PA constriction were examined by light microscope and the ultrastructures were observed with electron microscope. RESULTS All the parameters in group B and group C showed markedlly significant changes compared with group D(P<0.05). CONCLUSION The experimental data suggest that if the pulmonary artery is less than 50% of its normal size, surgery may be considered. However, clinical application of this principle must be carefully weighed in light of clinical manifestations and the results of other laboratory tests.