Experimental study of abdominal aorta strain reserve on early atherosclerosis in rabbits

Objective To explore the value of abdominal aorta strain reserve(SR) of rabbits during the period of early atherosclerosis using velocity vector imaging(VVI) techniques combined with nitroglycerin (NTG) vasodilation experiment.Methods Fifty-two male New Zealand White rabbits were used in this experiment.Group A(n=12) was the normal control group.Forty rabbits were made into atherosclerosis models.The SR of abdominal aortas of all rabbits were analyzed in short axis views using VVI and NTG vasodilation experiment at the forth week and the eighth week after feeding.The period of atherosclerosis into endothelial injury stage(group B) and intima thickening stage(group C) were divided.Results There were eighteen rabbits at the endothelial injury stage in group B and thirteen at the intima thickening stage in group C.Compared with control group,arterial SR values of group B and group C were significantly decreased in turn [4.13±1.21＞2.31±0.89＞1.22±0.77,Z=-2.978,P=0.003;Z=1.959,P=0.001],IMT of group C was significantly higher than that of group A(Z=-3.108,P=0.002),strain of group C was significantly lower than that of group A(Z=-2.415,P=0.016),the strain and IMT had no significant difference among three groups except group A and group C (P>0.05).A cut-off value was 3.67 of SR for diagnosing the endothelial injury aretary had a sensitivity of 70% and spectificity of 92.3% respectively obtained by the area under the ROC curve.The agreement of this diagnosis was very good.Conclusions The variable of the SR could stand for the variable of the vascular elasticity during the period of the early atherosclerosis.VVI and NTG vasodilation experiment could quantitatively assess SR of abdominal aortas of rabbits. Key words: Ultrasonography; Aorta,abdominal; Arteriosclerosis; Nitroglycerin; Velocity vector imaging