The Correlative Study Between Ascending Aortic Elasticity Of Stanford B Type Aortic Dissection And Coronary Stenosis Evaluated By CT

Objective:Since the change of elasticity of ascending aorta affects coronary blood flow and left heart function,the abnormal elasticity of ascending aorta is closely related to the occurrence and development of coronary artery stenosis,but no relevant research has been reported so far.Therefore,the purpose of this study was to investigate the value of 256-slice CT ECG gating scan in evaluating the elasticity of ascending aorta in Stanford type B aortic dissection and its correlation with coronary artery stenosis.Methods:Patients diagnosed with Stanford Type B aortic dissection and 256-slice CT ECG scan in our hospital from December 2019 to October 2020 were collected,and CTA examinations of aorta and coronary arteries were completed within one week,with good image quality and no obvious respiratory or cardiac pulse artifacts.According to the presence of coronary stenosis,the patients were divided into two groups:the positive group and the negative group,and the positive group was further divided into three groups:mild,moderate and severe stenosis.The ascending aortic images were reconstructed every 5%R-R intervals.The cross-sectional areas and diameters of aortic in each R-R interval were measured,then aortic distensibility(AoD),aortic compliance(AoC),aortic stiffness(AoSI)and diameter variation rate(%AO)were calculated to evaluate aortic elasticity.The extent of coronary stenosis was evaluated by Gensini score.Results:Fifty-six patients,including 37 males and 19 females,were included in the study.Thirty-five patients were positive for coronary artery stenosis and 21 were negative for coronary artery stenosis.In the stenosis positive group,there were 15 cases with mild stenosis,8 cases with moderate stenosis and 12 cases with severe stenosis.1.Comparison of coronary artery stenosis positive and negative group’s ascending aorta elastic index:coronary artery stenosis positive group compared with the negative group,four elastic index of the ascending aorta(%AO,AoD,AoC,AoSI)has obvious statistical significance difference(P<0.01),of which the aortic stiffness index(AoSI)between the two groups is the most significant difference.2.The elasticity indexes of ascending aorta between different stenosis degree groups:relative diameter change rate(%AO),dilatancy(AOD)and compliance(AOC)decreased with the increase of stenosis degree,and stiffness(AOI)increased with the increase of stenosis degree.3.Comparison of elasticity indexes of ascending aorta between different stenosis degree groups:there was no statistical significance differences in elasticity indexes except the aortic stiffness index(AOSI)between mild stenosis group and moderate stenosis group.There were statistically significant differences between mild stenosis group and severe stenosis group,moderate stenosis group and severe stenosis group.4.Correlation analysis of Gensini score and the positive group’s ascending aorta elastic index:Spearman correlation analysis results show that the Gensini score and the%AO,AoD and AoC has significant negative correlation(P<0.01,r-0.688,0.723 and 0.638 respectively),and the AoSI has significant positive correlation(P<0.01,r value was 0.965).5.Comparison of Gensini scores among groups with different degree of coronary artery stenosis:In this study,the Gensini scores of Stanford type B aortic dissection patients increased with the increase of degree of coronary artery stenosis.Conclusions:It is feasible to evaluate the arterial elasticity of Stanford type B aortic dissection and its correlation with coronary artery stenosis by using 256 slice spiral CT,the aortic elastic index of ascending aorta in Stanford type B aortic dissection is related to the degree of coronary artery stenosis.