| Objectives To explore the relationship between transluminal attenuation gradient distal with corrected contrast opacification?TAG-CCO?and myocardial bridge?MB?type,severity of coronary artery stenosis,and nature of plaque in patients with MB,so as to better guide the clinical adoption of appropriate treatment measures.Methods From March 2017 to June 2018,200 patients with single left anterior descending artery?LAD?MB diagnosed by Philips Brilliance i CT 256-slice CT coronary angiography?CCTA?were collected from our hospital because of chest distress and chest pain,and the patients with coronary atherosclerosis in the anterior segment of the bridge and no artifacts in the diastolic images were taken as the study objects.The Philips intellispace portal workstation was used to process the diastolic image of the research objects,and to measured CT values of the LAD and the lumen of the same-layer aorta and the distance from the opening of left coronary artery.The least square method is used to calculate the linear regression equation,and the linear regression coefficient is TAG-CCO.Depending on the type of MB,they were divided into complete MB group and incomplete MB group.After that,compared whether there was a difference in TAG-CCO of anterior coronary artery between the two groups.Each type of MB component was further divided into mild,moderate and severe stenosis groups,and the TAG-CCO of the study subjects at the same degree of anterior segment of coronary stenosis groups in different types of MB groups was compared.And compared the TAG-CCO of the subjects with different degrees of anterior bridge coronary atherosclerosis in the same type of MB group.Coronary atherosclerotic plaque properties were further divided into calcified plaque group,non-calcified plaque group,and mixed plaque group.The difference in TAG-CCO between different plaque properties was compared.First of all,the normality test is carried out for each group of data,and the measurement data conforming to the normal distribution is expressed by ???±s,the count data is expressed by percentage.The difference of measurement data was compared with independent-samples t-test between the two groups;the three groups of measurement data are compared by using one-way ANOVA,the intragroup pairwise compared by LSD method for statistical analysis.Results There were 84 patients with complete MB and 116 patients with incomplete MB.The difference of TAG-CCO between the two groups was statistically significant?t=-4.518,P=0.000?.The difference of TAG-CCO between different types of MB patients with the same degree of stenosis was statistically significant?P<0.05?.Among 84 patients with complete MB,36,30 and 18 patients had mild,moderate or severe coronary atherosclerosis in the anterior segment of MB;among 116 patients with incomplete MB,45,42 and 29 patients with mild,moderate or severe coronary atherosclerosis in the anterior segment of MB.In the complete MB group,the TAG-CCO in the anterior segment of MB subgroups were?-0.0086±0.0014?,?-0.0170±0.018?,?-0.0230±0.0026?10mm-1,respectively,in mild,moderate,and severe subgroups?F=404.728,P<0.001?.In the incomplete MB group,the TAG-CCO of patients with mild,moderate and severe coronary stenosis in the anterior segment of MB were?-0.0039±0.0011?,?-0.0100±0.014?,?-0.0160±0.0020?10 mm-1,respectively,and the difference among the different stenosis groups was statistically significant?F=17.756,P<0.001?;the TAG-CCO of patients with mild?t=16.519,P<0.001?,moderate?t=2.570,P<0.05?and severe anterior segment coronary stenosis?t=10.714,P<0.001?were significantly lower in the complete MB group than in the incomplete MB group.There was no significant difference in TAG-CCO between calcified plaque,non calcified plaque and mixed plaque in the same degree of stenosis in complete MB group?P>0.05?;there was also no significant difference in TAG-CCO between calcified plaque,non calcified plaque and mixed plaque in the same degree of stenosis in incomplete MB group?P>0.05?.Conclusions TAG-CCO is related to MB type,the complete type's TAG-CCO is significantly lower than those of incomplete type.Coronary artery stenosis of the anterior segment is correlated.In the same myocardial bridge type and the same degree of stenosis,different plaque properties had no effect on TAG-CCO.This study suggests that TAG-CCO has certain value for clinical evaluation of patients' conditions and development of treatment plans.Figure 4;Table 7;Reference 108. |
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