Study On Evaluation Of Abdominal Aortic Aneurysm Wall Elasticity With Ultrasound

Objective:Abdominal aortic aneurysm?AAA?is defined as a disease in which the abdominal aorta is partially or diffusely abnormally dilated,and it is an acute and critical macrovascular disease.The previous evaluation of vascular wall elasticity mostly depended on physical modeling or in vitro specimens.It is rarely reported that non-invasively evaluate the tube wall elasticity of AAA patients in vivo.D-Dimer and c-reactive protein?CRP?are commonly used serum biomarkers of AAA phase in clinical practice,which are used to dynamically evaluate the occurrence and development of AAA.However,the study on the correlation between ultrasound index and D-Dimer or CRP is rarely reported.The purpose of this study was to conduct non-invasive analysis of abdominal aortic wall movement using ultrasound technology in AAA patients,and to evaluate the elastic change of AAA wall.Meanwhile,this study will preliminarily discuss the correlation between ultrasonic parameters in AAA patients and major serological markers D-Dimer and CRP.Methods:43 patients with true spindle AAA diagnosed by CT angiography?CTA?and ultrasound in the department of vascular and thyroid surgery of the first affiliated hospital of China medical university from October 2017 to December 2018 were selected,including 34 males and 9 females.In the control group,37 cases,including24 males and 13 females,were selected from the routine physical examination in the physical examination center of our hospital during the same period and whose age and gender matched the case group,and all of them were confirmed to be AAA free by imaging examination.GE Vivid E9 color doppler ultrasound diagnostic instrument and M5S probe were used to collect images.Two-dimensional ultrasound images of the largest AAA tumor were retained for three consecutive cardiac cycles.In the control group,two-dimensional ultrasound images were taken at the level of15-20mm above the bifurcation of the common iliac artery in the middle and lower segment of the abdominal aorta,more than 15mm below the opening of the renal artery of the abdominal aorta in the control group.The anterior and posterior diameters?APD?,transverse diameters?TD?,systolic cross-sectional areas?SA?,and diastolic cross-sectional areas?DA?of AAA were measured routinely,and fractional area change?FAC?of AAA was calculated.The measured values by M-type ultrasound were:anterior wall displacement?d_a?,posterior wall displacemen?d_p?,systolic diameter?SD?.The relative displacement of the anterior wall?d_a/SD?and the relative displacement of the posterior wall?d_p/SD?were calculated.Spectral doppler ultrasound measurements:blood flow velocity at the entrance of AAA?V₁?,blood flow velocity at the maximum cross-sectional area?V₂?,and blood flow velocity at the exit?V₃?.Echo Pac image post-processing software was used to analyze the image offline.The system automatically tracked the trajectory of the blood vessel wall to obtain the abdominal aorta or AAA global peak circumferential strain GCS of systolic period.Results:1.Compared with the control group,D-Dimer and CRP were significantly increased in the case group?P<0.05?.2.Compared with the control group,APD,TD and SA in the case group were significantly increased,while FAC,d_a,d_a/SD,d_p/SD,V₂,V₃ and GCS were decreased?P<0.05?.3.Compared with the small AAA group,the APD,TD,SA and V₁ of the large AAA group increased,while the FAC,d_a/SD and GCS decreased?P<0.05?.V₃ was increased in the group with thrombus formation compared with the group without thrombus formation?P<0.05?.There was no significant difference in ultrasound parameters between different age groups.4.GCS is negatively correlated with APD,TD and SA,while positively correlated with FAC and d_a?P<0.05?.5.APD,TD and SA of abdominal aorta were positively correlated with age,D-Dimer and CRP?partial P<0.05?.FAC,d_a and GCS are negatively correlated with age,D-Dimer and CRP?partial P<0.05?,while FAC is positively correlated with BSA?P<0.05?.Conclusions:1.The FAC,d_a,d_a/SD,d_p/SD and GCS of abdominal aorta were decreased in AAA patients.2.Large AAA group FAC,d_a/SD and GCS reduction.3.APD,TD and SA of abdominal aorta were positively correlated with d-dimer and CRP,and negatively correlated with GCS,while FAC,d_a and GCS were negatively correlated with D-Dimer and CRP.