A Correlation Study On The Evaluation Of Fatty Acid-binding Protein4 And Carotid Vulnerable Plaques Based On Contrast-enhanced Ultrasound

ObjectiveTo investigate the value of predicting the vulnerability of plaques in assessment of intraplaque neovascularization using contrast-enhanced ultrasound.Contrast-enhanced ultrasound was used to diagnose vulnerable plaques and then analyze the relationship between fatty acid-binding protein 4(FABP4)and carotid artery atherosclerotic stenosis.Methods1.The total of 24 cases which were admitted neurosurgical treatment from September 2017 to October 2018 in the Chinese PLA General Hospital,with complete base characteristics,diagnosed as moderate to severe carotid stenosis by digital subtraction angiography(DSA)underwent carotid endarterectomy.They were performed preoperative carotid contrast-enhanced ultrasound and postoperative pathological examination.The correlation between the grading of enhancement by CEUS and the density of neovascularization was analyzed by Pearson correlation.The diagnostic value of assessment of intraplaque neovascularization using contrast-enhanced ultrasound was estimated by ROC(Receiver operating characteristic curve).The diagnostic accuracy of CEUS was judged by the value of AUC(Area under curve).2.We selected 30 cases with moderate-severe carotid stenosis diagnosed with DSA and CEUS(including 6 cases not performed by CEA).Venous blood specimens from left antecubital vein(6 ml volume)were collected in the first morning(06:00 am)from the patients after admission under fasting state.Blood samples were centrifuged at 2000 g for 10 min.The serum fatty acid-binding protein was determined using ELISA(Enzyme-linked immunosorbent assay).The plaque samples were obtained from 24 cases in the first portion of the study.The plaque samples were stored with liquid nitrogen and then the FABP4 in the plaque samples were assayed by Western blot(WB).The grayscale of bindings were analyzed by Image J software.14 healthy volunteers in the same period were recruited as controls in our hospital.Venous blood specimens from left antecubital vein(6 ml volume)were collected in the morning from the controls after an overnight fast.The serum fatty acid-binding protein was also assayed by ELISA.The comparisons between stenosis group and controls in the serum FABP4,vulnerable and non-vulnerable plaque subgroups in the serun FABP4,vulnerable and non-vulnerable subgroups in the grayscale value of plaque FABP4 were evaluated by independent samples t-test.The comparisons of the serum FABP4 in the symptomatic subgroup,asymptomatic subgroup and controls were analyzed by One-Way ANOVA and then analyzed the serum FABP4 in every two groups using Student Newman Keuls-q test and Least Significance Difference-t test.The correlation between the serum FABP4 and laboratory parameters in stenosis group,grading of enhancement in CEUS and the serum FABP4,grading of enhancement in CEUS and the grayscale value of plaque[FABP4 were analyzed by Pearson correlation.Results1.Compared with postoperative pathological results,22 cases were clearly diagn-osed by preoperative carotid contrast-enhanced ultrasound,and 2 cases were misse-d.The precision rate of preoperative diagnosis was 91.67%(22/24).Meanwhile car-otid plaques were divided into four grades(Grade ???)according to the degree of enhancing extent of contrast-enhanced ultrasound.Each grade included 6 cases.Pea-rson correlation analysis showed there was an evidently positive correlation betwee-n preoperative grade of carotid plaques and number of intraplaque CD34-positive ne-ovessels(r=0.871,P=0.000).The value of area under curves(AUC)was 0.927(95%CI:0.848?1.006,P=0·000)·2.There were sig1ificant differences in the serum value of FABP4 between stenosis group and controls(t=3.725,P=0.001),vulnerable and non-vulnerable plaque subgroups(t=3.457,P=0.002).There was a significant difference in the grayscale value of plaque FABP4 between vulnerable and non-vulnerable plaque subgroups(t=3.936,P=0.001).Thecomparisons of the serum FABP4 in symptomaticsubgroup,asymptomatic subgroup and controls were not completely equivalent(F=8.129,P=0.001).There were significant differences in the serum value of FABP4 between symptomatic and asymptomatic groups(LSD-t=37.335,P=0.024),symptomatic group and controls(LSD-t=50.879,P=0.000),however,there was no significant difference in the serum FABP4 between asymptomatic group and controls(LSD-t 13.544,P=0.433).There was a positivecorrelation between the serum FABP4 and HCY(hom-ocysteine)(r=0.483,P=0.007).There was a modest correlation between grading of enhancement in CEUS and the serum FABP4(r=0.551,PL=0.005)and a strong correlation between grading of enhancement in CEUS and the grayscale value of plaque FABP4(r=0.782,P<0.001).Conclusions1.The grade of carotid plaques was positively related to intraplaque CD34-positive neovessels.Hence,contrast-enhanced ultrasound plays an important role in predicting the vulnerability of atherosclerotic plaques and risk of ischemic stroke and judge optimal aurgical time.2.Compared with the healthy controls,the value of the serum FABP4 in moderate-severe carotid stenosis group was much higher.3.Compared with asymptomatic carotid stenosis subgroup,the value of the serum FABP4 in symptomatic group was higher.And the value of the serum FABP4 and plaque FABP4 in vulnerable plaque group were both higher than the value of non-vulnerable group,which demonstrated that the value of FABP4 was correlated with the vulnerability of plaques.4.The study was the first to evaluate the vulnerlbility of plaques using CEUS to analyze FABP4,discovering that the level of FABP4 was much higher in vulnerlble plaque ones.The FABP4 concentrations might serve as a reliable biomarker to predict carotid vulnerable plaques and ischemic stroke.