A feasibility study of Doppler ultrasonography in evaluating the vulnerability of carotid atherosclerotic plaque / 中国脑血管病杂志

ABSTRACT

Objective To investigate the feasibility of Doppler ultrasonography in evaluating the vulnerability of carotid atherosclerotic plaque prospectively. Method A total of 44patients (46plaques) who performed carotid endarterectomy were continuously enrolled in the Department of Neurosurgery of the First Affiliated Hospital of Soochow University from March 2019 to October 2019. Several examinations such as carotid Doppler ultrasonography (CDU) , CT angiography, CT perfusion imaging, and/or digital subtraction angiography were scheduled conventionally before surgery. Pathologic examination, including the plaque morphology, histopathologic hematoxylin eosin(HE) staining, and immunohistochemical CD31 staining, were evaluated after surgery. The plaque vulnerable score was calculated based on the parameters of CDU consisting of plaque morphology, characteristic of echo, fiber cap integrity, presence of ulcer, degree of vascular stenosis, assigned with 0 to 3 points, respectively. The plaque was defined as the vulnerable plaque if vulnerable score was more than 4, otherwise, the plaque was the stable plaque. Then the plaques were divided into vulnerable group ( n =36) and stable group ( n = 10) according to the pathological results. The patients were divided into the stroke group ( n = 33) and the non-stroke group (n = 11) based on the incidence of ischemic stroke within the last 6 months. The evaluation of neovascularization in the plaque was referring to the immunohistochemical CD31 staining. The independent-sample t test, Wilcoxon rank-sum test, and χ2test were used to compare the differences between the two groups in general data, laboratory tests, clinical symptoms, vulnerable scores, and the rates of vulnerable plaques. Kappa value was used to evaluate the consistency between CDU and histopathological HE staining in the evaluation of plaque vulnerability. Results ( 1) The differences in the National Institute of Health stroke scale score and neurological symptoms between the vulnerable group and stable group were statistically significant (all P < 0. 05). (2) The vulnerable score was significantly different between the vulnerable group and stable group (6.00 [5.00,7.00] scores vs. 4.00 [4.00,4.25] scores, P<0.01), and between the stroke group and non-stroke group (6.00 [5.00,7.00] scores vs. 4.00 [4.00,5.00] scores, P = 0.002). (3) Diagnostic efficacy compared with histopathologic results, the sensitivity and specificity of CDU were respectively 88.9% and 8/10, positive predictive value was 94. 1% .negative predictive value was 8/12, and the Youden index was 68. 9%. The consistency between CDU and histopathological HE staining was strong ( Kappa = 0. 642, P < 0. 01). (4) Neovascularization; immunohistochemical CD31 staining showed neovascularization in vulnerable plaque; the microvessel density in vulnerable group was higher than that in stable group([2. 84 ± 1. 56] mm3vs. [ 1. 38 ±0. 61 ] mm3). (5) The relationship between plaque vulnerability score and ischemic stroke the rates of vulnerable plaques in the stroke group was higher than that in the non-stroke group (88. 6% [31/35 ] vs. 3/11 ;χ2= 13. 286, P < 0. 01 ). Conclusion The plaque vulnerable score evaluating by vascular ultrasound can accurately and quantitatively assess the vulnerability of carotid plaques, and angiogenesis can be observed in the vulnerable plaque, which provides a theoretical basis for clinical diagnosis and accurate treatment.