Background Scanning electron microscopy (SEM) studies found that the porosity of thrombi might vary among individuals. However, its relationship with the clinical presentation and efficacy of mechanical thrombectomy (MT) remains unknown. We aimed to characterize the ultrastructure of thrombi and explore its association with the complexity of MT and clot perviousness.
Methods SEM was used to observe the morphological features of different components of thrombi obtained from patients with anterior circulation large vessel occlusion undergoing MT and to determine the porosity of thrombi by semi-quantitative analysis. Non-porous thrombi were defined as thrombi with porosity <2%. Clot perviousness was also evaluated using thrombus attenuation increase on CT perfusion (TAIctp). We assessed the complexity of MT by attempts of retrieval >3 and procedural duration >60 min, defined as the time interval between groin puncture and recanalization.
Results A total of 49 thrombi were analyzed and 31 (63.3%) were classified as non-porous thrombi. The presence of non-porous thrombi was negatively associated with procedure >60 min (OR 0.152, 95% CI 0.031 to 0.734, p=0.019) and attempts >3 (OR 0.194, 95% CI 0.046 to 0.822, p=0.026) after adjustment. Additionally, receiver operating characteristic curve analysis indicated that TAIctp <17.9 Hounsfield units could predict the presence of non-porous thrombi with an area under the curve of 0.915.
Conclusions Non-porous thrombi on SEM are easier to be retrieved during MT and could be identified as less pervious clots on CT images.
Data availability statement
Data are available upon reasonable request. Not applicable.
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YH and JX contributed equally.
Contributors ML contributed to the conception of the study and is responsible for the overall content as guarantor. YH, JX, YZ, JL and ZL collected thrombus samples. YH and JX processed and analyzed the images. YH and WZ performed the data analyses and drafted the manuscript. ZC, YZ and ML edited the manuscript with constructive discussions.
Funding This study was supported by the National Natural Science Foundation of China (81971101, 82171276), and the Science Technology Department of Zhejiang Province (2018C04011).
Competing interests None declared.
Provenance and peer review Not commissioned; externally peer reviewed.
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