[Exploration of thrombus histological composition and clinical effect in mechanical thrombectomy of acute ischemic stroke]

Correlation between thrombus composition and regulatory T cell counts with clinical outcomes of acute ischemic stroke patients with thrombectomy

OBJECTIVES

To analyze the relationship of thrombus composition and regulatory T cell expression with clinical outcome in acute ischemic stroke (AIS) patients with thrombectomy.

METHODS

A total of 44 AIS patients who underwent thrombectomy in the Department of Neurology of Shaoxing Hospital from June 2021 to October 2022 were enrolled. All thrombus specimens were subjected to hematoxylin-eosin staining and immunohistochemistry. Semi-quantitative analysis was performed to determine the content of red blood cells, fibrinogen/platelets, and regulatory T (CD4+CD25+) cells. Clinical data, vascular recanalization status, and neurologic outcomes at 3 months after thrombectomy were collected. A modified Rankin Scale score of 0-2 was defined as a favorable outcome.

RESULTS

Among 44 patients with complete thrombus data there were 15 cases of red cell type, 11 cases of mixed type and 18 cases of fibrin/platelet type. There was a significant difference in trial of ORG 10172 in acute stroke treatment (TOAST) etiological classification among the three groups (P<0.01), while no significant differences were found in other general clinical and surgical data (all P>0.05). According to the TOAST etiology, 28 cases were classified as large atherosclerosis type and 16 cases as cardioembolic type. The proportion of red blood cells in thrombus was significantly higher in patients with large atherosclerosis type than that in those with cardioembolic type [58.0% (44.2%, 72.5%) vs. 24.5% (12.7%, 48.0%), P<0.01]. The ratio of fibrin to platelet in patients with cardiogenic embolism was significantly higher than that in patients with large atherosclerosis [73.0% (49.2%, 84.5%) vs. 40.0% (25.2%, 54.5%), P<0.01). Among the 44 patients, 19 had good while 25 had poor neurological outcomes. Univariate binary logistic regression analysis showed that age, operation time, CD4+CD25+T cell number were correlated with the functional outcomes of the patients (all P<0.05). Multivariate binary logistic regression analysis showed that thrombus CD4+CD25+T cell count was an independent factor affecting the functional outcome of patients (OR=1.369, 95%CI: 1.101-1.701, P<0.01).

CONCLUSIONS

There is no significant correlation of erythrocyte and fibrin/platelet components in thrombus with functional outcome in AIS patients, but an increased count of regulatory T cells associates with good functional outcome.

Clot Composition Analysis as a Diagnostic Tool to Gain Insight into Ischemic Stroke Etiology: A Systematic Review

Mechanical thrombectomy renders the occluding clot available for analysis. Insights into thrombus composition could help establish the stroke cause. We aimed to investigate the value of clot composition analysis as a complementary diagnostic tool in determining the etiology of large vessel occlusion (LVO) ischemic strokes (International Prospective Register of Systematic Reviews [PROSPERO] registration # CRD42020199436). Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, we ran searches on Medline (using the PubMed interface) and Web of Science for studies reporting analyses of thrombi retrieved from LVO stroke patients subjected to mechanical thrombectomy (January 1, 2006 to September 21, 2020). The PubMed search was updated weekly up to February 22, 2021. Reference lists of included studies and relevant reviews were hand-searched. From 1,714 identified studies, 134 eligible studies (97 cohort studies, 31 case reports, and six case series) were included in the qualitative synthesis. Physical, histopathological, biological, and microbiological analyses provided information about the gross appearance, mechanical properties, structure, and composition of the thrombi. There were non-unanimous associations of thrombus size, structure, and composition (mainly proportions of fibrin and blood formed elements) with the Trial of Org 10172 in Acute Stroke Treatment (TOAST) etiology and underlying pathologies, and similarities between cryptogenic thrombi and those of known TOAST etiology. Individual thrombus analysis contributed to the diagnosis, mainly in atypical cases. Although cohort studies report an abundance of quantitative rates of main thrombus components, a definite clot signature for accurate diagnosis of stroke etiology is still lacking. Nevertheless, the qualitative examination of the embolus remains an invaluable tool for diagnosing individual cases, particularly regarding atypical stroke causes.