Atrial cardiopathy and thrombus composition in acute ischemic stroke: histological examination reveals insights into etiology and outcomes.

Introduction: In a subset of acute ischemic stroke (AIS) patients, particularly those with large-artery atherosclerosis (LAA) and atrial cardiopathy, multiple embolic sources may coexist. Histological analysis of thrombi presents an opportunity for discerning insights into both etiology and prognosis.

Methods: In our investigation, we meticulously examined 97 retrieved thrombi through histological staining and immunohistological techniques.

Results: Thrombi originating from patients diagnosed with atrial fibrillation (AF) (n = 43) presented notably elevated levels of fibrin (54.16 ± 18.57% vs. 36.07 ± 18.23%, P < 0.001) and neutrophil extracellular traps (NETs) [13.21 (9.42, 15.36)% vs. 7.96 (4.98, 15.13)%, P = 0.01], alongside reduced red blood cell content (35.09 ± 16.74% vs. 51.58 ± 19.67%, P < 0.001). Within the subgroup of AIS patients with LAA, those presenting with atrial cardiopathy (n = 29) presented higher platelet levels within the thrombus (12.44 (7.59, 19.25)% vs. 8.90 (0.60, 12.37)%, P = 0.04), with the association remaining significant after generalized linear model (GLM) adjustments (P = 0.004). Notably, NETs identified within the thrombus emerged as an independent prognostic indicator for poor outcomes, defined as the modified Rankin scale (mRS) score > 2 at 90 days (OR: 1.12, 95% CI: 1.02-1.25; P = 0.02).

Conclusions: These observations provide histopathological evidence supporting the presence of overlapping mechanisms contributing to thromboembolism that are potentially associated with underlying atrial cardiopathy. Consequently, histopathological evaluation of thrombi holds promise as a valuable tool for distinguishing between various etiologies and predicting clinical outcomes in AIS patients.