An old thrombus may potentially identify patients at higher risk of poor outcome in anterior circulation stroke...

To investigate thrombus age and its association with clinical and procedural parameters in patients with acute ischemic stroke (AIS) due to anterior circulation occlusions.

The thrombi of 107 consecutive AIS patients with occlusions in anterior circulation large-arteries were collected during mechanical recanalization. By hematoxylin-eosin staining analysis, thrombi were classified as fresh (< 3 days) or old (≥ 3 days) according to the hemosiderin positivity. Old thrombi were further classified as thrombi with focal hemosiderin or diffuse hemosiderin according to their predominant distribution. Neuro-interventional data and clinical outcomes were compared based on thrombus age.

We identified fresh thrombi in 29 patients and old thrombi in 78 patients. Compared with patients with fresh thrombi, patients with old thrombi were associated with (i) a longer mechanical recanalization time (p = 0.027), (ii) a higher percentage of fibrin/platelets and leukocytes (all p = 0.02) and a lower percentage of erythrocytes (p = 0.001), and (iii) less favorable clinical outcomes at discharge (p = 0.019) and 90 days later (OR = 2.76, 95% CI = 1.09-6.99, p = 0.032). Furthermore, 18 (16.8%) of all patients had focal hemosiderin in old thrombi, which was independently linked to a poor clinical outcome 90 days later (adjusted OR = 5.37, 95% CI = 1.14-25.28, p = 0.034).

The presence of old thrombi, particularly those with focal hemosiderin, may aid in identifying patients with acute ischemic anterior circulation stroke who are at a higher risk of poor clinical outcome at 3-month follow-up.