A case report of thrombolysis resistance: thrombus ultrastructure in an ischemic stroke patient

BACKGROUND: Following acute ischemic stroke (AIS), approximately half of patients do not achieve recanalization after intravenous administration of tissue plasminogen activator (rt-PA). Thrombolysis resistance is a possible reason for recanalization failure. Thrombolysis resistance is likely related to the ultrastructure and composition of the thrombus. However, there is a paucity of published information on the relationship between thrombus ultrastructure and thrombolysis resistance. CASE PRESENTATION: Two patients who underwent mechanical thrombectomy were observed within 4.5 h after stroke onset. One patient failed to respond to rt-PA (defined as thrombolysis resistant), and the other patient did not receive rt-PA treatment (non-rtPA). In each patient, the occluded artery was the internal carotid artery or middle cerebral artery. According to the Trial of ORG 10172 in Acute Stroke Treatment classification, both patients had large atherosclerotic cerebral infarction. By scanning electron microscopy (SEM) and transmission electron microscopy (TEM), we found that the thrombus structure was significantly different between the two patients. CONCLUSION: Grid-like dense fibrin, compressed polyhedral erythrocytes, and large accumulation of neutrophils may be characteristics of thrombolysis resistant thrombi.