Multiparametric Characterization of Tough Clots Following Stroke Thrombectomy

Area of Science:

• Neuroscience
• Biomedical Engineering
• Pathology

Background:

• Mechanical thrombectomy (TE) is standard for large vessel occlusion stroke.
• A subset of clots, termed 'tough clots,' require multiple TE maneuvers, leading to higher complication rates and poorer outcomes.
• The biological characteristics of these tough clots remain poorly understood.

Purpose of the Study:

• To investigate the distinct structural and etiological properties of tough clots resistant to thrombectomy.
• To correlate clot composition with clinical parameters and patient outcomes.

Main Methods:

• Prospective, single-center study analyzing clot composition in 33 ischemic stroke patients.
• Subgroup analysis of 16 'tough clots' using preinterventional imaging, ex vivo high-field MRI (9.4 T MR-microscopy), and histopathology.
• Correlation of imaging findings with clinical data and patient outcomes.

Main Results:

• MR-microscopy revealed predominantly platelet-rich (white) clots (64%), with mixed (27%) and RBC-rich (9%) clots being less common.
• Tough clots were predominantly white (87.5%) and associated with increased procedure time and maneuver count.
• Tough clots were frequently observed in cancer patients (63%) and cardiac patients with periprocedural emboli (67%).
• Stroke patients with cancer undergoing TE had significantly worse outcomes at discharge and 90 days.

Conclusions:

• Tough clots are characterized by a platelet-rich composition and are associated with underlying comorbidities, particularly malignancies.
• Clot composition and pre-existing conditions significantly influence thrombectomy success.
• Individualized stroke management strategies are necessary, considering both clot characteristics and patient comorbidities.