Is Clot Composition Associated With Cause of Stroke? A Systematic Review and Meta-Analysis

Area of Science:

• Neurology
• Pathology
• Biomedical Engineering

Background:

• Prior research suggests a link between clot composition and stroke cause, but findings are inconsistent.
• Mechanical thrombectomy for acute ischemic stroke involves clot retrieval and analysis.
• Understanding clot histology aids in determining stroke etiology.

Purpose of the Study:

• To conduct a systematic review and meta-analysis on clot histological composition and stroke cause in patients undergoing mechanical thrombectomy.
• To update existing literature with current data.

Main Methods:

• Systematic search of Cochrane Library, Embase, and MEDLINE databases (January 2000-March 2024).
• Inclusion of English-language studies on adult patients undergoing mechanical thrombectomy for acute ischemic stroke.
• Random effects meta-analysis of clot composition (red blood cells, fibrin, platelets, white blood cells) and stroke cause.

Main Results:

• Analysis included 17 studies with 1656 patients.
• Cardioembolic clots had significantly lower red blood cells (-10.3%) and higher fibrin/platelets (+9.9%) compared to large artery atherosclerosis/non-cardioembolic clots.
• White blood cell differences were minimal (+1.1%).

Conclusions:

• Cardioembolic clots exhibit distinct histological features (higher fibrin/platelets, lower RBCs) compared to large artery atherosclerosis clots.
• These histological differences currently lack sufficient clinical utility for differentiating stroke etiology.
• Future research should explore clot constituents beyond basic cellular composition for better etiological insights.