Ischaemic stroke, thromboembolism and clot structure

Ischaemic stroke is a major cause of morbidity and mortality worldwide. Blood clotting and thromboembolism play a central role in the pathogenesis of ischaemic stroke. An increasing number of recent studies indicate changes in blood clot structure and composition in patients with ischaemic stroke. In this review, we aim to summarise and discuss clot structure, function and composition in ischaemic stroke, including its relationships with clinical diagnosis and treatment options such as thrombolysis and thrombectomy. Studies are summarised in which clot structure and composition is analysed both in-vitro from patients’ plasma samples and ex-vivo in thrombi obtained through interventional catheter-mediated thrombectomy. Mechanisms that drive clot composition and architecture such as neutrophil extracellular traps and clot contraction are also discussed. We find that while in-vitro clot structure in plasma samples from patients with ischaemic stroke are consistently altered, showing denser clots that are more resistant to fibrinolysis, current data on the composition and architecture of ex-vivo clots obtained by thrombectomy are more variable. With the potential of advances in technologies underpinning both the imaging and retrieving of clots, we expect that future studies in this area will generate new data that are of interest for the diagnosis, optimal treatment strategies and clinical management of patients with ischaemic stroke.