ESOC 2018 – Pathophysiology and Mechanisms
A preclinical study by Anfray et al., University of Caen, investigated the effects of single chain (sc) tPA versus two chain (tc) tPA. These forms are contained at variable rates in commercial tPA. Thrombolytic activity is equivalent but only sc-tPA displays excitotoxicity. However, sc-tPA was superior to tc-tPA in reducing lesion size and behavioral deficits after thromboembolic stroke in mice.
Okar et al., Hacettepe University, Ankara, reported the surprising finding of cerebral volume loss in the contralateral hemisphere of ischemic stroke patients. In a prospective study they included 31 patients with stroke in the MCA territory, which showed 1.26% monthly volume reduction in the contralateral hemisphere associated with stroke severity and inflammation.
Several studies investigated the features of thrombi from ischemic stroke patients after endovascular treatment. Di Megio et al, Inserm, Paris, analyzed 164 thrombi by immunohistology and 17 thrombi by scanning electron microscopy. They found common traits related to the composition with a red blood cell-rich core surrounded by a compact shell-like structure made of fibrin(ogen), vWF, platelets, and neutrophil extracellular traps, that could participate in thrombolysis resistance. In contrast, after studying 27 thrombi, Semerano et al., Hospital San Raffaele, Milan, Italy, reported macroscopic heterogeneity of thrombi in terms of consistence, dimensions, color and gross appearance, and the pattern of red blood cells, platelets, fibrin and vWF. Thrombi composition correlated with the density of the occluded vessel on CT scan. A large international consortium, the Curam and Mayo Clinic international acute ischemic stroke clot registry, presented results of a preliminary study with 50 patients. They found no correlation between the number of passes for clot retrieval or final TICI score with the suspected clot etiology and components. Again, they concluded that non-contrast CT may indicate histological characteristics of AIS clots.
Fani et al. reported results from the Rotterdam study where CBF was investigated in 5,289 persons (46-98y) free of stroke. Measures were associated with risk of stroke and TIA and markers of SVD, retinal vessel diameters and markers of large vessel disease. Lower total brain perfusion was associated with higher risk of stroke or TIA. However, indicators of failing autoregulation were only associated with TIA, which was suggestive of a different pathophysiology underlying TIA and stroke.
Several studies investigated atherosclerotic plaques in patients with ischemic stroke. Sharma et al., National University Hospital, Singapore, performed an imaging study with 18F-fluorodeoxyglucose PET/CT and high-resolution MRI in 85 patients within 30-days of recent stroke onset and ipsilateral carotid stenosis greater than 50%. 14% of the patients showed recurrence in the stenosed carotid territory and showed distinct imaging features predictive of recurrence. Leung et al., Chinese University, Hong Kong, studied intracranial atherosclerotic plaques in 173 patients using 3-dimensional rotational angiography. Patients with ulcerative plaques had more acute and chronic infarcts. Finally, Murphy and colleagues, Dublin, Ireland, compared blood cell counts and platelet activation and dynamics in asymptomatic versus symptomatic carotid stenosis patients (Heist study). They concluded that increased platelet counts and reticulated platelets could increase the risk of cerebrovascular disease.