PhD defence N. (Nikki) Boodt

Below is a brief summary of the dissertation: 

Ischemic stroke is caused by an obstruction of a blood vessel in the brain by a blood clot. If not resolved in time, this obstruction can lead to irreversible brain damage, resulting in symptoms like speech impairment, paralysis of limbs, and coordination problems. Endovascular thrombectomy (EVT) is a novel therapy for ischemic stroke and was globally implemented as standard of care for selected patients in 2015. With EVT, the caregiver attempts to mechanically remove the blood clot from the vessel with a catheter. However, in 20-30%% of cases, substantial reperfusion is not achieved. One area in which improvement of EVT outcomes could be achieved, is an in-depth evaluation of the clots that cause ischemic stroke. In this thesis, I show that 'white' (fibrin/blood platelet-rich) clots are substantially stiffer and exhibit more friction than 'red' (red blood cell-rich) ones, possibly explaining why white clots are so hard to remove. I also show that the percentage of these cells can partly be predicted with computed tomography (CT), which is routinely conducted in all patients before EVT. In clinical practice, I found a possible better performance of aspiration (a certain EVT-technique) over stent-retrievers in clots likely to be white based on CT. I also found that clot composition and CT-parameters are related to underlying stroke cause. White, small clots, located more distally in the brain, are more likely to originate from the heart than from the carotids. This may impact secondary stroke prevention.