Carotid Stenosis and Atrial Fibrillation as Targets for Individualised Prevention of Ischaemic Stroke

The studies in this dissertation aim to reduce stroke incidence by improving prevention strategies for atrial fibrillation (AF) and carotid stenosis-related ischaemic strokes. AF and carotid stenosis are usually clinically silent until occurrence of the ischaemic stroke. Prevention strategies should be considered in patients in whom AF or carotid stenosis has caused an ischaemic stroke or a transient ischaemic attack but should not be delayed until after these events.

Screening programmes to detect AF and carotid stenosis can improve detection rates, but systematic population-level screening has a low yield because these conditions are relatively uncommon. Targeted screening makes screening more effective. Most simply, this involves screening above a certain age threshold. Risk prediction models combine multiple characteristics, such as age, sex, and medical history, to provide risk predictions for patients individually. These models can be used to target screening to high-risk patients. We determined which risk prediction models could detect AF and carotid stenosis reliably.

Prevention strategies to reduce risks of ischaemic stroke are well defined for patients in whom AF is detected but are more controversial for carotid stenosis. Especially the role of carotid endarterectomy (surgery to remove the carotid stenosis) became less clear over time because of improved medical preventive therapy. We showed that carotid endarterectomy should be performed by high volume surgeons in high volume hospitals, and that procedural complications of carotid endarterectomy, that partly determine the net clinical benefit, can be predicted reliably for each patient individually.