Comment Author: Linxin Li, Wolfson Centre of Prevention of Stroke and Dementia, Nuffield Department of Clinical Neurosciences, Oxford University, UK
Original Article: : den Brok, M. G., Kuhrij, L. S., Roozenbeek, B., van der Lugt, A., Hilkens, P. H., Dippel, D. W., & Nederkoorn, P. J. (2020). Prevalence and risk factors of symptomatic carotid stenosis in patients with recent transient ischaemic attack or ischaemic stroke in the Netherlands. European Stroke Journal. https://doi.org/10.1177/2396987320932065
Stroke incidence has fallen in high-income countries in the last four decades and the trend of declining has been maintained in recent years,1,2 largely due to better control of blood pressure and the use of preventative drugs, such as statins. However, a previous systematic review suggested that among the different aetiological subtypes of ischaemic stroke, there was an increase of cardioembolic stroke in whites and an increase of large artery atherosclerosis in Asians.3 Less is known about the current estimates of symptomatic carotid stenosis in predominantly White population.
In this issue of the European Stroke Journal, Melina GHE den Brok and colleagues reported up-to-date data on the prevalence and risk factors of ipsilateral extracranial internal carotid artery (ICA) stenosis in patients with recent transient ischaemic attack (TIA) or ischaemic stroke from a retrospective multi-centre study in the Netherlands.4
Among all 938 patients with a recent TIA or ischaemic stroke in the ICA territory, 883 (94.1%) that had carotid imaging were included. The degree of ICA stenosis was first measured using predominantly duplex ultrasonography (58%), followed by computed tomography angiography (CTA-13.8%) and magnetic resonance angiography (MRA-1.1%). ICA stenosis was defined as atherosclerotic luminal narrowing in the proximal extracranial ICA or at the location of the carotid bifurcation and the degree of stenosis was determined using the NASCET criteria.
What are the key findings?
- Of all 883 patients (mean age 70 years), 110 (12.5%) had an ICA stenosis of 50-99%, with an additional 46 (5.2%) patients having an occlusion.
- The prevalence of any ICA stenosis of 50-100% was higher in men (23.4% vs. 10.6% in women) and in whites (21.8% vs. 11.7% in non-whites).
- Risk factors for ≥50% ICA stenosis included age, male sex, retinal ischaemia and current smoking.
Although it is difficult to reliably compare the current estimates to previous studies given the difference in study characteristics, the prevalence of 12.5% found in this study seemed to be lower than reported in historical cohorts (ranging from 12-25%), which also coincided with a high proportion of patients being on statins (39.2%) premorbidly. Whilst the findings are encouraging, there is perhaps still room for improvement. It is particularly worth noting that a third of patients with 50-100% stenosis were smokers and one in five had history of peripheral vascular disease.
As the authors concluded, the prevalence of symptomatic ICA appeared to be falling in recent years but it is not time to relax yet. With the aging population, we will need to work even harder to maintain the current trend. Moreover, the higher prevalence of stenosis in whites is intriguing and future studies will be needed to explore this more thoroughly.
- Feigin VL, Lawes CM, Bennett DA, Barker-Collo SL, Parag V. Worldwide stroke incidence and early case fatality reported in 56 population-based studies: A systematic review. Lancet Neurology. 2009;8:355-369
- Li L, Scott CA, Rothwell PM. Trends in stroke incidence in high-income countries in the 21st century, Stroke. 2020; 51: 1372-1380
- Ornello R, Degan D, Tiseo C, Di Carmine C, Perciballi L, Pistoia F, et al. Distribution and temporal trends from 1993 to 2015 of ischemic stroke subtypes: A systematic review and meta-analysis. Stroke. 2018; 49:814-819
- den Brok MGHE, Kuhrij LS, Roozenbeek B, van der Lugt A, Hilkens PHE, Dippel DWJ, et al. Prevalence and risk factors of symptomatic carotid stenosis in patients with recent transient ischaemic attack or ischaemic stroke in the Netherlands. European Stroke Journal. Epub 09/06/2020. DOI: 10.117/2396987320932065