18 Feb Stroke: Intracranial Atherosclerosis as a Major Risk Factor
MedicalResearch.com: What are the main findings of the study?
Dr. Ikram: The main finding of the study, carried out within the Rotterdam Study and led by drs. Daniel Bos and Arfan Ikram (both from the Erasmus Medical Center Rotterdam, the Netherlands), was that intracranial atherosclerosis is a major risk factor for stroke in the Western (white) population. Traditionally, intracranial atherosclerosis has not been considered of major importance to stroke risk in Western populations. In contrast, most research on intracranial atherosclerosis originates from Asian and African populations, where is was actually recognized as the most important risk factor of stroke. Our study demonstrates that also in the Western population intracranial atherosclerosis is a major risk factor for stroke and should get more focus in clinical practice. Moreover, our findings indicate that its contribution to the proportion of all strokes is greater than that of atherosclerosis in other vessel beds that are further away from the brain.
MedicalResearch.com: Were any of the findings unexpected?
Dr. Ikram: Our hypothesis was that atherosclerosis that is located in the vasculature directly supplying the brain would have more influence on the development of stroke compared to locations further away from the brain (such as heart or aorta). This was in conjunction with the second hypothesis that intracranial atherosclerosis would be a major risk factor of stroke in Western populations too. In that sense, our finding that intracranial atherosclerosis was indeed a strong risk factor for stroke, was not entirely unexpected. However, the magnitude of the association was larger than we anticipated. Especially, the finding that the association between intracranial atherosclerosis and stroke firmly remained after adjustment for the presence of atherosclerosis in the carotid bifurcation, aortic arch and the coronary arteries, emphasizes the importance of intracranial atherosclerosis.
MedicalResearch.com: What should clinicians and patients take away from your report?
Dr. Ikram: Over the past decades, there has not been much attention for intracranial atherosclerosis as cause of stroke in the Western (white) population. With the current study we demonstrated that from different important sites where atherosclerosis frequently occurs (carotid bifurcation, aorta, coronary arteries), the presence and amount of intracranial atherosclerosis seems to be the most important with regard to strokes. In other words, intracranial atherosclerosis is an underestimated risk factor for stroke and deserves significantly more attention in current practice.
MedicalResearch.com: What recommendations do you have for future research as a result of this study?
Dr. Ikram: The next step in research should include the investigation of the predictive value of intracranial carotid artery calcification for stroke. To a certain extent there is some analogy with the coronary arteries and coronary events, especially myocardial infarction. Compared to the extensive research that has been performed in this field, it is evident that much research is still to be done to assess the value of intracranial atherosclerosis as a potential predictor of stroke. The coronary calcium score for example, has proven added value in the prediction of acute cardiac disease beyond the Framingham risk score profile.
Additionally, more research is needed on prevention and treatment of intracranial atherosclerosis. In recent years, there have been some clinical trials specifically targeting intracranial atherosclerosis in stroke patients, but have not been entirely conclusive. Further research should also focus on preventing intracranial atherosclerosis in healthy populations.
Daniel Bos MD, PhD, Marileen L. P. Portegies MD, Aad van der Lugt MD, PhD, Michiel J. Bos MD, PhD, Peter J. Koudstaal MD, PhD, Albert Hofman MD, PhD, Gabriel P. Krestin MD, PhD, Oscar H. Franco MD, PhD, Meike W. Vernooij MD, PhD, M. Arfan Ikram MD, PhD