Intracranial Carotid Artery Atherosclerosis and the Risk of Stroke in Whites: The Rotterdam Study

Study Questions:

Does intracranial carotid artery calcification increase the risk of strokes?


Data from the Rotterdam Study were used for the present analysis. This was a population-based cohort of predominantly white participants with 6 years of follow-up. A random sample was taken of 2,323 adults who were stroke free at baseline (between 2003 and 2006) and underwent computed tomography (CT) scans to quantify intracranial carotid artery calcification volume. All participants were continuously monitored for the primary outcome of stroke until January 1, 2012.


A total of 91 participants experienced a stroke over 14,055 person-years of follow-up. Of these 91 stroke events, 74 were ischemia. A larger intracranial carotid artery calcification volume was associated with an increased risk of stroke, after adjustment for other cardiovascular risk factors, ultrasound carotid plaque score, and calcification in other vessels (fully adjusted hazard ratio per an increase of 1 standard deviation in intracranial carotid artery calcification volume, 1.43 [95% confidence interval, 1.04-1.96]). Intracranial carotid artery calcification contributed to 75% of all strokes; for aortic arch and extracranial carotid artery calcification, this incidence was only 45% and 25%, respectively.


The investigators concluded that intracranial atherosclerosis was a risk factor for stroke among whites of European ancestry. Intracranial atherosclerosis may be a larger contributor of strokes than large-artery atherosclerosis in more proximally located vessel beds.


These data suggest that measurement of intracranial carotid artery calcification may identify adults who are at increased risk for stroke. Whether aggressive risk factor modifications for patients with intracranial carotid artery calcification would lead to reduced risk for stroke has yet to be determined. Furthermore, these findings should be replicated among other racial and ethnic groups prior to generalizing these results to others.

Clinical Topics: Noninvasive Imaging, Vascular Medicine, Computed Tomography, Nuclear Imaging

Keywords: Stroke, Follow-Up Studies, Plaque, Atherosclerotic, Tomography, X-Ray Computed, Risk Reduction Behavior, Ruminants, European Continental Ancestry Group, Calcinosis, Carotid Arteries, Risk Factors, Intracranial Arteriosclerosis, Cardiovascular Diseases, Confidence Intervals

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