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Intracranial atherosclerosis may be more predictive of stroke than coronary artery calcification
Intracranial carotid artery calcification may be an important marker for intracranial atherosclerosis, which in turn is a major stroke risk factor in the general white population, according to data in a recent population-based cohort study.
Moreover, the researchers from the Netherlands found that intracranial atherosclerosis may have a more significant impact on stroke risk than large-artery atherosclerosis in proximal vessel beds.
They evaluated 2,323 white individuals, stroke-free at baseline, who participated in the Rotterdam Study between September 2003 and February 2006. The mean age of study participants was 69.5 years. These participants underwent nonenhanced intracranial CT of the intracranial carotid artery to evaluate intracranial carotid artery calcification volume, with continuous follow-up for incidence of stroke until 2012. Researchers also scanned the coronary arteries, aortic arch and extracranial carotid arteries.
During the course of 14,055 person-years of follow-up, 91 participants had a stroke; 74 of which were ischemic. There was a correlation between higher intracranial carotid artery calcification volume and an increased risk for stroke, independent of CV risk factors, ultrasound carotid plaque score and calcification in other vessels (adjusted HR=1.43; 95% CI, 1.04-1.96 per 1 standard deviation increase to intracranial carotid artery calcification volume). Similar results were observed for ischemic stroke specifically (OR=1.39; 95% CI, 0.98-1.99), but this association was not statistically significant.
Analysis of the etiology of all observed strokes indicated that intracranial carotid artery calcification played a role in as many as 75% of strokes, whereas aortic arch and extracranial carotid artery calcification were associated with 45% and 25%, respectively.
The researchers also wrote that, in post-hoc analysis, the correlation between coronary artery calcification and stroke was maintained “only in a crude age- and sex-adjusted model.”
“This further corroborates that [intracranial carotid artery calcification] is a more important determinant of stroke than coronary artery calcification,” they wrote.
In an accompanying editorial, Marc I. Chimowitz, MBChB, of the Medical University of South Carolina Stroke Program, emphasized the need to further explore the pathophysiologic causality between intracranial carotid artery calcification and stroke.
“Establishing that [causality] will require further prospective studies that correlate the association between [intracranial carotid artery calcification] and stenosis more clearly, identify atherosclerotic plaque features associated with calcification that may be associated with a high risk for distal embolism, and classify ischemic strokes that occur in patients with intracranial carotid calcification according to size, location, vascular territory, and the coexistence of other potential causes of stroke,” Chimowitz wrote. “Much work needs to be done.”
Disclosure: The researchers report no relevant financial disclosures.