Carotid Artery Atherosclerosis Leads to Stroke

A new study shows that intracranial carotid artery calcification (ICAC) is associated with an increased risk of stroke for older Caucasian patients.

Researchers at Erasmus Medical Center (Rotterdam, the Netherlands) conducted a population-based cohort study of 2,323 stroke-free persons (mean age 69.5 years, 52.2% women) who underwent computed tomography (CT) scanning to quantify ICAC volume between 2003 and 2006. All participants were continuously monitored for the occurrence of stroke until January 1, 2012. During the follow-up period, 91 patients suffered a stroke: 74 were ischemic, 10 were due to bleeding, and 7 were unspecified.

The results showed that larger ICAC volume was related to a higher risk of stroke, independent of cardiovascular risk factors, ultrasound carotid-plaque score, and calcification in other vessels. ICAC contributed to 75% of all strokes, a much higher percentage than atherosclerosis in the aortic arch (45%) and in the extracranial carotid artery (25%). There was no association between coronary artery calcification and stroke, indicating that although coronary calcification may be a major risk factor for myocardial infarction (MI), it is ICAC that poses the main risk for stroke. The study was published on February 17, 2014, in JAMA Neurology.

“Thus far, evidence of a role of intracranial atherosclerosis in the etiology of stroke comes primarily from research in populations of Asian and African descent,” said lead author Daniel Bos, MD, PhD. “Our findings establish intracranial atherosclerosis as a major risk factor for stroke in the general white population and suggest that its contribution to the proportion of all strokes may be greater than that of large-artery atherosclerosis in more proximally located vessel beds.”

“The results highlight the importance of physicians being aware that even their white patients can have intracranial calcification,” added study coauthor Arfan Ikram, MD, PhD. “And if doctors are screening for any patient's cardiovascular risks, they should consider intracranial calcification. The study also underlines the importance of carrying out more research into treating ICAC or preventing it in the first place.”

Unlike atherosclerosis of the carotid arteries, which often causes transient ischemic attacks (TIAs), ICAC is often only discovered after a major stroke has already occured.

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