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Vessel (artery) Calcium Points to Brain Disease
  By John Gever, Senior Editor, MedPage Today
Published: August 25, 2011
Calcification in major blood vessels measured with CT scans is not only a risk factor for heart disease but also for white matter lesions and small infarcts within the brain, Dutch researchers said.
In a study of nearly 900 participants in the population-based Rotterdam Study, calcification in coronary arteries, the aortic arch, and the carotid arteries both outside and inside the brain was significantly associated with increased white matter lesion volume and the risk of cerebral infarcts, reported Aad van der Lugt, MD, PhD, of Erasmus Medical Center in Rotterdam, Netherlands, and colleagues.
"Compared with ultrasound plaque imaging, quantification of CT calcification provides additional information in regard to the pathophysiology of vascular brain disease," the researchers wrote online in Arteriosclerosis, Thrombosis and Vascular Biology.
On the other hand, vessel calcification was not a significant predictor of the presence of cerebral microbleeds.
The findings emerged from a subgroup of participants in the Rotterdam Study, which has been following residents of a suburb of that city since 1990. It began with a cohort of about 8,000 people, with an additional 3,000 added in 2000. From 2003 to 2005, some 2,500 participants responded to invitations to undergo CT scans that included imaging the major blood vessels. Of them, 1,073 were randomly selected to be offered brain MRI scans as well in 2005 and 2006. After refusals and exclusions, van der Lugt and colleagues had usable MRI and CT scans from 885 people. The mean time between CT and MRI scans was eight months. Participants were equally divided between men and women and their mean age was about 67 when the CT scans were performed.
Calcification loads were substantially greater in men, especially in the coronary and extracranial carotid arteries. For example, at the 75th percentile, calcification volume in the coronary artery was 322 cubic millimeters in men versus 63 cubic millimeters in women.
After adjusting for gender, age, ultrasound carotid plaque volume, and intracranial plaque volume, calcification loads in each major arterial location were significantly associated with white matter lesion volume as measured in the MRI scans.
For each standard deviation of increase in calcification, the following increases in white matter lesion volume were calculated:
· Coronary artery: 0.09 mL (95% CI 0.02 to 0.15)
· Aortic arch: 0.08 mL (95% CI 0.02 to 0.15)
· Extracranial carotid: 0.12 mL (95% CI 0.05 to 0.19)
· Intracranial carotid: 0.11 mL (95% CI 0.05 to 0.17)
There were also associations between vessel calcification and the likelihood of cerebral infarcts visible in the MRI scans. The researchers reported the following odds ratios for each standard deviation of increase in calcification:
· Coronary artery: OR 1.34 (95% CI 0.99 to 1.79)
· Aortic arch: OR 1.38 (95% CI 1.00 to 1.91)
· Extracranial carotid: OR 1.61 (95% CI 1.15 to 2.25)
· Intracranial carotid: OR 1.60 (95% CI 1.18 to 2.18)
Odds ratios calculated on the same basis for cerebral microbleeds, however, were close to 1.0 and did not approach statistical significance.
The findings corroborated some previous studies that had found associations between calcifications in single arteries and white matter lesion volume and/or cerebral infarcts. But the Rotterdam analysis was the first to quantify these associations in carotid and thoracic vessels in a single study.
The researchers cautioned, however, that the clinical implications may be limited. They noted that the problem of radiation exposure raises questions about the practicality of large-scale CT screening of neurologically healthy people.
On the other hand, van der Lugt and colleagues pointed out, chest CT scans are becoming more common for a variety of purposes. Such scans could be used secondarily to examine risks of cerebrovascular disease, insofar as the Rotterdam results showed that aortic and coronary calcification is associated with white matter lesion volume and perhaps cerebral infarcts.
"Calcium scoring in clinical practice would ... be informative and applicable in people who receive a CT examination for other reasons," the researchers suggested.
The Rotterdam Study is supported by the Erasmus Medical Center and Erasmus University Rotterdam; the Netherlands Organization for Scientific Research; the Netherlands Organization for Health Research and Development; the Research Institute for Diseases in the Elderly; the Netherlands Genomics Initiative; the Ministry of Education, Culture and Science; the Ministry of Health, Welfare and Sports; the European Commission; and the Municipality of Rotterdam. Individual researchers performing the current analysis also reported funding from the Alzheimer's Association, and the Netherlands Heart Foundation.
Study authors declared they had no relevant financial interests.
Primary source: Arteriosclerosis, Thrombosis and Vascular Biology
Source reference:
Bos D, et al "Calcification in major vessel beds relates to vascular brain disease" Arterioscler Thromb Vasc Biol 2011; DOI: 10.1161/ATVBAHA.111.232728.
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