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Plaque hemorrhage linked to stroke.

Plaque hemorrhage linked to stroke

Stroke, the third most frequent cause ofdeath in the United States, can result from the buildup of fatty plaque, which narrows the arteries and induces blood to form clots that block blood flow to the brain.

In recent years, some physicians havealso come to suspect that small hemorrhages in the plaque's own capillary networks may further increase the risk of stroke or prestroke symptoms. The results of a new study support this link and, at the same time, demonstrate the usefulness of computer tomography (CT) scanning for pinpointing the cause of blood flow blockage.

At the 12th International Joint Conferenceon Stroke and Cerebral Circulation held recently in Tampa, Fla., Antonio Culebras of the State University of New York at Syracuse described his use of CT scanning in identifying plaque features in the neck's carotid arteries, which may lead to stroke. CT scanning is used for imaging the brain, but Culebras and his co-workers were the first to develop the technique for arterial studies in the neck. They have found that a plaque hemorrhage shows up on a CT scan as a small dot called a "lucent defect.'

The researchers looked for lucent defectsin the CT neck scans of 95 patients who, in the previous three months, had suffered a stroke or a transient ischemic attack (TIA), a temporary blockage of blood vessels that is often followed by a major stroke within days to months. For those patients who had plaque hemorrhages, Culebras's group found a high correlation between the side of the neck in which the plaque hemorrhage was discovered and the side of the body that experienced stroke or TIA. He says his group is now conducting a larger prospective study to further test the link between stroke and plaque hemorrhages.

Lucent defects were not correlatedwith every stroke or TIA case, but Culebras says that plaque hemorrhages make "a convincing contribution to the development of symptoms.' He and others think that the hemorrhage causes the plaque to grow, which further narrows the artery and may cause the plaque to burst open into the vessel, producing stroke- or TIA-triggering clots.

Louis R. Caplan at Tufts UniversitySchool of Medicine in Boston cautions that there have been other studies indicating that plaque hemorrhages do not play much of a part in strokes. He thinks that the importance of both CT neck scanning and an ultrasound technique being developed in Germany is that, unlike conventional methods, they show detailed cross sections of arteries: "They have real potential for letting people know what's happening with the arterial wall . . . and the more you know about [that], the more intelligently you can pick appropriate treatment,' such as what kind of anticoagulant to administer.

He also notes the importance of imagingcarotid arteries in particular, because his research has shown that strokes in some groups, particularly white males, are initiated predominantly in the neck.

Culebras says that CT scanning revealsall the stroke-related features of plaque seen by conventional imaging techniques, but it is the only "tool that can show us the microhemorrhage of the plaque.' Moreover, he says that CT scanning is safer than the commonly used arteriography, in which X-rays are taken of vessels that have been injected with an X-ray opaque dye. "This allows us to follow up on those patients at short intervals--such as every four to six months--with very little risk to the patient,' he notes. "By knowing how the plaque is behaving over time, it permits us to plan more reasonable treatment strategies.' In particular, he hopes the identification of lucent defects will lead to better-informed decisions about whether or not to resort to carotid endarterectomy surgery--which he says currently is overused--to clean out carotid arteries (SN: 2/8/86, p.89).

Photo: CT scanning of a carotid artery producesa cross section that shows much more detail--such as the plaque hemorrhage marked by the arrow--than do other imaging techniques.
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Author:Weisburd, Stefi
Publication:Science News
Date:Mar 14, 1987
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