Study Analyzes Plaque Vulnerability and Stroke Risk in Elderly CAS Patients

July 7, 2011—Guus W. van Lammeren, MD, et al published a study online ahead of print in Stroke that examined if atherosclerotic plaques become more unstable with increasing age and thereby might provide insight into the age-related increased risk of cerebrovascular events during carotid artery stenting (CAS).

The investigators noted that recent randomized trials showed an increased periprocedural risk for stroke with increasing age in patients undergoing CAS. Manipulation of atherosclerotic plaques during CAS can result in plaque rupture with subsequent superimposed thrombus formation, embolization, and cerebrovascular events.

As detailed in Stroke, carotid atherosclerotic plaques were harvested from 1,385 consecutive patients undergoing carotid endarterectomy between 2002 and 2010. The plaques were quantitatively analyzed for macrophages, smooth muscle cells, and microvessels; they were semiquantitatively analyzed for collagen, calcifications lipid cores, and intraplaque hemorrhages.

Patients were divided in four groups by age: < 60 years, 60 to 69, 70 to 79, and ≥ 80 years. Measures of association between age as a continuous variable and histological characteristics were also calculated.

The investigators reported that increasing age was associated with a decrease in the amount of smooth muscle cells in the carotid plaque. More plaques with large atheroma and heavy plaque calcifications were observed among elderly patients. After correction for baseline differences, risk factors, and medication use, age was independently associated with a more vulnerable carotid plaque composition.

The study concluded that plaque stability decreases gradually with age. Older patients with carotid stenosis have relatively unstable plaques with low smooth muscle cell content, a high amount of large lipid cores, and more calcified plaques as compared with younger patients. The underlying vulnerable plaque composition in the elderly might be an important contributing factor to the increased risk of stroke for older patients undergoing CAS, stated the investigators in Stroke.