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Arquivos Brasileiros de CardiologiaResumos das Próximas Publicações
Ano 2002Comparison between Adventitial and Intimal Inflammation of Ruptured and Nonruptured Atherosclerotic Plaques in Human Coronary Arteries
Maria L. Higuchi, Paulo S. Gutierrez, Hiram G. Bezerra, Suely A. Palomino, Vera D. Aiello, Júlia M. L. Silvestre, Peter Libby, José A. F. Ramires Objective - To verify the possible role of adventitial inflammation in atherosclerotic plaque vulnerability and coronary artery remodelling. Methods - We compared the mean numbers of lymphocytes present in the adventitia and within plaques from fatal thrombosed to stable equi-stenotic segments in histological sections of the same coronary tree of 34 patients who died due to acute myocardial infarction. We also counted adventitial microvessels, measured adventitial fibrosis, and, using confocal laser microscopy analysed the external elastic membrane. Results - In the adventitia, the number of lymphocytes and microvessels/mm2 were 69.5± 88.3 and 60.9± 32.1 in culprit lesions and 16.4± 21.1 and 44.3± 16.1 in stable lesions (lymphocytes- p<0.01; microvessels- p=0.04); within the plaques, the mean number of lymphocytes was 24.0±40.8 in culprit lesions and 10.9±13.2.06 in stable ones (p=0.17). The mean percent area of adventitial fibrosis/cross-sectional area of the vessel was significantly lower in unstable plaques (16.24±5.07% vs 28.95±9.76%, respectively; p<0.001). The confocal images showed holes in the external elastic membrane. Conclusion - Unstable plaques exhibit chronic pan-arteritis, accompanied by enlargement, medial thinning, and less fibrosis than in stable lesions, which is compatible with vessel aneurysm. Adventitial inflammation may contribute significantly to atheroma instability. Stable lesions may be associated with negative remodelling; consequently, small plaques may cause severe obstructive lesions. Key words: coronary atherosclerosis, unstable plaques, arteritis, aneurysm, adventitial inflammation Heart Institute (InCor), University of São Paulo Medical School, São Paulo, Brazil and Cardiovascular Division, Brigham and Women's Hospital, Boston, MA, USA Mailing address: Maria de Lourdes Higuchi - InCor
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