Plaque inflammation in restenotic coronary lesions of patients with stableor unstable angina

OBJECTIVES To evaluate immunohistochemically various parameters of inflamma tion in coronary atherectomy specimens obtained from restenotic culprit les ions of patients presenting with either stable or unstable angina (UA). BACKGROUND There is no information regarding the relationship between ather osclerotic plaque inflammation and the severity of the coronary syndromes i n patients with restenotic coronary lesions. METHODS A total of 37 patients with either stable angina or UA underwent di rectional coronary atherectomy for restenotic coronary lesions. Cryostat se ctions of atherectomy specimen were immunohistochemically stained with mono clonal antibodies CD68 (macrophages [MACs]), CD3 (T-lymphocytes) and alpha- actin (smooth muscle cells [SMCs]). smooth muscle cell contents and MAC con tents were planimetrically quantified as the percentage immunopositive tiss ue area of the total tissue area. T-lymphocytes were counted at 100-x magni fication throughout the entire section and expressed as number of cells per mm(2). RESULTS Restenotic coronary lesions of patients with UA or stable angina sh owed no significant difference in SMC areas (31.9% +/- 16.3% vs. 38.5% +/- 18.8%, respectively, p = NS). However, restenotic coronary lesions of patie nts presenting with unstable angina contained significantly more MACs (24.4 % +/- 15.1% vs. 10.5% +/- 5.8%, p = 0.001) and T-lymphocytes (18.8 cells/mm (2) +/- 15.1 cells/mm2 vs. 8.6 cells/mm(2) +/- 9.8 cells/mm(2); p = 0.034) than patients with stable angina. CONCLUSIONS These results suggested that inflammation appears to affect pla que instability in restenotic coronary lesions resulting in unstable corona ry syndromes. (C) 2000 by the American College of Cardiology.