Attenuation of the media of coronary arteries in advanced atherosclerosis.

Human coronary artery wall architecture was analyzed in detail in 127 histologic sections with varying degrees of narrowing due to atherosclerotic plaque. A planimetry-microscope system was used to morphometrically determine percent luminal cross-sectional area narrowing due to atherosclerotic plaque, absolute area of the coronary artery media and total cross-sectional area of the coronary artery section. In 65 sections in which the native coronary artery lumen was narrowed less than 75%, the area of the coronary artery media corrected for total coronary cross-sectional area (Mc) was 0.244 +/- 0.055 mm2. In contrast, among 62 sections in which the coronary artery lumen was narrowed more than 75% in cross-sectional area, Mc measured 0.180 +/- 0.078 (p less than 0.001). Thus, in coronary artery segments with advanced atherosclerosis, there is substantial attenuation of the media, normally the principal component of the coronary artery wall.