Histopathologic characteristics of atherosclerotic coronary disease and implications of the findings for the invasive and noninvasive detection of vulnerable plaques.

Objectives The goal of this study was to identify histomorphologic characteristics of atherosclerotic plaques and to determine the amenability of some of these components to be used as markers for invasive and noninvasive imaging. Background Rupture of the atherosclerotic plaques is responsible for the majority of acute coronary events, and the culprit lesions demonstrate distinct histopathologic features. It has been tacitly believed that plaque rupture (PR) is associated with angiographically minimally occlusive lesions. Methods We obtained 295 coronary atherosclerotic plaques, including stable (fibroatheroma [FA]; n = 105), vulnerable (thin-cap fibroatheroma [TCFA]; n = 88), and disrupted plaques (plaque rupture [PR]; n = 102) from the hearts of 181 men and 32 women who had died suddenly. The hierarchical importance of fibrous cap thickness, percent luminal stenosis, macrophage area, necrotic core area, and calcified plaque area was evaluated by using recursive partitioning analysis. Because clinical assessment of fibrous cap thickness is not possible by noninvasive imaging, it was excluded from the second set of partitioning analysis. Results Thickness of the fibrous cap emerged as the best discriminator of plaque type; the cap thickness measured 84-μm cap thickness. Although the majority of TCFA were found in the 54- to 84-μm thickness group, those with Conclusions This postmortem study defines histomorphologic characteristics of vulnerable plaques, which may help develop imaging strategies for identification of such plaques in patients at a high risk of sustaining acute coronary events.