Fig. 4

Coronary area change with isometric handgrip stress in four groups. Individual data bars (mean +/- SD) are shown for the following groups: 1) Normal coronary wall thickness (CWT) and eccentricity index (EI) defined as values within one standard deviation of that of healthy subjects’ values (white bar). 2) Coronary segments with abnormal CWT defined as CWT ≥1 standard deviation from the mean CWT of the healthy group (white bar, horizontal lines) 3) Segments with abnormal eccentricity index (EI, defined as EI ≥ 1 SD above the mean of the healthy group (gray bar, diagonal lines) and 4) Segments with both abnormal EI and abnormal CWT (black bar), illustrating that coronary endothelial function is more impaired in subjects with both abnormal CWT and abnormal EI than in those with either finding alone. Individual data points in open circles signify healthy subjects and those in black triangles signify CAD patients. * p < 0.05 (vs. Abnormal CWT group) and p < 0.05 (vs. Abnormal EI group)