Comparison of peripheral endothelial dysfunction and intimal media thickness in patients with suspected coronary artery disease

Abstract

Objective: Flow associated dilatation (FAD%) and intimal media thickness are established markers of early atherosclerosis. This study aimed to compare the ability of the non-invasive measurements FAD% and intimal media thickness to predict coronary artery disease.

Methods: FAD% and intimal media thickness were determined using high resolution ultrasound in 122 patients with clinically suspected coronary artery disease before coronary angiography. Results are given as mean (SD).

Results: Patients with coronary artery disease had reduced FAD% compared with those with angiographically normal coronary vessels (3.7 (4.1) v 7.0 (3.5)%, p < 0.001), whereas intimal media thickness tended to be increased in patients with coronary artery disease (0.58 (0.35) v 0.47 (0.11)mm, p = 0.054). There was a negative correlation between FAD% and intimal media thickness (R = -0.317, p = 0.0004). Receiver operating characteristic analysis showed that FAD% < or = 4.5% predicted coronary artery disease with a sensitivity of 0.71 (95% confidence interval 0.61 to 0.80) and a specificity of 0.81 (0.58 to 0.95). In contrast, intimal media thickness showed a positive correlation with the extent of coronary artery disease (number of vessels with a lesion > or = 50%) (R = 0.324, p = 0.0003), without a clear cut off point.

Conclusions: In patients with clinically suspected coronary artery disease, FAD% discriminates between the presence or absence of coronary artery disease, whereas intimal media thickness is associated more with the extent of coronary artery disease.

Figure 1

Flow associated vasodilatation (FAD%) related to the extent of coronary artery disease (CAD). NCAD, no vessel alterations; CAD-0, vessel alterations but lesion < 50%; CAD-1, lesion > 50% in one vessel; CAD-2, lesion > 50% in two vessels; CAD-3, lesion > 50% in three vessels; FAD%, flow associated (vaso)dilatation derived as percentage change during reactive hyperaemia relative to the baseline scan at rest (100%).

Figure 2

Intimal media thickness related to the extent of coronary artery disease (CAD). NCAD, no vessel alterations; CAD-0, vessel alterations, but lesion < 50%; CAD-1, lesion > 50% in one vessel; CAD-2, lesion > 50% in two vessels; CAD-3, lesion > 50% in three vessels.

Figure 3

Inverse relation of flow associated vasodilatation (FAD%) and intimal media thickness (R = − 0.317, p = 0.0004, FAD% log transformed). FAD% derived as percentage change during reactive hyperaemia relative to the baseline scan at rest (100%).

Figure 4

Receiver operator characteristic (ROC) analysis of flow associated vasodilatation (FAD%). Determination of a cut off point of FAD% ⩽ 4.5% as a predictor for coronary artery disease, showing a positive linear relation between intimal media thickness and coronary artery disease (R = 0.324, p = 0.0003). True positive rates (sensitivity) for the different criteria are plotted against false positive rates (1−specificity). FAD% derived as percentage change during reactive hyperaemia relative to the baseline scan at rest (100%).