Background: Evidence shows that the soluble tumour necrosis factor-related apoptosis-inducing ligand (sTRAIL) may play a protective role against atherosclerosis. This study sought to investigate the potential association of sTRAIL levels with intravascular ultrasound (IVUS) and virtual histology characteristics of coronary plaques.
Methods: Patients with stable angina or positive for ischaemia non-invasive test were submitted to left cardiac catheterisation. Coronary blood samples were collected and sTRAIL was measured. Coronary arteries with at least one 50% or greater stenosis were studied with IVUS.
Results: 56 coronary arteries were studied with significant coronary artery disease. Plaque volume per unit of arterial length was 63 ± 5 mm(3)/cm in arteries at the lower quartile of sTRAIL concentration versus 30 ± 4 mm(3)/cm at the upper quartile (p<0.001; 95% CI of the difference 19.7 to 46.3 mm(3)/cm). The necrotic core and fibrofatty content of atheromatous plaques were inversely associated with sTRAIL (p<0.001). Thin-cap fibroatheromas (TCFA) were discovered in 16 of the 56 arterial segments. The mean sTRAIL concentration in these segments was 56.8 ± 7.5 pg/ml versus 99.9 ± 5.7 pg/ml in those without TCFA (p<0.001; 95% CI of the difference 22.7 to 63.5 pg/ml). The association of sTRAIL with the presence of TCFA remained significant in the logistic multivariate analysis (p=0.009).
Conclusion: According to the findings of the present study, in addition to coronary artery disease burden, the sTRAIL concentration is also related to the composition of atheromatous plaques. A significant association is demonstrated between low sTRAIL levels and the presence of TCFA, the IVUS-virtual histology prototype of the vulnerable plaque.