Serum cystatin C level and coronary artery plaque characteristics: an optical coherence tomography study

Cystatin C, which is an endogenous marker for renal function, has been reported to be associated with outcomes and risk stratification of coronary vascular disease patients. In this study, the relationship between the serum cystatin C level and characteristics of coronary plaques is evaluated in patients with coronary artery disease. The study involved 137 lesions in 82 patients. Plaque vulnerability, rupture, fibrotic cap thickness, microchannel, and calcified nodules were evaluated by optical coherence tomography. Cystatin C levels in acute coronary syndrome (ACS) patients and in non-ACS patients were 1.160 ± 0.595 and 0.973 ± 0.158 mg/L, respectively ( P = 0.046). The cystatin C levels were not different between patients with and without ruptured plaques ( P = 0.396), or between stable and unstable lesions ( P = 0.223). There was correlation between cystatin C and calcified nodule in plaque ( r = 0.188, P = 0.032). A significant negative correlation exists between the cystatin C levels and fibrous cap tissue thickness ( r = −0.242, P = 0.018). Prior statin usage, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, and cystatin C were independent contributors to fibrous cap thickness ( P -value was 0.001, 0.001, 0.026, and 0.037, respectively). Cystatin C is not related with plaque rupture or stability, but it related with some plaque morphology, such as thin fibrous cap thickness and calcified nodule.