BACKGROUND: This study aimed to investigate the association between serum levels of cystatin C, N-terminal pro-B-type natriuretic peptide (NT-proBNP), and cardiac function in patients with unstable angina pectoris (UAP).

MATERIAL AND METHODS: A cross-sectional observational study was conducted at a single center and recruited 300 patients (214 men and 86 women), who were diagnosed with UAP between June 2018 to December 2018. The patients had serum levels of NT-ProBNP measured and were divided into four groups according to the serum levels of cystatin C: Q1, 0.49–0.83 mg/L; Q2, 0.84–1.04 mg/L; Q3, 1.05–1.38 mg/L; Q4, 1.39–4.21 mg/L. Cardiac function was graded according to the New York Heart Association (NYHA) class I to IV criteria.

RESULTS: In the 300 patients with UAP, there were significant differences in cardiac function and NT-ProBNP levels between the four study groups (Q1 to Q4) (p<0.05). Univariate analysis showed that body weight, heart rate, treatment with aspirin, ticagrelor, angiotensin-converting enzyme inhibitor and an angiotensin receptor blocker (ACE/ARB), diuretic use, uric acid level, and serum cystatin C levels were significantly associated with increased levels of NT-ProBNP. After adjusting for confounding factors screened in univariate analysis, multivariate regression analysis showed that increased serum cystatin C levels were significantly associated with increased levels of NT-ProBNP.

CONCLUSIONS: Increased serum levels of cystatin C were associated with poor cardiac function and increased levels of NT-ProBNP in patients with UAP.

Keywords: Angina, Unstable, cystatin C, Natriuretic Peptide, Brain, Cross-Sectional Studies, Heart, Peptide Fragments