Relationship between serum mature brain-derived neurotrophic factor level and coronary slow flow phenomenon: a cross-sectional study.

Brain-derived neurotrophic factor (BDNF) has been implicated in cardiovascular disease. However, the role of BDNF in coronary slow flow phenomenon (CSFP) remains unclear. This study explored the relationship between serum mature BDNF (mBDNF) levels and thrombolysis-in-myocardial-infarction frame count (TFC) as a measure of CSFP. Serum mBDNF was measured in 125 patients (mean age 60.2 years, 57% women) with suspected coronary artery disease before undergoing coronary angiography. Based on the corrected TFC, 77 patients were categorized as having CSFP and 48 normal coronary flow (NCF). The relationship of mTFC (mTFC) and CSFP with serum mBDNF was analysed using multivariable linear and logistic regression. mTFC ranged from 15.9 to 68.5 and mBDNF from 13.2 to 60.6 ng/mL. Serum mBDNF was inversely correlated with mTFC (Spearman rho - 0.327, P < 0.001) and reduced in CSFP (median 25.9 ng/mL IQR 20.6, 32.2 vs. 34.5 ng/mL IQR 27.4, 41.6, P < 0.001). Multivariable linear and logistic regression analyses indicated that log(mBDNF in ng/mL) has an inverse association with log(mTFC) (coefficient - 0.332,95% CI -0.513, -0.151; P < 0.001) and reduced odds of CSFP (odds ratio 0.188, 95% CI 0.062, 0.573; P = 0.003). This suggests that BDNF may serve as a biomarker of CSFP, and provides new insights into its pathophysiology.