Assessment of aortic propagation velocity (APV) in relation to coronary slow flow phenomenon (CSFP)

Coronary slow flow phenomenon (CSFP) is a marker of microvascular dysfunction and subclinical atherosclerosis, typically diagnosed invasively. Non-invasive indices such as aortic propagation velocity (APV), measured by echocardiography, may provide alternative diagnostic value. This study aimed to assess the association between APV and CSFP, and to evaluate the relationship of APV with traditional aortic stiffness parameters—namely aortic strain (AS) and aortic distensibility (AD). A cross-sectional study was conducted on 51 patients undergoing coronary angiography, classified into CSFP and normal flow groups based on angiographic findings. Demographic, clinical, and echocardiographic data were collected. APV, AS, and AD were measured using color M-mode Doppler echocardiography. Statistical analyses included group comparisons, correlation tests, logistic regression, and ROC curve analysis for APV cut-off determination. CSFP patients exhibited significantly lower APV, AS, AD, systolic aortic diameter, and heart rate, but higher systolic blood pressure compared to controls. APV showed strong positive correlations with AS ( r = 0.766, p < 0.001) and AD ( r = 0.700, p < 0.001), and a negative correlation with systolic blood pressure ( r = − 0.364, p = 0.009). The optimal APV cut-off for detecting CSFP was 64.0 cm/s (sensitivity 96.0%, specificity 92.3%, AUC = 0.993). APV is a promising, non-invasive marker for identifying patients at risk of CSFP and subclinical atherosclerosis. The proposed cut-off of 64.0 cm/s demonstrated high diagnostic accuracy. Larger, multi-ethnic studies are needed to validate these findings.