Echocardiographic and Laboratory Findings in Coronary Slow Flow Phenomenon: Cross-Sectional Study

Abstract

Background: Coronary slow flow phenomenon (CSFP) is characterized by delayed opacification of coronary arteries in the absence of obstructive coronary disease. Although often considered benign, CSFP has been associated with myocardial ischemia, arrhythmias, and subtle structural and functional cardiac alterations. This study aimed to evaluate echocardiographic and laboratory findings in patients with CSFP and identify predictors of severe slow flow.

Methods: In this cross-sectional study, 150 patients with angiographically confirmed CSFP were enrolled. Demographic and clinical data, including age, gender, body mass index (BMI), smoking status, diabetes, and hypertension, were recorded. Laboratory investigations included hemoglobin, white blood cell count, platelet count, fasting blood glucose, and lipid profile. Transthoracic echocardiography was performed to assess left ventricular ejection fraction (LVEF), ventricular dimensions, left atrial diameter, mitral E/A ratio, and pulmonary artery systolic pressure. Participants were stratified into mild/moderate (Grade 1–2) and severe (Grade 3) slow flow groups.

Results: The mean age of participants was 50.5 ± 10.2 years, and 63.3% were male. Laboratory analysis showed significantly higher white blood cell counts, fasting glucose, LDL cholesterol, and lower HDL cholesterol in the severe slow flow group (p < 0.05). Echocardiography revealed increased left ventricular diameters, higher pulmonary artery pressures, and reduced mitral E/A ratios in severe cases (p < 0.05). Multivariate logistic regression identified age, BMI, diabetes, elevated LDL, reduced HDL, increased LV end-diastolic diameter, and decreased mitral E/A ratio as independent predictors of severe coronary slow flow.

Conclusion: Patients with severe CSFP exhibit metabolic disturbances and subtle structural and diastolic functional cardiac alterations. Age, BMI, diabetes, lipid profile, and echocardiographic parameters are independent predictors of severity. Early recognition and monitoring of these factors may aid in risk stratification and management of CSFP.