1. Subjects Between November 2016 and October 2018, subjects were selected based on the premise that they had symptoms of chest tightness, shortness of breath or chest pain, were clinically diagnosed with coronary artery atherosclerotic heart disease and had undergone a coronary angiography (CAG). The CAG provided information concerning the absence of coronary artery stenosis or stenosis less than 40%. 46 patients diagnosed with CSFP via the corrected TIMI blood flow frame method were selected as the CSFP group. During the same period, 50 patients with normal CAG were randomly selected as the normal coronary blood flow group (no-CSFP group).
Patients were excluded on the basis of the following criteria: patients with coronary artery dilatation; deformity and spasm; intracoronary thrombosis; heart valvular disease; cardiomyopathy; acute and chronic cardiopulmonary insufficiency; connective tissue disease; severe infectious disease; hypertensive heart disease; hepatorenal insufficiency and metabolic disease; hyperthyroidism heart disease; a patient with a history of disease; patients who took statins, glucocorticoids and other drugs within the last 2 months; and patients who were contraindicated with antiplatelet and/or anticoagulant therapy.
Approval or this study was gained from the ethics committee. Informed consent was obtained and signed by patients, following the principle of voluntariness and harmlessness all throughout the duration of the study. After obtaining the consent of patients and their families, the researchers signed the informed consent for the study, and explained the purpose and significance of the study to the patients and their families in detail.
2. General information and Biomarker Measurements
2.1 General Information Medical data on the patients was obtained, including smoking, hypertension, diabetes and medication history. General information on all patients including gender, age, Body Mass Index (BMI, BMI = body weight/Hight2 (kg/m2)), Waist-to-Hip Ratio (WHR), blood pressure was also collected. Blood pressure was measured and categorised according to the Chinese Guidelines for the Prevention and Treatment of Hypertension (Version 2010). The mean values were measured in triplicate and the interval between measurements was approximately 5 minutes.
2.2 Laboratory Biomarkers Blood samples were collected from all eligible patients prior to treatment. Patients fasted for 12 hours before blood samples (5ml) were collected the following morning for laboratory analysis. Blood lipid analysis (TG, TC, LDL, HDL), fasting blood glucose (Glu) and hematuria were carried out using BECKMAN automatic biochemical analyzer CXCL–9 kits (USA). Acid (UA), highly sensitive C reactive protein (hs-CRP) and homocysteine (Hcy) content were measured.
2.3 Level Detection of Chemokines On the day of admission, venous blood (5 mL) was taken from all subjects using a disposable pyrogen-free and endotoxin-free test tube. EDTA was the recommended anticoagulant. The samples were then centrifuged at a speed of 3000 rpm for 15 minutes, and the serum separated temporally. Samples were frozen at –80℃ for future testing. ELISA KIT was employed by following the standard operation procedure. Finally, the coordinate points of each standard were connected by a smooth line, with the concentration of the standard substance set as abscissa and the OD value as ordinate. Hence, the concentration of a sample was found using the standard curve, via the OD value of the specimen.
3. Assessment of Coronary Blood Flow
3.1 Coronary Angiography With informed consent, all the selected subjects completed a CAG during hospitalization. Nitrate drugs were discontinued for 24 hours prior to the CAG. The CAG was performed through the right radial artery or femoral artery using Judkins method. Two experienced cardiologists performed the CAG.
3.2 Definition of CSFP and TFC CSFP refers to the absence of significant coronary artery lesions (normal or stenosis < 40%) during the CAG and absence of abnormal left ventricular contractile function as well as the exclusion of coronary artery spasm or gas thrombosis, coronary angioplasty or stent implantation, cardiomyopathy, valvular heart disease, connective tissue disease and thyroid function. The CAG demonstrates that following hyperactivity, patients with chest tightness or chest pain do not experience significant obstructive lesions in the main coronary artery, and instead, a phenomenon of delayed filling of distal angiographic agents is observed. The thrombolysis in myocardial infarction(TIMI) frame count method was used to record the number of image frames, observe the blood flow index and quantitatively analyze the results of CAG. The number of TIMI blood flow frames is the number of image frames from the beginning of filling the coronary artery with contrast medium to the distal end of the coronary artery during the CAG.
3.3 Evaluation of CSFP In this study, the mean TIMI frame count was used to measure coronary blood flow velocity. The coronary blood flow of patients was allocated to the CSFP group when the velocity of each coronary artery was greater than the two standard deviations of the published normal coronary blood flow velocity . The no-CSFP group was considered within the two standard deviations of normal blood flow velocity. In order to ensure the accuracy and consistency of blood flow assessment, two researchers evaluated and recorded the number of coronary artery blood frames according to the above criteria on the basis of CAG images.
4. Statistical Analysis The collected data was sorted and analyzed by software SPSS10.0. The resulting data were expressed using the mean±standard deviation, data counts by % and 2 test with p<0.05, with the difference being of statistical significance. A logistic regression method was used for correlation analysis. Receiver Operating Characteristic (ROC) curve analysis were performed to assess the diagnostic value of CXCL9 in the diagnosis of CSFP. The larger the area of the ROC curve, the higher the diagnostic value.