The Correlation Between Abdominal Fat Distribution And Severity Of Coronary Artery Disease

Objective: Coronary heart disease (CHD) refers to the failure of coronary circulation to supply adequate circulation to cardiac muscle and surrounding tissue, it can be due to lumen stenosis or obstruction caused by coronary artery atherosclerosis or other causes. Multiple pathogenic factors play very important role in the occurrence and development of CHD.Obesity, especially excessive abdominal visceral fat caused by central obesity, is considered to be associated with insulin resistance, and insulin resistance can lead to hypertension, lipid metabolism disorder, glucose metabolism impair and increase of plasma plasminogen activator inhibitor (PAI)-1. All of the above are important risk factors of atherosclerosis. Body mass index (BMI), waist circumference (WC), waist-hip ratio (WHR) and waist to height ratio (WHtR) are commonly used to assess obesity. Considerable number of CHD patients are in the normal range of BMI (BMI<25), which make some CHD patients be neglected. Recently, the focus of the study in obesity has been transferred to the human adipose tissue (AT) distribution, rather than overall degree of obesity. Computerized Tomography (CT) technology provides a more direct way to accurately quantify human obesity and whole body AT volume, especially the regional AT, such as subcutaneous or visceral fat. Obesity as a risk factor of CHD has been widely accepted, but there are few detailed descriptions of the association between the abdominal fat distribution which accurately reflect the central obesity and the degree of coronary artery stenosis.The aim of our study was to analyze the correlation between ratio of visceral and subcutaneous adipose tissue (VAT/SVT, V/s) and the degree of coronary artery stenosis, then investigate whether V/s is a available indicator for predicting the degree of coronary artery stenosis.Methods: Sixty participants (39 males, 21 females) were drawn from the Cardiology Department of Hebei Medical University Second Hospital from March to October 2008, diagnosed as CHD, accepted the coronary angiography and underwent abdominal multi detector computed tomography assessment of SAT and VAT volumes. Routine biplane coronary angiography, using the Judkins technique, was performed in all patients. Significant coronary artery stenosis was defined as >50% narrowing in the vessel diameter on the coronary angiogram. All patients were divided into non-stenosis group (group1) or coronary stenosis group (group2) (defined as at least 1 vessel with coronary artery stenosis >50%) [including: single-vessel group(group2a) and multi-vessel group(group2b)]. Gensini scores BMI, WC, WHR, WHtR and V/s were calculated. Sensitivity and specificity of each parameter on diagnosis of CHD were calculated according to the following standard, V/s ( >0.6 and≤0.6), BMI ( >25kg/m2 and≤25 kg/m2), WC (male >90cm, female >85cm and male≤90cm, female≤85cm), WHR (male >0.92, female >0.81 and male≤0.92, female≤0.81) and WHtR ( >0.5 and≤0.5).All statistical analyses were performed using the SPSS 11.5 program package. Data were expressed as the mean value±standard deviation. Data between two groups were compared by t test. Sample rate was compared byχ2 test. Analysis of risk factors was performed by Logistic regression analysis and multivariate linear stepwise regression analysis. A P value of less than 0.05 was considered to be statistically significant.Results: There were no significant differences in BMI and WC between group1 and group2 (P>0.05); the age, WHR, WHtR and V/s was significantly higher in group2 than in group1 (P<0.05); only V/s was significantly higher in group2a when compared with group1(P<0.001); there were no significant differences in BMI between group1 and group2b(P>0.05), the age, WC, WHR, WHtR and V/s all increased in group2b (P<0.05), the most significant difference was observed in V/s(P<0.001); High rate of coronary stenosis was observed according to corresponding standard of WHR, WHtR and V/s (P<0.05), more significant difference was observed in V/s(P<0.01); Take coronary stenosis as the dependent variable, and age, BMI, WC, WHR, WHtR and V/s as independent variable, multi-factor Logistic regression analysis showed that V/s was independence risk factor of CHD, but age, BMI, WC, WHR, WHtR, at P>0.05 level, could not enter the model; Take the coronary score as the dependent variable, and age, BMI, WC, WHR, WHtR and V/s as independent variable, the line multivariate linear stepwise regression analysis, showed that V/s and WHtR with coronary stenosis score had a linear regression relationship, standardization regression coefficient were 0.655 and 0.195(P<0.001, P=0.043), other factors did not reveal the relationship, suggested that above all factors V/s had the greatest impact in degree of coronary stenosis on CHD. Sensitivity and specificity of V/s >0.6 on diagnosis of CHD was 97.37% and 86.34%.Conclusion: Higher V/s was observed in the coronary stenosis group, especially in the multi-vessel group, suggest that V/s increased in CHD patients; The rate of coronary stenosis was significantly higher, in high WHR, WHtR and V/s group; Logistic regression analysis showed that V/s was an independent risk factor of CHD; Line multivariate linear stepwise regression analysis showed that V/s had the greatest impact in degree of coronary stenosis on CHD, suggested that V/s was a available indicator, better than BMI, WC, WHR and WHtR, for predicting the degree of coronary artery stenosis, and CHD. V/s has higher sensitivity and specificity on diagnosis of CHD.