Correlation Between GGT(Gamma-Glutamyltransferase) And The Severity Of Coronary Lesion In Acute Coronary Syndrome

BackgroundWith reference to epidemiological data, cardiovascular disease is the single largest leading cause of death worldwide and is commonly associated with myocardial infarction(MI). Of cardiovascular diseases, according to WHO, 7.3 million of 17.3 million deaths in 2008 were attributed to MI. Approximately, 1 in 6 people in the United States died of coronary heart disease in 2009.Gamma-glutamyltransferase(GGT) is the enzyme responsible for the extracellular catabolism of glutathione, the mainthiol antioxidant in mammalian cells. The determination of serum GGT activityis a well-established diagnostic test for hepatobiliary diseases and is used as a sensitive marker of alcohol consumption and abuse. It is demonstrated that serum GGT activity is an independent risk factor for myocardialinfarction and cardiac death in patients with coronary arterydisease(CAD). Elevated gamma-glutamyltransferase(GGT) level is independently correlated with conditions associated with increased atherosclerosis, such as obesity, elevated serum cholesterol, high blood pressure and myocardial infarction. It is demonstrated that serum GGT activity is an independent risk factor for myocardial infarction and cardiac death in patients with coronary artery disease. Although the relationship between GGT and coronary artery disease has been reported, there are limited data exploring the changes of GGT in acute coronary syndromes, especially in regards with the severity of the atherosclerotic lesion. Throughout the clinical and epidemiological studies data, it is shown that GGT is an important factor for most cardiovascular diseases, stroke, hypertension, type 2 diabetes and has largely been a marker for excessive alcohol consumption and liver disease.The SYNTAX score is a unique tool to score complexity of coronary artery disease. It is a new angiographic toolused to characterize the coronary vasculatureand predict outcomes of coronary intervention based on anatomical complexity. A higher SYNTAX score was significantly associated with cardiac mortality and major cardiac events.This study aimed to determine changes in GGT level with the increase in the severity of the atheroclerotic lesion in acute coronary syndromes using SYNTAX score.The study was carried out at the second affiliated hospital of Dalian medical university.MethodThe research described the levels of GGT and other laboratory and radiological findings in AMI and UA patients who were reported to the cardiology department of the second affiliated hospital of Dalian Medical University. A total of 916 consecutive patients(435 with AMI and 481 with Unstable Angina) presenting with acute coronary syndromes between January 2008 and December 2011 were included in the study. This population consisted basically of patients from the Han Chinese. The diagnostic criteria used to diagnose patients with acute myocardial infarction and unstable angina were a rise and/or fall of cardiac bio-markers, along with supportive evidence in the form of typical symptoms, suggestive electrocardiographic(ECG) changes, and/or imaging evidence of new loss of viable myocardium or new regional wall motion abnormality. All patients underwent angiography and had a complete clinical data, age ≥ 18 years old, < 99 years. Patients excluded for the study were those with past history of coronary artery disease, underwent any coronary artery intervention, coronary artery stenosis <50%, severe heart failure or rheumatic heart disease or cardiomyopathy, acute urinary tract infection, cancer or chemotherapy or organ transplantation.SYNTAX scorewas applied to evaluate the severity ofcoronary artery disease with coronary angiography integration. Patients were divided into Syntax 1(SYNTAX score ≤ 22), Syntax 2(SYNTAX score 23-32) and Syntax 3(SYNTAX score ≥33) groups according to their respective SYNTAX score where Syntax 1 group was mild, Syntax 2 was moderate and Syntax 3 was severe. Linear correlation analysis was done to find out respective correlation of each variable with regards to the SYNTAX score and each variable with significant correlation were then analyzed for multiple step-wise linear regression analysis to find out the independent predictive factors and the regression equation.ResultsSignificant statistical differences were observed regarding serum levels of GGT, sex, cholesterol, e GFR, AST, ALB, creatinine, HDL-C and LDL-C. The prevalence of hypertension was recorded as above 50% in all patient groups. Smoking percentage was found to be increased as the severity of the ACS increased. Comorbidities such as CKD and diabetes were also found to be increased as the disease worsened. Echocardiographic comparative statistical analysis indicates significant difference of LVEF among the study groups and the ECG analysis suggested the incidence of NSTEMI to be higher in Syntax 2(74.5%) and Syntax 3(92.7%) groups of AMI patients. Correlation analysis of GGT levels and SYNTAX scores showed a marked positive correlation between the plasma GGT levels and SYNTAX score and the multiple step-wise linear regression analysis showed GGT to be an independent predictive factor the increase of the SYNTAX score for ACS patients.ConclusionThis study demonstrates that serum GGT level is correlated with the severity of the coronary atherosclerotic lesions and is an independent predictive risk factor for acute coronary syndrome.