Comparison of serum gamma-glutamyltransferase levels between patients with cardiac syndrome X and healthy asymptomatic individuals

Background: Gamma-glutamyltransferase (GGT) enzyme has an increasing importance in the pathophysiology and prognosis of cardiovascular diseases. It is an indirect marker of microvascular endothelial dysfunction, atherosclerosis, and elevated oxidative stress. There are no adequate data on the relationship between GGT and cardiac syndrome X. Aim: To compare serum GGT levels between patients with cardiac syndrome X and asymptomatic healthy individuals. Methods: Fifty consecutive patients (29 female, 21 male, aged 28-81 years) who underwent coronary angiography due to objective ischaemia and were eventually diagnosed with cardiac syndrome X between July 2009 and January 2010, and 50 healthy asymptomatic control individuals (28 female, 22 male, aged 30-78 years) were studied. Venous blood samples were collected for GOT measurements. A metabolic syndrome (MS) subgroup composed of 15 individuals was formed within the cardiac syndrome X group. Results: Serum total cholesterol, LDL-cholesterol, and triglyceride (TG) levels were significantly higher in the cardiac syndrome X patients than in the control group (195.28 +/- 33.71 mg/dL and 168.82 +/- 31.45 mg/dL, p < 0.01, 121.62 +/- 30.53 mg/dL and 98.44 +/- 27.28 mg/dL, p < 0.01, 144.30 +/- 68.54 mg/dL and 108.94 +/- 43.59 mg/dL, p < 0.01, respectively). Serum GGT levels were also significantly higher in the cardiac syndrome X patients than in the control group (30.48 +/- 16.36 and 17.88 +/- 6. 89 U/L, p < 0.001). The MS patients (n = 15) had significantly higher TG and GGT levels (230.00 +/- 41.37 mg/dL and 107.57 +/- 37.90 mg/dL, p < 0.01, 38.47 +/- 21.27 U/L and 27.06 +/- 12.61 U/L, p < 0.001, respectively) and lower HDL levels (35.47 +/- 6.91 mg/dL and 48.26 +/- 9.97 mg/dL, p < 0.05) compared to patients without MS. The cardiac syndrome X group exhibited a significant positive correlation between GGT and body mass index, and GGT and TG (r = 0.321, p = 0.023, r = 0.293, p = 0.039, respectively). Conclusions: GGT activity in patients with cardiac syndrome X was higher than in healthy controls. Moreover, GGT activity was further increased in those patients with cardiac syndrome X who had also MS.