Gamma-glutamyltransferase activity in patients with calcific aortic stenosis

OBJECTIVES
We evaluated gamma-glutamyltransferase (GGT) activity in patients with calcific aortic stenosis (AS) and investigated the association between GGT levels and the maximum and mean aortic gradients.

STUDY DESIGN
The study included 34 patients (5 women, 29 men; mean age 63±13 years) with calcific AS. Thirty-eight subjects (8 women, 30 men; mean age 57±10 years) with echocardiographically normal aortic valves constituted the control group. Echocardiographic evaluation was performed in all the subjects and venous blood samples were obtained to determine plasma glucose, fibrinogen, total cholesterol, LDL and HDL cholesterol, triglyceride, and GGT levels. The activity of GGT was determined by the kinetic method. Associations were sought between GGT levels and the maximum and mean aortic gradients.

RESULTS
In the AS group, the mean maximum and mean gradients of the aortic valve were 74±15 mmHg and 39±9 mmHg, respectively. Fibrinogen concentrations differed significantly between the patient and control groups (3.9±1.7 mg/dl and 2.9±0.9 mg/dl, respectively; p<0.02). Activity of GGT was not influenced by gender in both groups (p>0.05). Compared to controls (21±14 U/l), the mean GGT level was significantly higher in the AS group (39±13 U/l; p=0.005). In linear regression analysis, weak but significant sex- and age-adjusted correlations were found between the GGT level and the maximum (r=0.20, p<0.001) and mean (r=0.17, p<0.001) aortic gradients.

CONCLUSION
Patients with calcific AS have higher GGT levels compared to controls, suggesting the presence of a common etiologic mechanism for both calcific AS and coronary artery disease.