Relationship between elevated serum gamma-glutamyltransferase activity and slow coronary flow.

Objectives: We evaluated the relationship between coronary blood flow and serum gamma-glutamyltransferase (GGT) activity in patients with slow coronary flow (SCF).

Study Design: The study included 90 patients (47 men, 43 women; mean age 50.8+/-9.4 years) with SCF and 88 patients (45 men, 43 women; mean age 51.4+/-8.8 years) with coronary artery disease (CAD), whose diagnoses were made by coronary angiography. Patients with CAD had normal coronary flow. Coronary flow was quantified using the corrected TIMI frame count (TFC) method and serum levels of gamma-glutamyltransferase were measured. The results were compared with those of a control group consisting of 86 age- and sex-matched patients who had normal coronary arteries and normal coronary flow.

Results: The three groups were similar with respect to body mass index, presence of hypertension and diabetes mellitus, lipid profiles, and fasting glucose. The use of medications was significantly more common in the CAD group (p<0.01). Compared to the control group, serum GGT activity was significantly increased in both SCF and CAD groups (p<0.01), but these two groups did not differ significantly in this respect (p=0.71). The TFCs for all the epicardial coronary arteries and the mean TFC were significantly higher in the SCF group (p<0.01). Patients with CAD and the controls had similar TFC parameters. The mean TFC showed a positive and moderate correlation with serum GGT activity (r=0.326; p<0.001). In regression analysis, serum GGT activity was found as the only independent predictor of the mean TFC (beta=0.309; p<0.001).

Conclusion: We have shown for the first time an association between increased serum GGT activity and SCF. Further clinical studies are needed to clarify the physiopathologic role of serum GGT activity in SCF.