Prognostic value of serum gamma-glutamyl transferase activity after myocardial infarction

Aims Serum gamma-glutamyl transferase activity (gamma -GT) is able to catalyse low-density lipoprotein oxidation and has been detected in coronary atherosclerotie plaques. gamma -GT has been documented as an independent risk factor for cardiac mortality in middle-aged men. The purpose of this study is to determine the prognostic value of gamma -GT in patients with coronary artery disease. Methods and Results In a prospective study, gamma -GT and other cardiac risk factors were evaluated in 469 consecutive subjects with angiographically documented coronary artery disease, using mortality and mortality plus non-fatal myocardial infarction as end-points. gamma -GT showed an independent prognostic value beyond known established risk factors in the subgroup of 262 patients with previous myocardial infarction. At a 6-year follow-up, cardiac mortality was 25.2% in patients with gamma -GT > 40 U.l(-1) vs 13.9% in those with gamma -GT < 40 U.l(-1) (P=0038). When both cardiac mortality and non-fatal myocardial infarction were considered as end-points, these events were recorded in 32.7% of patients with gamma -GT > 40 U.l(-1) and in 20.4% of those with levels < 40 U.l(-1) (P=0031). Excess mortality and non-fatal infarction in patients with high gamma -GT levels were concentrated in the first 2 years of follow-up (P=0014). The association of gamma -GT values > 40U.l(-1), previous myocardial infarction, and multiple vessel disease identified a subgroup of 168 patients with the highest risk of cardiac events at 6 years (P=0024). The relationship between gamma -GT levels and cardiac events remained significant after adjustment for cardiac risk factors, and possible confounders, including alcohol consumption. gamma -GT did not show significant prognostic value in the 207 patients without previous myocardial infarction. Conclusion gamma -GT is an independent cardiac risk factor in ischaemic patients with established coronary atherosclerosis and previous myocardial infarction. (C) 2001 The European Society of Cardiology.