Adenosine deaminase (ADA) regulates purine metabolism through the conversion of adenosine to uric acid (UA). A close association is known to exist between adenosine and UA and cardiovascular events. Tang et al. summarized the impact of ADA on the cardiovascular system in the form of a medical hypotheses involving ADA-mediated inflammatory processes, superoxide radical generation, and the effect of ADA on myocardial ischemia and its potential clinical value (13).Xuan et al. were the first to show an independent correlation between low serum ADA activity levels and CAD occurrence. Those authors reported significant attenuation of serum ADA activity in CAD patients with MI, compared to patients with stable and unstable angina pectoris (14).In the present study, ADA activity in the DNS group was higher than in the IWBC group at all time points.However, the only statistically significant difference was determined 20 min after removal of the cross-clamp (p=0.020). We think that the value obtained 20 min after removal of the cross-clamp being higher in the DNS group also shows that myocardial protection is not poorer than IWBC.