Zyllt and acetylsalicylic acid in coronary atherosclerosis patients after coronary artery bypass graft intervention. Main results of the ZEUS Study: medication effectiveness, acetylsalicylic acid resistance mechanisms, short and long-term clinical outcomes
Aim. To study the effectiveness and safety of Clopidogrel and acetylsalicylic acid (ASA) in coronary atherosclerosis (CA) patients after coronary artery bypass graft surgery (CABG). To investigate intracellular metabolic activity of platelets and its association with platelet aggregation. Material and methods. In total, 94 45-72-year-old men with coronary heart disease (CHD) and initially increased platelet aggregation (PLA) were randomised into two groups, receiving clopidogrel (75 mg/d; n=44) or ASA (75-100 mg/d; n=50). The patients not responding to the two-week therapy were regarded as therapy-resistant. Results. In CHD patients after CABG, ASA resistance developed in 24%. In contrast to ASA, clopidogrel action mechanisms are based on the inhibition of platelet energy metabolism, and increased substrate flow towards nonprotein synthesis in red blood cells. These features could explain the development of laboratory-diagnosed resistance for ASA, but not clopidogrel. End-point analysis demonstrated that clopidogrel is more effective than ASA in the prevention of acute coronary syndrome, de novo angina, and cardiovascular death during the two-year follow-up of the post-CABG patients. Conclusion. Clopidogrel therapy was not associated with laboratory-diagnosed resistance, and was more effective in terms of acute coronary event prevention than ASA.