Adenosine myocardial protection - Preliminary results of a phase II clinical trial

Objective To evaluate the safety, tolerance, and efficacy of adenosine in patients undergoing coronary artery bypass surgery. Summary Background Data Inadequate myocardial protection in patients undergoing coronary artery bypass surgery contributes to overall hospital morbidity and mortality. For this reason, new pharmacologic agents are under investigation to protect the regionally and globally ischemic heart. Methods In a double-blind, placebo-controlled trial, 253 patients were randomized to one of three cohorts. The treatment arms consisted of the intraoperative administration of cold blood cardioplegia, blood cardioplegia containing 500 mu M adenosine, and blood cardioplegia containing 2 mM adenosine. Patients receiving adenosine cardioplegia were also given an infusion of adenosine (200 mu g/kg/min) 10 minutes before and 15 minutes after removal of the aortic crossclamp. Invasive and noninvasive measurements of ventricular performance were obtained before, during, and after surgery, Results The high-dose adenosine cohort was associated with a trend toward a decrease in high-dose dopamine support and a lower incidence of myocardial infarction. A composite outcome analysis demonstrated that patients who received high-dose adenosine were less likely to experience one of five adverse events: high-dose dopamine use, epinephrine use, insertion of intraaortic balloon pump, myocardial infarction, or death. The operative mortality rate for all patients studied was 3.6% (9/253). Conclusions Adenosine treatment is safe and well tolerated and may be associated with fewer postoperative complications.