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

Objective To evaluate the safety, tolerance, and efficacy of adenosine in p atients undergoing coronary artery bypass surgery. Summary Background Data Inadequate myocardial protection in patients underg oing coronary artery bypass surgery contributes to overall hospital morbidi ty and mortality. For this reason, new pharmacologic agents are under inves tigation to protect the regionally and globally ischemic heart. Methods In a double-blind, placebo-controlled trial, 253 patients were rand omized to one of three cohorts. The treatment arms consisted of the intraop erative administration of cold blood cardioplegia, blood cardioplegia conta ining 500 mu M adenosine, and blood cardioplegia containing 2 mM adenosine. Patients receiving adenosine cardioplegia were also given an infusion of a denosine (200 mu g/kg/min) 10 minutes before and 15 minutes after removal o f the aortic crossclamp. Invasive and noninvasive measurements of ventricul ar 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 re ceived high-dose adenosine were less likely to experience one of five adver se events: high-dose dopamine use, epinephrine use, insertion of intraaorti c balloon pump, myocardial infarction, or death. The operative mortality ra te for all patients studied was 3.6% (9/253). Conclusions Adenosine treatment is safe and well tolerated and may be assoc iated with fewer postoperative complications.