Background—The benefits of vessel recanalization in acute myocardial infarction (AMI) are limited by reperfusion damage. In animal models, adenosine limits reperfusion injury, reducing infarct size and improving ventricular function. The aim of this study was to evaluate the safety and feasibility of adenosine adjunct to primary PTCA in AMI.

Methods and Results—Fifty-four AMI patients undergoing primary PTCA were randomized to intracoronary adenosine or saline. The 2 groups were similar for age, sex, and infarct location. Adenosine administration was feasible and well tolerated. PTCA was successful in all patients and resulted in TIMI 3 flow in all patients given adenosine and in 19 given saline (P<0.05). The no-reflow phenomenon occurred in 1 adenosine patient and in 7 saline patients (P=0.02). Creatine kinase was lower in the adenosine group, and a Q-wave MI developed in 16 adenosine patients and in 23 saline patients (P=0.04). Sixty-four percent of dyssynergic segments improved in the adenosine group and 36% in the saline group (P=0.001). Function worsened in 2% of dyssynergic segments in the adenosine group and in 20% in the saline group (P=0.0001). Adverse cardiac events occurred in 5 patients in the adenosine group and in 13 patients in the saline group (P=0.03).

Conclusions—Intracoronary adenosine administration is feasible and well tolerated in AMI. Adenosine adjunct to primary PTCA ameliorates flow, prevents the no-reflow phenomenon, improves ventricular function, and is associated with a more favorable clinical course.