Impact of time to therapy and reperfusion modality on the efficacy of adenosine in acute myocardial infarction: the AMISTAD-2 trial.

Aims: The purpose of this analysis was to determine whether the efficacy of adenosine vs. placebo was dependent on the timing of reperfusion therapy in the second Acute Myocardial Infarction Study of Adenosine (AMISTAD-II).

Methods And Results: Patients presenting with ST-segment elevation anterior AMI were randomized to receive placebo vs. adenosine (50 or 70 microg/kg/min) for 3 h starting within 15 min of reperfusion therapy. In the present post hoc hypothesis generating study, the results were stratified according to the timing of reperfusion, i.e. > or = or < the median 3.17 h, and by reperfusion modality. In patients receiving reperfusion < 3.17 h, adenosine compared with placebo significantly reduced 1-month mortality (5.2 vs. 9.2%, respectively, P = 0.014), 6-month mortality (7.3 vs. 11.2%, P = 0.033), and the occurrence of the primary 6-month composite clinical endpoint of death, in-hospital CHF, or rehospitalization for CHF at 6 months (12.0 vs. 17.2%, P = 0.022). Patients reperfused beyond 3 h did not benefit from adenosine.

Conclusion: In this post hoc analysis, 3 h adenosine infusion administered as an adjunct to reperfusion therapy within the first 3.17 h onset of evolving anterior ST-segment elevation AMI enhanced early and late survival, and reduced the composite clinical endpoint of death or CHF at 6 months.