Efficacy of Adenosine in Patients With Acute Myocardial Infarction Undergoing Primary Percutaneous Coronary Intervention: A PRISMA-Compliant Meta-Analysis

Whether adenosine offers cardioprotective effects when used as an adjunctive therapy for patients with acute myocardial infarction (AMI) undergoing primary percutaneous coronary intervention (PCI) remains controversial. To evaluate, via meta-analysis, the efficacy of adenosine in patients with AMI undergoing PCI. Randomized controlled trials (RCTs) published in Medline, Embase, and the Cochrane Central Register of Controlled Trials. RCTs of patients with AMI undergoing primary PCI, comparing adenosine treatment and placebo groups and reporting mortality, thrombolysis in myocardial infarction (TIMI) flow grade, myocardial blush grade (MBG), re-infarction, left-ventricular ejection fraction (LVEF), ST-segment elevation resolution (STR), recurrent angina, or heart failure (HF). Risk of bias was assessed by the Cochrane guidelines and publication bias by Egger's test. For studies reported in multiple publications, the most complete publication was used. Arms using different dosing schedules were merged. Mean differences (MDs) or risk ratios (RRs) were determined. Data were extracted from 15 RCTs involving 1736 patients. Compared with placebo, adenosine therapy was associated with fewer occurrences of heart failure (RR: 0.65, 95% confidence interval [CI]: 0.43-0.97, P�=�0.03) and no-reflow (TIMI flow grade <3, RR: 0.62, 95% CI: 0.45-0.85, P�=�0.003; MBG�=�0-1, RR: 0.81; 95% CI: 0.67-0.98, P�=�0.03), more occurrences of STR (RR: 1.19, 95% CI: 1.07-1.31, P�<�0.00001), but no overall improvement of LVEF (MD: 2.29, 95% CI: −0.09 to 4.67, P�=�0.06). Adenosine improved LVEF in the intravenous subgroup and the regular-dose intracoronary (IC) subgroup (0.24-2.25�mg) compared with placebo (MD: 2.68, 95% CI: 0.66-4.70, P�=�0.009). Adenosine was associated with a poorer LVEF in the high-dose (4-6�mg) IC subgroup (MD: −2.40; 95% CI: −4.72 to −0.09, P�=�0.04). There was no significant evidence that adenosine reduced rates of all-cause mortality, cardiovascular mortality or re-infarction after PCI. Adenosine dosage and administration routes, baseline profiles, and endpoints differed among included RCTs. Performance, publication, and reporting biases remain possible. Adenosine therapy appears to improve several outcomes in patients with AMI after PCI, but there is no evidence that adenosine can reduce mortality rates.