Open-label, randomized, placebo-controlled evaluation of intracoronary adenosine or nitroprusside after thrombus aspiration during primary percutaneous coronary intervention for the prevention of microvascular obstruction in acute myocardial infarction: the REOPEN-AMI study (Intracoronary Nitroprusside Versus Adenosine in Acute Myocardial Infarction).

OBJECTIVES This study sought to assess whether intracoronary adenosine or nitroprusside following thrombus aspiration (TA) is superior to TA alone for the prevention of microvascular obstruction (MVO) in ST-segment elevation myocardial infarction (STEMI) patients undergoing percutaneous coronary intervention (PCI). BACKGROUND MVO, due to its multifactorial pathogenesis, still occurs after TA in a sizeable portion of patients. METHODS We performed a placebo-controlled, randomized, open-label, blind-examination, multicenter trial. A total of 240 STEMI patients with Thrombolysis In Myocardial Infarction (TIMI) flow grade 0/1 were randomly allocated 1:1:1 to receive adenosine (n = 80), nitroprusside (n = 80), or saline (n = 80) given distal to the occluded site after TA. The primary endpoint was the incidence of ST-segment resolution (STR) >70% on surface electrocardiogram at 90 min after PCI. Secondary endpoints were angiographic MVO incidence (TIMI flow grade ≤2 or 3 with a myocardial blush grade <2) and major adverse cardiac event (MACE) rate at 30 days as a composite of cardiac death, myocardial infarction, target lesion revascularization, and heart failure requiring hospitalization. RESULTS STR >70% occurred in in 71% of adenosine-treated patients, in 54% of nitroprusside-treated patients, and in 51% of saline-treated patients (p = 0.009 and p = 0.75, respectively, vs. saline). Angiographic MVO occurred in 18% of adenosine-treated patients, in 24% of nitroprusside-treated patients, and in 30% of saline-treated patients (p = 0.06 and p = 0.37, respectively, vs. saline). MACE occurred in 10%, 14%, and 20% of patients, respectively (p = 0.08 and p = 0.29 vs. saline). CONCLUSIONS In STEMI patients treated by PCI and TA, the additional intracoronary administration of adenosine, but not that of nitroprusside, results in a significant improvement of MVO, as assessed by STR.