Background N-terminal fragment of the brain natriuretic peptide prohormone (NT-proBNP), a marker for neurohumoral activation, has been associated with adverse outcome in patients with myocardial infarction. NT-proBNP levels may reflect extensive ischemia and microvascular damage, therefore we investigated the potential association between baseline NTproBNP level and ST-resolution (STR), a marker of myocardial reperfusion, after primary percutaneous coronary intervention (pPCI).Methods we performed a post-hoc analysis of the On-TIME II trial (which randomized ST-elevation myocardial infarction (STEMI) patients to pre-hospital tirofiban administration vs placebo). Patients with measured NT-proBNP before angiography were included. Multivariate logistic-regression analyses was performed to investigate the association between baseline NTproBNP level and STR one hour after pPCI.Results Out of 984 STEMI patients, 918 (93.3%) had NT-proBNP values at baseline. Patients with STR 70% had higher NT-proBNP values compared to patients with complete STR (70%) [Mean +/- SD 375.2 +/- 1021.7 vs 1007.4 +/- 2842.3, Median (IQR) 111.7 (58.4-280.0) vs 168.0 (62.3-601.3), P < .001]. At multivariate logistic regression analysis, independent predictors associated with higher risk of poor myocardial reperfusion (STR < 70%) were: NT-proBNP (OR 1.17, 95%CI 1.041.31, P = .009), diabetes mellitus (OR 1.87, 95%CI 1.14-3.07, P = .013), anterior infarct location (OR 2.74, 95% CI 2.00-3.77, P < .001), time to intervention (OR 1.06, 95%CI 1.01-1.11, P = .021), randomisation to placebo (OR 1.45, 95%CI 1.05-1.99, P = .022).Conclusions In STEMI patients, higher baseline NT-proBNP level was independently associate with higher risk of poor myocardial reper fusion, suppor ting the potential use of NT-proBNP as an early marker for risk stratification of myocardial reperfusion after pPCI in STEMI patients
