background:Despite the achievement of optimal epicardial coronary artery patency after percutaneous coronary intervention(PCI), the prognosis of individuals are quite different in patients with ST-segment elevation myocardial infarction (STEMI). Objectives:This study was designed to identify independent predictors of in-hospital adverse events after successful PCI in patients with STEMI. Methods:We enrolled 149 patients (men,115;mean age,60.1짹12.6 years) with STEMI who underwent successful PCI. At emergency room, we measured plasma B-type natriuretic peptide(BNP) and highly-sensitive complement reactive protein(CRP) level as well as cardiac enzymes. We also described the pain-to-door and door-to-balloon times and TIMI flow grades in individual patients after PCI. During the admission periods, we measured the remained height of ST-segment elevation 24 hours after primary PCI. In-hospital adverse events were defined as cardiogenic shock, acute pulmonary edema, acute renal failure, fatal ventricular arrhythmia and cardiac death. We analyzed the relationships of BNP and the height of sustained ST-segment elevation with the incidence of in-hospital adverse events by multiple logistic regression analysis. Results:First, initial plasma BNP was moderately correlated with chest pain to door time (r=0.462, p<0.0001 ). Second, initial BNP is significantly higher in no-reflow group (TIMIgrade 0,1,2) than that of normal-flow group (TIMI grade 3) (409.23 pg/ml vs. 114.24 pg/ml, p < 0.001, respectively).Third, initial BNP is significantly higher in patients with In-hospital adverse events than the other (972,2 vs. 68.9 pg/ml, p < 0.001, respectively). Finally, remained ST-segment elevation (>2mm) 24 hours after primary PCI(OR = 17.557, p = 0.026)and initial level of BNP (OR = 1.009, p=0.007) were associated with the in-hospital advere cardiac events. Conclusions:The high plasma level of initial BNP reflects delayed visit at emergency unit after onset of chest pain in patients with STEMI. On top of that, remained ST-segment elevation 24 hours after successful primary PCI and initial plasma BNP level were independent predictors of in-hospital adverse events.