The objective of the present prospective multicenter case-control study was to investigate the long-term clinical outcome (5 years) of primary stenting compared to primary percutaneous transluminal coronary angioplasty (PTCA) without stenting (POBA) in patients with acute myocardial infarction at 7 cardiovascular centers in Hokkaido, Japan. Forty-one patients with acute myocardial infarction treated with successful primary stenting (stent group: case) and paired with 41 matched control subjects with acute myocardial infarction treated by successful primary PTCA without stenting (POBA group: control) were analyzed. After 1 year, the stent group had a lower incidence of the combined clinical endpoint (death, rehospitalization due to congestive heart failure, nonfatal myocardial infarction, repeat angioplasty, CABG, or cerebrovascular events) compared to the POBA group (17.1% versus 39.0%, P = 0.049). After 5 years, the incidences of congestive heart failure and cardiac death were the same in both groups. However, compared to the POBA group, the stent group had a lower combined clinical endpoint (34.1% versus 61.0%, P = 0.027). The Kaplan-Meier event-free survival curves of the stent group showed a significantly lower occurrence of clinical events compared to the POBA group (P = 0.0116). Multiple logistic regression analysis of clinical events identified age > or = 69 years (P = 0.0092, odds ratio = 4.179) and stenting (P = 0.0158, odds ratio = 0.279) as explanatory factors. Compared with POBA, primary stenting for acute myocardial infarction results in a better long-term clinical outcome.