BACKGROUND AND OBJECTIVES: The intracoronary stent may be useful in the preventing of abrupt closure and coronary restenosis after coronary angioplasty, and recently primary stenting has been one of therapeutic modalities. We assessed the clinical and angiographic results of primary NIR stenting in patients with acute myocardial infarction (AMI). MATERIALS AND METHODS: Between November 1997 to January 1999, 55 stentings with NIR stents were done in 51 patients with acute myocardial infarction. Angiographic follow-up was available at 7+/-2.3 days in 35 patients. RESULTS: 1) Among 51 patients (M/F: 37/14), 44 patients had Q-wave MI (86%), 7 patients had non-Q-wave MI (14%). 2) The mean age was 61+/-12.4 years (range: 26 to 82 years). 3) The mean time from the onset of chest pain to the arrival at emergency room was 4.6 +/- 4.2 hours. The mean door-to-balloon time was 93+/-46 minutes 4) Treated vessels were as follows: 28 in LAD, 17 in RCA, 10 in LCX. 5) The indications for stent implantation were suboptimal angiographic results after PTCA in 38 lesions (69%), dissection in 9 lesions (16%), abrupt vessel closure in 1 lesion and elective in 7 lesions (13%). 6) Single stent implantation was done in 47 patients. Overlapping stents were done in 4 patients. 7) A procedure related complication occurred in one patient, peri-stent dissection without flow limitation. 8) Full expansion of the stent failed in three lesions with coronary calcifications and the residual stenosis was 35, 40, 50% in each case. In these cases, in-stent thrombus was not demonstrated in follow up angiography. 9) The minimal lumen diameter increased from 0.11+/-0.39 to 2.96+/-0.40 mm. 10) Angiographic follow-up on 38 stents in 35 patients demonstrated in-stent thrombus in 3 stents, in-stent restenosis in 1 stent. But in-stent flow limitations were not found in these 4 cases and TIMI III flow were maintained. Patients with Q-wave MI and coronary thrombus on initial angiography were more prone to subacute thrombosis. CONCLUSION: The NIR stent could be used successfully in primary coronary stenting in acute myocardial infarction. The present study shows relatively low risk of subacute stent thrombosis. The rate of restenosis needs to be confirmed by long term study.