The optimal anti-thrombotic strategy for primary stenting in acute myocardial infarction (AMI) is still controversial. We evaluated prospectively the efficacy and safety of low-molecular-weight-heparin (LMWH) for primary stenting in AMI.

From 1/1997 to 7/1998, 54 AMI pts underwent primary stenting with 96% of procedural success rate (52/54). Of these, five pts were excluded from the study for warfarinization or use of GP II b/ III a inhibitor despite of successful stenting (TIMI 3 flow and less than 30% of residual stenosis). In 47 pts included in the study, 5,000-10,000 U of unfractionated heparin was administered (IV/bolus) bofore primary stenting. After sheath removal, LMWH(Fraxiparine, 7500 U/S.C.BID) maintained for 10.6±5.7 days. Aspirin and ticlopidine (500mg/day for ≥4 weeks) were given before stenting. Pts were followed to determine early (0-30 days) and late (31-180 days) major adverse cardiac events (MACE). Subsequent revascularization involving other coronary arteries did not constitute an end point.

In 47 Pts (M:F=32:15, age=57.7±11.3 yrs, range: 37-88), 50 stents (Nir:38, micro:7, Jo:5, LAD:LCX:RCA-=24:9:14) were implanted. Their immediate post-stenting MLD and diameter-stenosis (%) were 2.9±0.4 mm, 4.3±8.7%, respectively. No patient showed sub-acute stent thrombosis or major bleeding requiring blood transfusion or surgery. During 0-30 days, the primary combined end point occurred in 2 (4.2%):one repeated angioplasty for in-stent restenosis; one hospital death for pump failure (1 of 2 Killip IV pts at admission). 44 patients were followed for 180 days and additional three TVR (3/44(6.8%), one CABG, one repeated angioplasty and one recurrrent myocardial infarction)occurred between 30-180 days due to recurrent ischemia.

Anti-thrombotic therapy with LMWH (Fraxiparine) is safe and feasible for primary stenting in AMI. But to illuminate the impact on the clinical outcomes such as major adverse cardiac events and restenosis, we need more large and controlled study.