The several kinds of coronary stents have proven successful in their role to treat acute or subacute closures after balloon angioplasty as well as to reduce the restenosis rate in de novo lesions. However, investigations continue in order to develop an ideal stent with a strong, highly flexible, radial force, especially useful in cases of tortuous vessels, lesions at bends, and lesions distal to previously deployed stents. The NIR stent is a recently developed balloon-expandable, stainless-steel, slotted tube stent; it is designed for improved flexibility with a higher radial force when compared with the traditional Palmaz-Schatz stent. We report the immediate results of our experience with the NIR stent. The purpose of the present study was to assess the feasibility, safety and efficacy of the deployment of manually crimped NIR stents in patients with complex coronary anatomy as well as the clinical outcomes within the first month.

Between January and July 1997, 143 NIR stents were implanted in the coronary arteries of 124 patients (male 76%, mean age 56±10 years). Sixty-one patients had UAP, 43 had SA, and 20 patients had AMI.

1) Indications of stenting were de novo lesions in 123(95%) and restenosis lesion in 6(5%).

2) Frequency of used stent length was 16mm in 65 cases(46%), 32mm in 60 cases(42%), 25 mm in 12 cases(8%), and 9mm in 6 cases(4%).

3) Single stents were implanted in 115(89%) lesions, and overlapping stenting with 2nd NIR stents in 14(11%) lesions.

4) Procedural success rate(defined as the angiographically residual stenosis of <30% immediately after the procedure with no major clinical events within 4 weeks after the procedure) was 95.2% (118/124 pts). Angiographic success rate(defined as a residual stenosis of <30% without major dissection) was 96.1%(124/129 lesion). The procedural success rate and the angiographic success rate in calcified lesions and/or thrombi containing lesions were 100%. The procedural success rate and the angiographic success rate in cases of tortuous proximal vessels to the lesion were 91% and 91%, respectively. The procedural success rate and the angiographic success rate in more than 45 degrees angulated lesions were 98% and 94%, respectively.

The mean lumen diameter of target lesions was increased from 0.6±.4mm to 3.1±.5mm(p<0.001) after stent implantation. The percent of diameter stenosis was decreased from 82±2% to -1±3%(p<0.001) after stent implantation. The mean diameter of the reference artery was 3.1±.6mm.

6) Incidence of peristent dissection after stenting was 6.2%(8/129 lesion).

7) The rate of stenting failure was 4.8%(6 pts). There were 2 cases of stent migration, 2 cases of failure to cross the lesion and 2 cases of procedure-related emergency CABG.

There is a higher tendency for stent migration with manually crinped stents compared with that of premounted stents. However, coronary stenting with manually-crimped NIR stents can be safely performed and may be particularly useful in patients with unfavorable clinical and angiographic characteristics for percutaneous coronary intervention. Follow-up data is needed to assess long term patency of this stent.