Direct coronary stent implantation without predilatation - a new therapeutic approach with a special balloon catheter design

Stent implantation serves as the gold standard for proximal lesions of the coronary arteries with a diameter between 2.75-3.5 mm. Our new concept aims at a reduced procedure duration and fluoro-time as well as a decreased isc hemic period during stent implantation. A new therapeutic concept of a direct stent implantation without predilatat ion was tested using a specially developed balloon catheter on which variou s 14-16 mm long "slotted-tube" stents are mounted between two conical, radi opaque markers. In 105 consecutive patients, who were scheduled for angiopl asty, this method of direct stent implantation was performed. Six of the pr ocedures were performed for acute myocardial infarction and 8 in socalled h igh-risk procedures. The direct stent implantation was successful in 88%. I n 6%, predilatation of the lesion site was necessary before stent placement . In the remaining 6%, a stent could not be successfully implanted despite the availability of various other systems. Comparison of the direct stent implantation with conventional stent placeme nt with predilatation revealed that 1) The fluoro-time for direct stent imp lantation, compared to the conventional method, was 8.4 +/- 4.9 min vs. 13. 7 +/- 8.0 min; p < 0.05, respectively Furthermore, there were less balloons used per lesion for direct stent implantation (1.4 +/- 0.4) compared to th e conventional method (1.7 +/- 0.7), but there was not a significant differ ence. 2) If we compare those patients with successful direct stent implanta tion with those with the unsuccessful procedures, the latter group had a hi gher percent of angiographically visible calcification at the site of the l esion (80% vs. 18%; p < 0.01). In addition, these patients had an increased average age (72 +/- 7 vs. 61 +/- 11 yrs; p < 0.01). The success rate of di rect stent implantation did not depend on lesion diameter stenosis before P TCA. Stent dislocation was observed in 3.8% of the procedures, and a single case of stent embolism was seen. In conclusion, the direct stent implantation offers the advantages of a sho rtened fluoro-time, the use of fewer balloons, and has the potential of les s ischemic stress compared to the conventional method of stent implantation with predilatation, if old patients with calcified lesions are excluded. T his should be proved on a large scale in future studies also considering a learning curve with regard to the new method. Whether this new approach als o reduces the restenosis rate, warrants further studies.