DIFFERENCES IN RESTENOSIS PROPENSITY OF DEVICES FOR TRANSLUMINAL CORONARY INTERVENTION - A QUANTITATIVE ANGIOGRAPHIC COMPARISON OF BALLOON ANGIOPLASTY, DIRECTIONAL ATHERECTOMY, STENT IMPLANTATION AND EXCIMER-LASER ANGIOPLASTY

With the increasing clinical application of new devices for percutaneo us coronary revascularization, maximization of the acute angiographic result has become widely recognized as a key factor in maintained clin ical and angiographic success. What is unclear, however, is whether th e specific mode of action of different devices might exert an addition al independent effect on late luminal renarrowing. The purpose of this study was to investigate such a difference in the degree of provocati on of luminal renarrowing (or 'restenosis propensity') by different de vices, among 3660 patients, who had 4342 lesions successfully treated by balloon angioplasty (n=3797), directional coronary atherectomy (n=2 00), Palmaz-Schatz stent implantation (n=229) or excimer laser coronar y angioplasty (n=116) and who also underwent quantitative angiographic analysis pre- and post-intervention and at 6-month follow-up. To allo w valid comparisons between the groups, because of significant differe nces in coronary vessel size (balloon angioplasty=2 . 62+/-0 . 55 mm, directional coronary atherectomy=3 . 28+/-0 . 62 mm, excimer laser cor onary angioplasty=2 . 51+/-0 . 47 mm, Palmaz-Schatz=3 . 01+/-0 . 44 mm ; P<0 . 0001), the comparative measurements of interest selected were the 'relative loss' in luminal diameter (RLoss=loss/vessel size) to de note the restenosis process, and the 'relative lumen at follow-up' (RL fup=minimal luminal diameter at follow up/vessel size) to represent th e angiographic outcome. For consistency, lesion severity pre-intervent ion was represented by the 'relative lumen pre' (RLpre=minimal huminal diameter pre/vessel size) and the luminal increase at intervention wa s measured as 'relative gain' (relative gain=gain/vessel size). Differ ences in restenosis propensity between devices was evaluated by univar iate and multivariate analysis. Multivariate models were constructed t o determine relative loss and relative lumen at follow-up, taking acco unt of relative lumen pre-intervention, lesion location, relative gain , vessel size and the device used. In addition, model-estimated relati ve loss and relative lumen at follow-up at given relative lumen pre-in tervention relative gain and vessel size, were compared among the four groups. Significant differences were detected among the groups both w ith respect to these estimates, as well as in the degree of influence of progressively increasing relative gain, on the extent of renarrowin g (relative loss) and angiographic outcome (relative lumen at follow-u p), particularly, at higher levels of luminal increase (relative gain) . Specifically, lesions treated by balloon angioplasty or Palmaz-Schat z stent implantation (the predominantly 'dilating' interventions) were associated with more favour able angiographic profiles than direction al atherectomy or excimer laser (the mainly 'debulking' interventions) . Significant effects of lesion severity and location, as well as the well known influence of luminal increase on both luminal renarrowing a nd late angiographic outcome were also noted. These findings indicate that propensity to restenosis after apparently successful intervention is influenced not only by the degree of luminal enlargement achieved at intervention, but by the device used to achieve it. In view of the clinical implications of such findings, further evaluation in larger r andomized patient populations is warranted.