INTER-SERIES DIFFERENCES IN THE RESTENOSIS RATE OF PALMAZ-SCHATZ CORONARY STENT PLACEMENT - DIFFERENCES IN DEMOGRAPHICS AND POSTPROCEDURE LUMEN DIAMETER

Restenosis rates following Palmaz-Schatz stenting vary between 13 and 36%. To determine whether the nearly three fold interseries difference in restenosis rates reflects systematic factors (demographic and procedural variables such as post-treatment lumen diameter) rather than random variation, we pooled 486 lesions treated with the Palmaz-Schatz coronary stent in the U.S. Multicenter Registry (n = 259) with the single-center Beth Israel Hospital experience (n = 227) and analyzed the combined series using a continuous geometric model of restenosis. A greater proportion of lesions (66 vs. 50%; P < 0.001) in the Multicenter cohort represented restenosis after a prior intervention. The Multicenter experience also showed a smaller minimum lumen diameter following stent placement (2.61 vs. 3.43 mm; P < 0.001), higher post-stent percent stenosis (1 6 vs. - 2%; P < 0.001), and less acute gain (1.79 vs. 2.67 mm; P < 0.001) than lesions treated in the Beth Israel cohort. At 6-month follow-up, the angiographic restenosis rate (greater-than-or-equal-to 50% diameter stenosis) was significantly higher in the Multicenter group (35 vs. 27%; P = 0.05), despite the development of less absolute late loss (0.96 vs. 1.32 mm; P < 0.001). Multivariable modeling, however, showed that the only independent predictors of restenosis were a post-procedure lumen diameter < 2.80 mm (odds ratio = 1.57; P = 0.04), diabetes mellitus (odds ratio = 3.55; P < 0.001), and prior restenosis (odds ratio = 1.84; P = 0.008). Since center (Beth Israel vs. Multicenter) was eliminated from the multivariable model after inclusion of these variables, the observed higher restenosis rate in the Multicenter series of Palmaz-Schatz coronary stents can thus be explained in part by differences in demographics (more previously treated lesions) and procedural details (a smaller post-treatment lumen diameter). Since post-procedure lumen diameter is a strong predictor of freedom from restenosis in the pooled experience, the probability of restenosis within a Palmaz-Schatz stent can be decreased by obtaining a large post-procedure lumen diameter. (C) 1994 Wiley-Liss, Inc.