Inter‐Series differences in the restenosis rate of palmaz‐schatz coronary stent placement: Differences in demographics and post‐procedure lumen diameter

Abstract

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 (16 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 (≥ 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 posttreatment 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.