Background: Studies on balloon angioplasty, atherectomy, and bare metal stent have shown a direct relation between residual plaque burden and restenosis. We investigated the relation between residual plaque burden and neointimal proliferation after drug-eluting stent (DES) implantation.
Methods: Over a period of 12 months, 65 patients (Cypher, n = 25; Taxus, n = 28; Endeavor, n = 12) from two centers underwent intravascular ultrasound (IVUS) examination at 8.2 (interquartile range 6.8-9.5) months after coronary stent implantation in native de novo coronary arteries. IVUS images were acquired with motorized pullback at 0.5 mm/s, and cross-sectional measurements were performed within the stents at 1-mm intervals. The following measurements were obtained: (1) lumen area (LA), (2) stent area (SA), (3) external elastic membrane area (EEMA), (4) percent neointimal hyperplasia area (SA-LA/SA) x 100, and (5) percent residual plaque area (EEMA-SA)/EEMA x 100.
Results: The analysis of 1,173 cross sections (Cypher, n = 436; Taxus, n = 532, Endeavor, n = 205) using mixed model to account for intrasubject correlation showed an absence of relation between percent residual plaque area and percent neointimal hyperplasia area (P = 0.189). Mean residual plaque burden outside the stent for Cypher, Taxus, and Endeavor groups was similar (45.7%, 44.8%, and 42.4%, respectively). Mean percent neointimal hyperplasia area for the Cypher, Taxus, and Endeavor groups was 12.0%, 15.0%, and 16.2%, respectively (P = 0.163).
Conclusion: In patients after first-generation DES implantation and without significant in-stent restenosis, late in-stent neointimal proliferation is not related to the amount of residual plaque burden after stent implantation. This suggests against routine plaque removal before DES implantation to reduce neointimal proliferation.