ELLIS Study: Comparative Analysis of Excimer Laser Coronary Angioplasty and Intravascular Lithotripsy on Drug-Eluting Stent as Assessed by Scanning Electron Microscopy

BACKGROUND: Stent underexpansion is a significant challenge in percutaneous coronary intervention, critically impacting patient outcomes. While excimer laser coronary angioplasty (ELCA) and intravascular lithotripsy (IVL) are increasingly used to address this issue, their full impact on the integrity of drug-eluting stents remains unclear, raising concerns about their safety and efficacy. METHODS: This in vitro study assessed the effects of ELCA and IVL on the structural integrity of drug-eluting stents using scanning electron microscopy. Nine stents, 5 Onyx Frontier (with durable circumferential polymer coating) and 4 Cre8 (polymer-free), were implanted in a 3-dimensional coronary artery simulator following standardized protocols. After implantation, treatments with saline-ELCA, contrast-ELCA, IVL, and high-pressure balloon dilatation were applied. A comprehensive evaluation of the stent surface was performed at 60-fold magnification. RESULTS: Scanning electron microscopy analysis revealed significant differences in polymer damage between the techniques. High-pressure balloon dilatation and contrast-ELCA exhibited substantial polymer fragmentation and detachment compared with IVL, saline-ELCA, and conventional dilatation. High-pressure balloon dilatation demonstrated the highest incidence of polymer shaving and overcoating. No significant alterations were observed in polymer-free stents, regardless of the technique used. CONCLUSIONS: IVL and saline-ELCA applied immediately after stent implantation produce minimal polymer damage, whereas high-pressure balloon dilatation and contrast-ELCA cause significant damage to the polymer coating. The integrity of polymer-free drug-eluting stent appears stable regardless of the technique used. Further research is needed to validate these findings and explore their clinical implications.