Stent malapposition and the risk of stent thrombosis: Mechanistic insights from an in vitro model

Aims: The aim of this report was to examine the effect of underexpansion on stent thrombogenicity with an in vitro perfusion model. Methods and results: Drug-eluting stent (DES) samples were partially underdeployed in silicone tubes and perfused with porcine blood containing 10% anticoagulant citrate dextrose solution for four minutes at a flow rate of 200 ml/min. Thrombus formation was evaluated and compared between the well-apposed and malapposed sections. The malapposed sections showed significantly more thrombus formation compared to the well-apposed sections (13.9 vs. 0.41 mm2, p<0.001). Conclusions: Stent malapposition has a very direct impact on thrombus formation. Optimised stent implantation is required to minimise malapposition in DES and BVS to reduce thrombus formation.