Aims: Overlapping drug-eluting stents (DES) are frequently implanted to cover long segments of diseased and injured vessel, or as a bailout technique for edge dissection or incomplete lesion coverage. DES overlap is, nevertheless, associated with strut malapposition and poor intimal coverage, which may increase the risk of stent thrombosis. The aim of this study is to evaluate stent strut apposition in overlapping DES.
Methods and results: We assessed strut apposition in 10 overlapped segments (20 DES, 10 patients, 661 struts) immediately after implantation, using optical coherence tomography (OCT). Struts were defined as malapposed when no contact with the intima was detected by OCT, taking into consideration the strut thickness of each stent type.
Despite aggressive stent optimisation using balloons with a final balloon/artery ratio of 1.26±0.18 at a maximum inflation pressure of 18.0±1.9atm, 41.8±21.5% of struts were malapposed in the overlapping segment, compared to 20.1±17.6% in the proximal and 9.7±10.6% in the distal segment (p < 0.05 for both).
Conclusions: OCT revealed that 40% of struts within an overlapped DES segment were malapposed, and this may explain the reported delay in endothelialisation in such segments.