Background A potentially adverse vascular response to overlapping drug eluting stents (DES) has been suggested in current research.

Objective To evaluate the impact of baseline disease severity at the site of stent overlap.

Methods and results This is a substudy of ODESSA, a prospective, randomised controlled trial designed to evaluate healing of overlapping stents. 71/77 patients with a total of 86 overlapping stents were studied: 25 sirolimus, 24 paclitaxel, 26 zotarolimus-eluting stents; and 11 bare metal stents (BMS). Patients were categorised into high-grade stenosis (HGS, ≥70% diameter stenosis) and low-grade stenosis (LGS, <70%) at the site of stent overlap. Angiography and intravascular ultrasound were performed after stent deployment and repeated at 6 months, together with additional optical coherence tomography. Images were analysed by an independent core laboratory. End points were binary restenosis, percentage neointimal hyperplasia (%NIH), mean lumen and stent areas and degree of strut coverage/apposition at overlapping stents at 6 months. Stent overlaps occurred in 49 HGS and 37 LGS. Restenosis was found in 5/6 HGS versus 0/5 LGS treated with overlapping BMS (p=0.01) and 4/43 HGS versus 0/32 LGS treated with overlapping DES. There was a trend towards higher %NIH at BMS overlap in HGS versus LGS (p=0.07). DES overlaps had lower lumen and stent areas and similar %NIH in HGS versus LGS. Any uncovered or malapposed struts occurred more often in overlapping DES at LGS than at HGS (59.4% vs 32.6%, p=0.03).

Conclusions Overlapping DES in normal-appearing coronary segments showed a higher incidence of uncovered or malapposed struts, while restenosis occurred exclusively in overlapping stents at HGS. These findings should be considered when deploying overlapping stents.