Abnormal endothelium-dependent relaxation at both coronary conduit and resistance arteries was demonstrated after overlapping PES implantation. Profound localized inflammatory reaction, as well as enhanced local oxidative stress, may contribute to vasomotor dysfunction.

This study shows favourable vascular compatibility and efficacy for a novel fully bioabsorbable salicylate-based SES. This device has good mechanical performance during deployment and stays well-apposed to the vessel wall at long-term follow-up. These initial results are highly encouraging and support progress into more extensive preclinical studies as well as early clinical testing.

No abstract

Background-Systematic analysis of in vivo angioscopy and postmortem histopathology for paclitaxel-eluting stents (PES) has not been previously reported. We assessed 1-month angioscopic and histopathologic sequelae of overlapping PES in pig coronary arteries. Methods and Results-Overlapping PES and bare-metal stents (BMS; nϭ9, one pair per pig) were implanted, and animals were euthanized at 1 month. Late lumen loss was reduced in PES compared with BMS (0.46Ϯ0.63 mm versus 1.30Ϯ0.50 mm; Pϭ0.01). Angioscopically, PES stent struts were clearly visible and accompanied by substantial red material indicating mural thrombi. In contrast, stent struts and mural thrombi were barely visible in BMS (PϽ0.001 versus PES). Macroscopically, mural thrombi were abundant but distributed irregularly throughout the PES, with greater concentration in overlapping segments. Only occasional mural thrombi were noted for BMS. Microscopically, neointima of BMS was fibrocellular and mature, whereas only a thin layer of immature neointima was seen in PES. Neointimal thickness was less in PES than BMS (0.11Ϯ0.07 mm versus 0.33Ϯ0.12 mm; Pϭ0.018). Additionally, extensive para-strut and intramural thrombi, red blood cell debris, and minute luminal thrombi were observed in PES. Despite normal angioscopic appearance of both proximal and distal nonstented reference segments, endothelium-dependent relaxation to substance P was notably diminished (PES, 0Ϯ7% versus BMS, 10Ϯ6%; Pϭ0.007), whereas nitroglycerin response was preserved (PES, 9Ϯ5% versus BMS, 12Ϯ7%; Pϭ0.34