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; n=9, one pair per pig) were implanted, and animals were euthanized at 1 month. Late lumen loss was reduced in PES compared with BMS (0.46+/-0.63 mm versus 1.30+/-0.50 mm; P=0.01). 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 (P<0.001 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 (0.11+/-0.07 mm versus 0.33+/-0.12 mm; P=0.018). 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, 0+/-7% versus BMS, 10+/-6%; P=0.007), whereas nitroglycerin response was preserved (PES, 9+/-5% versus BMS, 12+/-7%; P=0.34). CONCLUSIONS: In the porcine coronary model, overlapping PES is associated with marked intramural thrombi, which was accurately detected on angioscopy at 1 month. Moreover, despite normal luminal angioscopic appearance, adjacent nonstented reference segments demonstrated impaired endothelium-dependent vasoreactivity.
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; n=9, one pair per pig) were implanted, and animals were euthanized at 1 month. Late lumen loss was reduced in PES compared with BMS (0.46+/-0.63 mm versus 1.30+/-0.50 mm; P=0.01). 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 (P<0.001 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 (0.11+/-0.07 mm versus 0.33+/-0.12 mm; P=0.018). 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, 0+/-7% versus BMS, 10+/-6%; P=0.007), whereas nitroglycerin response was preserved (PES, 9+/-5% versus BMS, 12+/-7%; P=0.34). CONCLUSIONS: In the porcine coronary model, overlapping PES is associated with marked intramural thrombi, which was accurately detected on angioscopy at 1 month. Moreover, despite normal luminal angioscopic appearance, adjacent nonstented reference segments demonstrated impaired endothelium-dependent vasoreactivity.
Authors: Seung-Woon Rha; Kang-Yin Chen; Dong Joo Oh; Yong-Jian Li; Zhe Jin; Kanhaiya Lal Poddar; Sureshkumar Ramasamy; Yoshiyasu Minami; Amro Elnagar; Byoung Geol Choi; Sang Pyo Hong; Byoung Won Cheon; Sang Ki Moon; Sung Il Im; Sun Won Kim; Jin Oh Na; Cheol Ung Choi; Hong Euy Lim; Jin Won Kim; Eung Ju Kim; Seong Woo Han; Chang Gyu Park; Hong Seog Seo; Jung Ha Kim; Young Joon Hong; Myung Ho Jeong Journal: Korean Circ J Date: 2012-06-28 Impact factor: 3.243