BACKGROUND: In-stent neointimal hyperplasia typically has a homogenous echoreflective appearance during intravascular ultrasound (IVUS) imaging. However, the neointimal hyperplasia of some brachytherapy failure lesions contains a very echolucent, dark zone that has been termed black hole. We sought to investigate the frequency and determinants of black holes (BH) after sirolimus-eluting stent (SES) implantation. METHODS: A prospective, consecutive series of 33 intrastent SES restenosis (> 50% neointimal hyperplasia with a minimal lumen area < 4.0 mm2) was studied with IVUS. Patients were divided into 2 groups: 8 patients with BH versus 25 patients without BH. RESULTS: Fifty percent of the BH cases occurred in saphenous vein graft lesions. BH tissue was noticed in 8% of all patients with in-stent restenosis. Three patients in each group had previous vascular brachytherapy failure (p = 0.1). Compared to non-BH cases, a greater proportion of BH cases occurred after SES treatment of bare-metal stent restenosis (75% vs. 32%; p = 0.035). BH cases presented earlier (89.9 +/- 34.3 vs. 161.3 +/- 78.8 days; p = 0.001) with more severe in-stent restenosis, as indicated by greater absolute and relative amounts of neointimal hyperplasia (41.3 +/- 10.0 vs. 26.9 +/- 19.5 mm3; p = 0.012, and 19.6 +/- 6.8 vs. 10.4 +/- 7.9%; p = 0.0001, respectively). CONCLUSIONS: Echolucent restenotic tissue (black hole) is more often observed in SES restenosis after treatment of saphenous vein graft lesions or treatment of bare-metal stent restenosis. It occurs earlier and is more severe than typical SES failures.
BACKGROUND: In-stent neointimal hyperplasia typically has a homogenous echoreflective appearance during intravascular ultrasound (IVUS) imaging. However, the neointimal hyperplasia of some brachytherapy failure lesions contains a very echolucent, dark zone that has been termed black hole. We sought to investigate the frequency and determinants of black holes (BH) after sirolimus-eluting stent (SES) implantation. METHODS: A prospective, consecutive series of 33 intrastent SES restenosis (> 50% neointimal hyperplasia with a minimal lumen area < 4.0 mm2) was studied with IVUS. Patients were divided into 2 groups: 8 patients with BH versus 25 patients without BH. RESULTS: Fifty percent of the BH cases occurred in saphenous vein graft lesions. BH tissue was noticed in 8% of all patients with in-stent restenosis. Three patients in each group had previous vascular brachytherapy failure (p = 0.1). Compared to non-BH cases, a greater proportion of BH cases occurred after SES treatment of bare-metal stent restenosis (75% vs. 32%; p = 0.035). BH cases presented earlier (89.9 +/- 34.3 vs. 161.3 +/- 78.8 days; p = 0.001) with more severe in-stent restenosis, as indicated by greater absolute and relative amounts of neointimal hyperplasia (41.3 +/- 10.0 vs. 26.9 +/- 19.5 mm3; p = 0.012, and 19.6 +/- 6.8 vs. 10.4 +/- 7.9%; p = 0.0001, respectively). CONCLUSIONS: Echolucent restenotic tissue (black hole) is more often observed in SES restenosis after treatment of saphenous vein graft lesions or treatment of bare-metal stent restenosis. It occurs earlier and is more severe than typical SES failures.