Résumé
BACKGROUND: Restenosis after percutaneous coronary intervention (PCI) still remains a matter to be solved. We examined the inhibitory effects of local delivery of 99mTc-HMPAO (hexamethylprophylene amine oxime), a radioisotope, on neointimal hyperplasia after coronary stenting through an animal experiment, and observed its safety and efficacy for the patients with coronary stent restenosis. METHODS: Stent overdilation injuries were performed in coronary arteries of 10 pigs. After stent overdilation injury, local radioisotope delivery using a 99mTc-HMPAO were performed in one coronary artery (Group I) and control therapy in another coronary artery in each pig (Group II). Follow-up coronary angiogram (CAG) and histopathologic assessment were performed at 4 weeks after stenting. Eleven patients (10 males, 62.4+/-5.7 years of age) underwent local administration of 30 mCi/ 2 mL of 99mTc-HMPAO shortly after PCI via Dispatch CatheterTM, and whole body bone scan and thallium-SPECT afterwards. Major adverse cardiac events (MACE) were assessed during one-year clinical follow-up. RESULTS: On histopathologic analysis, neointimal area was 1.2+/-0.6 mm2 in Group I and 2.7+/-0.4 mm2 in Group II (p=0.002), and histopathologic area stenosis was 27.1+/-6.3% in Group I, 53.4+/-5.2% in Group II (p=0.001). In clinical study, eleven patients with coronary in-stent restenosis were enrolled. There was no in-hospital MACE. On quantitative coronary angiographic analysis minimal luminal diameter and diameter stenosis increased from 0.4+/-0.3 mm and 84.2+/-9.5% to 2.9+/-0.2 mm and 16.3+/-11.0% after PCI, respectively. Follow-up CAG was performed in 9 cases (81.8%) and restenosis occurred in 2 cases (22.2%). On follow-up CAG minimal luminal diameter was 2.0+/-0.8 mm, diameter stenosis rate 27.7+/-2.9 %, lumen loss 0.7+/-0.7 mm and loss index 0.2+/-0.3. During one-year clinical follow-up there were no cases of death and acute MI, but two cases of target vessel revascularization (18.2%). CONCLUSION: Local delivery of 99mTc-HMPAO, one of the novel radiotherapies, can be used safely and effectively for coronary stent restenosis.