A Novel Method of Brachytherapy Using Local Delivery of (99m) Tc-HMPAO for Coronary Stent Restenosis

BACKGROUND: Restenosis after percutaneous coronary intervention (PCI) is a matter that still remains to be resolved. Herein, the inhibitory effect of locally delivered (99m) Tc-HMPAO (hexamethyl propylene amine oxime) on neointimal hyperplasia after coronary stenting was examined in a pocine model, and its safety and efficacy observed in patients with coronary stent restenosis. METHODS: After a stent overdilation injury, local radioisotope delivery using (99m) Tc-HMPAO was applied to one coronary artery (Group I) and control therapy to another (Group II) in each of 10 pigs. Follow-up coronary angiogram (CAG) and histopathologic assessment were performed 4 weeks after stenting. Eleven patients (10 males and one female, 62.4 +/- 5.7 years of age) underwent local administration of 30 mCi/ 2 mL (99m) Tc-HMPAO shortly after PCI, via a Dispatch CatheterTM, followed by a whole body scan to evaluate the distribution of the (99m) Tc-HMPAO, as well as a thallium-201 (Tl-201) myocardial scan to evaluate myocardial perfusion. The major adverse cardiac events (MACE) were assessed during a one-year clinical follow-up. RESULTS: On histopathological analysis, the neointimal areas were 1.2 +/- 0.6 and 2.7 +/- 0.4 mm2 (p=0.002), and the histopathological areas of stenosis were 27.16.3 and 53.4 +/- 5.2% in Groups I and II (p=0.001), respectively. In the clinical study, there was no in-hospital MACE. On a quantitative coronary angiographic analysis, the minimal luminal diameter was increased from 0.4 +/- 0.3 to 2.9 +/- 0.2 mm, and diameter stenosis decreased from 84.2 +/- 9.5 to 16.3 +/- 11.0% following PCI. Follow-up CAG was performed in 9 cases (81.8%) and restenosis occurred in 2 (22.2%). On a follow-up CAG, the minimal luminal diameter, diameter stenosis rate, lumen loss and loss index were 2.0 +/- 0.8 mm, 27.7 +/- 2.9%, 0.7 +/- 0.7 mm and 0.2 +/- 0.3, respectively. During the one-year clinical follow-up there were no cases of death or acute MI, but two cases of target vessel revascularization (18.2%). CONCLUSION: Local delivery of (99m) Tc-HMPAO, a novel radiotherapy, can be used safely and effectively for coronary stent restenosis.

A novel method of brachytherapy using local delivery of 99mTc-HMPAO for coronary stent restenosis / 대한내과학회지

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.