A novel method of brachytherapy using local delivery of 99mTc-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 99mTc-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 99mTc-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 99mTc-HMPAO shortly after PCI, via a Dispatch Catheter, followed by a whole body scan to evaluate the distribution of the 99mTc-HMPAO, as well as a thallium-201 (TI-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%).


CONCLUSIONS
Local delivery of 99mTc-HMPAO, a novel radiotherapy, can be used safely and effectively for coronary stent restenosis.
Kim
Weon
W
The Heart Center, Chonnam National University Hospital, Gwangju, Korea.
Jeong
Myung Ho
MH
Kim
Sung Hee
SH
Park
Woo Seok
WS
Park
Ok Young
OY
Kim
Ju Han
JH
Bom
Hee-Seung
HS
Jeong
Hwan Jung
HJ
Ahn
Young Keun
YK
Cho
Jeong Gwan
JG
Park
Jong Chun
JC
Kang
Jung Chaee
JC
D015906:Angioplasty, Balloon, Coronary; D000818:Animals; D001918:Brachytherapy / Q000379:methods*; D017023:Coronary Angiography; D023903:Coronary Restenosis / Q000532:radiotherapy*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D019275:Radiopharmaceuticals / Q000627:therapeutic use*; D015607:Stents; D013552:Swine; D019690:Technetium Tc 99m Exametazime / Q000627:therapeutic use*
D019275:Radiopharmaceuticals; D019690:Technetium Tc 99m Exametazime