A multicenter, randomized, dose-finding study of gamma intracoronary radiation therapy to inhibit recurrent restenosis after stenting.
OBJECTIVE
The objective of this double-blind, randomized study was to determine the safety and efficacy of intracoronary radiation therapy (ICRT) with a dose of 17 Gray (Gy) compared to the currently recommended dose prescription of 14 Gy for the treatment of in-stent restenosis within bare metal stents.


BACKGROUND
While gamma ICRT for in-stent restenosis has been proven efficacious, the optimal dose is unknown, and radiation failure due to recurrent neointimal hyperplasia remains a significant clinical problem for some patients. A higher radiation dose may improve outcomes, but may potentially increase adverse events.


METHODS
Following coronary intervention, 336 patients with in-stent restenosis were randomly assigned to receive ICRT with either 14 Gy or 17 Gy at 2 mm from an 192-iridium source.


RESULTS
At 8-month follow up, fewer patients in the 17 Gy group underwent target lesion revascularization (TLR = 15.2% versus 27.2%; p = 0.01), target vessel revascularization (21.3% versus 33.1%; p = 0.02), or reached the composite endpoint of death, myocardial infarction, thrombosis, or TLR (17.1% versus 28.4%; p = 0.02). There were no differences in late thrombosis or mortality between treatment groups. There was a strong trend toward reduced in-lesion late loss (0.36 +/- 0.63 mm vs. 0.51 +/- 0.64 mm; p = 0.09) and a significantly lower rate of binary restenosis (23.9% versus 38.1%; p = 0.031) in the high dose group.


CONCLUSIONS
Gamma ICRT with 17 Gy is safe and, compared to 14 Gy, reduces recurrent stenosis and clinical events at 8-month follow up. An increase in the currently recommended gamma radiation dose prescription from 14 Gy to 17 Gy should be strongly considered.
Price
Matthew J
MJ
Division of Cardiovascular Diseases, Scripps Clinic, La Jolla, California, USA.
Moses
Jeffrey W
JW
Leon
Martin B
MB
Mehran
Roxana
R
Negoita
Manuela
M
Lansky
Alexandra
A
Collins
Michael
M
Giap
Huan
H
Lin
Ray
R
Jani
Shirish
S
Steuterman
Stephen
S
Balter
Stephen
S
Dalton
Jack
J
Lipsztein
Roberto
R
Tripuraneni
Prabhakar
P
Teirstein
Paul S
PS
D000368:Aged; D023903:Coronary Restenosis / Q000209:etiology* / Q000532:radiotherapy*; D003331:Coronary Vessels / Q000528:radiation effects*; D004307:Dose-Response Relationship, Radiation; D004311:Double-Blind Method; D005260:Female; D005500:Follow-Up Studies; D005720:Gamma Rays / Q000627:therapeutic use*; D006801:Humans; D008297:Male; D008670:Metals; D008875:Middle Aged; D015607:Stents / Q000009:adverse effects*; D016896:Treatment Outcome
D008670:Metals