Intraarterial (192)Ir high-dose-rate brachytherapy for prophylaxis of restenosis after femoropopliteal percutaneous transluminal angioplasty: the prospective randomized Vienna-2-trial radiotherapy parameters and risk factors analysis.
OBJECTIVE
The aim of the Vienna-2-trial was to compare the restenosis rate of femoropopliteal arteries after percutaneous transluminal angioplasty (PTA) with or without intraarterial high-dose-rate (HDR) brachytherapy (BT) using an (192)Ir source.


METHODS
A prospective, randomized trial was conducted from 11/96 to 8/98. A total of 113 patients (63 men, 50 women), with a mean age of 71 years (range, 43-89 years) were included. Inclusion criteria were (1) claudication or critical limb ischemia, (2) de-novo stenosis of 5 cm or more, (3) restenosis after former PTA of any length, and (4) no stent implantation. Patients were randomized after successful PTA for BT vs. no further treatment. A well-balanced patient distribution was achieved for the criteria used for stratification, as there were "de-novo stenosis vs. restenosis after former PTA," "stenosis vs. occlusion," "claudication vs. critical limb ischemia" and above these for "diabetes vs. nondiabetes." PTA length was not well balanced between the treatment arms: a PTA length of 4-10 cm was seen in 19 patients in the PTA alone group and in 11 patients in the PTA+BT group, whereas a PTA length of greater than 10 cm was seen in 35 patients and 42 patients, respectively. A dose of 12 Gy was prescribed in 3-mm distance from the source axis. According to AAPM recommendations, the dose was 6.8 Gy in 5-mm distance (vessel radius + 2 mm). Primary endpoint of the study was femoropopliteal patency after 6 months.


RESULTS
PTA and additional BT were feasible and well tolerated by all 57 pts in this treatment arm. No acute, subacute, and late adverse side effects related to BT were seen after a mean follow up of 12 months (6-24 months) in 107 patients (PTA n = 54; PTA+ BT n = 53). Crude restenosis rate at 6 months was in the PTA arm 54% vs. 28% in the PTA + BT arm (chi(2) test; p < 0.013). Actuarial estimate of the patency rate was at 6 months 45% vs. 72% (p < 0.004). Comparison of restenosis rates for the different subgroups with risk factors (restenosis after former PTA, occlusion and PTA length >10 cm) showed significant decrease of the restenosis rate, if BT was added. Significant reduction was not achieved in diabetes patients.


CONCLUSIONS
BT after femoropopliteal PTA is feasible and a safe therapeutic option. No BT related morbidity was observed. A significant reduction of the restenosis rate was obtained in the PTA+BT arm. Subgroup analysis showed significant decrease of restenosis rate in the subgroups with restenosis after former PTA, occlusion and PTA length of greater than 10 cm. With dose escalation and reduction of dose variation by a centering device a further significant decrease of restenosis rate can be expected.
Pokrajac
B
B
Department of Radiotherapy and Radiobiology, University of Vienna, General Hospital of Vienna, Vienna, Austria.
Pötter
R
R
Maca
T
T
Fellner
C
C
Mittlböck
M
M
Ahmadi
R
R
Seitz
W
W
Minar
E
E
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000800:Angioplasty, Balloon / Q000379:methods*; D001157:Arterial Occlusive Diseases / Q000517:prevention & control / Q000532:radiotherapy*; D001918:Brachytherapy / Q000379:methods*; D003251:Constriction, Pathologic / Q000517:prevention & control / Q000532:radiotherapy; D005260:Female; D005263:Femoral Artery; D006801:Humans; D007383:Intermittent Claudication / Q000517:prevention & control / Q000532:radiotherapy; D007496:Iridium Radioisotopes / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D011150:Popliteal Artery; D011446:Prospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D055502:Secondary Prevention
D007496:Iridium Radioisotopes