Angiographic restenosis following intravascular beta-brachytherapy does not correlate with delivered dose: a study with dose volume histograms. Recurrence of in-stent restenosis after brachytherapy.
BACKGROUND
Vascular brachytherapy reduces recurrence after treatment of in-stent restenosis. However, there are still failures. The aims of the study were to investigate the relationship between two distinct dose prescriptions and the calculated dose delivered versus binary angiographic restenosis.


METHODS
Fifty-five lesions in 47 patients underwent catheter-based beta-brachytherapy with a (32)P source. Doses delivered were calculated using intravascular ultrasound (IVUS) measurements. Patients randomly received 20 Gy either at 1 mm beyond mean reference lumen or 1 mm beyond mean reference external elastic membrane. Using subsequent off-line volumetric IVUS measurements, dose volume histograms (DVHs) for the adventitia were determined.


RESULTS
There were 13 restenotic lesions including four total occlusions. All recurrences localized within stented segment. The frequency of restenosis was similar between dosimetry groups (20% vs. 28%; P=.5). DVH calculations were similar in restenotic versus restenosis-free lesions. However, postprocedural IVUS minimal lumen area was significantly smaller for lesions that recurred (5.03+/-1.19 mm(2) vs. 6.13+/-1.7 mm(2); P=.042).


CONCLUSIONS
Calculated cumulative doses delivered to the tissues do not correlate with clinical outcome. However, an adequate lumen may be important to accommodate even a small amount of recurrent intimal hyperplasia to limit restenosis and need for target lesion revascularization.
Institute of Cardiology, Warsaw, Poland. witkowski@hbz.pl
Adam
A
Witkowski
Jerzy
J
Pregowski
Gary S
GS
Mintz
Zbigniew
Z
Chmielak
Łukasz
Ł
Kalińczuk
Jarosław
J
Łyczek
Maria
M
Kawczyńska
Wojciech
W
Bulski
Anna
A
Kulik
Cezary
C
Kepka
Mariusz
M
Kruk
Tomasz
T
Deptuch
Jacek
J
Owczarczyk
Stanisław
S
Pszona
Witold
W
Ruzyłło
D000368:Aged; D001918:Brachytherapy / Q000379:methods*; D017023:Coronary Angiography; D005260:Female; D006083:Graft Occlusion, Vascular / Q000000981:diagnostic imaging* / Q000532:radiotherapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011874:Radiometry; D011879:Radiotherapy Dosage; D012008:Recurrence; D017211:Treatment Failure; D018084:Ultrasonography, Interventional