Failure of a novel balloon-expandable gamma-emitting ((103)Pd) stent to prevent edge effects.
BACKGROUND
Balloon-expandable beta-particle-emitting ((32)P) stents inhibit within-stent neointimal hyperplasia but induce lumen narrowing beyond the stent margins, ie, the so-called "edge effects."


RESULTS
We prospectively investigated the performance of novel stents impregnated with the gamma-emitting isotope (103)Pd, designed to reduce edge effects, in 24 rabbits. The stents had a length of 18 mm and were mounted on 20-mm-long delivery balloons for deployment. Angiograms were obtained immediately and 1 month after direct implantation of control and 1-, 2-, and 4-mCi (103)Pd stents into the iliac arteries without predilatation or postdilatation. Late lumen loss was measured with quantitative angiography. Neointimal hyperplasia and vascular remodeling were evaluated by histomorphometry. Late lumen loss was inhibited within (103)Pd stents (control 0.18 mm, 1 mCi 0.08 mm, 2 mCi 0.05 mm, and 4 mCi -0.03 mm, P<0.05 all activities versus control). Conversely, late lumen loss occurred at the edges of (103)Pd stents, correlating with areas of high balloon/artery ratios and vessel overstretch injury. Edge effects were primarily due to neointimal hyperplasia but were also caused by negative vessel remodeling at high stent activities.


CONCLUSIONS
Edge effects after implantation of radioisotope stents can occur independently of the isotope chosen for stent impregnation.
Hehrlein
C
C
Department of Cardiology, University of Freiburg, and the Forschungszentrum Karlsruhe, Germany. hehrlein@med1.ukl.uni-freiburg.de
DeVries
J J
JJ
Arab
A
A
Haller
S D
SD
Schloesser
K
K
Tio
F O
FO
Fischell
T A
TA
D000792:Angiography; D000818:Animals; D019917:Blood Vessel Prosthesis Implantation / Q000009:adverse effects; D004307:Dose-Response Relationship, Radiation; D004343:Drug Implants / Q000009:adverse effects; D005260:Female; D005720:Gamma Rays; D006083:Graft Occlusion, Vascular / Q000209:etiology* / Q000473:pathology / Q000517:prevention & control; D007083:Iliac Artery / Q000473:pathology / Q000528:radiation effects / Q000601:surgery; D020007:Implants, Experimental / Q000009:adverse effects*; D010165:Palladium; D010761:Phosphorus Radioisotopes; D011446:Prospective Studies; D011817:Rabbits; D011868:Radioisotopes / Q000009:adverse effects*; D011874:Radiometry; D015607:Stents / Q000009:adverse effects*; D017539:Tunica Intima / Q000473:pathology / Q000528:radiation effects; D014654:Vascular Patency / Q000528:radiation effects
D004343:Drug Implants; D010761:Phosphorus Radioisotopes; D011868:Radioisotopes; D010165:Palladium