Acta Med. 2004, 47: 37-42
The “Edge Effect” After Implantation of β-Emitting (55Co) Stents with High Initial Activity
The aim of this study was to evaluate the incidence and the cause of “edge restenosis” after implantation of high activity 41.1 μCi±1.2 μCi=1520 kBq±44 kBq, β-emitting (55Co) stents. Proton bombarding in cyclotron has brought the radioactivity. Intravascular ultrasound (IVUS) investigation has been completed in 10 patients. The angiographies performed at 6 month revealed restenosis >50 % in 5 cases (50 %). The analysis of edges (5 mm distally and proximally to the last stent struts) showed no significant changes in TVV (187.3±62.60 mm3 and 176.9±53.5 mm3) but PMV increase significantly (i.e. neointimal proliferation) from 61.9±31.2 mm3 to 82.2±43.4 mm3 (p<0.04) and was the major contributor (from 66 %) to lumen volume loss (125.4±40.7 mm3 and 94.7±22.2 mm3, p<0.02). In conclusion, neither statistically significant positive nor negative remodelling at the “stent edges“, were present. Statistically significant increase in plaque+media volume (i.e. neointimal hyperplasia) and reduction in lumen volume were found. The cause of “edge restenosis” was especially (from 66 %) due to increase in plaque+media volume (i.e. neointimal hyperplasia). Probably, main reason for “edge effect”/neointimal hyperplasia was in this trial sharp fall-off in radiation at the edges of the stents.
Keywords
Radioactive stents, Angioplasty, Remodelling, Intravascular ultrasound.
Funding
This study was supported by a grant from IGA Ministry of health Czech Republic, number NA 4786-3/98.
References
Copyright
Published by the Karolinum Press. For permission to use please write to actamedica@lfhk.cuni.cz.