Radioisotope stents

Abstract

Intracoronary stent placement following PTCA improves the long-term outcome of the treated patient, but in-stent restenosis remains problematic, especially in smaller vessels and longer lesions. Intravascular brachytherapy is a rapidly evolving field of research and clinical treatment, with a number of different irradiation techniques being used clinically. Many clinical data are now available that indicate clearly that either <FONT FACE="MetaPress 7">&#110</FONT> or <FONT FACE="MetaPress 7">&#103</FONT> radiation can reduce, and hopefully cure restenosis. The combination of radiation with stents has several distinct advantages over radiation with balloon angioplasty. It should be possible to use the stent as the radioactive source, as the radioactivity levels required by a permanent implant are extremely safe (< 1/1000 of the radioactivity of the least radioactive brachytherapy catheters). Once the stent has been implanted, the procedure is complete; catheter-based brachytherapy requires a second procedure after stent implantation. Unfortunately, in many human studies of the efficacy of radioisotope stents, although an excellent result in terms of a dramatically reduced neointima was seen in the stent, the incidence of an 'edge effect', with a reduced lumen just beyond the stent-edge occurred at an unacceptable rate. The encouraging results of the 'hot ends' study, where the stent ends were made more radioactive to reduce the edge effect, coincided with even more encouraging results from sirolimus drug-eluting stents. As a result, most work on radioisotope stents for the treatment of restenosis has been abandoned. There may, however, be applications for radioisotope stents in the treatment of malignant ducts, such as the esophagus and bronchia, which could justify further study of the devices.

Antiproliferative Agents Alter Vascular Plasminogen Activator Inhibitor-1 Expression

“…2 Numerous mechanical and pharmacological strategies have failed to further reduce restenosis until recently. 3,4 The development of drug eluting stents (DES) that release small amounts of antiproliferative agents locally provides an effective strategy for reducing the risk of restenosis after angioplasty to levels below 10%. 5,6 These impressive effects on restenosis were tempered initially by concerns about possible increases in the rate of in stent thrombosis with DES.…”

Interfacing exogenous stents with human coronary artery by self-assembled coating: designs, functionalities and applications

“…This offered an effective approach to obtain autografts for clinical therapy. The study also provided a direction for the research of autologously generated stents 10 . The concept of radioactive stent was proposed to address the issue of restenosis caused by BMS in 1989.…”

Is the “candy‐wrapper” effect of 32P radioactive β‐emitting stents due to remodeling or neointimal hyperplasia?: Insights from Intravascular Ultrasound

“…The clinical phase I of IRIS with 0.5-1.5 Ci 32 P Palmaz-Schatz stents demonstrated similar target lesion restenosis rates after 6 months compared with expected late outcomes for nonradioactive stents [16,23]. The results of the following dose-escalation trials from the centers of Rotterdam and Milan with activities of 0.75-20 Ci 32 P have recently been published [14 -17].…”