CURRENT STATUS AND POTENTIAL APPLICATIONS OF THE HARTS REMOVABLE STENT

Permanent intracoronary stents have demonstrated considerable efficacy in the treatment of PTCA-induced abrupt arterial occlusion, suboptima l dilatation, and restenosis. Despite their benefit, permanent stents have significant limitations including subacute thrombosis, need for a nticoagulation with resultant vascular complications, prolonged hospit alization, and high costs. Temporary stents have the potential for ach ieving many of the beneficial effects of permanent stenting without so me of the iatrogenic complications. The HARTS (Heat Activated Removabl e Temporary Stent) removable stent employs the shape memory alloy Niti nol, and has the properties of being balloon deployable, but recoverab le to a preset ''memory'' shape by heating it with warmed crystalloid solution, Preclinical experience first with a wire stent design and mo re recently with a slotted tubular design, has demonstrated the feasib ility of implanting and recovering the HARTS device. Speculative appli cations of this technology include: treatment of acute postangioplasty occlusion and suboptimal angioplasty results; ''stentoplasty''-the ap plication of a temporary stent for several hours at the time of a prim ary angioplasty; and reduction of restenosis rate by inhibition of ela stic recoil following short-term (hours) stenting. Further, the HARTS device may be an important vehicle for local delivery of drugs or othe r biologically active agents to the arterial wall. All research to dat e has been preclinical and controlled clinical trials will be necessar y to define the safety, efficacy, and potential applications of the HA RTS removable stent.