Current Status and Potential Applications of the Harts Removable Stent

Permanent intracoronary scents have demonstrated considerable efficacy in the treatment of PTCA-induced abrupt arterial occlusion, suboptimal dilatation, and restenosis. Despite their benefit, permanent stents have significant limitations including subacute thrombosis, need for anticoagulation with resultant vascular complications, prolonged hospitalization, and high costs. Temporary stem's have the potential for achieving many of the beneficial effects of permanent stenting without some of the iatrogenic complications. The HARTS (Heat Activated Removable Temporary Stent) removable stent employs the shape memory alloy Nitinol, and has the properties of being balloon deployable, but recoverable to a preset “memory” shape by heating it with warmed crystalloid solution. Preclinical experience first with a wire stent design and more recently with a slotted tubular design, has demonstrated the feasibility of implanting and recovering the HARTS device. Speculative applications of this technology include: treatment of acute postangioplasty occlusion and suboptimal angioplasty results; “stentoplasty”—the application of a temporary stent for several hours at the time of a primary angioplasty; and reduction of restenosis rate by inhibition of elastic recoil following short-term (hours) stenting. Further, the HARTS device may be an important vehicle for local delivery of drugs or other biologically active agents to the arterial wall. All research to date has been preclinical and controlled clinical trials will be necessary to define the safety, efficacy, and potential applications of the HARTS removable stent.