The Biology of In-Stent Restenosis and the Rationale for Debulking

New techniques and technologies have been developed in the past several decades for the endovascular treatment of arterial occlusive disease affecting the superficial femoral artery (SFA) and infrapopliteal arteries. Dedicated stents have been extensively used to address the problem of elastic recoil, flow-limiting dissection, and residual stenosis after balloon angioplasty. Their development has allowed the treatment of very complex and extensive lesions with a low complication rate. As a result of the favorable outcomes that can be achieved (as compared to plain balloon angioplasty), endovascular treatment with stenting has become the treatment modality of choice, with a total number of more than 80,000 stents implanted in the United States in 2014 (number based on the volume of Medicare patients that constitutes 70% of all-payer volume; source The Advisory Board Company, personal communication). Restenosis rates in the various randomized ABSTRACT: Over the past several decades, new devices have been developed for endovascular therapy of arterial occlusive disease in the superficial femoral and infrapopliteal arteries. These new technologies and techniques have brought about an increase in endovascular treatment with stenting. With the increase in stenting has come an increase in the incidence of in-stent restenosis. Currently, there is a trend toward use of drug-coated balloon angioplasty instead of stents, and this is expected to lead to a significant reduction in the number of stents that will be implanted in the superficial femoral artery. However, bail-out stenting after drug-coated balloon angioplasty can be as high as 40% in long lesions. Therefore, ISR will remain a problem with a significant effect on midand long-term outcomes of SFA stenting. This paper will provide a description of the biology of in-stent restenosis as well as an overview of the literature on the treatment of in-stent restenosis using various available techniques and the role of debulking.