Limitations and Long Term Outcome of Intracoronary Radiation Therapy With Catheter Based Systems and Radioactive Stents

Abstract

__Abstract__ Balloon angioplasty was the first non-surgical therapeutic modality for coronary artery disease introduced in 1977. It was related with high rates of acute complications and restenosis that limited its application to a minority of patients with coronary artery disease with relatively simple lesion morphology. Continuous developments during the next decade led to the introduction of stents in 1986. They were proven extremely efficient in reducing acute complications, dramatically expanding the indications for percutaneous interventions. In addition they were associated with favourable outcome in reducing restenosis compared to balloon angioplasty but they were also limited by the development of in-stent restenosis. Instent restenosis remained a therapeutic challenge for almost a decade and many mechanistic and pharmacological attempts failed to solve it. Ionic forms of radiation (radioactive stents and localised catheter based intracoronary radiation therapy) were introduced. Radioactive stents showed no benefit compared to conventional stenting. However intracoronary brachytherapy, which was first applied in human coronaries in 1995, was proven effective for the treatment of in-stent restenosis (secondary prevention of restenosis). Its efficiency for treatment of de novo lesions (primary prevention of restenosis) especially in combination with the use of stents is limited. In 2001 drug eluting stents were introduced into clinical practice and they revolutionised the treatment of coronary artery disease. They are the first therapeutic modality in interventional cardiology expected to show equal or superior results in comparison to coronary artery by pass surgery. In Europe were conducted the majority of the human trials with radioactive stents and pioneering and exploratory studies with intracoronary radiotherapy with catheter based systems mainly with beta emitters for de-novo lesions. This thesis addresses issues central to both of these therapeutic modalities