Dose finding in intracoronary brachytherapy--consequences from empirical trials

Abstract

In-stent restenosis has been shown to be associated with a high recurrence rate of repetitive restenosis and remains a challenging task in interventional cardiology. Randomized, placebo-controlled trials have established that beta- as well as gamma-based vascular brachytherapy reduces the incidence of restenosis and clinical event rates following percutaneous coronary intervention (PCI) for the treatment of in-stent restenosis with focal and moderate length. Despite the number of clinical trials with impressive and convincing data, dose finding in most trials is empirical and remains an open question in this fairly new field of percutaneous interventional procedures. Current clinical trials have unequivocally demonstrated a clear dose dependency for the inhibition of intimal proliferation and a significant effectiveness for the treatment of in-stent restenosis with a dose around 20 Gy. Theoretical considerations and empirical data, however, support the need for a dose escalation with current systems to even further improve clinical results. A controlled dose escalation seems, thus, justified and is apparently not related with an increased risk of major adverse cardiac events. The current article gives an overview about theoretical considerations of dosing for intracoronary brachytherapy, presents recent data from important clinical trials in different views, and opens new perspectives for the successful treatment of in-stent restenosis.