Intravascular brachytherapy for peripheral vascular disease

SCIENTIFIC BACKGROUND: Percutaneous transluminal angioplasties (PTA) through balloon dilatation with or without stenting, i.e. vessel expansion through balloons with or without of implantation of small tubes, called stents, are used in the treatment of peripheral artery occlusive disease (PAOD). The intravascular vessel irradiation, called intravascular brachytherapy, promises a reduction in the rate of repeated stenosis (rate of restenosis) after PTA. RESEARCH QUESTIONS: The evaluation addresses questions on medical efficacy, cost-effectiveness as well as ethic, social and legal implications in the use of brachytherapy in PAOD patients. METHODS: A systematic literature search was conducted in August 2007 in the most important medical electronic databases for publications beginning from 2002. The medical evaluation included randomized controlled trials (RCT). The information synthesis was performed using meta-analysis. Health economic modeling was performed with clinical assumptions derived from the meta-analysis and economical assumptions derived from the German Diagnosis Related Groups (G-DRG-2007). RESULTS: MEDICAL EVALUATION: Twelve publications about seven RCT on brachytherapy vs. no brachytherapy were included in the medical evaluation. Two RCT showed a significant reduction in the rate of restenosis at six and/or twelve months for brachytherapy vs. no brachytherapy after successful balloon dilatation, the relative risk in the meta-analysis was 0.62 (95% CI: 0.46 to 0.84). At five years, time to recurrence of restenosis was significantly delayed after brachytherapy. One RCT showed a significant reduction in the rate of restenosis at six months for brachytherapy vs. no brachytherapy after PTA with optional stenting, the relative risk in the meta-analysis was 0.76 (95% CI: 0.61 to 0.95). One RCT observed a significantly higher rate of late thrombotic occlusions after brachytherapy in the subgroup of stented patients. A single RCT for brachytherapy vs. no brachytherapy after stenting did not show significant results for the rate of restenosis at six months. Both, early and late thrombotic occlusions appeared more frequently in the brachytherapy group. HEALTH ECONOMIC EVALUATION: Additional costs of brachytherapy were estimated to be 1,655 or 1,767 Euro according to the used G-DRG. The incremental cost-effectiveness ratio per avoided restenosis was calculated to be 8,484 Euro or 9,058 Euro for brachytherapy use after successful balloon dilatation, 19,027 Euro or 20,314 Euro for brachytherapy after PTA with optional stenting and -39,646 Euro or -48,330 Euro for brachytherapy after stenting. DISCUSSION: Partially poor performing and reporting quality of the RCT exacerbate the interpretation and the transferability of the study results. The used methodical approach enables the highest evidence level for the determined results and presents a good approximation of the current brachytherapy related costs for the German health care system. CONCLUSIONS: Brachytherapy after successful balloon dilatation in PAOD can be recommended from a medical point of view for the reduction of the rate of restenosis at one year. However from a health economic view the answer is not yet clear. Based on the current data the use of brachytherapy after stenting in PAOD cannot be recommended neither from a medical nor from a health economic point of view. The informed consent of the patients is an important ethical aspect in the use of brachytherapy.