Effects of percutaneous transluminal angioplasty and endovascular brachytherapy on vascular remodeling of human femoropopliteal artery by noninvasive magnetic resonance imaging.

BACKGROUND Percutaneous transluminal angioplasty (PTA) of severely stenotic peripheral vascular lesions is hampered by a higher restenosis rate. The effects of PTA on vascular wall as well as the effects of the antirestenotic properties of endovascular brachytherapy (EVBT) remain unclear. MRI allows in vivo noninvasive assessment of the vascular effects of such treatment strategies. We sought to elucidate the vascular effect of PTA and PTA+EVBT by serial MRI. METHODS AND RESULTS Twenty symptomatic patients with severe stenosis of the femoropopliteal artery were randomly assigned to PTA (n=10) or PTA+EVBT (n=10; 14 Gy by gamma-irradiation source) and imaged by high-resolution MRI before and 24 hours and 3 months after intervention. An independent observer blinded to the procedure analyzed the MRI data. At 24 hours, cross-sectional MRI revealed that lumen area (86% and 67%) and total vessel area (47% and 34%) increased similarly in the PTA and PTA+EVBT groups, respectively. All patients showed severe splitting of the atherosclerotic plaque, resulting in an irregularly shaped lumen. At 3 months, MRI revealed a significant difference in lumen area change between the PTA and PTA+EVBT groups (40% and 106%, respectively; P=0.026) and in the total vessel area (14% and 39%, respectively; P=0.018). At 3 months, plaque disruption was still present in 50% of the patients treated with PTA+EVBT. CONCLUSIONS After PTA, there is deep disruption of the atherosclerotic plaques and an extensive remodeling process of the arterial wall. Luminal loss after PTA is partially due to inward vessel remodeling. Brachytherapy prevents inward remodeling and induces an increase in lumen area but partially prevents healing of disrupted vessel surface.