The effect of 32P beta-radiotherapy on both vessel remodeling and neointimal hyperplasia after coronary balloon angioplasty and stenting: A three-dimensional intravascular ultrasound investigation

Intracoronary radiation is a promising therapy to decrease restenosis after percutaneous intervention. The aim of this pilot study was to determine th e mechanism of intracoronary beta-radiation after balloon angioplasty and s tenting in a double-blind placebo-controlled randomized fashion. Twenty-six patients were randomized to either placebo (n = 6) or 3 doses (28, 35 and 42 Gy) of beta-radiation (n = 20) using the Guidant brachytherapy system (2 7 mm long P-32 source mire). Of these, 21 patients underwent postprocedure and 6-month follow-up three-dimensional intravascular ultrasound (IVUS) ass essment. Volumetric quantification was performed by means of a semi-automat ed contour detection system after an EGG-gated motorized pullback IVUS imag ing and three-dimensional reconstruction. We compared the volumetric change s (Delta) of total vessel volume (TVV), plaque volume (PV) and lumen volume (LV) after 6 months between placebo (dummy wire) and irradiated patients. In addition, the volume of neointimal hyperplasia was quantified within the stented segments. There was an opposite behavior of TVV and LV change betw een placebo (Delta TVV = -24 mm(3) and Delta LV = -42 mm(3)) and irradiated (Delta TVV = +18 mm(3) and (Delta LV = +5 mm(3)) patients. The mean neoint imal formation within the stented segment in the irradiated patients (n = 7 ) was 1.9 mm(3) (1.5%). Our results suggest that beta-radiation affects ves sel remodeling after percutaneous intervention and inhibit neointimal forma tion in stented patients.