Effects of probucol on vascular remodeling after coronary angioplasty

Background-We have shown that probucol reduces restenosis after balloon ang ioplasty. Whether probucol acted via prevention of neointimal formation or improvement in vascular remodeling could not be addressed by angiography an d required the use of intravascular ultrasound (IVUS). Methods and Results-Beginning 30 days before angioplasty, 317 patients were randomly assigned to receive probucol, multivitamins, combined treatment, or placebo. Patients were then treated for 6 months after angioplasty. IVUS examination was performed immediately after angioplasty and at follow-up i n 94 patients (111 segments). The cross section selected for serial analysi s was the one at the angioplasty site with the smallest lumen area at follo w-up. In the placebo group, lumen area decreased by -1.21+/-1.88 mm(2) at f ollow-up, and wall area and external elastic membrane (EEM) area increased by 1.50+/-2.50 and 0.29+/-2.93 mm(2), respectively. Change in lumen area, h owever, correlated more strongly with the change in EEM area (r=0.53, P=0.0 02) than with the change in wall area (r=-0.13, P=0.49). Lumen loss was -1. 21+/-1.88 mm(2) for placebo, -0.83+/-1.22 mm(2) for vitamins, -0.25+/-1.17 mm(2) for combined treatment, and -0.15+/-1.70 mm(2) for probucol alone (P= 0.002 for probucol, P=0.84 for vitamins). Change in wall area was similar f or all groups. EEM area increased by 0.29+/-2.93 mm(2) for placebo, 0.09+/- 2.33 mm(2) for vitamins only, 1.17+/-1.61 mm(2) for combined treatment, and 1.74+/-1.80 mm(2) for probucol only (P=0.005 for probucol). Conclusions-Lumen loss after balloon angioplasty is due to inadequate vesse l remodeling in response to neointimal formation. Probucol exerts its antir estenotic effects by improving vascular remodeling after angioplasty.