Background: It has been shown in the MultiVitamins and Probucol (MVP) trial that probucol reduces angiographic lumen loss by 68% after percutaneous transluminal coronary angioplasty (PTCA). Restenosis occurred in 40% of patients not treated with probucol and in 20% of those in the probucol alone group.
Objective: To determine the morphological predictors of restenosis in patients treated with probucol.
Patients and methods: Beginning 30 days before angioplasty, 317 patients were randomly assigned to receive probucol, multivitamins, the combined treatment or placebo. Patients were then treated for six months after angioplasty. Intravascular ultrasound (IVUS) examination was performed immediately after angioplasty and at follow-up in 94 patients (108 segments). The angioplasty operator was blinded to the IVUS results. The cross-section selected for serial analysis was the one at the angioplasty site with the smallest lumen area at follow-up. Receiver operating characteristic curves were used to determine the performance of criteria to predict angiographic restenosis at follow-up.
Results: In probucol-treated patients, the cross-sectional area (CSA) narrowing of 67.6% or less was the best IVUS predictor for the absence of restenosis (P=0.03). Diameter stenosis of 35% or less almost reached significance as a predictor in these patients (P=0.056). The restenosis rate when either of these predictors was met was less than 13%. Rates of repeat PTCA in patients treated with probucol were 9.7% when CSA narrowing was 67.6% or less on IVUS and 3.1% with a post-PTCA stenosis of 35% or less on quantitative coronary angiography (QCA). No predictor of the absence of restenosis in patients not treated with probucol was identified.
Conclusions: The presence after balloon angioplasty of a CSA narrowing of 67.6% or less on IVUS or a diameter stenosis of 35% or less on QCA is associated, in patients treated with probucol, with extremely low rates of coronary restenosis and repeat angioplasty.