Impact of residual plaque burden after balloon angioplasty in the MultiVitamins and Probucol (MVP) trial

BACKGROUND: It has been shown in the MultiVitamins and Probucol (MVP) trial that probucol reduces angiographic lumen loss by 68% after percutaneous tr ansluminal coronary angioplasty (PTCA). Restenosis occurred in 40% of patie nts not treated with probucol and in 20% of those in the probucol alone gro up. OBJECTIVE: To determine the morphological predictors of restenosis in patie nts treated with probucol. PATIENTS AND METHODS: Beginning 30 days before angioplasty, 317 patients we re randomly assigned to receive probucol, multivitamins, the combined treat ment or placebo. Patients were then treated for six months after angioplast y. Intravascular ultrasound (IVUS) examination was performed immediately af ter angioplasty and at follow-up in 94 patients (108 segments). The angiopl asty operator was blinded to the IVUS results. The cross-section selected f or serial analysis was the one at the angioplasty sire with the smallest lu men area at follow-up. Receiver operating characteristic curves were used t o determine the performance of criteria to predict angiographic restenosis at follow-up. RESULTS: In probucol-treated patients, the cross-sectional area (CSA) narro wing of 67.6% or less was the best IVUS predictor for che absence of resten osis (P=0.03). Diameter stenosis of 35% or less almost reached significance as a predictor in these patients (P=0.056). The restenosis rare when eithe r of these predictors was met. was less than 13%. Rates of repeat PTCA in p atients treated with probucol were 9.7% when CSA narrowing was 67.6% or les s 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 p atients not treated with probucol was identified. CONCLUSIONS: The presence after balloon angioplasty of a CSA narrowing of 6 7.6% or less on IVUS or a diameter stenosis ui 35%,, less on QCA is associa ted, in patients treated with probucol, with extremely low rates of coronar y restenosis and repeat angioplasty.