734-1 Interim Analysis of the EPISODE Trial

Abstract

Application of intravascular ultrasound (IVUS) is evolved rapidly and now we have a better insight in the mechanism of balloon angioplasty (PTA) of the superficial femoral artery (SFA). The EPISODE trial (Evaluation Peripheral Intravascular Sonography on Dotter Effect) is a multicenter study evaluating whether IVUS is a better predictor of the outcome after PTA of the SFA than standard angiography. We studied 41 patients (pts) with angiographic successful PTA (26 M, 15 F; mean age 70 ± 8 yr). Of each patient, the smallest free lumen area seen on IVUS before and after PTA was selected. Oualitative analysis included lesion morphology and geometry before PTA and dissection, plaque rupture and internal elastic lamina rupture after PTA. Quantitative analysis included free lumen area (FLA), free lumen diameter (FLD), media-bounded area (MBA) and percentage area stenosis (%S) before and after PTA. Success or failure at 1 month and at 6 months was defined using a combination of clinical and objective vascular laboratory criteria, including ankle/brachial index and duplex. At one month success of PTA was evidenced in 30 pts and failure in 11 pts. After 6 months success was seen in 19 pts (46%; Group I) and failure in 22 pts (54%; Group II). No differences in outcome could be demonstrated on the basis of qualitative IVUS findings before and after PTA. Quantitative data before PTA of both groups were not significantly different. After PTA both groups showed a significant increase in FLA and FLD and a significant decrease in %S. Significant differences were encountered between the Group I and II for FLA (13.0 vs 9.7 mm 2 and FLO (4.0 vs 3.5 mm). whereas no significant differences were encountered in MBA and %S. The present study indicates for the first time that the presence of a narrow free lumen site within the lumen evidenced by IVUS following PTA is the most common mechanism underlying restenosis. Given the high incidence of failures seen at 1 month it is likely that rest-stenosis rather than restenosis may be the underlying mechanism to the failures evidenced.