701-6 Dissociation Between Minimal Luminal Diameter and Clinical Outcome at 6 Month Follow-up in Randomized Trials of Percutaneous Revascularization

Abstract

There is considerable controversy as to whether quantitative coronary angioplasty is a meaningful surrogate index for clinical outcomes after coronary intervention. If a larger MLD reduces the incidence of restenosis, this in turn should be associated with a decrease in the incidence of subsequent clinical events. To study this phenomenon, we analyzed 6 major randomized trials evaluating a variety of approaches to reduce restenosis following percutaneous revascularization. In 3 of the 6 trials compared to the control arm, treatment was associated with significant decrease in the incidence of clinical events secondary to restenosis (myocardial infarction, death and need for repeat revascularization) and an improvement in the MLD at the time of follow-up catheterization. However, a similar or greater absolute MLD improvement did not yield clinical benefit in 2 trials, and 1 trial showed only clinical benefit. MLD (mm) Event Rate p Difference Treatment Control Angiopeptin 0.01 22% 30% 0.03 CAVEAT I 0.11 28% 30% NS BENESTENT 0.12 23% 33% <0.05 ACCORD 0.16 32% 32% NS CAVEAT II 0.17 22% 33% 0.04 STRESS 0.20 20% 27% 0.08 The magnitude of the difference in MLD between the control and treatment arms of each group is small in comparison with the difference in clinical events detected, and there is no correlation between the magnitude of MLD benefit and outcomes. While in some individual trials there is concordance in angio-clinical results, there is little evidence for this with inter trial comparison. This suggests a treatment (medical or device) or trial specific relationship rather than a direct linkage between MLD and clinical outcomes.