Robustness of late lumen loss in discriminating drug-eluting stents across variable observational and randomized trials.

BACKGROUND Binary angiographic and clinical restenosis rates can vary widely between clinical studies, even for the same stent, influenced heavily by case-mix covariates that differ among observational and randomized trials intended to assess a given stent system. We hypothesized that mean in-stent late loss might be a more stable estimator of restenosis propensity across such studies. METHODS AND RESULTS In 46 trials of drug-eluting and bare-metal stenting, increasing mean late loss was associated with higher target lesion revascularization (TLR) rates (P<0.001). When the class of bare-metal stents was compared with the class of effective drug-eluting stents, late loss was more discriminating than TLR as measured by the high intraclass correlation coefficient (rho) (late loss, rho=0.71 versus TLR, rho=0.22; 95% CI of difference=0.33, 0.65). When the individual drug-eluting stents and bare-metal stents were compared, late loss was a better discriminator than TLR (0.68 versus 0.19; 95% CI of difference=0.24, 0.60). Greater adjustments of study covariates are needed to stabilize assessments of TLR compared with late loss because of greater influence of reference vessel diameter on TLR than on in-stent late loss. Optimization of late loss with the use of a novel method of standardization according to diabetes prevalence and mean lesion length resulted in minor adjustments in late loss (<0.08 mm for 90% of reported trials) and an ordered array of mean late loss values for the stent systems studied. CONCLUSIONS Late loss is more reliable than restenosis rates for discriminating restenosis propensity between new drug-eluting stent platforms across studies and might be the optimum end point for evaluating drug-eluting stents in early, nonrandomized studies.