ANALYSIS OF REPRODUCIBILITY OF REFERENCE LUMEN QUANTITATION WITH INTRAVASCULAR ULTRASOUND IN STENTED CORONARY-ARTERIES

Intravascular ultrasound is widely used to guide coronary stent implan tation. The key quantitative criterion for successful implantation is the demonstration of adequate expansion of the stented lumen relative to that of the adjacent reference vessel segments. In this study we ai med to establish the reproducibility of intravascular ultrasound measu rements of the reference segments in lesions undergoing coronary stent ing. Measurements of the reference segment lumen dimensions were made in a blinded fashion by two experienced observers, and reproducibility was assessed by calculating the mean difference and standard deviatio n of the paired measurements. The unselected Intraobserver random vari ability of the mean reference lumen area measured 0.8 mm(2). The inter observer random variability was 0.94 mm(2). The intraobserver and inte robserver variability of minimum lumen area within the stent was small er, measuring 0.30 mm(2) and 0.52 mm(2), respectively. There was 91% i ntraobserver agreement, and 75% interobserver agreement, in identifyin g adequate stent expansion as defined by a stent-to-mean reference lum en area ratio of >0.8. The potentially significant level of variabilit y inherent in selecting and measuring the reference segments, and its impact on clinical decisionmaking, should be remembered when this meth od of assessing the acute quantitative outcome of stent implantation i s applied. (C) 1997 Wiley-Liss, Inc.