IN-VITRO ASPECTS OF AN ANGIOGRAPHIC AND ULTRASOUND QUANTIFICATION WITH IN-VIVO CORRELATION

Background - The validity of quantitative coronary angiography (QCA) a fter stent placement has been questioned because the optical density o f a metallic stent, added to the density of a contrast-filled lumen, c ould affect border definition. Methods and Results - We deployed 3.0- and 4.0-mm Palmaz-Schatz, Wiktor, Multilink, NIR, and InStent stents i n precision-cast phantoms. Central lumens of 2.0 mm were created. Ther e was no difference between the ''true'' diameters of any stented lume n by both QCA and quantitative ultrasonic (QCU) measurement poststenti ng. QCA systematic error (SE) varied from 0.01 for the Wiktor stents t o 0.14 mm for the Palmaz-Schatz stents; the random error (RE) was 0.03 to 0.13 mm. QCU SE varied from 0.05 to 0.11 mm, and RE ranged from 0. 01 to 0.07 mm. At the next stage, 4.0-mm Wiktor and Palmaz-Schatz sten ts were deployed into the phantom lumens; 1.5-, 2.0-, 2.5- and 3.0-mm lumens were created inside the stents. QCA and QCU measurements of 1.5 - to 2.5-mm residual lumens were overestimated by 0.1 to 0.3 mm. In th e 3.0-mm residual lumen within the Wiktor stent, QCA underestimated th e luminal size by -0.1 mm. There was no QCA inaccuracy for a 3.0-mm lu men within the Palmaz-Schatz stent. In patients, in 25 stented segment s in both the Palmaz-Schatz and Wiktor groups, there was no difference between QCA and QCU diameters. Conclusions - QCU is sufficiently prec ise for the assessment of the coronary lumen after stenting. QCA can b e used as an accurate method of poststent assessment, except when a ve ry mild recurrence within a highly opaque stent is measured. In that i nstance, QCA may underestimate the luminal diameter.