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Impact of frame selection on quantitative coronary angiographic analysis after coronary stenting

This study examined the impact of frame selection on the results of quantitative coronary angiographic analysis (QCA). Thirty‐nine patients who had stent implantation and a follow‐up angiogram 5–7 months later were studied using the CMS Medis QCA system. The acute and follow‐up films (n = 39) were read in three different ways to assess the impact of frame selection: frame chosen making the stent appear least narrowed (best); frame chosen making the stent appear most narrowed (worst); and measurement from the mean value from three consecutive end‐diastolic frames (core). We measured the mean percent diameter stenosis immediately postintervention and at follow‐up, the binary restenosis rate, and the late lumen loss (mm). There was a statistically significant difference in all of these variables when comparing the three methods of frame selection (best vs. worst, P values < 0.001; best or worst vs. core, P values < 0.01). This study demonstrates a marked variability in the results obtained using QCA to measure the acute and late coronary stent outcomes when operators have the ability to select which frame to analyze (frame bias). Catheter Cardiovasc Interv 2005;64:460–467. © 2005 Wiley‐Liss, Inc.