Measuring maximal percent area stenosis poststent placement with intracoronary Doppler and the continuity equation and correlation with intracoronaryultrasound and angiography

Quantitative coronary angiography (QCA) and intracoronary ultrasound (ICUS) are methods for anatomic assessment. of stent deployment. Intracoronary Do ppler is primarily a method for the physiologic assessment of coronary sten oses, It correlates well with traditional noninvasive measurements of lesio n significance, Intracoronary Doppler was used for the anatomic assessment of de novo coronary artery stenosis with variable success; however, its use for anatomic assessment of adequate stent deployment is unavailable. A rap id, automated software program was developed based on a modified continuity equation to calculate the maximal in-stent percent area stenosis by compar ing the maximal in-stent velocity to an average reference velocity (proxima l and distal). This study was designed to compare the Dappler method of an anatomic assessment with QCA and ICUS in 15 patients. Physiologic success o f stent deployment was determined by the distal coronary flow reserve to 24 to 36 mu g of intracoronary adenosine. Following successful stent deployme nt, distal coronary flow reserve increased significantly from a baseline of 1.6 +/- 0.5 to 2.9 +/- 1.1. There was a significant correlation between th e maximal in-stent percent area stenosis as measured by Dappler and both QC A (r = 0.78, p <0.01) and ICUS (r = 0.84, p <0.01). This study demonstrates that maximal in-stent percent area stenosis can be measured by intracorona ry Doppler and a novel software program. The intracoronary Doppler guide-wi re method can assess the adequacy of stent deployment using both anatomic a nd physiologic principles and may supplement other quantitative methodologi es. (C) 1999 by Excerpta Medica, Inc.