Quantitative measurements of in-stent restenosis: A comparison between quantitative coronary ultrasound and quantitative coronary angiography

While quantitative coronary angiography (QCA) remains the standard used to assess new interventional therapies, intracoronary ultrasound (ICUS) is gai ning interest. The aim of the study was to determine the relationship betwe en QCA and quantitative coronary ultrasound (QCU) measurements after stenti ng. Sixty-two consecutive patients with both QCA and QCU analysis after ste nt implantation were included in the study. The mean luminal diameter (QCU vs. QCA) were 2.74 +/- 0.46 mm and 2.41 +/- 0.49 mm (P < 0.0001), the minim al luminal diameter (MLD) 2.08 +/- 0.44 mm and 1.62 +/- 0.42 mm (P < 0.0001 ), and the projected QCU MLD 1.90 +/- 0.42 mm (P < 0.0001 with respect to Q CA). Percentage obstruction diameter (QCU vs. QCA) were 41.53% +/- 10.78% a nd 43.15% +/- 12.72% (P = NS). The stent diameter (QCU vs, QCA) were 3.54 /- 0.65 mm and 3.80 +/- 0.37 mm (P = 0.0004). Stent length measured by QCU were longer at 31.11 +/- 13.54 mm against 28.63 +/- 12.75 mm, P < 0.0001 wi th respect to QCA. In conclusion, while QCA and QCU appear to be comparable tools for measuring corrected stent diameters and stent lengths, smaller l uminal diameters were found using QCA. This is of particular relevance to q uantitative studies addressing absolute changes in vascular or luminal diam eters. (C) 1999 Wiley-Liss, Inc.