CAN INTRACORONARY ULTRASOUND CORRECTLY ASSESS THE LUMINAL DIMENSIONS OF CORONARY-ARTERY LESIONS - A COMPARISON WITH QUANTITATIVE ANGIOGRAPHY

In 62 patients with angina pectoris Canadian Class III and IV the luminal dimensions of 25 pre-PTCA and 56 post-PTCA lesions without occlusion were examined with a 4.3 F30 MHz mechanical ultrasound imaging catheter, and analysed off-line using ultrasound cross-sectional area (U-CSA) measurements from s-VHS video images (n = 81). In addition, 42 angiographically normal coronary segments were examined At the site of the examination, the U-CSA was integrated centrally to the leading edge echo of the inner contour of the vessel wall and the corresponding angiographic cinefilm images were analysed by edge detection using the Cardiovascular Angiography Analysis System. The obstruction diameter (at the lesion) and the mean vessel diameter (at normal sites) were (sed to calculate the angiographic cross-sectional area (A-CSA) assuming a circular model. U-CSA values were compared with the corresponding A-CSA values using t-test and linear regression analysis. The study showed that larger CSA are measured with ultrasound than,vith angiography. (P < 0.0001). An acceptable correlation was found between U-CSA and A-CSA values in normal coronary segments (correlation coefficient. r = 0.73, mean diff = 1.44 +/- 1.22 mm(2)). However, the correlation was poor at the site of pre-PTCA lesions (r = 0.62, mean diff = 1.81 +/- 1.14 mn(2)) and deteriorating following PTCA (r = 0.47, mean diff:= 1.28 +/- 2.20 mm(2)). No correlation was found between the degree of lumen eccentricity measured with intracoronary ultrasound (ICUS) and the individual differences between U-CSA and A-CSA values. It ions concluded that U-CSA at coronary lesions shows poor correlation with A-CSA. Basic methodological differences between the techniques may explain the overestimation of cross-sectional areas by ICUS.