[Intravascular ultrasound assessment at the site of balloon angioplasty: comparison with quantitative coronary angiography].

The effect of coronary angioplasty is usually evaluated on the basis of coronary angiography. However, angiographic images taken after angioplasty vary and the angiographic assessment of the therapeutic success of angioplasty is limited by local disruptions and dissections at the site of the dilatation, which are often difficult to detect by angiography. Intravascular ultrasound imaging is a new method for evaluation of coronary dimensions and wall morphology. Quantitative coronary angiographic analysis was compared with intravascular ultrasound assessment after balloon angioplasty in 42 patients. A diagnostic ultrasound imaging catheter was used during percutaneous transluminal coronary angioplasty (PTCA) to image both the lesion and the vessel segment just proximal (reference segment). Correlation between angiographic and ultrasound findings of vessel diameters and areas at reference segments was closer (r = 0.78, 0.66) than at the sites of PTCA (r = 0.54, 0.36). Dilated sites were analyzed in two subgroups segregated by degree of lumen eccentricity. An eccentric vessel lumen, defined as a circular shape factor of less than 0.92, was present at 25 of 42 sites. The correlation between angiographic and ultrasonic cross sectional area was not as close for these eccentric segments (r = 0.37). The difference in luminal areas between eccentric lumens estimated by edge detection and densitometry methods was 0.93 +/- 0.3 mm2, significantly greater than 0.54 +/- 0.31 mm2 in the circular group (p < 0.01). Luminal area after balloon angioplasty is clinically important to confirm by intravascular ultrasound especially in patients with large differences in measured values by quantitative coronary angiography.