Assessment of percutaneous transluminal coronary angioplasty by quantitative coronary angiography: Diameter versus densitometric area measurements

Abstract

Cineangiograms of 138 patients who underwent percutaneous transluminal coronary angioplasty (PTCA) were analyzed with a computer-based coronary angiography analysis system. The results before and after dilatation are presented. In a first study group (120 patients), the severity of the obstructive lesions derived from the automatically detected contours was evaluated in absolute terms and in percent-diameter reduction. In a second group of patients, 18 coronary lesions were selected for their extreme severity and symmetric aspect before angioplasty as assessed from multiple views. In the second group, the densitometric percent-area stenosis was used to assess the changes in cross-sectional area after PTCA and was compared with the circular percent-area stenosis computed from the diameter measurements. Before PTCA, a good agreement exists between the densitometric percent-area stenosis and the circular percent-area stenosis. After PTCA, important discrepancies between these 2 types of measurements are observed. It is suggested that these discrepancies in results after PTCA can be accounted for by asymmetric morphologic changes in luminal cross section, which cannot be assessed accurately from diameter measurements in a single-plane view.

The effect of coronary angioplasty on coronary flow reserve.

“…Several of our results confirm previous reports by other groups of [25][26][27][28] investigators. Additionally, our finding that coronary flow reserve late after angioplasty is correlated with angiographic measurements of the residual luminal stenosis (area stenosis, minimum cross-sectional area, and integrated optical density) is consistent with a recent study from our laboratory demonstrating a close relationship between luminal stenosis and flow reserve in undilated coronary vessels.15 In both studies, lesions producing less than 70% area stenosis or with more than 2.5 mm2 minimal cross-sectional area had normal coronary reserve.…”

Quantitative angiography of the left anterior descending coronary artery: correlations with pressure gradient and results of exercise thallium scintigraphy.

“…For these theoretical and practical reasons, we favor the use of an automated definition of the reference area (or diameter) with the interpolated technique. 14 23 From these data, obtained in a clinical setting, a curvilinear relationship was found between the pressure drop across the stenosis and the minimal obstruction area as well as the percent cross-sectional area reduction. Both relationships are similar to those calculated on theoretical grounds by Brown et al 34 as well as to those experimentally derived from isolated human arteries35 or in canine experiments.3 Such a curvilinear relationship is expected from the general equation of fluid dynamics showing that a pressure drop across a stenosis is influenced mainly by viscous losses in the stenotic segment and separation losses at the exit of the stenosis.…”

Quantification of coronary artery stenosis in vivo.

“…Automated border recognition programs offer a promising solution to reducing these uncertainties when combined with densitometric analysis of the arterial x-ray image. The combination of the border recognition and density techniques is particularly useful, because background-corrected radiodensity is integrated across the artery image (including the entire border zone) to yield a measure of vessel crosssectional area independent of its sectional shape (Rutishauser, 1971;Crawford et al, 1977;Kirkeeide et al, 1984;Nichols et al, 1984;Serruys et al, 1984). They also eliminate the human error in visual interpretation of the penumbra.…”