[Endocoronary ultrasonography and quantitative coronary angiography. Correlations before and after transluminal coronary angioplasty]. / Echographie endocoronaire et coronarographie quantitative. Corrélations avant et après angioplastie transluminale coronaire.

A comparative study of the results of quantitative coronary angiography and endocoronary ultrasonography was performed in 37 patients undergoing percutaneous transluminal coronary angioplasty to determine the correlations between the two methods. The analyses were made before and after angioplasty at the site of stenosis and on a reference segment. A complete study before and after angioplasty using both techniques was only possible in 24 cases. The quantitative ultrasonographic analysis consisted of measurement of two orthogonal diameters, total surface area of the vessel, the endoluminal surface area and surface area of plaque. Transluminal coronary angioplasty acts mainly by forcing the plaque outwards. Ultrasonography showed a decrease in plaque area, from 10.5 +/- 6 mm2 to 9.8 +/- 5.5 mm2 and the total surface area of the vessel increased from 12.8 +/- 0.7 to 15.3 +/- 6.9 mm2 (p < 0.05). This accounted for the gain in main surface area of the stenosed lumen, from 2.28 +/- 1.28 to 5.9 +/- 2.65 mm2 (p < 0.001). The correlations between quantitative coronary angiography and ultrasonography at the site of stenosis were only significant after angioplasty both the vessel diameter (r = 0.67; p < 0.0002) and endoluminal surface area (r = 0.63; p < 0.0001). A correlation was not observed before angioplasty because of the complexity of the plaque and its excentric location. At the reference site, the correlations between ultrasonography and angiography before and after angioplasty were significant but not very close (Spearman coefficient 0.53 and 0.82 respectively, p < 0.001). Therefore, correlations between quantitative data obtained by coronary angiography and ultrasonography are modest in patients undergoing transluminal coronary angioplasty. The ultrasonographic information is more qualitative, enabling a better understanding of the mechanism of the therapeutic procedure and allowing optimal choice of the appropriate tool.