Article

Quantitative assessment of coronary artery lesions

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Abstract

In today's practice, the degree of coronary obstructions is usually estimated; descriptions are expressed as percent stenosis with the understanding that these values are not based on accurate measurements. This evaluation technique, however, leads to substantial intraobserver and interobserver variability.1, 2 Thus, (1) the recommended scoring systems are hampered by the individual grading standards, (2) the comparison of results from different centers is of limited value, and (3) the relation between anatomical (obstruction) and functional (flow) criteria remains inaccurate and indications for bypass surgery for instance are, therefore, often doubtful.

Intravital quantitative evaluation of coronary morphology was first reported by Gensini et al3 who studied the diameter changes of normal coronary arteries after nitroglycerin. In subsequent years, various reports based on different techniques to assess and objectivate coronary obstructions were published.4–8 Some of the major difficulties are related to the complex geometry of the coronary arteries, the relatively small vessel size, the phasic motion of all vessels, and the varying concentration of contrast medium during injection.

Our quantitative morphometric method is based on direct measurements of coronary findings from the angiographic screen. Diameters of normal coronary arteries (Table) and the degree of obstruction are measured with a vernier caliper (accuracy: 0.05 mm). The 35-mm cinefilms of coronary angiography are projected on the screen of a Tagarno projector. The enlargement factor due to the image amplifier and the projection is approximately 1:3 and is exactly determined for each case by measuring the catheter tip placed into the coronary ostium . . .


 

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