Assessment of stenosis severity

Visual interpretations of coronary arteriograms are marked by such great interobserver and intraobserver variability that comparison of arteriograms from different subjects, or at different times in the same subject, are of limited value for assessing severity, changes in severity or functional significance of coronary artery stenosis. The universal use of percent diameter narrowing as a clinical measure of severity ignores other geometric characteristics of stenoses such as length, absolute diameter, multiple lesions in series or eccentric narrowings which may be worse in one view as compared to another view. Accordingly, we have developed an approach for analyzing coronary artery stenoses in both anatomic and functional terms. In this chapter an overview of the functional and anatomic approaches for quantifying severity of coronary artery stenoses is presented, their validation and equivalence outlined and the remaining problems to be solved indicated.