QUANTITATIVE CORONARY ARTERIOGRAPHY AND ITS ASSESSMENT OF ATHEROSCLEROSIS .1. EXAMINING THE INDEPENDENT VARIABLES

Background. Previous work has demonstrated that quantitative coronary arteriography (QCA) can accurately measure phantom images to within +/ - 0.1 mm and has been accepted as a reliable and reproducible method o f measuring human coronary artery disease (CAD). Assessment of CAD by QCA involves the measurement of numerous variables, which are currentl y required to calculate stenosis flow reserve (SFR). Methods and Resul ts. In this study 1040 stenotic lesions were analyzed by two well-acce pted methods with demonstrated accuracy and reproducibility. These met hods measure percent diameter stenosis (%DS), absolute diameter, perce nt area stenosis, length, as well as entry and exit angles to and from a stenotic coronary artery lesion respectively. Based upon these resu lts, the mean +/- standard deviations and range seen in CAD were deter mined for each of these independent variables. This study demonstrated that atherosclerotic coronary artery lesions do not appear to exceed an entry angle of -39-degrees, an exit angle of +35-degrees, or an abs olute length of 4.84 cm when accurately measured by QCA. It was also n oted that, once percent diameter stenosis exceeded 89% (regardless of the visual estimate) or percent area stenosis exceeds 99%, coronary ar teries become completely occluded as measured by QCA. Conclusions. Whi le previously suspected that once certain critical limits are exceeded in the deposit of cholesterol and calcium within the coronary artery, the artery will close, this study demonstrated by QCA what the limita tions in human coronary arteries appear to be. These limits may be in part due to turbulent factors resulting in platelet activation or loca l mediators from endothelium of the coronary artery. Contemporary quan titative coronary arteriography (QCA) was used to measure the differen t variables present in atherosclerotic coronary arteries. While the in teraction of each of the independent variables undoubtedly plays a rol e in the determination of coronary artery blood flow and closure, the limitations of each of these variables have not yet been defined in hu mans. This study, based on the results of human coronary arteriograms as analyzed by QCA, demonstrates the limitations of each of these vari ables, after which coronary arteries close and blood flow equals zero.