Hemodynamics of critical arterial stenoses.

The mechanics and the physiological problems related to critical arterial stenosis have been investigated by mathematical, biological and clinical models in experimental and clinical conditions. The value of critical stenosis has been defined in many ways but all the previous report on this subject agree in defining critical stenosis a reduction in section of the artery that can alter the poststenotic flow and pressure. Experimentally appreciable changes in pressures and flow do not occur until the cross-sectional area of a vessel has been reduced by more than 75% and these data are comparable to clinical situations. The data of several reports on this subject are plotted and compared and the different experiences are analysed to evaluate the best criteria to define the critical value of one stenosis and the clinical utilizations.