Quantitative techniques for the control of regression of coronary atherosclerosis

Abstract

The extent and degree of coronary atherosclerosis may be assessed by indirect parameters and by direct angiographic measurements. Determinations of the hemodynamic significance and properties of coronary stenoses by classical fluid dynamics, and semi-quantitative evaluation of regional hypoperfusion or abnormalities of metabolism and of regional contractile performance are indirect parameters, that do not provide precise information on progression or regression of coronary atherosclerosis. To obtain reliable and reproducible angiographic measurements of coronary stenoses, angiographic pitfalls (film exposure and processing as well as distance of the patient to x-ray tube and image intensifier must be constant, pincushion distortion must be compensated for, standard reference must be used), physiological variables (respiratory and cardiac cycle and coronary vascular tone must be identical on repeat films, slitlike stenoses must be visualized in different projections), and problems with the measurement procedure itself (reproducibility is important, inter- and intra-observer variability must be minimized, stenosis dynamics and plaque volume can only be quantitated by a computer system) have to be overcome or be compensated for. Using a standardized angiographic protocol, we were able to follow progression and regression in a cohort of 10 patients with familial hypercholesterolemia IIa, who were successfully treated with long-term specific LDL-cholesterol immunoabsorption (LDL-apheresis), that favorably influenced the long-term atherosclerotic activity in the coronary arteries of these patients.