[Standardized experimental coronary stenosis. Reduction of diameter and cross-sectional area following eccentric...

The hemodynamic relevance of a coronary stenosis depends essentially upon the reduction of the cros-sectional area of the coronary lumen. However, the extent of experimental coronary narrowing is measured generally by determining the coronary diameter. In a series of experiments, the relationship between diameter and cross-sectional area (d/a) was determined using a micrometer constrictor and four different silastic tubings the size of which reflected actual coronary diameters as measured in coronary casts of German shepherd dogs. The d/a relationship was linear over a range of diameter reductions from 50 to 90%. A "physiologic" wall of thickness of 0.3-0.4 mm had no major influence on the d/a relationship. However, identical reductions of diameters and cross-sectional areas could only be achieved with the tubing fitting exactly into the curvature of the coronary constrictor.