Q. Grading of Stenosis and Grading of Coronary Artery Disease?

Multiple views are necessary to quantify coronary stenosis accurately. Further, there should be no foreshortening, no artifact and no other vessels crossing that area and obscuring the viewer's judgment. Though the width of the vessel may appear almost normal, thinning of the contrast column will eventually give out the severity of luminal narrowing. The ability of the coronary angiogram to quantify the degree of stenosis at various points is limited by the fact that it consists of a "lumen-o-gram" in which stenosis is evaluated by comparison with the adjacent "reference" segment which is presumed to be normal and free of disease.

Normal Range of Caliber of Vessels

Vessel                                                  Range of Caliber

Left main                                              4.5 + 0.5 mm

Left anterior descending                      3.7 + 0.4 mm

Left circumflex (Dominant)                   4.2 + 0.6 mm

Left circumflex (Non-dominant)            3.4 + 0.5 mm

Right coronary (Dominant)                   3.9 + 0.6 mm

Right coronary (Non-dominant)            2.8 + 0.5 mm

By comparing the diameter of the disease free segment of the coronary artery to the size of the diagnostic catheter (6F=2mm), we can surmise that those vessels that are less that the diameter of the diagnostic catheter may, infact, be diffusely diseased.