Can you explain this short statement from a medical book?

Question

“angiographically significant” coronary stenosis is considered to be present when the diameter is reduced by more than 50%, corresponding to a reduction in cross-sectional area greater than 75%.
I really don't understand this statement...and by he way how do you test for ventricular ejection fraction?

Answer 1

I speak medicalese! You are in BIG trouble to a greater degree, or it's "significant" a.k.a the medical term "stenosis", if only half of your artery is open or unblocked (if you cut open the artery cross ways it would appear to be 75% blocked).

More or less...

Answer 2

I'll take a swing at it.

Coronary stenosis would be narrowing of the arteries which supply the heart with oxygen and nutrients. This narrowing falls in the category of angiographically significant when the diameter (distance from one side of the artery to the other) is reduced by half. The cross section is also smaller, when the diameter is reduced.

area= (pie) x radius squared
radius= 1/2 diameter

Let's say that the original diameter was 8 milimeters:
Diameter= 8mm Radius= 4mm
A= 3.14 x 4 squared
A= 3.14 x 16
A= 50.24 mm squared

Restricted by 50%:
Diameter=4mm Radius= 2mm
A= 3.14 x 2 squared
A= 3.14 x 4
A= 12.56 mm squared

You can see the diameter has a larger than expected effect on the area. The point being that the vessel has approximately one fourth of it's usual capacity.

Answer 3

i think its saying if there is a blockage in the artery and there is a swelling of the heart then those two together combine to make that problem..

Answer 4

Dear Mike, If you know the answer , you need not test us.