[Effects of stenosis on blood flow in the coronary artery of dogs].

The effects of stenosis on coronary blood flow (CBF) were studied in 22 open-chest mongrel dogs. A progressive stenosis was produced by a micrometer constrictor on the left circumflex coronary artery. Mean aortic pressure (Pa), distal coronary pressure (Pc) and stenotic segment pressure drop (delta P) were measured. Curve of CBF versus % stenosis showed that CBF was relatively constant with stenosis less than 85%, CBF rapidly decreased with stenosis of 85-95%, and then slowly reduced as stenosis was further increased. The change in CBF versus % stenosis was expressed as follows: CBF = 1.48 X 10(10) theta -27.6 A (where A = % stenosis in lumen area). With progressive coronary artery stenosis (greater than 75%), the change in percent stenosis and Pc showed a negative correlation: Pc = 159.1-1.36A (r = -0.73, P less than 0.01); the change in Pc and CBF showed a positive correlation: Pc = 16.9 + 1.3 CBF (r = 0.74, P less than 0.01).