The Journal of Thoracic and Cardiovascular Surgery, Vol 85, 499-507, Copyright © 1983 by The American Association for Thoracic Surgery and The Western Thoracic Surgical Association
Coronary artery stenoses. Relationship between angiographic severity and impact on mean diastolic pressure gradient
TM Bateman, RJ Gray, MJ Raymond, AT Miyamoto, A Chaux, RM Kass, ME Lee, ME Stewart and JM Matloff
Coronary angiography provides important anatomic information about coronary
artery stenoses. However, it is unclear whether specific assumptions about
hemodynamic impact can be made from the angiogram. We therefore studied the
relationship between angiographic severity of coronary stenoses and the
mean diastolic pressure gradient measured directly at coronary bypass
operation. We studied 29 stenoses selected because they were the only
lesions in a given vessel, they were well seen in two angiographic views,
and there was no change in clinical status of the patient between
angiographic and surgical procedures. Fourteen stenoses were in the left
anterior descending artery, nine were in the right coronary artery, and six
were in the left circumflex artery. Correlation between mean diastolic
gradient and percent stenosis was good (r = 0.78, p = 0.001) and especially
so for lesions in the left anterior descending artery (r = 0.84, p =
0.001). Lesions over 90% had a wide range of gradients, while lesions less
than 90% tended to have more predictable gradients. Collaterals invariably
identified vessels with stenoses causing major pressure gradients. History
of myocardial infarction was associated with major gradients in supplying
vessels. Length of stenosis was not an important influence on gradient over
a stenosis. We conclude that in some defined instances, generalizations
about hemodynamic (and presumed functional) impact of stenoses can be made
from the angiographic assessment, but precise assumptions are not possible.