Collateral circulation grading

Associate Editor-In-Chief:

Grade 0
No collaterals present. Angiography fails to reveal evidence of collateral vessels.

Grade 1 (or partial)
Minimal collaterals present. Evidence of minimal to partial filling of the recipient branch epicardial arteries/infarct region. It is not necessary for one to see the branches connect directly to the major epicardial artery.

Grade 2 (or complete)
Well-developed collaterals. Evidence of collateral circulation with near complete to complete filling of the recipient major epicardial artery/infarct region.

Grade 3 (myocardial)
Filling of the myocardium by collaterals. If the collaterals are not filling any visible arterial branch, but are only participating in the perfusion of the myocardium.