Myocardial collateral flow - Rentrop grading of collateral filling from the contralateral vessel on coronary angiography in coronary artery occlusion

Rentrop et al. researched collateral filling of stenotic coronary artery during inflation of the PTA balloon. Contrast dye was injected as soon as the patient developed ST-T changes on ECG or angina, but no later than 90 seconds after inflation of the balloon.

Grades of collateral filling Description
0 none
1 filling of side branches of the artery via collateral channels without visualisation of the epicardial segment
2 partial filling of the epicardial segment via collateral channels
3 complete filling of the epicardial segment of the artery via collateral channels


1. Rentrop KP, Cohen M, Blanke H, Phillips RA. Changes in collateral channel filling immediately after controlled coronary artery occlusion by an angioplasty balloon in human subjects. J. Am. Coll. Cardiol. 1985 Mar;5(3):587–92.