Lack of evidence for improvement in internal mammary graft flow by occlusion of side branch.

Coronary steal due to unligated side branches of an internal mammary artery graft has been reported previously. Embolization of these side branches has been shown to result in symptomatic improvement, but objective evidence of improved flow to the coronary artery has been lacking. We studied intracoronary Doppler flow in a patient presenting with symptoms thought to be due to a large unligated side branch of mammary graft. There was no significant change in the mammary flow after balloon occlusion of the side branch. More objective data may be required to routinely prescribe side branch embolization for symptomatic patients with unligated side branches of a mammary graft.