AN ESSENTIAL part of current accepted techniques of internal mammary artery (IMA)-myocardial implantation is the making of side holes or the leaving open of branches of the artery within the myocardial tunnel. This stems from the assumption that they will be the origin of the new communications with the myocardial arterioles.
There is evidence, nevertheless, that the creation of "bleeders" is not essential to later branching. Sewell et al1,2 observed that arteries implanted into dogs' myocardiums with all branches tied later developed communications, either direct or indirect, with the coronary arterial system. In a previous communication we3 also reported that all of nine arteries implanted with their branches tied and studied by histology two to six months later showed patency in the myocardial tunnel. Five of the seven of these that were studied by angiography showed myocardial communications.
A precise description of the behavior of side holes or