The purpose of this study is to determine the feasibility of augmenting myocardial blood flow by extracardiac methods. Specifically, the use of the internal mammary implant coupled to laser drilled ventricular channels and omental and/or splenic onlay wraps are to be considered. Additionally, the use of endothelial cell seeding together with growth factor may provide further augmentation. The rationale of the proposal is that many patients are not candidates for the coronary artery bypass procedure because of extreme atheroslerosis. There is a possibility that one of the major deficits in long term IHSS patients is ventricular mass/vascular supply disproportion. As an initial stop to determine feasibility and develop techniques, forty dogs, in various groups were treated with combinations of the internal mammary implant, omental wrapping, and application of ameroid constrictors (AC). These groups were (1) control of IMA implant which was ligated and an AC applied to the left anteriod descending coronary artery (LAD); (2) same as group (1) but no IMA ligation; (3) same as (2) plus omental wrap after epicardial abrasion; and (4) same as (2) except additional AC applied to the circumflex artery. The results shows that the IMA remained patent in all cases and collaterialized flow to the LAD and circumflex arteries. No animals developed myocardial infarction except group (1) controls. Blood flow through IMA averaged 8.ml/min which increased 33-50% with catecholamine stimulation. Microsphere studies demonstrated an augmentation of catecholamine stimulation. Microsphere studies demonstrated an augmentation of 0.15 ml/gm of heart at rest and a 33% increase with stimulation. No influence of omental wrapping on flow augmentation was shown. The data shown that augmentation is possible with internal mammary artery implantation in the ischemic myocardium.
