Techniques to Enhance Extramyocardial Collateral Blood Flow After a Cardiomyoplasty

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Abstract
Chronic stimulation of a cardiomyoplasty was combined with low-dose infusion of heparin into the arterial supply of the cardiomyoplasty in order to determine if latissimus-derived collateral blood flow could be further enhanced. Acute and chronic stimulation of a latissimus dorsi cardiomyoplasty increased extramyocardial collateral blood flow to 35 +/- 9% and 27 +/- 5%, respectively, of normal myocardial blood flow. A model of coronary artery disease was created with an ameroid constrictor in goats, and a cardiomyoplasty was performed. Heparin (15 to 50 U/h) was delivered into the left subclavian artery for a period of 4 weeks. Simultaneously, the latissimus dorsi was chronically stimulated at 2 Hz. Chronic ischemic myocardium received a collateral flow per gram from the skeletal muscle equivalent to 11.8 +/- 5.2% of the blood flow to normal myocardium. The extramyocardial collateral flow correlated with the latissimus muscle flow (r = 0.72). Enhancement of extramyocardial collateral flow was not found with heparin treatment. In view of the correlation of extra-coronary collateral flow with latissimus muscle flow, the lack of a heparin effect may have been due to low latissimus blood flow. These results suggest that extramyocardial collateral blood flow to the myocardium is highest if the blood flow to the latissimus dorsi muscle is maintained.