BLOOD-FLOW CAPACITY VIA DIRECT ACUTE MYOCARDIAL REVASCULARIZATION

The concept of direct myocardial revascularization, achieving myocardi al perfusion through means other than the normal coronary vasculature, has a long history with the most widely investigated technique being the Vineberg procedure;current interest centers around the encouraging preliminary clinical results obtained with transmyocardial laser reva scularization. Despite significant previous research, the acute blood flow potential through the direct myocardial route remains unknown. No ntransmural laser channels were made in the distal LAD territory from the epicardial surface of 5 mongrel dogs to which an internal mammary artery was connected. A flow probe was placed on the distal most porti on of the artery and an intercostal branch was cannulated for infusion of colored microspheres. Measurements were taken under baseline condi tions and following LAD and epicardial collateral ligation. Under all conditions, blood flow pattern was of a to-and-fro nature. At baseline , there was an average 0.60 +/- 0.24 ml/min net flow into the myocardi um which was all contained within 0.5 cm of the central channel with a final myocardial perfusion of 0.011 +/- 0.016 mllminlg. Following ind uction of ischemia average flow increased to 1.41 +/- 0.51 ml/min whic h extended as far as 1 cm from the channel with a final myocardial per fusion of 0.22 +/- 0.19 ml/min/g. In conclusion, a limited amount of a cute myocardial perfusion can be achieved by the present technique of direct myocardial revascularization and the amount of flow is highly d ependent upon the amount of flow through the native circulation.