Myocardial Vascular Morphology and Capillary blood flow after Mammary Artery Implantation in dogs

Abstract

The angiographic and histological findings at myocardial vascularization were studied in dogs, where an internal mammary artery implantation had been performed either acutely or three or six weeks earlier. The findings were related to the myocardial blood supply from the implants, studied with Kr⁸⁵ clearance technique during temporary occlusions of the cognate coronary artery. The study failed to demonstrate filling of the intramural section of the implants at in vivo angiography immediately after implantation, which was shown under artificial conditions. Neither the histological findings nor the measurements of myocardial capillary blood flow did support the view of significant function immediately after the implantation. Three weeks later, however, anastomoses between the implants and the coronary arteries were seen, associated with a significant increase of nutritive blood flow in the myocardium. The blood flow from the six weeks implants was almost double that from the three weeks and in both series there was a good relationship between the number of such vascular connections and their contribution to the capillary flow. Histologically the communicating branches could be shown to emanate from both cut side branches and made side holes. The anastomoses develope from proliferating vessels from both the implanted artery and the traumaticed myocardial vessels meeting in the surrounding scar tissue.