Arterial and Venous Circulation in the Ischaemic Myocardium in Young Animals

Abstract

The descending ramus of the left coronary artery was ligated below the branching off of the septal artery in 15 (2 to 4-month-old) puppies, and 10 and 11 min later retrograde blood flow was measured in the peripheral stump and blood flow in the anterior interventricular vein. Veno-venous anastomoses After ligating the descending ramus 8.7–42% of the initial amount of blood flowed through the ischaemic area in the anterior interventricular vein. The origin of the blood is two-fold: arterial, via artero-arterial anastomoses, and venous, via veno-venous anastomoses. Retrograde blood flow in the peripheral stump of the descending ramus was 0–0.45 ml/min. After ligating the descending ramus in puppies 73–99% (average 91%) of the total blood flow from the infarcted area, measured in the anterior interventricular vein, can be attributed to veno-venous anastomoses. In two puppies arterial flow was zero.The injection of the vessels showed insignificantly formed arterio-arterial anastomoses in contrast to the network of veno-venous anastomoses. Both the blood flow values and the morphological findings are evidence that in puppies it is mostly venous blood which flows through the ischaemic area. The proportion is greater (91%) than in adult dogs (47%).