Comparative morphological study of the epicardial ventricular lymphatics in the dog before and after ligature of the superficial veins.

Studies performed in dogs showed that the caliber of the lymphatic vessels increased in the first week after ligature of the superficial veins and decreased thereafter. We noticed that this progressive adjustment of the heart venous backflow is due to the Thebesian veins which were able to replace the ligated superficial veins only after some time. When these veins were not yet performing their function, the transudate was drained by the lymphatics, thus explaining their increase in caliber 1 week after ligature of the superficial veins.