Heparin Catabolism Under Extracorporeal Circulation in Cardiac Surgery: Experimental Study

Extracorporeal circulation E. C. C. was performed on 13 Beagle dogs to deter mine heparin catabolism. Three types of heparin were used: a cold heparin and two radio-active(R. A.) heparins (S-35 and H-3) The E.C.C. was performed for 70 minutes (mn.) in all dogs, at a temperature of 37°C. in 4 dogs, 28°C in 4 and 20°C. in 5, (duration of hypothermia: 30 mn.).1) Plasmatic heparin elimination was related to the E. C. C. temperature: 42.6% at 37°C., 30 7% at 28 ° C. and 14.6% at 20°C. The biological half-lives were respectively 60 + 10 mn, 80 + 10 mn, and 200 + 20 mn.2) Urinary heparin elimination was delayed with respect to the E. C. C. temperature and independant of the type of heparin used. At the same time, the relation of heparin in plasmatic R.A, to urinary R.A. was constant(≈ 10) during the entire E. C. C.3) The study of the gastric fluid in 8 dogs showed an heparin elimination increased to a maximum at the end of the E.C.C.; at that time, the plasmatic R. A. to gastric R.A.heparin relation, in 5 dogs, was equal to 1.The study indicates that a)there is a correlation between the dosage made, try classical and radta-active melhods, b) the lowering of E. C. C. temperature diminfshes the catabolism of heparin, and c) a gastric heparin elimination during E. C. C.