Platelets and blood coagulation in arterial and venous blood

¹ Department of Physiological Sciences, Ontario Veterinary College, Guelph; Blood and Vascular Research Unit, Department of Medicine, University of Toronto; and Sunnybrook Hospital, Department of Veterans Affairs, Toronto, Ontario, Canada

Various tests of blood coagulation have been made on samples of blood collected simultaneously from the carotid arteries and contralateral veins in a series of pigs. Thirty-eight pigs were receiving Dicumarol in various doses and fifty-eight were receiving no treatment. Most of the tests showed no significant differences. The adhesive index, however, was higher in the arterial samples than in the venous in the pigs receiving Dicumarol. In the same group of animals, the platelet count was significantly higher in the arterial blood by about 8%. There is no ready explanation for this latter finding but the possible mechanisms are discussed at some length. Similar but not significant differences were found for these two measurements in blood samples from the untreated pigs. These findings raise some interesting questions and suggest that for purposes of comparison, samples should be obtained consistently from either the artery or the vein.

Key Words: Dicumarol • platelet adhesive index • platelet count • prothrombin time • thromboplastive generation • clotting time • A-V differences in blood clotting

Submitted on May 8, 1963