The Lysis of Artificial Thrombi

Abstract

SummaryThe susceptibility to lysis of artificial thrombi formed from native rabbit blood in the presence or absence of dextran was determined using the Chandler loop technique. Thrombi of identical weight were formed in the presence of saline or dextran and when spontaneous thrombolysis was allowed to take place, thrombi formed in the presence of dextran 70 were lysed to a greater extent than those formed under control conditions.The possible factors influencing this observation were studied. Increasing concentrations of streptokinase increased the extent of thrombolysis in both control and dextran treated thrombi. Maximal streptokinase induced thrombolysis occurred in the presence of a 2 per cent final concentration of dextran Mw 40,000 and 500,000 and dextran 70 at a final concentration of 1.2 per cent.Increased thrombolysis was not observed when albumin was substituted for dextran.Finally, similar observations were recorded for streptokinase induced thrombolysis using human blood.

Fibrinolytic properties of lysine‐derivatized polyethylene in contact with flowing whole blood (Chandler loop model)

“…Thrombus formation in recalcified, citrated blood in a rotating circular loop of polymer tubing was first described by Chandler14 and later by Connor 15. The Chandler Loop has since been used by a number of investigators to assess the blood compatibility of various materials,6–8, 19 to study the effects of pro‐ and anticoagulant drugs on thrombus formation,20 and to investigate the fibrinolytic potential of various agents 21. In the present work, this device was used to evaluate the fibrinolytic activity of lysine‐containing biomaterials in contact with nonanticoagulated flowing whole blood.…”

“…For this purpose we used a version of the Chandler Loop device 14. This device has been used by a number of investigators for various purposes8, 15–21 and is, in general, well suited to the evaluation of materials in contact with blood under defined flow conditions 22, 23…”

The antithrombotic effect of dextran-40 in man is due to enhanced fibrinolysis in vivo

“…Reduced levels of vWF were thought to be responsible for reduced stability of thrombi formed in a Chandler loop with blood from healthy human volunteers given 500 mL dextran-70. 14 These observations and others investigating thrombus formation in vivo in rabbits 15,16 also suggested that dextran may be affecting the fibrinolytic system, and a small number of studies from the 1980s and 1990s supported this hypothesis. For example, Carlin et al 17 observed an increase in fibrinolytic activity in patients given 500 mL of 6% dextran-70 during the postoperative period, and similar effects have been reported in rabbits.…”