Clot burst assessment of AV shunt grafts treated with different concentrations of rThrombin. Rabbits were treated with heparin + clopidogrel. The grafts were wrapped with AGS containing either 125 IU/mL rThrombin (top row) or 1000 IU/mL rThrombin (bottom row). After hemostasis was achieved, blood flow was clamped for 10 seconds, and clot burst was assessed. Images were obtained after the 10 second assessment period. Upper images show sponge saturation and bleed-thru in representative grafts whose hemostasis did not survive clot burst challenge (125 IU/mL rThrombin; 11 of 14 grafts ruptured [79%]). Lower images show representative grafts that maintained hemostasis following clot burst challenge (1000 IU/mL rThrombin; 0 of 14 grafts ruptured [0%]). In the placebo group, most grafts did not maintain hemostasis (8 of 10 grafts ruptured [80%]; data not shown).