The effectiveness and mechanism of collagen-induced topical hemostasis.

Microcrystalline collagen is a recently developed material possessing remarkable topical hemostatic properties. The potential utility of this substance for cardiovascular surgery was evaluated in a canine arterial bleeding model. A hemostatic protocol allowed comparison of initial and final hemostasis rates as well as the time required to accomplish hemostasis. The results of these studies revealed that microcrystalline collagen, or MCC, achieved hemostasis more frequently and rapidly than either pressure alone or oxidized cellulose cloth. MCC also was highly effective initially after large doses of heparin and in the presence of platelets with function rendered deficient by acetyl salicylate. Only in the presence of profound thrombocytopenia was any loss of initial effectiveness observed. Some delayed hemorrhage occurred in the heparin-treated groups leading to a lessened incidence of final hemostasis, a result intimately related to MCC's probable mechanism of action. However, even under the extreme conditions imposed by this severe experimental model, MCC remained effective in greater than 70 percent of the trials. On this basis MCC seems to possess great potential as a useful adjunct during cardiovascular surgical procedures.