Comparative behaviour of antithrombin III antigen and antithrombin III activity in cardiovascular patients.

Antithrombin III-functional (AT III F) and immunoprotein (AT III I) assessed by two comparative methods in various cardiovascular conditions, showed significant differences between the two parameters, namely: a simultaneous decrease of both AT III F and AT III I during acute embolic episodes of only AT III F in transient ischemic attacks (with normal level of AT III I) and increase of AT III I (with apparently normal AT III F) in patient with mitral valve prosthesis. It is considered that in condition of "hypercoagulability" various patterns of AT III F/AT III I ratio can be obtained: decompensated, compensated and hypercompensated consumption.