Clinical implications of the new understanding of thrombophilia

Summary

 Thrombophilia used to be viewed as a disorder caused by a single congenital thrombophilic abnormality with thrombosis often triggered by an exogenous risk situation. It is becoming clear, however, that it is often a compound state with several congenital and acquired thrombophilic abnormalities. Activated protein C resistance is the most commonly found congenital abnormality. Protein C-, protein S-, and antithrombin III-deficiency continue to play an important role. Hyperhomocysteinemia as a risk factor for arterial and venous thrombosis is being recognized more frequently and is of particular interest, since elevated homocysteine levels can be decreased by simple means: treatment with folic acid and vitamin B₆. However, whether this decreases the risk of thrombosis is not known. Antiphospholipid antibodies are also being recognized more frequently. The special treatment considerations in these patients will be discussed.

Polymorphisms of proteins involved in coagulation, such as prothrombin and thrombomodulin, leading to an increased risk of thrombosis are increasingly being discovered. Several well performed clinical studies exist which allow recommendations for the length and intensity of anticoagulation for patients who have suffered a thromboembolic event. However, these studies have grouped together patients with different risk factor profiles and, therefore, only lead to generalized recommendations. By discovering more thrombophilic abnormalities and testing patients for these, a more individual risk stratification will be possible. This will eventually lead to more individual treatment recommendations.