Activated protein C resistance: the most common risk factor for venous thromboembolism.
BACKGROUND
Venous thromboembolism is a major cause of morbidity and mortality. Although activated protein C resistance (APC-R) is the most commonly recognized inherited risk factor for venous thromboembolism, little is known about its long-term implications on health.


METHODS
MEDLINE was searched from January 1989 through August 1999 using the key words "thromboembolism," "thrombosis," "activated protein C resistance," and "factor V Leiden."


RESULTS
One in 1000 people in the United States is affected by venous thromboembolism annually. APC-R is now understood to be responsible for up to 64% of these cases. APC-R, which occurs widely in some ethnic groups and is nearly absent in others, is due to a single point mutation in the gene for clotting factor V. As a result, inactivation of factor V by activated protein C is impaired, leading to a hypercoagulable state. This condition creates a lifelong increased risk of thrombosis and, possibly, anticoagulant therapy..


CONCLUSIONS
Family physicians have a new tool for assessing risks for venous thromboembolism. Recognizing that up to 64% of patients with venous thromboembolism can have APC-R and treating this disorder with prophylactic and therapeutic anticoagulation might reduce patient morbidity and mortality from venous thromboembolism. Screening high-risk patients might now be indicated.
Sheppard
D R
DR
General Leonard Wood Army Community Hospital, Ft Leonard Wood, MO 65473, USA.
D020016:Activated Protein C Resistance / Q000150:complications / Q000175:diagnosis* / Q000188:drug therapy / Q000235:genetics; D000925:Anticoagulants / Q000627:therapeutic use*; D003937:Diagnosis, Differential; D005838:Genotype; D006801:Humans; D012307:Risk Factors; D013923:Thromboembolism / Q000209:etiology / Q000503:physiopathology / Q000517:prevention & control*; D020246:Venous Thrombosis / Q000209:etiology / Q000503:physiopathology / Q000517:prevention & control
D000925:Anticoagulants