HYPERCOAGULABILITY AND THE HYPERCOAGULABILITY SYNDROMES

Hypercoagulability is a state in which an alteration of the blood shif ts the hemostatic balance toward excessive platelet/ fibrin deposition leading to arterial and/or venous thrombosis [I]. Although the concep t of hypercoagulability has been recognized clinically for more than a century, in recent years a number of specific disorders have been def ined, diagnostic tests developed, and treatment regimens improved. The currently recognized disorders are generally classified as primary or secondary states, although some of the primary conditions may develop as a result of other disorders (Table 1). The primary disorders gener ally result from abnormalities of proteins in the coagulation or fibri nolytic systems. Although the number of secondary conditions is much g reater, generally these syndromes are not as precisely defined on a mo lecular basis, Secondary hypercoagulability syndromes are subclassifie d into abnormalities of platelets, coagulation and fibrinolysis, and b lood vessels and rheology (Table 1), While the prevalence and clinical significance of hypercoagulability are becoming increasingly apparent to physicians in general, this pathologic state is an especially prac tical concern to vascular internationalists, as hypercoagulability is an important cause of early thrombosis after otherwise uncomplicated a rterial interventional procedures. The purpose of this review is to de scribe the clinical presentation, diagnosis, and treatment of the hype rcoagulability syndromes most likely to be encountered by the interven tional radiologist.