Hypercoagulable States

Frequently, patients who have deep venous thrombosis or pulmonary embolism are labeled has having a hypercoagulable state. Labeling  patients as hypercoagulable has implications in many aspects of their care. These include, but are not limited to, medications (life long warfarin treatment & careful selection of medications so as not to alter the bioavailability of warfarin) and diet (to limit ingestion of Vitamin K if on warfarin).

It is important to realize that clots develop for many reasons. The true Hypercoagulable States are only one category in this differential diagnosis. Therefore, before labeling a patient as hypercoagulable, these other causes must be ruled out.

• Patient has had a recent surgical procedure. Surgery allows exposure of blood to tissue factor.
• Immobilization causing stastis of blood.
• Obesity
• Malignancy, especially adenocarcinoma
• Previous history of  deep venous thrombosis (DVT) or pulmonary embolus (PE)
• Pregnancy (up to 2 months postpartum)
• Fracture
• Heart failure (causes stasis)
• Travel
• Oral contraceptive use

Therefore, all that clots is not hypercoagulable. When a person presents with a DVT, PE, or some other clot, the patient's history should be probed for the above risk factors. Then, one can pursue looking for a true hypercoagulable state. For someone to be labeled as having a hypercoagulable state, the following four criteria must be considered; usually any two will justify laboratory investigation:

• Thrombosis, first time at age < 40 y/o
• Recurrent thrombosis
• Family history of thrombosis
• Thrombosis in unusual sites (cerebral veins, hepatic veins, renal veins, IVC, mesenteric veins)

There are several disease processes related to the clotting cascade that result in a hypercoagulable state. To be considered for such a disease, the patient should meet at least 1 or 2 of the above 4 criteria. Identifying these individuals is very important because of the necessity of instituting prophylactic anticoagulation as well as making dietary changes and providing genetic counseling. These diseases and their dates of discovery are the following:

Please note: Congenital deficiency of a normal protein which in turn leads to thrombosis is a special hypercoagulable state termed thrombophilia. Therefore, the above disorders are more appropriately termed thrombophilic states. This is in contrast to hemophilia which results from the congenital deficiency of a procoagulant protein. The conditions listed above account for only about 50% of inherited thrombophilia, implying that we have more illnesses to discover. Also, some rare patients may be doubly or even triply heterozygous for the above disorders and therefore have additive risk for thrombosis.