Thrombosis

Thrombosis is the formation of a blood clot within a blood vessel causing a partial or total occlusion and preventing blood from flowing normally through the circulatory system. Propensity to hypercoagulability (caused by genetic, environmental, or unknown factors), endothelial cell injury of the vessel wall (exacerbated by infection or trauma), and static blood flow contribute to the formation of blood clots.

Partial or complete detachment of the thrombus from the blood vessel wall permits the clot to embolize to vital organs such as the brain, heart, lungs, or leg arteries. The free-flowing embolus lodges within the vasculature and obstructs blood flow. Life threatening pathological conditions ensue, such as stroke, heart attack, pulmonary embolism, or limb-threatening gangrene. Risk factors that contribute to DVT are varied and include:

• Immobilization
• Hypercoagulability
• Vessel wall damage
• Age
• Surgery
• Cancer
• Heredity (including the Factor V Leiden genetic mutation)
• Pregnancy
• Increased estrogen levels (oral contraception, HRT)
• Obesity
• Smoking
• Crohn?s Disease

Arterial thrombosis within the coronary arteries leads to myocardial infarction, while occlusion of the cerebral vasculature causes stroke. Of note is that venous and arterial thromboses share many of the same risk factors, including cigarette smoking, hypertension, and diabetes mellitus.

Deep vein thrombosis is the most common form of venous thrombosis. Post-Thrombotic Syndrome (PTS) develops in at least half of patients with a DVT. Chronic leg swelling, calf pain, calf heaviness/fatigue, skin discoloration, and/or venous ulcers in the affected limb characterize PTS. Quality of life is significantly impaired in patients with PTS.
Pulmonary embolism (PE) results from DVT. Symptoms and signs of PE include shortness of breath, chest pain, hemoptysis, fast or irregular heart rate, and/or lightheadedness. An acute, massive PE can lead to cardiac arrest.

North American Thrombosis Forum