Deep Vein Thrombosis Risk Factors
Mar 25, 2025
Thrombosis is the pathologic clotting of blood inside blood vessels, and is separate and distinct from hemostasis, which is a normal and restorative physiological response . A blood clot in a vessel prevents adequate blood flow, increasing the risk of heart attack or stroke. Some clots form just below the skin. Deep vein thrombosis (DVT) occurs deep in the veins, typically in the legs.
DVT complications include pulmonary embolism (PE). When a clot or part of it moves to the lungs, it causes a blockage that affects breathing and blood circulation. PE symptoms include chest pain, shortness of breath, and fainting. DVT can also cause postphlebitic syndrome, where reduced blood flow to, say, the toesresidual damage to veins, causes swelling, skin sores, or skin color changes.
Many factors increase the risk of developing DVT. The more risk factors one has the greater the risk of DVT. Although it can occur at any age, the risk increases past age 60.
Lack of movement also heightens the risk of DVT. Muscle contractions enhance blood flow, meaning prolonged calf muscle dormancy can result in DVT in the legs. Sitting down for a long time such as when flying or driving may increases the risk of DVT (especially in people with additional risk factors), as does a lengthy bed rest or paralysis.
Another common DVT risk factor is injury to the veins due to a bone fracture. Surgery can also result in DVT.
Pregnancy also heightens the risk of developing DVT due to increased pressure in the pelvic and femur veins. The risk persists six weeks after delivery. Women with a family history of clotting disorders are at a higher risk. The pressure in the veins in the pelvic area or legs due to obesity also increases the risk of DVT.
Speaking of family history, some people have DNA that predisposes them to abnormal blood clots. The presence of Factor V Leiden, an inherited genetic mutation, changes the clotting process and increases the risk of DVT.
Some cancers and cancer medications increase blood clotting tendencies by triggering the release of blood clotting agents. Oral contraceptives and hormonal replacement therapy can increase the blood’s ability tendency to clot.
Heart failure causes blood flow to slow down, which increases the risk of blood pooling or resting in one place. The longer blood stays in one location, the higher the chances of it clotting. This happens when the heart and lungs aren’t working well due to heart failure.
Given the knowledge of how thrombosis happens, it’s possible to reduce the risk of DVT. Preventive measures include regular exercise and avoiding sitting for long periods. Exercising also reduces the risk stemming from obesity or being overweight. Avoiding smoking, which alters how blood clots, also helps reduce the risk of DVT.
DVT treatment options include medications to interfere with clotting or dissolve blood clots. Blood thinners, also called anticoagulants, however, increase the risk of excessive bleeding due to impaired clotting capabilities. A wire mesh tube may also be inserted in the vein to prevent it from closing. Another option is to insert a catheter (a thin tube) to widen the affected vein.
Many DVT risk factors are interlinked, meaning one factor on its own cannot may not cause DVT. Still, DVT can occur unprovoked, without any identifiable risk, as is the case with venous thromboembolism (VTE). Being active, eating a healthy diet, not smoking, and managing other health conditions like diabetes heart failure and COPD helps lower the risk of DVT.f DVT.