Blood clots in the leg, called deep venous thromboses (DVTs), can occur in a very broad spectrum of the population. Diabetics, the elderly and those who recently had surgery are not the only people who are at risk of developing a blood clot. Did you know if you travel by plane frequently, are on birth control or have cancer, you are at risk of getting a blood clot? These are just a few of the risk factors associated with this potentially deadly condition. Risk factors are inherited, acquired or highly associated. The following is a listing of those factors.

Inherited Blood Disorders: Genetic thrombophilias or an inherited tendency to develop blood clots are rare but can and do occur. Genetic clotting disorders are reported to exist in 20 to 30 percent of those with blood clots1. Most patients and their family members only discover the condition after genetic testing for blood clot disorders is performed on a person immediately after developing a blood clot. It is important for the entire family to know about the disorder, so they can get tested and prevent it from happening to them. For those who are found to have the disorder, simple changes in lifestyle discussed below can prevent them from developing a blood clot.

Acquired Risk Factors: Many, but not all, of these risks factors are avoidable and are due to unhealthy lifestyle choices. The following factors are associated with an increased risk of developing blood clots:

1) Obesity: Those who are overweight or obese are not only prone to having diabetes, heart disease and high blood pressure, but they are also at risk for blood clots. Blood clots are more frequent in overweight people especially after surgery, bed rest or immobilization as it is harder for the valves in the deep veins to push blood up against gravity due to the extra weight.

2) Immobilization: Those who are in an above or below knee cast or splint and/or are non-weight bearing after an injury or surgery especially those involving the lower extremities are also at risk as the weakened leg muscles are not helping to push the blood in the veins up to the heart.

3) Over 40 years of age

4) Sedentary lifestyle

5) Prolonged bed rest

6) Long hospital stay

7) Prolonged air plane rides

8 Heart & lung failure

9) Varicose veins

10)Birth control pills

11)Estrogen therapy

12)Cigarette smoking

13)Pregnancy

14)Diabetes

15)High cholesterol

Highly Associated Risk Factors:

1) Previous history of blood clots

2) Cancer

3) Positive family history of blood clots

If so many people are at risk of getting a blood clot, how do you prevent it from happening to you? The best form of prevention are simple lifestyle modifications such as maintaining a healthy weight, exercising, quitting smoking, and maintaining an active lifestyle. These modifications not only help reduce the risk of developing heart disease, high cholesterol, high blood pressure and diabetes but they can also reduce the risk of getting a blood clot. As a general rule, if you have 2 or more of these risk factors, it is important to take precautionary measures especially if you just had surgery or are off your feet for a prolonged period of time. Support stockings and compression devices are widely available not only in the hospital but in your local pharmacy and drug store to prevent blood clots. Your doctor will start you on a blood thinner if you are of high risk even if you do not have a blood clot. For those with an inherited blood disorder and those with a history of blood clots in the past, it is especially important to take preventive measures. If you are on a long plane ride, one can reduce the chance of getting a blood clot by not crossing your legs while sitting, getting up to go to the bathroom, walking around the aircraft periodically, and by wearing support stockings. Calf pain and swelling, increased warmth, girth, and redness in the calf and/or a firm mass in the calf, are all potential symptoms of a blood clot. Also shortness of breath, chest pain, coughing, coughing up blood, increased breathing and heart rate and fever are also signs of a blood clot that traveled to the lung called a pulmonary embolism (PE). Blood clots in the leg can dislodge and travel through the bloodstream to the lung to become a PE, stop oxygen from getting into the blood, cause shock and even sudden death. If you experience any of these symptoms, it is imperative that you seek medical treatment immediately. Go to your podiatric or orthopedic surgeon, primary care physician or other treating physician or, if after hours, go to the emergency room immediately for evaluation, diagnosis and treatment. If diagnosed, usually by venous ultrasound, treatment of blood clots consists of blood thinners to dissolve the clot.

1Murin, S., Marelich, G.P., Arroliga, A.C., Matthay, R.A. Hereditary thrombophilia and venous thromboembolism. Am J Respir Crit Care Med. 158:1369-1373, 1998.