By Kevin McKenna and Derek Culnan
Everyone in the hospital keeps talking about Deep Venous Thrombosis (DVT), but I am here for pneumonia. Why is everybody worried about a disease that I don’t have? What’s the big deal with DVTs anyway?”
Deep Venous Thrombosis means you develop a clot in one of the deep veins, usually in the leg or pelvis. In the hospital you’re more likely to develop a clot for two reasons. First, you do not move around as much as you do at home. This makes your blood tend to stagnate in your veins, which can lead to clots. Second, your blood is thicker when you’re sick due to your body’s natural immune response. Your risk of developing a DVT in the hospital without any preventative treatment ranges up to 20 percent for a general medical patient and up to 80 percent for a major trauma patient.
The major reason we worry about DVTs is the clot can break off in the blood stream and go to the lungs and block blood flow throughout the body. We call this a pulmonary embolism, and it can be a potentially fatal condition. In fact, up to 600,000 people are affected by a DVT leading to pulmonary embolism every year, and up to 200,000 will die. This makes pulmonary embolism a leading cause of hospital mortality.
To determine who is at risk, every patient is assessed for their DVT risk. Risk factors include your age, mobility, medical history, surgical procedures and why you are in the hospital. If you are determined to be at risk for a DVT, you will be placed on preventive therapy, if appropriate for your condition.
Preventive therapies can be broken down into four categories: ambulation, compression, anticoagulation and IVC filters. Ambulation is one of the most important treatments, and patients play a pivotal role in its success. Simply walking around helps to prevent blood pooling in your veins and stimulates your body’s natural ability to thin the blood and prevent clots.
There are two types of compressive therapies that we use to reduce your risk of DVT’s. Thromboembolic-deterrent stockings are tight elastic stockings that compress the legs. Sequential compression devices are pneumatic devices which intermittently squeeze the legs. This squeezing simulates walking and helps to pump the blood out of the veins in the legs, preventing pooling of blood and clot formation. Intermittently squeezing of the legs also stimulates your body’s clot-fighting ability. These compressive therapies help reduce your risk of DVT.
A mainstay of DVT prevention is blood thinning with drugs such as Fragmin. These medications reduce the ability of your blood to make clots and significantly reduce your risk of a DVT that leads to pulmonary embolism. Unfortunately, there are times that we are unable to prescribe these blood thinners due to high risk of bleeding. For example, if you have a gastrointestinal bleed, spinal surgery or head trauma, the risk of blood thinners making bleeding worse may outweigh the benefit of reducing DVT risk.
In some cases where the risk of a DVT-induced embolism is high and the risk of bleeding from blood thinners is also high, we may place an inferior vena cava (IVC) filter. This is a screen placed through a vein in your groin into the main vein in your abdomen. The filter does not reduce your risk of DVTs; rather it serves to catch clots before they are able to make it to the lung, reducing the risk of a fatal pulmonary embolism.
Your doctors and nurses talk about DVT-induced embolisms because they pose a significant risk of death to our patients. There are ways to reduce the risk by using ambulation, compression, blood thinners and filters. These treatments cannot eliminate the risk, but they can cause significant reduction. As a patient, you play a role in the success of these treatments by walking as much as possible and wearing compression stockings or using compression devices when not walking. Working together is the best chance of preventing this disease.
Kevin McKenna is an assistant professor of surgery, division of colon and rectal surgery, Penn State Milton S. Hershey Medical Center. Derek M. Culnan is a post doctoral research fellow, department of surgery, Penn State Milton S. Hershey Medical Center.