Vein specialist Suresh Vedantham M.D., has spent most of his career studying the diagnosis and treatment of venous thromboembolism (VTE), deep-vein thrombosis (DVT) and pulmonary embolism (PE). Nearly 1 million Americans suffer from DVT, and 500,000 of them develop PE, which causes some 300,000 deaths. These conditions remain the most common preventable causes of hospital death in the United States. VEIN’s Claudia Schou recently caught up with Dr. Vedantham to discuss his venous thromboembolism studies and his recently approved National Institutes of Health research grant.
What types of measures are in place to assess the quality of care for persons at risk for venous thromboembolism, deep-vein thrombosis and pulmonary embolism?
In 2005, the Joint Commission on Accreditation of Healthcare Organizations initiated a project to develop quality assessment tools that could be applied in hospitals nationally to monitor quality of care for VTE. This measure set is expected to be implemented by next year. Many hospitals have proactively developed VTE quality initiatives in anticipation of these guidelines.
What are the risk factors for each condition?
The risk factors for DVT and PE are nearly identical since they are really two manifestations of the same disease. DVT is a blood clot in the deep-venous system, and PE refers to a blood clot that has migrated to the lungs. The most significant risk factors for VTE (DVT and PE) are a history of recent surgery or major trauma; cancer; immobility due to medical/surgical illness; pregnancy or postpartum state; use of hormonal drugs, including birth control pills; and inherited conditions that increase clotting tendency.
What types of prevention practices are available for VTE, DVT and PE?
Two-thirds of VTE cases occur in hospitalized patients, so it is particularly important for all hospitalized patients to be assessed for their level of DVT risk upon admission. Injectable blood-thinning drugs are the most commonly used and best-validated preventive measure. In addition, the use of calf compression devices is also likely to be beneficial, especially in those who cannot receive blood-thinning drugs. Placement of a filter device in the inferior vena cava is another option that some physicians use for patients who [have a] particularly high VTE risk and who cannot receive blood thinners, but this practice has not been rigorously validated in clinical trials.
What type of screening is available?
At present, routine “screening” tests are not done for VTE. However, some groups, including the American Venous Forum, are trying to validate such measures. The AVF Screening involves a basic questionnaire, a brief physical exam, and an abbreviated ultrasound exam. When patients are found to have a blood clot, physicians will often do a number of blood tests to evaluate for inherited blood disorders.
What type of medical trends do you feel are going to make a difference in the future?
Key trends include increased use of catheter-based clot-removal treatments to prevent long-term DVT complications; increased public awareness of the dangers of VTE, [which] should drive better prevention practices; and application of genetics and molecular biological techniques to VTE, [which] should result in better ways to determine who is at risk.
Why is it important to raise awareness of DVT in the patient population and among health-care providers?
VTE is preventable in the vast majority of cases. Patients need to proactively ask their physicians what measures are being used to prevent DVT when they or their family members are in the hospital. Patients need to know that the development of leg pain and/or swelling is a reason to seek medical care immediately. Health-care providers need to know that failure to use DVT prophylaxis is among the most morbid, preventable medical errors they can make. The amount of funding for venous disease research needs to be increased, and this can be helped by the involvement of Congress and other government agencies which listen to public sentiment. Many lives could be saved, but public awareness of the problem is an important first step.
What are the consequences of DVT?
There are two important consequences of DVT. The first is PE, which can be fatal. In fact, PE is estimated to account for between 100,000 and 300,000 deaths each year in the U.S. PE is the most common cause of unexpected in-hospital death and the most common cause of maternal death in pregnant women in the U.S. The second, and often under-recognized, complication of DVT is the post-thrombotic syndrome (PTS). Because blood thinners do not actually dissolve blood clots, they remain in the veins and cause permanent damage to the venous valves. This results in long-term pain, swelling, and skin changes in the leg which have been shown to markedly impair patients’ quality of life. PTS also results in venous ulcers (sores), which are difficult and expensive to treat.
How well are preventative measures being used?
Many studies have clearly shown that available measures to prevent VTE are highly effective and save lives. Unfortunately, however, the rates of utilization of these measures are far lower than they should be. Perhaps 50 percent to 60 percent of surgical patients receive DVT prophylaxis, whereas only 30 percent to 40 percent of patients with medical illnesses receive prophylaxis. Failure to routinely use prophylaxis accounts for many thousands of PE-related deaths each year in the U.S. and many DVT cases, which is why VTE is a major public health issue. In addition, once DVT is already present, the use of blood-thinning drugs and elastic compression stockings can prevent long-term complications—but patient compliance with these treatments is often poor. This is partly due to the economics of health-care reimbursement and partly due to a failure to educate patients on what they can do to help themselves.
How is DVT treated?
DVT is treated using blood-thinning drugs. They are very effective in preventing PE, but PTS still occurs in a significant proportion of patients despite their use. Patients who cannot receive blood-thinning drugs often have a filter device placed in their inferior vena cava to prevent PE. Patients should also wear elastic compression stockings for prevention of PTS. In patients with extensive iliofemoral DVT (DVT that extends to the groin or higher), consideration should be given to the up-front use of catheter-based clot-removal treatments as they may hasten symptomatic improvement, prevent PTS and thereby improve long-term quality of life. However, these methods have not yet been tested in a randomized clinical trial.
Treatment of superficial venous disease is very common. What is the risk of DVT in that setting? What are the prevention measures?
Published rates of DVT after endovenous ablation procedures average around 0.3 percent, perhaps, with many studies finding no cases of DVT. With meticulous procedural technique, DVT can usually be prevented in this setting. In patients at higher up-front risk for DVT, use of blood-thinning drugs in the peri-procedure period may be helpful.
Congratulations on your newly approved NIH research grant. What are your research plans?
Over the next few years, my first research priority will be to conduct the now NIH-funded ATTRACT Trial. This study is a multicenter randomized trial which will evaluate whether the use of innovative image-guided clot-removal methods (“pharmacomechanical catheter-directed thrombolysis”) prevents long-term complications in DVT patients. If the study is positive, it will fundamentally change the DVT treatment paradigm that has been used since 1960 and thereby have great impact upon clinical practice.
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