DEAR DR. ROACH: I am a 47-year-old woman. Five years ago, I developed a blood clot in my left leg after fracturing my ankle and being immobilized for several months. I was put on a blood thinner, and my ankle healed. Recently that leg started swelling again, and I went for an ultrasound. I was told that I have a chronic DVT, but that I don’t need blood thinners. Why do I not need a blood thinner now when I did before? What does “chronic” mean? Why am I getting swelling again five years after the first clot? — L.S.B.
ANSWER: Blood clots can happen in veins or arteries, but the type that happen due to surgery and immobilization are almost always in the vein. That’s the “V” in “DVT,” which stands for “deep vein thrombosis.”
A brand-new blood clot has a high risk of propagating further up the vein, and also of breaking off and traveling through the vein into the heart. Most often, the clot will go on into the lungs, then called a “pulmonary embolus.” But in the rare case, the clot can go through a patent foramen ovale, which is sometimes called a hole in the heart, and cause a stroke.
Because of the risk of life-threatening complications, acute DVTs are treated with anticoagulants, such as warfarin (Coumadin) or apixaban (Eliquis). This stabilizes the clot, and after a week or two the risk of propagation or embolization becomes much lower. Most people are treated for at least three months for maximum benefit. Treatment does not dissolve the clot, and a follow-up ultrasound will detail changes that show the clot is no longer acute, hence “chronic.” The vein itself is scarred and damaged, and never returns to normal.
“Chronic DVT” isn’t the best term, since it confuses many, both patients and physicians alike. I prefer scarred, and some experts use “chronic luminal changes” to differentiate it from an acute clot. Whatever it is called, it may still be symptomatic.
Most people with a history of a large clot on one leg will notice that leg swells more than the other in heat or with a large salt load. Even so, anticoagulant treatment is neither necessary nor helpful.
Effective treatment for swelling associated with previous DVT includes salt restriction, compression stockings and leg elevation several times during the day. People with more severe symptoms that do not respond to conservative management may benefit from more aggressive therapies, such as placement of a metal stent to let the blood flow better through the damaged area.
DR. ROACH WRITES: I am often asked about screening tests for pancreatic cancer. Despite the promise of new tests, the U.S. Preventive Services Task Force recently re-reviewed the available evidence and continues to recommend against screening in the general population. However, it’s important to recognize that these recommendations do not apply to people at increased risk for pancreatic cancer, such as those with familial pancreatic cancer or with some genetic syndromes, such as Peutz-Jeghers syndrome. However, it does apply to people with other risk factors for pancreatic cancer, including smokers and those with new-onset diabetes or chronic pancreatitis.
With better screening tests, or with improved treatments for pancreatic cancer, the balance of benefits (it’s currently unlikely to find early pancreatic cancer when it can be treated) to harms (false positive results can lead to unnecessary surgery) may shift.
Dr. Roach regrets that he is unable to answer individual questions, but will incorporate them in the column whenever possible. Readers may email questions to ToYourGood- Health@med.cornell.edu.