Doc: Vena cava filter stops clots from reaching lungs
Dear Dr. Roach: In November 1997, while traveling, I had a pulmonary embolism. I was treated with urokinase to the lungs and a vena cava filter was placed. In November 2006, I had a CT scan of my abdomen. The report says there is an IVC filter in place. A posterior limb appears to have extended beyond the caval wall consistent with perforation. I am now seeing ads on TV that people with an IVC filter should be concerned and that the Food and Drug Administration considers them dangerous. I am 62 years old and never had any problem. Should I be concerned? Are there any studies being done on the long-term effects of these filters?
Dear H.L.: The inferior vena cava is the large vein that receives blood from the legs, pelvis and abdominal organs and returns it to the heart. A blood clot in the legs or pelvis must pass through the vena cava if it is going to the lungs, a potentially life-threatening complication called pulmonary embolism (an embolus is any foreign material, such as cholesterol, blood clot or air that moves from one part of the body to another). The IVC filter was designed to capture the clot, preventing it from going to the lung. Over time, the body dissolves the clot on its own.
The vena cava filter is an alternative to anticoagulation, such as warfarin (Coumadin) or a newer agent like rivaroxaban (Xarelto). The vena cava filter often is used in people who will need anticoagulation forever; this can be due to recurrent clots, an unmodifiable risk factor or sometimes a life-threatening clot (what it sounds like yours was). Compared with not getting treatment, both anticoagulation and IVC filters are effective, reducing the risk of pulmonary embolism to about 2 percent per year.
There are complications of IVC filters, including penetration of the IVC wall by the filter legs, which is what your CT scan shows. In most people, this doesn’t cause problems, although it can rarely cause bleeding or injury to the bowel wall. Other complications include the filter moving into the chest, fracture and infection, all of which happen less than 1 percent of the time. The filter itself can cause a blood clot, at a rate of 1 to 2 percent per year. Because any IVC filter does affect blood flow, there is a small increase in the rate of blood clots below the filter (in the legs or pelvis), but these are still protected from going into the heart.
The complication rate needs to be compared against the alternatives, including doing nothing and using anticoagulation. For most people with a long-term need for treatment to prevent blood clots, IVC filters are a reasonable choice.
Dear Dr. Roach: I take omeprazole 40 mg. My new gastroenterologist just changed the dose to 20 mg. Unfortunately, just before this, I had ordered a 90-day supply of the 40-mg capsules. I pulled apart one of the capsules and found that it contains granules, not powder. Can I just divide the granules? I would hate to throw away all the 40-mg pills.
Dear H.B.S.: Without a coating, omeprazole is destroyed in the stomach, so manufacturers use a coating to delay absorption until the medicine reaches the intestine. Prilosec OTC tablets cannot be broken. If the capsules you have contain granules, it’s likely that the granules themselves are coated, so you could divide the contents into two. However, you should speak to your pharmacist to be sure.
Email questions to ToYourGoodHealth@med.cornell.edu.