Years before, the patient had fallen in the bathtub, broken his ribs and punctured a lung. Blood filled his chest and collapsed the lung. He had to be rushed to the hospital. Patients who are stuck in bed while in the hospital are at risk of developing blood clots in the veins of their legs because they are immobilized. Clots form when blood isn’t moving. These patients are usually started on blood thinners to reduce that risk. Because this man had bled into his chest, blood thinners weren’t a good option for him. Clots that form because of immobility block veins and cause swelling and pain, but they can also be deadly if they travel through the body and end up in the lungs or brain. So his doctors had chosen to put a filter in the main vein that brought blood from his legs back to his heart — a vessel called the inferior vena cava — to catch any clots that formed and broke free.
These filters are supposed to be removed a few months later when the risk of clotting goes down, but many are not removed on schedule. This one had been left in place for more than 15 years. What if, Slief suggested after explaining this history, the filter had done its job and captured clots and they were now blocking the entire vessel? Could that cause his positional hypotension? Centor listened thoughtfully. He’d been a doctor for 45 years and had never seen this. And yet it was an interesting idea. Certainly worth considering.
One of the many advantages of the V.A. Hospital system is that it has computerized medical records going back decades. Slief did a deep dive into this man’s medical history and hit what looked like some promising results. Seven years earlier, the man had a CT scan that showed an almost total blockage of his vena cava. Was it possible that the extra blood that was supposed to go from the legs to the brain when the man stood up didn’t get there fast enough because of the narrowed vena cava?
The Daddy-Longlegs Device
There was really no way to test this hypothesis, but it made sense. They explained to the patient that the next step was to get the filter out. The patient was eager to try. The team reached out to Dr. Bill Parkhurst at the University of Alabama at Birmingham Hospital, who specialized in this kind of procedure.
The patient was sedated for the operation. Parkhurst put a tiny tube through an incision into the patient’s jugular vein in his neck and slowly advanced it down past the heart into the vena cava where the filter was located. These contraptions look like daddy longlegs with tiny hooks at each foot to hold them in place in the vein. Where the body of the insect would be located was a small hook. Parkhurst used a tiny gripping tool to grasp the hook and pull the filter up through the vena cava and out through the small incision in the patient’s neck. Next Parkhurst inserted tiny balloons that he inflated to reopen the threadlike stream through the narrowed vena cava. He then positioned a stent to hold the vessel open. He continued this process down the primary vein of each leg. The procedure took six hours and required nine stents, but finally there was good blood flow between the legs and the heart.
The first time the patient stood up after this procedure, he was amazed. The dizziness was gone. It has been four months and it hasn’t come back. No weak legs, no lightheadedness, no falls. His feet are still numb, but he can live with that so long as they remain on the ground and he remains upright.
Slief is modest about making this obscure diagnosis. There are only a handful of case reports in the medical literature. Still, Slief told me, it does make you wonder if maybe this is happening more often than reported. He’s certainly going to be looking for it.
Lisa Sanders, M.D., is a contributing writer for the magazine. Her latest book is “Diagnosis: Solving the Most Baffling Medical Mysteries.” If you have a solved case to share, write her at Lisa.Sandersmdnyt@gmail.com.
