Duplicated Inferior Vena Cava Complicated with Left Iliofemoral Deep Vein Thrombosis: A Case Report
This case report details the successful management of left iliofemoral deep vein thrombosis in a patient with a rare duplicated inferior vena cava, highlighting the diagnostic pitfalls that led to initial filter malposition and outlining effective interventional strategies for safe filter placement and thrombus removal.
Original paper licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). This is an AI-generated explanation of the paper below. It is not written or endorsed by the authors. For technical accuracy, refer to the original paper. Read full disclaimer
The human body's plumbing system relies on a network of veins to return blood from the legs back to the heart. One of the largest and most critical pipes in this system is the inferior vena cava, a single large vessel that runs up the center of the abdomen. Sometimes, however, people are born with a variation where this vessel splits into two separate channels instead of one, a condition known as a duplicated inferior vena cava. While this anatomical difference often causes no symptoms and goes unnoticed for a lifetime, it becomes a significant challenge when a patient develops a dangerous blood clot in the leg veins. In such cases, doctors often place a small, umbrella-like device called a filter into the main vein to catch any clots that might break loose and travel to the lungs. If the doctor does not realize the vein is duplicated, they might place the filter in the wrong channel, leaving the patient unprotected.
A recent case report from researchers in China details a situation where this exact problem occurred and how the medical team corrected it. The story begins with a 51-year-old man who had undergone hip surgery and leg fracture repair in the past. Six months after his leg surgery, he developed sudden, severe swelling in his left leg. Medical imaging confirmed that a large blood clot had formed, blocking the major veins in his left thigh and pelvis. Because the clot was extensive and the risk of it breaking off and causing a pulmonary embolism was high, the medical team planned to remove the clot and place a protective filter in the main vein.
The procedure started with the patient lying on his back. Using X-ray guidance, the team inserted a catheter through a vein in the right leg to reach the main abdominal vein. They identified the level where the kidneys drain into the main vein and, believing they were looking at a standard single vessel, they deployed a retrievable filter. However, when the team switched the patient to lie on their stomach to treat the clot from the back of the knee, they discovered a critical error. The wire guiding the treatment had traveled up a separate, parallel vein that the filter was not protecting. Further imaging revealed that the patient indeed had two inferior vena cava vessels that merged together higher up in the abdomen, above the level where the doctors had placed the filter. The filter was sitting in the right-hand channel, completely missing the left-hand channel where the dangerous clot was located.
Recognizing the mistake, the team retrieved the misplaced filter and prepared to try again. This time, they placed a new filter higher up in the abdomen, in the single common vessel where the two channels had already joined. This position, known as the suprarenal location, ensured that any clot traveling from either of the lower channels would be caught. With the filter safely in place, the team proceeded to clear the blockage. They used a specialized machine to mechanically break up and suction out the bulk of the clot, followed by a catheter that slowly released medication to dissolve the remaining residue. Over the next three days, the medication worked to clear the veins completely.
Three weeks later, once the immediate danger had passed and the veins were clear, the team removed the temporary filter. Follow-up scans confirmed that the patient's veins were open and free of clots. The researchers used this case to highlight a common pitfall in medical practice: the assumption that the main vein is always a single tube. They noted that while advanced imaging before surgery could have prevented the initial error, it is not always standard procedure due to cost and safety concerns with contrast dye. Instead, they emphasized that during the procedure, doctors must carefully check the anatomy, specifically by looking at where the kidney veins connect, to ensure the filter is placed correctly. The case demonstrates that even when an anatomical surprise occurs, careful observation and a willingness to adjust the plan can lead to a successful outcome, protecting the patient from life-threatening complications.
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