LAUSR

Popliteal vein aneurysms cause no symptoms in their early stages and have no specific signs, which can lead to under-diagnosis or misdiagnosis. Most serious symptoms are due to blood clots, as explained below. Lumps behind the knee, pain, swelling, skin ulcers, or varicose veins can also occur. The most important complication of an untreated popliteal vein aneurysm is a blood clot, which may be a deep vein thrombosis (DVT) and/or a pulmonary embolism (PE). Slow venous blood flow, increased blood viscosity (stickiness or thickness), venous valves, thin vein walls, and vulnerability to mechanical damage make veins four times more likely to develop blood clots than arteries. Blood flows slowly through a dilated blood vessel and is especially slow within an aneurysm sac. Furthermore, the blood in an aneurysm tends to swirl like a whirlpool. These unique features lead to abnormal blood flow, with a popliteal vein aneurysm, blood clotting, and potential blockage of the vessel (Figure 2A). Age, smoking, and obesity are additional factors that can increase clotting risk. Unlike