Pulmonary embolism is one such condition where the blood clot may start in any other part of the body. If left untreated, the clot may travel through the legs and reach the lungs. This situation is dangerous as the clot may affect blood flow in the lung arteries.
Pulmonary embolism (PE) is a blockage of blood vessels supplying the lungs (pulmonary artery) due to blood clot. These blood clots arise from deep veins of lower leg or thigh or arm (Deep vein thrombosis aka DVT). This leads to decreased blood flow to the lungs, decreased oxygen levels that can potentially be dangerous and life-threatening.