Deep vein thrombosis, or DVT, is a blood clot that develops within a deep vein, usually in the leg. If the clot travels to the lungs and becomes lodged there, it becomes pulmonary embolism (PE), and is exceedingly dangerous if left alone.
"Left untreated, more than 50 per cent of the patients with DVT will get PE," said Dr Yap Eng Soo, a consultant at the haematology division of the Department of Haematology-oncology at the National University Cancer Institute, Singapore. Dr Yap is also an assistant professor at NUS Medicine’s Department of Medicine. One-quarter of the patients who show symptoms of PE could die within 14 days, if they are not treated. DVT and PE are known together as venous thromboembolism (VTE).
One of the most common risk factors for VTE include being immobile for long periods of time, due to the slowing of the blood flow in the veins. Although DVT has been associated with long-haul flights, Dr Yap said this is actually rare. "Worldwide, only 30 out of one million passengers who take long-haul flights of more than four to six hours will get VTE.”
Patients should see a doctor for symptoms of unexplained lower-limb swelling, redness and pain or unexplained breathlessness, a fast heart rate and chest discomfort and pain, as VTE can be prevented and treated with medication or lifestyle modifications. Medication such as blood thinners can be used if you are hospitalised. Alternative methods such as mechanical calf pumps can also be used in place of medication, said Dr Yap. Lifestyle changes such as losing weight, quitting smoking and getting regular exercise will also lower the risks of blood clots, he added.