Context

The annual incidence of Pulmonary Embolism (PE) is about 60-70/100,000. Patients undergoing hip or knee replacement surgery, surgery for lower limb fractures and cancer surgery are at particular risk. However, the largest numbers of thromboembolic events occur in patients hospitalised for acute medical illness¹. It is estimated that 25,000 patients die every year in the UK from preventable hospital acquired venous thromboembolism (VTE)². Amongst those not in hospital or long term care, patients who suffer from thromboembolism are more or less equally divided between those who have identifiable risk factors and those who suffer from “idiopathic” PE. The in-hospital mortality for pulmonary embolus ranges from 6% to 15%^3,4.

PE is an important and difficult diagnosis to make confidently since it cannot be either confirmed or excluded on clinical grounds alone. The diagnosis is frequently overlooked in hospitalised, older patients with multiple co-morbidities and the majority of fatal pulmonary emboli are not clinically suspected prior to death. Conversely, Wells’ reported⁵ that only 9.5% of those patients presenting with symptoms suggestive of the diagnosis, were finally determined to have suffered a pulmonary embolus. The importance of getting the diagnosis right is that treatment leads to about a 20% reduction in mortality. Accurate diagnosis is also essential to prevent the unnecessary provision of anticoagulation therapy which is associated with a range of serious side effects.

The UK National Institute of Clinical Excellence (NICE), the European Society of Cardiology, the American College of Emergency Physicians, the American Heart Association and the American College of Chest Physicians have all published guidelines on the management of patients with suspected PE. The UK NICE guidelines on the subject, last updated in 2020 can be found here.