Pulmonary embolism-an update on thrombolytic therapy.

Abstract

Pulmonary embolism is a commonly encountered disorder, usually precipitated by deep venous thrombosis, and is associated with significant morbidity and mortality. It accounts for 10% of all deaths in hospital, and is a major contributing factor in a further 10%.1 It can result in pulmonary hypertension and right ventricular dysfunction, and its mortality rate of approximately 14%,2 has changed little over the last 30 years.1We review the treatment of pulmonary embolism, with particular reference to thrombolytic therapy. The role of surgical or catheter‐based embolectomy will not be discussed. The initial diagnosis of pulmonary embolus is not always straightforward. In one report, pulmonary embolus was not clinically suspected in 70% of patients in whom it was subsequently considered to be the major cause of death.3 Conversely, another autopsy series found that 63% of patients thought to have had a pulmonary embolus had no such evidence.4 The ‘classical’ presentation is pleuritic chest pain of acute onset associated with shortness of breath and perhaps haemoptysis (peripheral pulmonary infarction). A preceding history of deep venous thrombosis may be present. The patient is usually tachycardic and tachypnoeic and may be hypoxic and hypotensive. However, patients may present with isolated dyspnoea, circulatory collapse (in particular cases with central pulmonary arterial obstruction) or pleuritic chest pain alone. Over 70% of fatal and non‐fatal pulmonary emboli have proximal deep‐vein thrombosis.5 One or more predisposing factors are present in 80–90% of patients with pulmonary embolus.6 The most common are immobilization for more than 1 week, a history of previous thromboembolism, recent trauma, and surgery (particularly of the lower limbs). Other risk factors include long‐distance air travel, inherited clotting disorders (e.g. factor V Leiden, antithrombin III deficiency, antiphospholipid antibodies)7 or the contraceptive pill in women who smoke or are diabetic. In …