Venous Thromboembolism in Older Adults

Introduction

Venous thromboembolism (VTE) is the third most common cardiovascular disease and an important cause of morbidity and mortality. Older people account for nearly two thirds of episodes. Between 65 and 69 years of age, annual incidence rates per 1000 for deep vein thrombosis (DVT) and pulmonary embolism (PE) are 1.3 and 1.8, respectively, and rise to 2.8 and 3.1 in individuals aged between 85 and 89 years. Older men are more likely than women of similar age to develop PE. About 2% develop PE and 8% develop recurrent PE within 1 year of treatment for DVT.

VTE causes 25,000 to 32,000 deaths in hospitalized patients in the United Kingdom. It accounts for 10% of all hospital deaths. This, however, is likely to be an underestimate because many hospital deaths are not followed by a postmortem examination. The cost of managing VTE in the United Kingdom is estimated to be approximately 640 million pounds. About 25% of patients treated for a DVT subsequently develop debilitating venous leg ulceration, the treatment of which is estimated to cost 400 million pounds in the United Kingdom. The most serious complication of VTE is PE, which untreated has a mortality of 30%. With appropriate treatment, mortality is reduced to 2%. The diagnosis of VTE is often delayed until the occurrence of a clinically obvious (and occasionally fatal) PE. The diagnosis of PE is more often missed in older people and is sometimes made only at postmortem.

The Virchow triad (named after Rudolf Virchow, 1821–1902) describes the three main predisposing factors for development of thrombosis. The first is alteration in blood flow, which may be reduced in people with heart failure (a common problem in older people) and in less mobile individuals. The second factor, injury to the vascular endothelium, is more relevant to arterial thromboembolism than to VTE. The third factor, hypercoagulability, is important because increases in clotting factor concentration, platelet and clotting factor activation, and a decline in fibrinolytic activity have all been reported in older people.