ABSTRACT
INTRODUCTION Until the past decade, the risk of thromboembolic events (TEs), (stroke; pulmonary and peripheral thromboembolism), in patients with heart failure (HF) was poorly defi ned. The analyses that existed were from retrospective analyses of large HF treatment trials and from population based studies. Many of these studies enrolled patients with atrial fi brillation (AF) and fl utter and did not specify thromboembolism as an endpoint. This is a particular problem since it has been shown that using precise scales to detect stroke signifi cantly increases the detection of subtle neurological events (1). It is believed that HF in the absence of AF is associated with an increased risk of TE. This belief is based on several observations. First, many patients who present with stroke or TE have depressed left ventricular function (2-4). In the population-based Framingham Heart Study (5), the relative risk of stroke in individuals with HF was 4.1 for men and 2.8 for women, but many of these individuals had concurrent AF. In HF trials, annual stroke rates between 1.3% and 3.5% have been reported; however, almost all of these analyses included patients with AF. An analysis reported thromboembolic rates of only 1% per year in a population of patients in NYHA class II and III HF without AF (Table 20.1) (6). The Warfarin Aspirin Reduced Cardiac Ejection Fraction (WARCEF) study is the largest prospective, randomized, placebo controlled study that found an overall event rate (death, ischemic stroke, and intracerebral hemorrhage of 7.47 events/100 patient-years (7).
