Despite the availability of an array of medical therapies for the treatment of heart failure, quality of life is often poor for the majority of patients, and the mortality remains high. In addition, treatment is regularly not well tolerated and this results in frequent hospital admissions for some patients. This article reviews the management and medical treatment of acute heart failure, focusing on the emerging role of levosimendan.
Levosimendan is currently licensed in 10 European countries (Simdax, Orion Pharma, Finland) for the treatment of acute heart failure. It is a new inotropic drug with a dual mechanism of action: sensitisation of the cardiac myofilament to calcium, thus enhancing cardiac contractility, and vasodilation of vascular smooth muscle. The published clinical studies so far have utilised intravenous levosimendan. However, the agent is also well absorbed orally, and phase two trials of its use in stable patients with less severe heart failure are underway.
With an estimated prevalence of 12%, chronic heart failure is a major public health problem. It accounts for approximately 12% of healthcare expenditure in developed countries; in the US chronic heart failure has an incidence of 2.2/1,000, which makes it more frequent than breast, cervix and colon cancer combined. Furthermore, it has been estimated that heart failure accounts for 5% of acute hospital admissions, and re-admission rates in this population are also high. The prevalence is increasing since most new cases occur in the elderly population.
Heart failure is a progressive clinical syndrome with multiple aetiologies, and may occur as a result of many different structural or functional cardiac abnormalities. In the developed world the most common cause is coronary artery disease, either alone or in combination with hypertension. Table 1 lists the common underlying conditions involved in the aetiology of heart failure. Other predisposing factors, such as diabetes mellitus, hypercholesterolaemia, obesity and smoking, may increase the risk of developing this syndrome.
Symptoms of heart failure include fatigue, limited exercise tolerance, anorexia and dyspnoea. Clinical signs include pulsus alternans, an elevated jugular venous pressure, a third heart sound, pulmonary crepitations, peripheral oedema and ascites. The classification of chronic heart failure can be staged according to guidelines published by the American College of Cardiology and the American Heart Association. This can be used in conjunction with the more traditional functional classification provided by the New York Heart Association ( Table 2 ).
Those patients with chronic heart failure who experience symptoms on mild exertion or at rest are at greatest risk for recurrent or prolonged hospital admissions for acute decompensation. This often results from myocardial ischaemia, arrhythmias, non-compliance with treatment and/or intercurrent infection. Acute heart failure may also arise suddenly following a cardiac insult in a patient without previous evidence of overt cardiovascular disease, e.g. following acute myocardial infarction (MI). Whatever the aetiology, the morbidity and mortality remain high despite maximal medical therapy.