Towards a blood test for heart failure: the potential use of circulating natriuretic peptides

Autor: Iain B. Squire, Leong L. Ng, S Talwar, P. F. Downie
Rok vydání: 2000
Předmět:
Zdroj: British Journal of Clinical Pharmacology. 50:15-20
ISSN: 0306-5251
DOI: 10.1046/j.1365-2125.2000.00232.x
Popis: Heart failure is one of the most common conditions of industrialized society and at its most florid encompasses a constellation of symptoms and signs associated with demonstrable left ventricular systolic dysfunction (LVSD) [1]. Many patients with clinical symptoms and signs of heart failure have no apparent abnormality of ventricular contractile function but may have diastolic heart failure; in addition many patients with left ventricular systolic or diastolic dysfunction do not have any symptoms of heart failure. For the purposes of this review, LVSD refers to demonstrable left ventricular systolic dysfunction, and heart failure to symptomatic left ventricular dysfunction. Since heart failure is often asymptomatic and for other reasons the diagnosis of heart failure is often difficult. As a result many patients with the condition, in particular when asymptomatic, are denied appropriate pharmacological intervention. The ability to diagnose heart failure from a blood test would not have been predicted even a few years ago. However our increased understanding of heart failure as a complex clinical syndrome associated with marked neurohormonal activation has led to the search for a simple, diagnostic blood-test for the condition. That search may now be coming to fruition with the natriuretic peptides showing the most promise. The primary aetiological factors in industrialized countries are ischaemic heart disease, hypertension and diabetes, either singly or in combination [2]. Approximately 85% of cases of heart failure in the general population are associated with either coronary disease or hypertension [3]. The clinical syndrome has an estimated prevalence of approximately 1% of the population as a whole and perhaps as high as 10% of those greater than 75 years old [4]. Many patients with significant myocardial damage pass through a period of asymptomatic left ventricular dysfunction before developing overt symptoms, i.e. clinical heart failure. Indeed at any one time there are at least as many individuals with asymptomatic (and largely undiagnosed) LVSD as there are patients with clinical heart failure; the prevalence of asymptomatic LVSD in a recent population based echocardiographic study was around 3% [5]. Clearly, the apparent incidence and prevalence of LVSD and asymptomatic heart failure depend upon definitions of the terms ‘LVSD’ and ‘symptoms’. However in the study of McDonagh et al. [5], LVSD was defined as an echocardiographic ejection fraction of ≤ 30%, a strict definition which excluded many patients who in day to day clinical practice would be considered to have LVSD (i.e. ejection fraction 30–40%). A combination of factors explains the increasing incidence and prevalence of heart failure: improvements in survival following acute myocardial infarction, in the treatment of hypertension, and in secondary prevention following such events coupled with an increasing number of elderly individuals within the population. Increasing awareness of the problem may also be a contributory factor. It should be emphasized at this point that a diagnosis of heart failure carries with it a very poor prognosis, with mortality similar to that for the common malignant diseases. Even in the current era of vasodilator therapy for the treatment of heart failure, approximately 65% of subjects will die within 5 years of diagnosis [6]. In addition, the potential impact upon quality of life should not be understated. A number of studies of common illnesses have indicated that quality of life for patients with heart failure is worse than that in arthritis, diabetes or chronic obstructive pulmonary disease [7, 8]. In addition heart failure represents one of the major reasons for emergency hospital admission [9]. Therefore it is not surprising that heart failure is a major economic burden to the health care systems of developed countries, accounting for 1–2% of total health care expenditure, 70% of which is related to hospitalization [10]. Although there are clearly major implications incumbent on health services provision, there has been a relative neglect of the problem of heart failure by those responsible for the provision of services, a point illustrated by the absence of mention of heart failure in the Government's Health of the Nation report published in 1991 [11].
Databáze: OpenAIRE
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