Angiotensin II Receptor Blockers: A New Lease of LIFE?

Michael Kirby; Rubin Minhas

Disclosures

Br J Cardiol. 2004;11(4) 

In This Article

Abstract and Introduction

Professor Mike Kirby and Dr Rubin Minhas review recent studies in hypertension and the role of angiotensin II receptor blockers in the primary care management of hypertension and prevention of stroke.

Hypertension is a significant risk factor for both coronary artery disease and cerebrovascular disease. Isolated systolic hypertension and left ventricular hypertrophy are well-recognised risk factors for cardiovascular mortality. The management of hypertension in elderly patients, patients with isolated systolic hypertension or left ventricular hypertrophy is discussed in the context of recent British Hypertension Society guidelines, recent trial evidence and an appraisal of the LIFE study results. Compelling indications for the use of angiotensin II receptor blockers in the management of hypertension are examined and the need for combination therapy in achieving satisfactory blood pressure control is established through examination of the trial evidence.

Hypertension is one of the most prevalent and commonly managed conditions in primary care. Recent data indicate that the prevalence of hypertension may be as high as 40% for men and 39% in women[1] in the general population. Primary prevention of cardiovascular disease, and cerebrovascular disease in particular, have not been fully addressed in practice partly because of implicit recognition that the associated resource implications, workload and costs attached to primary prevention are considerable.

Against this background, approximately 110,000 people every year in England and Wales have their first stroke. Some 30,000 go on to have further strokes. Stroke is the third most common cause of death in the UK but is ranked as the number one cause of severe disability. Certain population groups appear to be at higher risk of stroke than others. Afro-Caribbean and South Asian men, for example, have a prevalence of stroke between 40-70% higher than that of the general population after adjusting for age. The elderly are a well recognised risk group and there is also a social class gradient which indicates that people in socioeconomic group V (unskilled manual workers) have a 60% higher chance of having a stroke than those in socio-eco-nomic group I (professionals). The mortality rates from stroke are 50% higher in socio-economic group V than in socio-economic group I.[2]

In recognition of this significant morbidity and mortality, the National Service Framework for Older People[2] has recognised the prevention and treatment of stroke as a priority for all those involved in the planning and delivery of services affecting older people. Hypertension and its adequate management are highlighted as specific areas that require attention.

The secondary prevention of coronary heart disease (CHD) is well ingrained in the clinical psyche but prevention and management of stroke has received less widespread recognition. That hypertension is a major risk factor for stroke is well established and it is thought that lowering diastolic blood pressure by 5-6 mmHg and systolic blood pressure by 10-12 mmHg for three years could reduce the annual stroke risk from 7% to 4.8%. In practical terms, approximately 45 people would require treatment at this level to prevent one stroke.[3]

Hypertension is a risk factor for both ischaemic and haemorrhagic stroke. Its presence in an individual signifies an approximate doubling of risk. The Framingham study indicated that systolic hypertension was a better predictor of risk in individuals over the age of 45 and characterisation of the benefits of treating isolated systolic hypertension (ISH)[4] have since led to recognition that both diastolic and systolic hypertension should be regarded as important targets for treatment.

Epidemiological studies suggest that isolated systolic hypertension may be a distinct hypertension subgroup where ISH may reflect an increased rigidity of the major arteries over the peripheral circulation.[5] Data from statistical analy-ses suggest that systolic hypertension may be a more potent contributor to cardiovascular mortality than diastolic hypertension[6] and a better predictor of stroke.[7] The prevalence of ISH is estimated at around 15% in men and women over the age of 60.[4] The age-adjusted prevalence of ISH is higher in men than women by up to 100% and higher in Afro-Caribbeans by up to 30%.[5]

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