INTRODUCTION

Ischaemic heart disease (IHD) is a disease characterised by reduced blood supply to the heart muscle, usually due to a narrowing of the coronary arteries as a result of atherosclerosis. In Australia and New Zealand, as in most Western nations, IHD is a major public health problem and accounts for a major proportion of health expenditure (Australian Institute of Health and Welfare (AIHW), 2004; Hay, 2004). Although mortality from IHD has declined over the past two decades, we are now facing the challenge of managing chronic heart diseases in the long term, and thus there is a shift towards managing disability due to IHD and enhancing quality of life in addition to longevity (Access Economics (AE), 2005).

IHD may result in a condition known as angina pectoris, characterised by discomfort in the chest, which may radiate to the jaw, shoulder, back or arm. Typically, it is aggravated by exertion or emotional stress, and relieved by nitroglycerin and rest. Although angina pectoris usually occurs in clients with coronary artery disease involving at least one large epicardial artery, it may also occur in persons with valvular heart disease, hypertrophic cardiomyopathy and uncontrolled hypertension. It can also be present in clients with normal coronary arteries and myocardial ischaemia related to coronary artery spasm or endothelial dysfunction (Gibbons et al, 2003).

The majority of people with IHD can be adequately treated with pharmacological therapy and/or revascularisation procedures (coronary artery bypass surgery and percutaneous transluminal coronary angioplasty), but there is a group of individuals that have severe ongoing and debilitating angina that is refractory to conventional forms of treatment. Refractory angina pectoris is chronic and cannot be controlled by a combination of medical therapy or revascularisation procedures (Mannheimer et al, 2002). Nurses caring for clients with this condition should have in-depth knowledge of the modifiable biomedical and behavioural risk factors that contribute to this condition and the contribution that nurses can make in terms of assisting clients to maximise their quality of life in the presence of this chronic disease.

Case study 19.1 will be used as a framework to discuss the nursing contribution to chronic disease management for clients with ischaemic heart disease.

RISK FACTORS AND BEHAVIOURS THAT CONTRIBUTE TO THE DEVELOPMENT OF IHD

A number of clearly defined genetic, behavioural and biomedical risk factors are associated with IHD. Risk for IHD rises progressively according to the number of risk factors present in an individual. People with existing IHD are in the highest risk group for future cardiac events, so a more stringent approach to risk factor management through pharmacological and lifestyle interventions will be required.

Cardiac risk factors are traditionally thought of as those that cannot be changed by lifestyle change or medical treatment, and those that are modifiable through interventions such as pharmacotherapy and/or lifestyle change. These modifiable risk factors may be further divided into biomedical or behavioural risk factors.

Non-modifiable biomedical risk factors include:

Although these risk factors cannot be modified, awareness of these risks may encourage clients to take positive steps in addressing other risk factors that are modifiable.

Modifiable biomedical risk factors include:

Modifiable behavioural cardiovascular risk factors include:

Most cardiac clients tend to have multiple risk factors, thus multiplying the overall extent of the risk. Similarly, the presence of one disease, for example diabetes, can increase the risk of developing another.

The evolution in the treatment of heart disease has had a major effect on mortality and morbidity outcomes in recent times, but despite these advances, risk factors and genetics do not always provide a complete explanation as to why heart disease develops. More recently, evidence has emerged relating to the impact that psychological and social factors have on the development of and recovery from heart disease. Clients with IHD often cite stress as the prime cause of illness and, in particular, those with myocardial infarction often claim that stress is the cause. There is evidence to suggest that there is an ‘independent causal association’ between depression, social isolation, poor social support and the development and prognosis of IHD (Bunker et al, 2003). Australians who have socioeconomic disadvantages are more likely to smoke, have diabetes and be obese, thus having a greater risk of death from cardiovascular disease. Aboriginal and Torres Strait Islander peoples have a high cardiovascular mortality and morbidity and are 2.6 times more likely to die from a vascular event than non-Indigenous Australians (AIHW & ABS, 2005). Similarly, Máori and Pacific people have poor cardiovascular health outcomes compared with non-indigenous New Zealanders (Bramley et al, 2004).

Clients with IHD therefore need to be educated about secondary prevention activities involved in the management of established disease in order to restore maximal function, minimise negative effects of the disease, prevent disease-related complications and reduce the risk of further cardiovascular events. Introducing strategies to address modifiable risk factors that affect health status are core business for nurses involved in the management of clients with IHD. The best time to identify and raise awareness of the impact of the risk on cardiac disease is in the primary care setting. However, in reality, the opportunity to do this often presents following an acute event.

CARDIAC REHABILITATION

Cardiac rehabilitation (CR) is described by the NHFA and the Australian Cardiac Rehabilitation Association (ACRA) (2004) as ‘all measures used to help people with heart disease return to an active and satisfying life and to prevent recurrence of cardiac events’. It is an important component of IHD management. CR is usually first offered to in-hospital clients following an acute event, such as myocardial infarction or unstable angina, or following re-vascularisation procedures, but may also be made available to clients with stable angina, controlled heart failure and other vascular or heart disease, or those awaiting cardiac investigation or intervention (NHFA & ACRA, 2004).

In the acute setting, CR begins as soon as is practical following admission, with the aim of moving the client into the recovery phase as soon as possible after an acute event. This is often referred to as ‘Phase 1’ CR and involves initial contact and introduction to the service, basic information and reassurance, supportive counselling, guidelines for mobilisation and information on pharmacotherapy. Prior to discharge from hospital, clients should be fully informed of their risk factor status, and know what their specific biomedical target levels are. Discharge planning also begins soon after admission, including referral to outclient CR (NHFA & ACRA, 2004) and general practitioner (GP) follow-up. CR aims to encourage clients and their families to embrace secondary prevention principles and goals, including compliance with pharmacotherapy, and facilitate the development of self-management skills to enhance long-term lifestyle change, particularly with regard to reducing risk of recurrent cardiac events. Clients are made aware of community resources and encouraged to utilise these resources in their long-term care. CR is generally continued as an outpatient and ongoing prevention approach (known as ‘Phase 2′ CR), but clients may access these services at different levels of the disease management continuum, depending upon factors such as the client’s readiness to take part in a CR program, or availability of CR services (NHFA & ACRA, 2004).

Unfortunately, it has been reported that compliance with lifestyle modification falls by the wayside at about six months from the index event, when clients feel that they have been ‘cured’ of their disease (EUROASPIRE II, 2001). Developing partnerships between clients and clinicians, and assisting clients to understand the long-term impact of risk factors on health may assist and enhance long-term secondary prevention strategies. Timing of the intervention is often a key factor on how an educational strategy may be received by the client and family members. Thus consideration of variables that may affect the client’s ability to receive and process information must be taken into account when developing an educational program.

CLIENT EDUCATION: UNDERSTANDING THE DISEASE

Educational information about the cause of IHD and subsequent management options are usually available to the client as print materials, supported by counselling and advice by health professionals, including medical and nursing staff, dietitians, pharmacists and social workers. Although it is recognised that clients need information to enable them to actively participate in their rehabilitation and management, in many instances client education programs fail to influence clients’ behaviour in relation to risk factor reduction. It is important for the nurse to ascertain which factors the client considers are the major influences on their illness. Some clients demonstrate an internal locus of control; they feel responsible for becoming ill and believe that their lifestyle behaviour has caused their illness. Others exhibit an external locus of control in that they believe their illness is attributed to external factors over which they had no control. Those with an internal locus of control may be more amenable to behavioural change because they take some responsibility for the state of their health and physical recovery. It is important for nurses to recognise the health beliefs of individual clients and what they see as important information at each stage of their illness.

In Case study 19.1, it is clear that Dave needs education about risk factors for IHD and to be actively involved in secondary prevention plans. As with most clients with IHD, Dave has multiple risk factors, thus multiplying the overall extent of the risk. Similarly, the presence of one disease, for example diabetes, can increase the risk of developing another. Risk factor information is interdependent; thus CR should present a holistic view rather than attempting to manage each risk as a stand-alone entity. When planning risk management strategies, the nurse involved in CR will include management of co-morbidities that impact on cardiovascular risk.

Dave has risk factors that can’t be changed: he is a male approaching middle age and has a strong family history of IHD. Although Dave cannot change these risk factors, he needs to be aware that having them means that the presence of other risk factors exponentially elevates his risk of further cardiac events; thus it is in his best interests to address those risk factors that can be modified.