1            Background

1.1    Changes in the burden of coronary heart disease

Coronary heart disease (CHD) is the single largest cause of death in England and Wales, with approximately 115,000 men and women dying in 1999 as a direct consequence of heart disease – comprising more than 20% of all deaths (excluding neonates). Since the early 1980s, mortality from coronary heart disease has shown a declining trend in both men and women in England and Wales ( see Figure 1 ). This decline is partially explained by falls in risk factors, in particular smoking, blood pressure and blood cholesterol levels, and reduced case-fatality attributable to better medical care (Tunstall-Pedoe et al., 2000). It is likely that the decline in mortality is mirrored by a decline in incidence of CHD (Tunstall-Pedoe et al., 1999; Volmink et al., 1998).

The British Regional Heart Study has demonstrated that while the incidence of both fatal and non-fatal coronary heart disease events has declined since the late 1970s, and the prevalence of symptomatic coronary heart disease (largely angina) has also declined, the overall prevalence of diagnosed disease has shown virtually no change ( see Table 1 ). Therefore, as people are now more likely to survive acute cardiac events and with an ageing population, the total number of high risk people in the population will increase further, resulting in more people requiring revascularisation.

1.2    Social inequalities in the decline in coronary heart disease

While the general picture is optimistic, when time trends are broken down by social class, it is apparent that the social class gradient has become much steeper than in the past, with CHD mortality in social class V only 3% lower in 1991/3 than it was in 1970–2 ( see Figure 2 ).  Social class I enjoyed a far greater decline of 59% over the same period (Drever and Whitehead, 1997). These mortality trends would suggest that lower social classes will continue to be at greater risk and to have a greater need for revascularisation.
 

1.3    The National Service Framework for Coronary Heart Disease

The major aim of the NSF programme is to develop explicit sets of standards that would form the basis for developing and monitoring the quality of services provided by the NHS. The NSF for Coronary Heart Disease identified 12 standards ( see Box 1 ). Improved access to revascularisation is highlighted in the NSF and this report uses Hospital Episodes Statistics and other data to examine issues of provision and inequity in use of revascularisation for CHD prior to implementation of the NSF for CHD.
 

1.4    The value of revascularisation for coronary heart disease

In comparison with medical treatment, a systematic review of randomised controlled trials (RCTs) has demonstrated that coronary artery bypass grafting (CABG) reduces post-operative 5-year mortality by about 39% (95% CI 23%, 52%) although it does not reduce the risk of subsequent myocardial infarction. Since these trials were conducted, medical treatment has improved greatly, but more severely ill patients are now having CABG. Furthermore, many patients allocated to medical treatment received CABG, so, on balance it is likely that this systematic review under-estimated the true effects of CABG (Sudlow et al., 2000).

In patients with stable CHD, percutaneous transluminal coronary angioplasty (PTCA) is more effective than medical treatment in alleviating symptoms and improving exercise tolerance. PTCA does not reduce the risk of mortality or future myocardial infarction, probably because of the risk of complications during and shortly after the procedure (Sudlow et al., 2000).

RCT comparisons of CABG with PTCA have been made. The trials are small but suggest that in low and medium risk patients both procedures are associated with similar mortality and acute myocardial infarction (AMI) rates, and quality of life.  PTCA is more likely to need repeating (Pocock et al., 1995; BARI Investigators, 1996).  However, the equivalence of the two procedures is not confirmed, particularly in patients with more severe disease.

In people aged 75+ a recent RCT has shown evidence of greater symptomatic and quality of life benefits in those treated with revascularisation compared with optimised medical treatment (Time Investigators, 2001). This trial also demonstrated an increased mortality among those randomised to revascularisation, but a reduction in hospital admissions for acute coronary syndromes. This evidence is likely to increase the pressure for considering revascularisation in patients at least up to 85 years old.

The use of intracoronary stents is associated with better clinical and angiographic results than PTCA alone (Meads et al., 2000). Greater use of antiplatelet and antithrombolytic drugs preceding and following stent placement has reduced early thrombosis (Taniuchi et al., 2001; Calver et al., 2000).  Consequently, earlier studies comparing PTCA with CABG are less relevant to current practice.  In unstable angina, PTCA in combination with aggressive antiplatelet and antithrombolytic treatment is associated with better outcomes and such treatment should be given urgently (Mehta and Yusuf, 2000; Vernon, 2001; Husted et al., 2001).

Since this evidence suggests that revascularisation is of benefit for selected patients, fair access to these treatments is of importance in reducing inequalities in CHD. In a study examining need in terms of ability to benefit from treatment much more precisely than can be done using routine hospital admission data, it was shown that between a quarter and a third of patients treated medically had indications for revascularisation (Hemingway et al., 2001).

The Public Health Observatory is part of the South West Observatory, a wider Regional intelligence function, currently supported by the South West Regional Assembly, the Department of Health, the Department for Education and Skills. Government Office South West, the South West of England Regional Development Agency and the Environment Agency.