New guideline on secondary prevention of myocardial infarction gives practical advice on lifestyle, pharmacotherapy, and cardiac rehabilitation, explains Dr Rubin Minhas


The guideline from NICE on secondary prevention for patients following a myocardial infarction (MI)1,2 replaces the existing NICE guidance, and updates relevant sections of the national service framework on coronary heart disease.3

It represents the first of three major NICE cardiovascular guidelines being released over the next 2 years, the other two dealing with lipid modification and familial hypercholesterolaemia, respectively. There are also guidelines on chest pain and venous thromboembolism prevention in preparation, but dates are yet to be confirmed.

In the foreword to the post-MI guideline, Professor Roger Boyle, National Director for Heart Disease and Stroke at the Department of Health, praises the significant improvements already seen in the levels of secondary prevention medication for patients leaving hospital.

Professor Boyle notes the need to build on this progress by focusing on the issues that, although not as simple to address, nonetheless represent important 'pillars that support full recovery'.2 The new NICE guideline identifies many of these important issues.

How the guideline has been revised

The recommendations within this updated guideline incorporate practical advice around lifestyle interventions and cardiac rehabilitation that extend beyond the boundaries of many traditional guidelines. Guidance on pharmacological treatment has also been augmented by recommendations for newly introduced drugs, based on recent trials, and a discriminating approach to continuing drug treatment in low-risk groups.2

The post-MI guideline makes recommendations that target the healthcare system in order to address the barriers to achieving good outcomes, which may, in turn, also lead to lives saved. This guideline is, therefore, of relevance to a wide range of healthcare professionals, patients, and those responsible for commissioning cardiac care.

The guideline is evidence-based and incorporates multidisciplinary viewpoints. Patients (experts with the condition), practising cardiologists, public health physicians, GPs, nurses, and pharmacists were all represented on the guideline development group, and were involved in writing this guideline. The draft recommendations were subject to a national consultation that allowed the widest range of feedback possible, including that from diverse patient advocacy groups, the pharmaceutical industry, and specialist bodies. Only after 2 years, and at the conclusion of this exhaustive process, were the recommendations finalised.

Implementing the guideline

Dietary changes

Lifestyle interventions listed in the guideline have been identified as some of the key priorities for implementation. The importance of recommending a Mediterranean-style diet is emphasised: more bread, fruit, vegetables, and oily fish; less meat; and butter and cheese replaced by products based on vegetable and plant oils.

Patients are advised to eat 7 g of omega 3 fatty acids per week from 2–4 portions of oily fish. A useful list of the types of fish that can provide specific quantities of the appropriate fish oil can be found in Appendix G of the full guideline.2 For patients who have had an MI within 3 months and are not achieving a sufficient dietary intake, treatment with 1 g daily of licensed omega-3-acid ethyl esters should be considered for up to 4 years. Alcohol consumption should be kept within safe limits (no more than 21 units per week for men and 14 units per week for women). The need to provide advice regarding diet and exercise that is tailored for individuals, but which can be extended to the whole family is discussed in detail.2

Supplements

Patients often raise the issue of supplements and the evidence around this was also evaluated. Patients should be specifically advised not to take supplements containing beta carotene due to the potential risk of harm. Consumption of beta carotene by post-MI patients may lead to increased deaths from cardiovascular causes.2 Vitamins C and E are not recommended for cardiovascular risk reduction because of a lack of sufficient evidence of beneficial effects.

Physical activity

Specific advice is given, which recommends 20–30 minutes of physical activity a day, to be undertaken to the point of slight breathlessness. Starting at a level that is comfortable, duration and intensity should increase gradually with fitness.1 It will be no surprise that smoking cessation also receives a strong recommendation and that NICE guidance on reducing obesity rates is also signposted.4,5

NICE implementation tools

NICE has developed the following tools to support implementation of its guideline on secondary prevention of myocardial infarction. They are now available to download from the NICE website: www.nice.org.uk.

Costing tools
National cost reports and local cost templates for the guideline have also been produced.

Costing reports are estimates of the national cost impact arising from implementation based on assumptions about current practice, and predictions of how it might change following implementation of the guideline.

Costing templates are spreadsheets that allow individual NHS organisations and local health economies to estimate the costs of implementation taking into account local variation from the national estimates, and they quickly assess the impact the guideline may have on local budgets

Pharmacological interventions

The recommended traditional quartet of drugs—aspirin, beta blockers, statins, and angiotensin-converting enzyme (ACE) inhibitors—has been retained but their use has been refined and extended in some instances.

Following an ST-segment-elevation MI, it is recommended that patients continue to take aspirin and clopidogrel for at least 4 weeks if this treatment was initiated during the first 24 hours — the exact duration of treatment will need to be agreed between primary and secondary care. For patients experiencing a non-ST-segment-elevation MI, therapy with low-dose aspirin and clopidogrel for 1 year is advised; as outlined in previous guidance from NICE.6

The dual use of aspirin and moderate-intensity warfarin should be considered for patients who have had an acute MI, cannot tolerate clopidogrel, and have a low risk of bleeding. Patients who have existing indications for anticoagulation (i.e. mechanical valves, recurrent deep vein thrombosis, atrial fibrillation, left ventricular thrombus) should continue to take warfarin.1

In practice, the management of patients who are prescribed warfarin will require careful assessment of the indications for the treatment and the importance of continuing it, the level of individual patient cardiovascular risk, and bleeding risk, and their own wishes. It should also take into account other indications for prescribing antiplatelet agents, such as recent coronary stenting.

In patients with a history of dyspepsia, treatment with low-dose aspirin and a proton pump inhibitor should be considered in accordance with the NICE guidance on dyspepsia.7 After appropriate treatment, patients with a history of aspirin-induced ulcer, whose ulcers have healed and who are negative for Helicobacter pylori, should be considered for treatment with a full-dose proton pump inhibitor and low-dose aspirin.

A risk stratification approach has been adopted to employing beta blockers. For example, asymptomatic patients with a proven history of MI, with preserved left ventricular function, should not be routinely offered treatment with a beta blocker, unless they are identified to be at increased risk of further cardiovascular events, or there are other compelling indications for beta-blocker treatment.1

In accordance with the advice in the NICE technology appraisal 94,8 the guideline recommends statin therapy for adults with clinical evidence of cardiovascular disease. Treatment should begin as early as possible and baseline liver function tests should be measured before initiation of therapy. However, treatment should not be routinely excluded in those in whom test results are raised. A statin with a low acquisition cost should be used to initiate treatment. Patients who develop muscle aches (pain, tenderness, or weakness) should be advised to stop the drug and seek medical advice so that creatine kinase can be measured.

Recommendations for the intensity of statin treatment and cholesterol lowering in patients with vascular disease, including those post-MI, are being addressed by the NICE lipid modification guideline, which is scheduled for publication in January 2008.

Studies have demonstrated a beneficial role for aldosterone antagonists in patients who have had an MI and who have symptoms and/or signs of heart failure and a left ventricular systolic dysfunction (ejection fraction of <40%). These drugs have, therefore, also been added to the pharmacological armamentarium. Treatment should ideally be commenced within 3–14 days of the recent event, preferably after ACE inhibitor therapy, and the implication is that patients should receive an echocardiogram before discharge.

As many patients will already be taking ACE inhibitors, close monitoring of electrolytes2 will be required. In everyday practice, good liaison between primary and secondary care is needed to reduce the risk of hyperkalaemia arising from the use of multiple drugs, with potential potassium-sparing effects. The full guideline gives detailed guidance around the up-titration and monitoring of the effects of ACE inhibitors.2 All patients should be offered a cardiological assessment for consideration of revascularisation, which should take into account co-morbidity.

Cardiac rehabilitation

An interesting finding from a Cochrane review of cardiac rehabilitation7 was the positive contribution of an exercise-only component in reducing all-cause mortality when compared to comprehensive programmes without this component. Exercise is, therefore, now stipulated as a necessary component of such programmes.

The need for cardiac rehabilitation to be equally accessible for all patients, particularly those who are less likely to access this service, is emphasised. These include people from black and minority ethnic groups, older people, individuals from lower socioeconomic groups, women, people from rural communities, and those with mental and physical health co-morbidities. The use of bilingual peer educators, preferences for single or mixed classes, and the need to ascertain patients’ health beliefs are among the many recommendations made for the practising healthcare professional.1

Full guideline

The comprehensive full guideline addresses many other issues and makes recommendations on returning to work, sexual activity, flying, and issues for those engaged in competitive sport. It also offers explanations of the evidence base that underpins the recommendations.2

Conclusion

This NICE guideline on secondary prevention for patients following an MI represents an essential practical tool for NHS professionals involved in providing high quality care to patients who have experienced a heart attack. Guidance for patients and a quick reference guide are also available from the NICE website at www.nice.org.uk.

 

  • Effective treatment starts in hospital — PBC collectives should ensure through contracts that hospitals comply with NICE guidance and run audits to ensure this
  • Clopidogrel is now recommended to be prescribed for 1 month post ST-elevated ACS and 12 months post non-ST-segment ACS. This is expensive — £35.31 per month — and will impact on prescribing budgets1
  • Exercise is a vital component of cardiac rehabilitation and a good post-MI rehabilitation scheme will need to be commissioned from somewhere. This will be cheaper to provide locally than by commissioning one from the hospital
  • Omega 3 fatty acids are now recommended for all post-MI patients either in the diet or as supplements (potential cost £13.89 per month)1
  • ACE inhibitors and statins are now available generically and use of these generics will save money quickly on indicative budgets
  1. National Institute for Health and Care Excellence. MI: secondary prevention. Secondary prevention in primary and secondary care for patients following a myocardial infarction. Clinical guideline 48. London: NICE, 2007.
  2. Cooper A, Skinner J, Nherera L et al. Clinical guidelines and evidence review for post myocardial infarction: secondary prevention in primary and secondary care for patients following a myocardial infarction. London: National Collaborating Centre for Primary Care and Royal College of General Practitioners, 2007.
  3. Department of Health. National Service Framework for Coronary Heart Disease: Modern Standards and Service Models. London: DH, 2000.
  4. National Institute for Health and Care Excellence. Brief interventions and referral for smoking cessation in primary care and other settings. Public health intervention guidance 1. London: NICE, 2006.
  5. National Institute for Health and Care Excellence. Obesity: guidance on the prevention, identification, assessment and management of overweight and obesity in adults and children. Clinical Guideline 43. London: NICE, 2006.
  6. National Institute for Clinical Excellence. Clopidogrel in the treatment of non-ST-segment-elevation acute coronary syndrome. Technology appraisal 80. London: NICE, 2004.
  7. National Institute for Clinical Excellence. Dyspepsia: Managing dyspepsia in adults in primary care. Clinical guideline 17. London: NICE, 2004.
  8. National Institute for Health and Care Excellence. Cardiovascular disease—statins. Technology appraisal 94. London: NICE, 2006.
  9. Jolliffe J, Rees K, Taylor R et al. Exercise-based rehabilitation for coronary heart disease. Cochrane Database Syst Rev 2001, Issue 1. Article No: CD001800. DOI: 10.1;002/14651858.CD001800.G