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Cardiovascular disease: the place for the practice nurse

Hugh Bethell MBE
MD FRCP FRCGP DRCOG
GP and Medical Director
Basingstoke and Alton Cardiac Rehabilitation Centre
Alton
Hampshire
E:hugh@boyneswood.fsnet.co.uk

In chronic disease, it is known that care is improved by having an up-to-date register of affected patients, having guidelines for management and organising regular follow-up.(2) Several investigators have studied the effect of different strategies to improve the implementation of research findings, and most have come up with the same answer - the practice nurse.(3) In trials of different methods for recording information, practice nurses perform better than GPs. Unfortunately, better disease surveillance has not translated into improved patient outcomes.(4) There is a gap between the process of care, which can be improved by practice nurses, and the outcome of care, which has not been shown to improve.

Coronary heart disease
Patients with coronary heart disease (CHD) are known to benefit from the following interventions.

Stopping smoking 
Patients who stop smoking after acute myocardial infarction (MI) halve their risk of a future coronary event. Advice is very cost-effective, but only because it is cheap - it is also very ineffective.(5) Effective smoking cessation requires much greater input in the form of nicotine replacement or the newly introduced oral drug, bupropion, together with specialist counselling.(6,7) The role of the nurse running the CHD clinic should be restricted to checking whether the patient is smoking and, if so, referring them on to the local smoking advice service.

Low-dose aspirin
The evidence for the benefit of this drug continues to grow,(8) but so does the evidence that many potential beneficiaries are still missing out.(1)

Beta-blockade
After MI, beta-blockade reduces future coronary events by about 20%, but these drugs are greatly underused.9

Lipid lowering
The use of statins to treat even mildly raised cholesterol levels reduces mortality by 30%, but many coronary patients still do not receive them.(4) Recent evidence from the Heart Protection Study10 suggests that no level of blood cholesterol is too low to benefit from further reduction. The indication for prescribing statins should be widened to include all at high risk, including those who have suffered strokes and patients over the age of 40 with diabetes. Sadly, dietary advice is seldom followed, and it requires a great deal of dietician time to alter traditional habits.

Treatment of hypertension 
The protection against CHD produced by hypotensive medication is less than that seen in stroke but is still substantial. A recent study found that 55% of CHD patients had a raised BP - defined as >140/90mmHg.(1) Even using the higher level of 160/90mmHg, there are still 37% of CHD patients who exceed this.(9)

Angiotensin-converting enzyme (ACE) inhibition 
The recent HOPE trial has shown that all CHD patients, with or without left ventricular dysfunction, benefit from ACE inhibitors.(11) However, even those with left ventricular dysfunction often do not receive these drugs.

Exercise-based cardiac rehabilitation 
A meta-analysis of randomised controlled trials confirms that treated groups have a reduction in mortality of 20-25%.(12) Currently in the UK only about 50% of coronary artery bypass graft (CABG) patients, 20% of infarct patients and 10% of angioplasty (PTCA) patients are included in cardiac rehabilitation programmes.(13)

At each follow-up clinic the practice nurse should look at all these modifiable factors, preferably using a simple computer template to prompt throughout the consultation,(14) recording the findings and advice.

Hypertension
Regarding BP measurement, the essential basics have recently been summarised.(15) Unless the BP is very high or there are complications of hypertension, it is necessary to measure BP at least three times before starting treatment. The problem of "white-coat" hypertension remains. Ideally all patients would have 24-hour BP recordings before embarking on what is likely to be lifelong medication, but this is impracticable. An alternative is to encourage patients to measure their own BPs to establish whether the surgery reading is representative, and this compares well with 24-hour monitoring.(16)

When defining hypertension, a level of 160/90mmHg is no longer acceptable as a universal upper limit of normal. A level of 130-139mmHg systolic and 80-89mmHg diastolic is now seen as "high normal" for people with no evidence of vascular disease or diabetes. The decision to treat patients with mildly elevated BP should depend upon the overall cardiovascular risk,(17) which can be incorporated into the patient's computer record as the Framingham risk score. This system does not take family history or obesity into account, and more accurate scoring systems are likely to be developed.

Before drugs are prescribed other measures should be tried - reducing weight in the overweight and obese (nearly impossible), reducing alcohol intake, increasing exercise, and reducing salt intake (the only advice likely to be followed). Firstline treatments include thiazide diuretics, b-blockers, calcium channel blockers and ACE inhibitors. Recent research has shown that the reduction of complications of hypertension is related to the reduction of BP achieved rather than the drug used.(18) Some patients get additional benefits from one or other group (ie, b-blockers in angina, ACE inhibitors in patients with diabetes and coronary patients). ACE inhibitors also offer renal protection for patients with nephropathy due to either diabetes(19) or hypertension.(20) For many patients two, three or even four drugs may be needed to achieve satisfactory control.

Heart failure
Heart failure and left ventricular dysfunction are becoming increasingly important causes of morbidity and death. The reasons are the increase in the numbers of elderly and the improved prognosis of coronary disease - heart failure is most commonly a long-term result of previous MI. Heart failure carries a five-year mortality of over 50%, but this can be reduced by modern treatment. Heart failure is underdiagnosed and often misdiagnosed(21); accuracy of diagnosis will be a priority if its high mortality is to be controlled.

Advances in the treatment of heart failure and its chronic nature make it an ideal condition for management in the practice nurse-run clinic. Many hospitals use specially trained nurses to run heart failure clinics designed to stabilise the condition by gradually increasing medication before discharging the patient back to the GP. A randomised controlled trial of specialist nurse intervention has shown a 40% reduction of readmission with heart failure in the treated group.(22)

The diagnosis of heart failure
The echocardiogram has been the main diagnostic tool. However, most hospitals do not allow direct access, restricting the numbers likely to have this investigation. Community studies have found that the majority of patients who have been diagnosed clinically as having heart failure have been misdiagnosed. Other diagnostic methods are needed. The most promising is the blood level of brain natriuretic peptide (BNP) - a peptide secreted into the bloodstream by the failing left ventricle. Measurement of plasma BNP increases the accuracy of diagnosis of heart failure and allows more appropriate referral for echocardiography of patients suspected of suffering heart failure.(23) Moreover, the progress of heart failure patients and their response to medication can be monitored by repeated BNP measurements.(24)

The treatment of heart failure
ACE inhibitors are central to the treatment of heart failure, reducing both mortality and morbidity. Nevertheless, they are underprescribed.

Over the past few years the value of b-blockade in the treatment of heart failure has become increasingly accepted, reducing the risk of reinfarction and cardiovascular mortality in patients with even severe heart failure.(25) b-blockers need to be introduced cautiously in heart failure patients and require close monitoring. This is best done in hospital, with transfer of the patient back to the primary care team only once the treatment has been maximised and stabilised.
There are far more untreated heart failure patients in the community than could possibly be included in hospital clinics, and the future may see specialist cardiac nurses supervising this treatment in general practice. Resistance is likely!

Cerebrovascular disease
This is another chronic progressive disease that calls for regular follow-up - a register, a recall system and practice nurse-run clinic using a computer template. Patients who should be included are those who have suffered either a transient ischaemic attack (TIA) or a stroke.

Some recent advances in the management of this group of conditions are:

  • Antiplatelet therapy in the form of aspirin is made more effective by the addition of dipyridamole 200mg twice daily, which reduces the combined endpoint of stroke, MI and vascular death by 22%.(26)
  • Anticoagulation for stroke/TIA patients in atrial fibrillation remains the cornerstone of treatment.(27)
  • Carotid endarterectomy reduces the risk of disabling stroke or death for stroke/TIA patients with severe carotid stenosis.(28)
  • BP control is the most important secondary prevention measure for stroke patients - and even those with normal BP seem to benefit. The PROGRESS trial compared perindopril, perindopril and indapamide, and placebo for patients who had suffered a recent stroke or TIA. The combination reduced BP by 12/5mmHg and reduced the risk of stroke by 43%, whether or not the patient was hypertensive.(29)
  • There is no direct relationship between blood lipid levels and risk of stroke - although reduction of blood cholesterol by statins is thought to reduce stroke risk. The Heart Protection Study seems to confirm this.(10)

A final word about chronic disease management clinic. The main function of the practice nurse is to check that all risk factors are minimised and that all appropriate medication is being taken. The nurse cannot expect to modify behaviour and lifestyle such as smoking, obesity, inappropriate diet and lack of exercise, but should refer the patient on to appropriate agencies for specialist and usually time-demanding management.

References

  1. EUROASPIRE I and II Group. BMJ 2001;357:995-1001.
  2. Feder G, Griffiths C, Highton C, et al. BMJ 1995;311:1473-8.
  3. Campbell NC, Thain J, Deans HG, Ritchie LD, Rawles JM, Squair J. BMJ 1998;316:1434-7.
  4. Moher M, Yudkin P, Wright L, et al. BMJ 2001;322:1338-443.
  5. Hajek P, Taylor TZ, Mills P.BMJ 2002;324:87-9.
  6. West R, McNeill A, Raw M.Thorax 2000;55:987-99.
  7. Lancaster T, Stead LF. Individual behavioural counselling for smoking cessation. Cochrane Database Syst Rev 2001;3:CD003086.
  8. Antithrombotic Triallists' Collaboration. BMJ 2002;324:71-86.
  9. Brady AJB, Oliver MA, Pittard JB. BMJ 2001;322:1463.
  10. Heart Protection Study Group. Lancet 2002;360:7-23.
  11. Yusuf S, Sleight P, Pogue J, et al. N Engl J Med 200;342:145-53.
  12. Jolliffe JA, Rees K, Taylor RS, et al. Exercise-based rehabilitation for coronary heart disease (Systematic Review). Cochrane Heart Group. Cochrane Database of Systematic Reviews, Issue 1. Oxford: Update Software; 2002.
  13. Bethell HJN, Turner SC, Evans J, Rose L. J Cardiopulm Rehabil 2001;21:111-5.
  14. Bethell HJN. Ensuring patient benefit from effective services: the issues of access and equity. In Wood D, McLeod A, Davis M, Miles A, editors. Effective secondary prevention and cardiac rehabilitation. London: Aesculapius Medical Press; 2002.
  15. Beevers G, Lip GYH, O'Brien E. BMJ 2001;322:981-5.
  16. Asmar R, Zanchetti A on behalf of the Organising Committee and participants.J Hypertens 2000;18:493-508.
  17. Padwal R, Straus SE, McAlister FA. BMJ 2001;322:977-80.
  18. Blood Pressure Lowering Treatment Triallists' Collaboration. Lancet 2000;355:1955-64.
  19. Lewis EJ, Hunsicker LG, Clarke WR, et al. N Engl J Med 2001;345:851-60.
  20. African American Study of Kidney Disease and Hypertension Group. JAMA 2001;285:2719-28.
  21. Davies MK, Hobbs FDR, Davis RC, et al. Lancet 2001;358:439-44.
  22. Blue L, Lang E, McMurray JV, et al. BMJ 2001;323:715-8.
  23. Cowie MR, Struthers AD, Wood D, et al. Lancet 1997;350:1349-51.
  24. Murdoch DR, McDonagh T, Byrne J, et al. Am Heart J 1999;138:1126-32.
  25. Packer M, Coats AJ, Fowler MB, et al. N Engl J Med 2001;344:1651-8.
  26. The ESPS-2 Group. J Neuro Sci 1997;151:527-37.
  27. Hart RG, Benavente O, McBride R, Pearce LA. Ann Intern Med 1999;131:492-501.
  28. Cina CS, Clase CM, Haynes RB. Carotid endarterectomy for symptomatic carotid stenosis (Cochrane Review). The Cochrane Library. Oxford: Update Software; 2000.
  29. PROGRESS Collaborative Group. Lancet 2001;358:1033-41.

Resources
British Association for Nursing in Cardiac Care
c/o British Cardiac Society
T:020 7383 3887
F:020 7388 0903
E:akilpin@bcs.com
W:www.bcs.com/bancc
British Association for Cardiac Rehabilitation
c/o British Cardiac Society
Contact details as above
British Heart Foundation
T:020 7935 0185
F:020 7486 5820
E:internet@bhf.org.uk
W:www.bhf.org.uk
Coronary Prevention Group
T:020 7927 2125
F:020 7927 2127
W:www.healthnet.org.uk
Primary Care Cardiovascular Society
T:020 8994 8775
F:020 8742 2130
E:office@pccs.org.uk
W:www.pccs.org.uk
Family Heart Association
T:01628 628638
F:01628 628698
E:ad@familyheart.org
W:www.familyheart.org
British Society for Heart Failure
T:01865 391215
F:01865 391836
E:bsh@medical-interaction.com

Forthcoming events
4-5 October 2002
British Association for Cardiac Rehabilitation Annual Meeting
Brighton
4-5 October 2002
Primary Care Cardiovascular Society Annual Meeting TBC
28 April-1 May 2003
British Cardiac Society Annual Meeting
Glasgow