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Hypertension as a risk factor for coronary heart disease

Rachael Sian Tyrrell
BN(Hons) RGN
Nurse Specialist in Hypertension and Cardiovascular Risk
Department of Cardiology
Wales Heart Research Institute University of Wales College of Medicine
Cardiff

Coronary heart disease (CHD) caused over 135,000 deaths in the UK in 1998. In 1996 CHD was estimated to have cost the UK healthcare system about £1600 million, yet only 1% of this was directed towards primary prevention strategies.(1)
Standard 4 of the English National Service Framework (NSF) for CHD requires the identification of "…all people at risk of cardiovascular disease but who have not yet developed symptoms", and calls for health professionals to "offer them appropriate advice and treatment to reduce their risks".(2) Standard 2 of the Welsh NSF for CHD proposes that everyone at high risk of developing CHD and those who already have it should have access to "multi-factorial risk assessment and be offered an appropriate treatment plan".(3) Both of these standards are in line with the recommendations in the Joint British Guidelines,(4) which highlight the need for all healthcare professionals to adopt a holistic approach to multirisk factor management. Despite well-documented evidence that treatment should be based on a multifactorial approach, there are few "primary prevention" multirisk factor clinics in the UK, and only one patient self-referral clinic.(5)
This article examines the practice nurse's role in the prevention and management of hypertension as a risk factor for CHD. PNs have long been running blood pressure clinics in general practice, although there is little documented evidence on their specific role. It is becoming widely recognised that, with the expansion of the PN's role and better training, such clinics may have greater potential to achieve better blood ­pressure control than conventional clinics.(6)

Hypertension
The British Hypertension Society guidelines define hypertension (in non-diabetics) as a systolic pressure of less than 140mmHg and a diastolic of less than 85mmHg.(7) On this basis it is estimated that 14% of deaths from CHD in men and 12% of those in women are because of raised blood pressure. Current evidence suggests that, although 41% of men and 33% of women have hypertension, only 6% of men and 7.6% of women receive treatment. Of those that are treated, over two-thirds remain hypertensive.(1) 
As hypertension is a major risk factor for CHD and cerebrovascular accidents, there are significant challenges for those working in primary care. It is important to remember that there are socioeconomic, geographic, regional and ethnic differences in the incidence and prevalence of hypertension. For PNs the three major implications of the English and Welsh NSFs are the need: to develop opportunistic CHD screening programmes; to provide ­individualised risk assessment; and to offer structured care plans to lower the risks.

The role of the PN
Practice nursing has evolved in response to changing healthcare needs and the way that healthcare is delivered. PNs recognise that they have become increasingly more accessible to patients, particularly in situations where no clinical need is clearly identified.(8) In terms of opportunistic screening for CHD, if PNs are more approachable to their patients, it must surely be easier to encourage individuals to make positive lifestyle modifications, where appropriate. Roberts and Banning acknowledge that nurses have "the opportunity to improve the detection and enhance the management of hypertensive patients and those ­susceptible to CHD".(9)
The Cardiff CHD self-referral screening clinic is "nurse led but doctor supported". By training PNs on a local level, the clinic advocates an approach based on disease prevention rather than symptom management. Many PNs find this approach difficult but stimulating, as it requires them to call upon their skills of patient advocacy, communication and health education. Wiles  suggests that the PN role has been enhanced to include areas such as "health promotion and chronic disease management".(10) She identifies three main skills that PNs will need if they are to empower patients to make positive changes to their lifestyles. These are technical expertise, knowledge to be able to provide patients with information, and social/emotional skills to support patients and to motivate them to make lifestyle changes.

The Cardiff Hypertension/CHD and Multirisk Factor Screening Clinic
A year ago, in anticipation of the proposed Welsh NSF for CHD,(3) we established the UK's first patient self-referral clinic. In the first 48 hours of opening we received over 700 phone calls from people wanting to have their CHD risk measured. Initial criticism suggested that we would see only the "worried well" - motivated people who are willing to make changes to their lifestyles. However, analysis of the initial data clearly showed that, in the initial cohort, levels of hypertension, hypercholesterolaemia and obesity were significantly greater than the UK recommended levels.(5)
The clinic is ongoing and now has data on almost 1,000 patients. The method of referral remains largely patient self-referral, but we welcome referrals from GPs, PNs and other healthcare professionals. There are no exclusion criteria as to who can attend the clinic. The majority of patients refer themselves on the basis that they have one or more known risk factors for CHD, a premature family history or have recently been bereaved.
Each clinic appointment lasts approximately 35 minutes. Before their appointment, patients are asked to fast for six hours so that a full-fasting lipid/blood glucose profile can be checked using a desktop analyser. After filling in a brief health and lifestyle questionnaire, peripheral blood pressure is measured three times using a validated oscillometric sphygmomanometer. From the three readings the mean blood pressure is calculated. Height, weight and body mass index (BMI) are also taken. Once all the data have been gathered they are entered into an interactive computerised risk assessment package, which provides patients with an estimated calculation of their 10-year risk of developing CHD, myocardial infarction or stroke. Each patient is then offered an explanation of their CHD risk and appropriate evidence-based advice as to how their risk may be modified.
While the clinic aims to offer a primary prevention service, good blood pressure control is equally important in those special patient groups who come under the banner of secondary prevention, such as diabetic patients and those with established heart disease.

Conclusion
A recent BMA document acknowledged that if primary care is to function effectively in the future, then PNs as well as GPs will need to be recognised as "first-line gate-keepers".(11) This will have implications financially and in terms of education and training opportunities for PNs.(12) 
It has been suggested that work in relation to cardiovascular disease has often been incorporated into a general clinic set-up, such as a hypertension clinic. Brown et al. suggest that the nurse's role may be lost in an attempt to meet set targets.(8) They suggest that the development of specialist clinics may encourage better understanding of a specific subject. They also call for the establishment of a more systematic approach to ­multirisk factor assessment in high-risk patients and for follow-up where appropriate or referral to external agencies.

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References

  1. British Heart Foundation. Coronary heart disease statistics. London: BHF; 2000.
  2. Department of Health. National Service Framework for coronary heart disease. Modern standards and service models. London: HMSO; 2000.
  3. Department of Health and Social Services. An evidence based ­implementation plan for tackling coronary heart disease in Wales. Document number HSS1800; October 2000.
  4. Wood D, Durrington P, Poulter N, McInnes G, Rees A, Wray R. Joint British recommendations on prevention of coronary heart disease in clinical practice. Heart 1998;80:S1-29.
  5. Hall IR, Tyrrell S, Wilkinson IB, Cockcroft JR. Self referral multiple cardiovascular risk factor assessment - the cardiff experience. Br J Cardiol 2001;8:5.
  6. Beevers M. The role of nurses in the management of hypertension. Mod Hypertens Management 2000;2:11-13.
  7. Ramsay LE, Williams B, Johnston GD, et al. Guidelines for the ­management of hypertension: report of the Third Working Party of the British Hypertension Society. J Hum Hypertens 1999;13:569-92.
  8. Brown J, Shewan A, McDonnell A, Davies S. Factors in effectiveness: ­practice nurses, health promotion and cardiovascular disease. Clinical Effectiveness in Nursing 1999;3:58-65.
  9. Roberts C, Banning M. Managing risk factors for hypertension in primary care. Nursing Standard 1998;12(23):39-43.
  10. Wiles R. Empowering practice nurses in the follow-up of patients with established heart disease: lessons from patients' experiences. J Adv Nurs 1997;27:729-35.
  11. British Medical Association. Shaping tomorrow:?issues facing general practice in the new millennium. London: BMA; 2000. (See: www.bma.org.uk)
  12. Madden V. Health experts advocate the expanded nurse role. Practice Nurse 2000;19:193.

Resources
Cardiff Self-Referral Clinic Website
W:www.mrfc2000.fsnet.co.uk
British Cardiac Society
W:www.bcs.com
British Heart Foundation
W:www.bhf.org.uk
British Hypertension Society
W:www.hyp.ac.uk/bhs
Blood Pressure Association
W:www.bpassoc.org.uk

Further reading
Campbell N, Thain J, Deans HG, et al. Secondary ­prevention in ­coronary heart disease: baseline survey of provision in general practice. BMJ 1998; 316:1430-4.
Imperial Cancer Research OXCHECK Study Group. Effectiveness of health checks conducted by nurses in primary care: final results of the OXCHECK Study. BMJ 1995; 310:1099-104.
Pignone M, Mulrow CD. Using ­cardiovascular risk profiles to ­individualise ­hypertensive ­treatment. BMJ 2001;322:1164-6.
Qureshi N. A general practice based programme for the secondary prevention of heart disease: rationale and organisation. Br J Cardiol 2001;8(4):249-55.
Savage C. Self-referral heart clinic first of its kind in the UK. Western Mail 2000; 25 August