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Meeting the demands of the NSF for CHD: angina

Carol Clapham
RGN MSc BSc
Nurse Practitioner
The Health Station
Private Medical Clinic
Hitchin, Herts
Practice Nurse
Knebworth Surgery
Herts
Cardiology Specialist Nurse
E&N Herts NHS Trust
E:carol.clapham@ntlworld.com

Angina is a symptom of reversible myocardial ischaemia where the oxygen demands of the heart are not met by the supply. Supply may be reduced due to stenotic atheromatous disease of the coronary arteries, thrombosis within the arteries, spasm of normal arteries or inflammation of the arteries (arteritis). Increased oxygen demand occurs with exercise, thyrotoxicosis and stress. Angina may occur in conditions requiring an increased cardiac workload to maintain an adequate output, such as aortic stenosis, and with increased peripheral resistance, such as hypertension.(2)
Classically angina is experienced as central chest pain due to a reduction in coronary perfusion caused by chronic stenosing atherosclerosis.(3) Patients with angina have a threefold increased risk of developing unstable angina, myocardial infarction (MI) or sudden cardiac death within two years of presentation.(4)
Angina usually presents as central or left-sided chest pain, of short duration, lasting seconds to minutes (rarely over 15 minutes). The pain may radiate into both arms, back, neck, jaw and shoulders. It is usually described as a dull ache, with a tightness or bandlike pressure around the chest. The pain can occur postprandially, or be precipitated by exertion, cold and stress. It is relieved by rest and glyceryl trinitrate (GTN). The chest pain may be accompanied by sweating, nausea, dizziness, palpitations and shortness of breath, or it may be asymptomatic.
Table 1 lists the risk factors for angina and coronary heart disease (CHD). Diagnosis of angina is often made after taking a symptom history. Symptoms of ischaemia can be similar to the symptoms of musculoskeletal pain, oesophagitis and spasm of normal arteries, and can often be misdiagnosed. An exercise tolerance test will help to confirm the diagnosis and will also assess the risk and severity of angina, providing a prognostic assessment.

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Rapid-access chest pain clinics are now provided by most acute trusts and offer a one-stop service for assessment, diagnosis and the subsequent management of angina.(5)

Management of angina

Drug treatment

Antiplatelet agents
Aspirin has been shown to greatly reduce the risk of further cardiac events, and all angina patients should be encouraged to take 75mg of aspirin daily with food unless contraindicated. Clopidogrel is an alternative therapy in cases where aspirin is not tolerated, such as patients with asthma. Caution is always necessary if there is a previous history of gastric/duodenal ulcers.

b-blockers
b-blockers are the firstline treatment option for patients with angina. They reduce sympathetic tone by blocking b(1)-receptors,  reducing myocardial contractility and slowing the heart rate. They reduce the workload of the heart and oxygen demand of the myocardium by decreasing cardiac output and reducing blood pressure, and by increasing diastole they also allow greater perfusion of the myocardium. They are contraindicated in patients with asthma and peripheral vascular disease. They have been shown to reduce the incidence of MI.

Lipid-lowering therapy
Total serum cholesterol levels should be maintained below 5mmol/l, and low-density lipoprotein below 3mmol/l. Evidence suggests that statins can reduce the relative risk of death and MI by as much as 40%.(6) Most trusts have their own lipid-lowering guidelines with suggestions for first- and secondline treatment. Statins are well tolerated but are contraindicated in acute liver disease. Liver function tests should be performed at initiation and monitored at regular intervals, probably at 1-3 months after initiation of treatment. Lipid levels should also be assessed to monitor response to treatment.

Angiotensin-converting enzyme inhibitors (ACEIs)
ACEIs lower blood pressure by reducing peripheral vascular resistance and reducing aldosterone levels resulting in decreased sodium and water retention. The HOPE study has shown that using ramipril in patients with known CHD may reduce mortality and ischaemic events by 22%.(7)

Nitrates
Nitrates increase perfusion of the myocardium by relaxing coronary arteries. They also reduce the oxygen demand by the myocardium and improve the oxygen supply. Nitrates cause venous and arterial vasodilation, which reduces preload and afterload and increases coronary blood flow.
Nitrates are usually given as a short-acting GTN spray. Patients should be advised to use the spray whenever they get angina chest pain. If angina pain occurs patients should rest and take one to two puffs of their spray under the tongue. If no relief is obtained after five minutes they should continue to rest and take two more puffs. After a further five minutes this dose can be repeated, but if no relief is obtained within a further five minutes then the patient should call an ambulance. It is important that patients with angina are given written instructions on how to manage angina, how to use their spray and when to call 999. This is a major role for all practice nurses coming into contact with CHD patients. If patients lose their spray they can purchase further supplies over the counter at a pharmacy. GTN tablets have a short shelf-life, so  patients should be advised to check expiry dates regularly.
Patients who experience regular angina pain may be prescribed long-acting oral nitrates such as isosorbide
mononitrate (ISMN). They need to be advised to expect facial flushing and headaches, and occasionally these
drugs may cause hypotension and subsequent fainting.

Calcium antagonists
Calcium antagonists are vasodilators. They inhibit the uptake of calcium into the cardiac and smooth muscle cells of coronary and systemic arteries, causing peripheral arteriolar dilation. They also increase the refractory period, reducing the heart rate and decreasing blood pressure. Oxygen demand by the myocardium is reduced and the oxygen supply improved. Arterial vasodilation reduces afterload and coronary blood flow is increased. Angina pain is not always due to occlusive arterial disease but can be caused by spasm of the coronary arteries, called Prinzmetal's angina (variant vasospastic angina). Vasodilator drugs such as calcium antagonists (eg, diltiazem) can prevent spasm of the arteries.

Lifestyle advice
Angina can be reduced by altering modifiable risk factors, such as obesity, hypertension and hyperlipidaemia, and by maintaining good diabetes control. A practice nurse can help monitor risk factors and motivate patients to maintain a healthy lifestyle - healthy diet, smoking cessation, keeping active, and so on.

Activity
Physical activity and sexual intercourse may precipitate angina and prevent patients from keeping active. Patients can be advised to use a nitrate spray before the activity to prevent the onset of angina. If a patient can walk up two flights of stairs without chest pain then it is usually considered safe to have sex. If sex causes angina then patients should be encouraged to discuss this with a health professional. Advise that nitrate use is contraindicated with the use of sildenafil (Viagra; Pfizer).

Driving
If patients experience angina only with exertion then driving should be no problem. It is never safe for patients to drive if they have unstable angina (ie, pain at rest), and patients should be informed of this.

Travel
Travelling abroad and in aircraft is usually not a problem if angina is well controlled. Advise patients to plan well in advance, to plan ahead and take their time in order to avoid stress and also to avoid carrying heavy luggage. Problems can occur if walking at altitudes above 2,000 metres, and specialist advice should be sought.

The National Service Framework
The National Service Framework recommends regular review of patients with angina.(1) Reviews should be frequent until risk factors such as blood pressure and lipids are well controlled, and then should take place annually. This is an ideal opportunity for nurses to take the lead within the practice. A review should include:

  1. Symptom history - further episodes of angina, duration, frequency, precipitating and ­relieving factors.
  2. Blood pressure monitoring.
  3. Electrocardiogram - to assess for any changes from previous recordings.
  4. Medication concordance - check for any side-effects and problems, check that adequate dosages and ­correct preventive therapy have been ­prescribed.
  5. Lipid monitoring to check lipids are within the desirable range.
  6. Blood testing where appropriate to check ­haemoglobin, thyroid, kidney and liver function.
  7. Lifestyle advice.
  8. Advice on the recognition and management of symptoms, correct usage of GTN and when to call for help.

A structured systematic review of patients by a practice nurse can provide the necessary support, advice and monitoring to reduce CHD risks within the practice population and enable the appropriate management of angina. It can be a very rewarding role for both patient and nurse, while providing primary care with the necessary clinical support to meet the requirements of the NSF.

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References

  1. Department of Health. National Service Framework for coronary heart disease. London: The Stationery Office; 2000.
  2. Siva A, Noble M. Cardiology. London: Mosby; 1999.
  3. Cramer D. Endothelial injury and coronary artery disease. Australas J Emerg Care 1997;4(3):9-12.
  4. de Bono D. Investigation and management of stable angina: revised guidelines 1998. Heart 1998;81:546-55.
  5. Clapham C. The NSF on CHD: the rapid-access chest pain clinic. NiP 2002;Issue 6:19-21.
  6. Cruden N, Fox K. Management of stable angina in primary care. Prescriber 2002;13:19;28.
  7. Yusuf S, Sleight P, Pogue J, et al. Effects of an angiotensin converting enzyme inhibitor, ramipril, on -cardiovascular events in high risk patients. HOPE Study Investigators. N Engl J Med 2000;342:145-53.

Resources
NSF for Coronary Heart Disease
W:www.nelh.nhs.uk/nsf/chd
BMJ Journals
W:http://heart.bmjjournals.com
Department of Health
Coronary Heart Disease Information Strategy
W:www.doh.gov.
uk/ipu/strategy/ nsf/chd strat/chdisdoc4.htm
Health Evidence Bulletins Wales
Cardiovascular diseases
W:http://hebw.uwcm.ac.uk/cardio/index.htm
Effective
Health Care
Management of Stable Angina
W:www2.york.ac.uk/inst/crd/ehc35.pdf