The SIGN, NICE, and JBS2 guidelines are reviewed by Dr Alan Begg, who highlights recommendations on CVD prevention and the challenges for effective implementation

Following on from the publication in February 2007 of the Scottish Intercollegiate Guidelines Network (SIGN) guideline on risk estimation and the prevention of cardiovascular disease (CVD),1 NICE published guidance on secondary prevention following a myocardial infarction (MI) in May 2007.2 Both these documents illustrate the difficulty of guideline development groups in deciding whether to cover all aspects of the prevention of CVD, or whether to restrict their recommendations to a specific disease category. Evidence-based quality targets for general practice, set down by the quality and outcomes framework (QOF),3 are invariably based on disease categories and tend to reflect the recommendations of national clinical guidelines.

Lifestyle and dietary changes

Effective lifestyle and dietary changes remain the cornerstone of any intervention programme to reduce cardiovascular risk and prevent future events (Tables 1 and 2). One significant change is the importance that NICE2 places on the consumption of at least 7 g of omega 3 fatty acids per week by patients who have had an MI. This can be provided by eating 2–4 portions of oily fish per week. If in the first 3 months post-MI it is obvious that patients are not achieving that level of intake, then prescribing 1 g daily of omega-3-acid ethyl esters for up to 4 years should be considered. This treatment has been shown to have significant benefits, reducing death rates, non-fatal cases of MI, and stroke in patients who have experienced a recent MI.5

Table 1: Lifestyle changes

SIGN 97: risk estimation and the prevention of cardiovascular disease1 NICE CG48: MI—secondary prevention2 JBS2: prevention of cardiovascular disease in clinical practice4
Smoking Advise all people to quit and offer support to facilitate this Advise to quit. Offer assistance from smoking cessation service; patients with a desire to quit should be offered support and referral to an intensive support service. Pharmacotherapy should be offered to those unable or unwilling to accept a referral Advise to quit
Alcohol Light to moderate alcohol consumption may be protective (in patients with or without evidence of coronary heart disease) Keep within safe limits: men ?21 units/week; women ?14 units/week. Avoid binge drinking (more than three alcoholic drinks in 1–2 hours) 1–3 units per day may be considered safe
Physical activity Moderate intensity exercise is advised for the whole population to the point of slight breathlessness Exercise for 20–30 minutes per day to the point of slight breathlessness Regular aerobic activity lasting at least 30 minutes should be taken on most days of the week
Weight control Target with interventions to reduce weight and maintain reduction Offer advice and support to achieve and maintain a healthy weight Maintain ideal body weight and avoid central obesity

Table 2: Dietary changes

 

SIGN 97: risk estimation and the prevention of cardiovascular disease1 NICE CG48: MI—secondary prevention2 JBS2: prevention of cardiovascular disease in clinical practice4
Saturated fat Recommend a diet low in total and saturated fat Replace butter and cheese with products based on vegetable and plant oils Reduce saturated fats— increase intake of monounsaturated fats
Keep dietary fat intake to <30% total energy consumption, saturated fat to <10% total fat, and total dietary cholesterol to <300 mg/day
Omega 3 fats Eat two portions of fish per week, one of which should be a fatty fish Consume 7 g of omega 3 fatty acids per week from 2–4 portions of oily fish, or consider omega-3-acid ethyl esters 1 g daily, to be taken for up to 4 years post-myocardial infarction (MI) in patients who have had an MI within 3 months At least two servings of fish per week
Fruit/ vegetables Increase fruit and vegetable consumption Encourage Mediterranean-style diet—more bread, fruit, vegetables, and less meat Five portions per day
Salt Reduce as much as possible if hypertensive Limit intake to <6 g of sodium/day
Supplements Antioxidants not recommended. Folate, stanol esters, plant sterols, nuts, and soya require more evidence Advise against taking supplements containing beta carotene, and do not advise to take antioxidants (vitamins E or C), or folate No benefit shown for vitamins E and C. There is no evidence for folate. Beta carotene has an increased risk of cardiovascular death

Pharmacological prevention of future CVD events

The current guidelines from SIGN1,6 indicate that all patients experiencing an episode of MI or acute coronary syndrome (ACS) should receive combined treatment. This should include:

  • antiplatelet therapy
  • angiotensin-converting enzyme (ACE) inhibitors if there is unstable angina or evidence of myocyte necrosis or with clinical MI
  • beta blockers if there is unstable angina or evidence of myocyte necrosis or with clinical MI
  • statins (see Table 3).

Patients with stable angina will receive a similar combination of therapy, although beta blockers would be prescribed as first-line therapy for the relief of symptoms only.8 Consider ACE inhibitors for all patients with stable angina as they have been shown to reduce the risk of death, non-fatal MI, and stroke.

Based on the evidence of those exhibiting ACE inhibitor intolerance, SIGN6 only recommends long-term angiotensin receptor blocker (ARB) therapy in patients whose MI is complicated by left ventricular dysfunction or heart failure. By contrast, NICE2 appears to suggest substituting an ARB in patients intolerant of or allergic to an ACE inhibitor.

Table 3: Use of statins in the prevention of CVD

SIGN 97: risk estimation and the prevention of cardiovascular disease1 NICE TA 94: statins for the prevention of cardiovascular events7 JBS2: prevention of cardiovascular disease in clinical practice4
High risk threshold based on Framingham function Asymptomatic individuals with risk of first cardiovascular event over 10 years ?20% Adults who have a 20% or greater 10-year risk of developing CVD Total CVD risk ?20% over 10 years
Isolated risk factor TC ?8 mmol/l Elevated TC to HDL cholesterol ratio
?6.0 mmol/l or LDL cholesterol >5 mmol/l
Primary prevention Simvastatin 40 mg Initiate with a drug with low acquisition cost Statin—not all drugs in this class have been shown to reduce MI and coronary heart death
Secondary prevention Intensive statin therapy Clinically and cost effective. Initiate with drug with low acquisition cost—there is no data on clinical events to suggest one superior over the other As above
Target levels Quality target:
• TC <5 mmol/l
Audit standard:
• TC <5 mmol/l
• LDL cholesterol <3 mmol/l
Optimal target:
• TC <4 mmol/l or 25%
reduction
• LDL cholesterol <2 mmol/l
or 30% reduction

CVD=cardiovascular disease; TC=total cholesterol; HDL=high density lipoprotein; LDL=low density lipoprotein; MI=myocardial infarction

Antiplatelet therapy

Aspirin monotherapy remains the antiplatelet therapy of choice for occlusive vascular disease, although modified-release dipyridamole (200 mg twice daily) should be added to therapy in patients who have had a stroke or a transient ischaemic attack;1,9 the NICE technology appraisal specifies this should last for at least 2 years. Clopidogrel on its own is an alternative for patients in whom aspirin is contraindicated for all forms of occlusive vascular disease.1,9 Combination aspirin and clopidogrel should be prescribed for 4 weeks after an ST-elevation ACS episode and for 3 months in non-ST-elevation ACS.6 The current NICE advice2 is to continue combination therapy for 12 months in line with their previous technology appraisal,10 an approach which may give more adequate cover for those who have had a coated stent inserted as a revascularisation procedure.6,8

Drugs for primary prevention

The use of statins to lower cholesterol depends on the measured level of risk (see Table 3).4,7 The same risk cut-off point applies to the initiation of drug therapy in those with Grade I mild hypertension (Table 4),4,11 with consensus being reached on the use of the ACD algorithm for drug sequencing.1,4,12 The evidence supports the use of aspirin if the 10-year CVD risk exceeds 20%, with benefit outweighing harm if the patient's blood pressure has been reduced to <150/90 mmHg in patients over the age of 50 years.1,11

Table 4: Thresholds for commencing drug treatment to lower blood pressure

SIGN 97: risk estimation and the prevention of cardiovascular disease1 NICE CG48: MI—secondary prevention2 JBS2: Prevention of cardiovascular disease in clinical practice4
Mild hypertension Consider treatment if clinical evidence of CVD and SBP >140 mmHg and/or DBP >90 mmHg Treat to BP target of 140/90 mmHg Consider treatment if SBP ?140 mmHg and/or DBP ?90 mmHg and clinical evidence of CVD or diabetes or target organ damage or a total risk CVD risk ?20%
CVD and co-morbidities Consider treatment if CVD risk (post MI, stroke or TIA) and CKD or diabetes with complications and SBP >130 mmHg and/or DBP >80 mmHg Treat to BP target lower than 140/90 mmHg if diabetes or renal disease Consider treatment if SBP >130 mmHg and/or DBP >80 mmHg and very high CVD risk (post MI, stroke or TIA), established CKD, or diabetes with complications
Moderate or severe hypertension Treat all if SBP ?160 mmHg and/or DBP ?100 mmHg Treat all if SBP ?160 mmHg and/or DBP ?100 mmHg

CVD=cardiovascular disease; SBP=systolic blood pressure; DBP=diastolic blood pressure; BP=blood pressure; MI=myocardial infarction; TIA=transient ischaemic attack; CKD=chronic kidney disease

Cholesterol targets

The JBS2 guideline points out that 'there are no clinical trials that have evaluated the relative and absolute benefit of cholesterol lowering to different total and low density lipoprotein cholesterol in relation to clinical events'.4 Citing a systematic review of the evidence for cholesterol lowering to low targets using a statin,13 SIGN1 noted that there was a compelling case for the effectiveness of cholesterol lowering (see Table 3) but not to the level suggested by JBS2.4 The current cholesterol QOF quality target of 5 mmol/l is, therefore, likely to remain unchanged, especially if it is reflected in the forthcoming NICE guideline on cardiovascular risk assessment, which is due to be published in 2007.14

QOF review

The QOF is subject to ongoing review and development in order to ensure that it accurately reflects changing general practice.15 The expert panel, which was appointed for a period of 3 years in May 2006, is expected to submit to the QOF subgroup in autumn 2007 a report on whether the QOF categories reflect current health priorities and the evidence available to support them. At present the QOF clinical indicators include the secondary prevention of coronary heart disease and stroke as well as individual risk factors such as hypertension, obesity, and smoking. However, there is no requirement to carry out a full primary prevention risk assessment on patients at high risk of developing the disease.

Models of care

National achievement of the QOF indicators related to CVD prevention remains high across the UK,16 although the way in which to achieve these levels is left to the individual practice. Lowering of the individual targets for lipid and blood pressure control, for which there may not be the evidence, will make future high achievement extremely difficult. We know that long-term structured follow-up in primary care can improve secondary prevention components leading to fewer deaths and coronary events.8 The increased resources in terms of staffing, premises, and drug costs required in primary care to introduce a programme of primary prevention have been calculated by SIGN,17 and these would need to be in place before a national screening programme could be introduced.

Future developments

As with all guidelines, the challenge is in effective implementation. Practices have shown that a high level of effective secondary prevention measures for CVD is possible and, with the right resources, targeted primary prevention can also make a difference. There is an opportunity with the next QOF update for introduction in April 2008, the forthcoming NICE guidance,14 as well as a national screening programme, to make this a reality.

  • Effective lifestyle and dietary changes are key—investment may be needed outside the traditional health services budget to promote this
  • Smoking cessation is a very cost-effective intervention
  • There is no definitive evidence for energetic lipid lowering in primary prevention—most patients should be effectively treated with generic statins at lower cost
  • The cost in premises, staffing, and drugs for a primary prevention screening programme are considerable and have been mapped by SIGN1
  • Cost of statins per month: simvastatin 40 mg = £3.40; atorvastatin 20 mg = £24.64, 40 mg and 80 mg = £28.212
  1. Scottish Intercollegiate Guidelines Network (SIGN 97). Risk estimation and the prevention of cardiovascular disease. A national clinical guideline. Edinburgh: SIGN, 2007.
  2. 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.
  3. Department of Health. Revisions to the GMS contract, 2006/07: Delivering investment in general practice. London: DH, 2006.
  4. JBS2: Joint British Societies’ guidelines on prevention of cardiovascular disease in clinical practice. Heart 2005; 91 (suppl 5): v1–52.
  5. Gruppo Italiano per lo Studio della Sopravvivenza nell’Infarto miocardico. Dietary supplementation with n-3 polyunsaturated fatty acids and vitamin E after myocardial infarction: results of the GISSI-Prevenzione trial. Lancet 1999; 354 (9177): 447–455.
  6. Scottish Intercollegiate Guidelines Network (SIGN 93). Acute coronary syndromes. A national clinical guideline. Edinburgh: SIGN, 2007.
  7. National Institute for Health and Care Excellence. Statins for the prevention of cardiovascular events. Technology appraisal 94. London: NICE, 2006.
  8. Scottish Intercollegiate Guidelines Network (SIGN 96). Management of stable angina. A national clinical guideline. Edinburgh: SIGN, 2007.
  9. National Institute for Health and Care Excellence. Clopidogrel and modified-release dipyridamole in the prevention of occlusive vascular events. Technology appraisal 90. London: NICE, 2005.
  10. National Institute for Health and Care Excellence. Clopidogrel in the treatment of non-ST-segment-elevation acute coronary syndrome. Technology appraisal 80. London: NICE, 2004.
  11. Williams B, Poulter N, Brown M et al. Guidelines for management of hypertension: report of the fourth working party of the British Hypertension Society, 2004-BHS IV. J Hum Hypertens 2004; 18 (3): 139–185.
  12. National Collaborating Centre for Chronic Conditions. Hypertension: management of hypertension in adults in primary care (partial update). London: Royal College of Physicians, 2006.
  13. Hayward R, Hofer T, Vijan S. Narrative review: lack of evidence for recommended low-density lipoprotein treatment targets: a solvable problem. Ann Intern Med 2006; 145 (7): 520–530.
  14. National Institute for Health and Care Excellence. Guideline in development. Cardiovascular risk assessment: the modification of blood lipids for the primary and secondary prevention of cardiovascular disease. https://www.nice.org.uk/guidance/page.aspx?o=269597
  15. Developing the Quality and Outcomes Framework. http://www.nhsemployers.org/primary/primary-2173.cfm
  16. Online GP practice results database. Quality and Outcomes Framework for GP practices. http://www.qof.ic.nhs.uk/floats/faqs.asp
  17. Scottish Intercollegiate Guidelines Network. Management of coronary heart disease.A national clinical and resource impact framework. Edinburgh: SIGN, 2007.G