The four recently published Scottish Intercollegiate Guideline Network (SIGN) guidelines covering CHD and the guideline on the prevention of cardiovascular disease (CVD) provide a rigorous review and careful interpretation of the evidence.
GPs need to know the action they should take to change their current practice to implement these guidelines (see box).
Measurement of risk
Framingham scores have long been the basis of risk estimation in the UK. However, in some groups, such as populations with high CHD mortality, the risk is underestimated. The ASSIGN risk score, when available, will use standard risk factors, but incorporate family history, number of cigarettes smoked and social deprivation based on postcode.
Although the evidence supporting the decision to regard all patients with a 10-year CVD risk of M20 per cent as high risk is not clear, it does bring SIGN into line with JBS2.1
Cholesterol and BP
The guideline development group was unable to identify any clinical trials that evaluated the relative and absolute benefits of cholesterol lowering to different targets in relation to clinical events. The JBS2 total cholesterol and LDL targets of 4mmol/L and 2mmol/L could not be recommended.
Patients with confirmed CVD should be considered for BP-lowering drug therapy if systolic BP is >140mmHg and/or diastolic BP is >90mmHg. This threshold should be lower, that is, a systolic BP >130mmHg and/or diastolic BP >80mmHg, for patients who have chronic kidney disease, diabetes with complications, or target organ damage.
Preventive drug therapy
Patients who have had an episode of acute coronary syndrome (ACS) should be treated with antiplatelet therapy, a statin, a beta-blocker and an ACE inhibitor. The same combination applies to those with stable angina.
If the MI is complicated by left ventricular dysfunction (LVD) or heart failure, an angiotensin-receptor blocker (ARB) would be an alternative for those intolerant of an ACE inhibitor. Long-term eplerenone therapy is recommended if the MI is complicated by LVD (ejection fraction <0.40) in the presence of either clinical signs of heart failure or diabetes mellitus.
In patients with suspected heart failure, the measurement of B-type natriuretic peptide (BNP) is useful in deciding when an echocardiogram is required. Very high values make heart failure likely in the absence of other causes of raised BNP.
A chest X-ray is recommended to eliminate other potential causes of breathlessness, with echocardiography being helpful in diagnosing heart failure and determining its cause. In line with NICE,2 the SIGN guideline concludes that chronic heart failure can be excluded if BNP is low and ECG is normal.
The use of ACE inhibitors and beta-blockers in all classes of heart failure is recommended by the SIGN guideline. Diuretics should be considered for heart failure patients with dyspnoea or oedema, but digoxin should be considered only as an add-on therapy for heart failure patients in sinus rhythm who are still symptomatic after optimal therapy. An ARB can be used for patients unable to tolerate an ACE inhibitor.
Rate or rhythm control
AF is commonly due to CHD, but other factors, such as LVD, hypertension and valvular disease, should be considered. It is associated with an increased risk of stroke and sudden death, but in patients with well-tolerated AF, rate control is superior to rhythm control in terms of morbidity.
Depression and social isolation are significant risk factors for the development of CHD and its prognosis. Screening of CHD patients for depression is part of the quality framework.
The full guidelines, quick reference guides and notes for patients are available at www.sign.ac.uk .
- Dr Alan Begg is a GP in Montrose, Angus, honorary senior lecturer at the University of Dundee and a member of the SIGN CHD Guidelines Development Steering Group
1. JBS2: Joint British Societies' guidelines on prevention of cardiovascular disease in clinical practice. Heart 2005;91 Suppl 5:v1-52.
2. NICE. Management of chronic heart failure in adults in primary and secondary care . Clinical Guideline 5. NICE, London, 2003.
3. NICE. Statins for the prevention of cardiovascular events . Technology Appraisal 94. NICE, London, 2006.