Practical guidance for treating CHD

SIGN guidance on CHD offers a useful review of targets and treatment says, Dr Alan Begg looks at the review.

There have been a number of changes to guidance on CHD and the prevention of cardiovascular disease (CVD) recently. The four Scottish Intercollegiate Guideline Network (SIGN) guidelines in these areas provide a comprehensive overview.

Measurement of risk
Framingham risk scores underestimate risk in populations with high CHD mortality rates and men from lower social economic groups. The alternative ASSIGN risk score incorporates family history, smoking history and social deprivation into the risk assessment.

In line with the Joint British Societies' guideline (JBS2), SIGN regards all patients with a 10-year CVD risk of 20 per cent or greater as high-risk.

Cholesterol targets
No clinical trials evaluating the relative and absolute benefits of cholesterol lowering to different targets in relation to clinical events were identified.

Statin trials have shown an approximate linear relationship between the absolute reductions in LDL cholesterol and the proportional reductions in CVD events.

The JBS2 total cholesterol and LDL cholesterol targets of 4 and 2mmol/l could not then be recommended by SIGN.

BP lowering
Patients with confirmed CVD and systolic BP greater than 140mmHg and/or diastolic BP greater than 90mmHg should be considered for antihypertensive therapy. This is lower than the GMS quality targets.

The thresholds should be lowered to 130mmHg/ 80mmHg for patients with chronic kidney disease, diabetes with complications or target organ damage. Thresholds for treatment of patients without symptomatic CVD reflect JBS2.

Preventative drug therapy
Patients who have had an episode of acute coronary syndrome (ACS) should be given antiplatelet therapy, a statin, a beta-blocker and an ACE inhibitor. The same combination should be used in patients with stable angina.

If MI is complicated by left ventricular dysfunction (LVD) or heart failure (HF) then an angiotensin receptor blocker (ARB) is an alternative to ACE inhibitors.

Long-term therapy with the aldosterone antagonist eplerenone is recommended if the MI is complicated by LVD in the presence of either clinical signs of HF or diabetes.

Heart failure
In patients with suspected HF, a chest X-ray is recommended at an early stage to eliminate other causes of breathlessness. B-type natriuretic peptide (BNP) measurement can help decide whether an ECG is required.

In line with NICE, SIGN concludes that chronic heart failure can be excluded if BNP is low and ECG is normal.

ACE inhibitors and beta-blockers are recommended for all classes of heart failure. ARBs can be used in cases of ACE intolerance. For New York Heart Association (NYHA) class II and III patients candesartan is recommended. Spironolactone is the next drug recommended for NYHA class III and IV. These drugs should be started on specialist advice.

Diuretics should be considered for heart failure patients with dyspnoea or oedema but digoxin should be considered only as add-on therapy for heart failure patients in sinus rhythm who are still symptomatic after optimal therapy.

Rhythm control
The prevalence of AF rises with advancing age and will rise as the population gets older. AF is commonly due to CHD but hypertension, valvular disease and LVD should also be considered.

AF increases the risk of stroke and sudden death, however, in patients with well-tolerated AF, rate control is superior to rhythm control. There is no difference between the two approaches in the incidence of thromboembolism, incident heart failure or mortality.

Psychological interventions
Depression and social isolation are significant independent risk factors in CHD. Screening and assessment of patients with CHD for depression is now part of the QOF.

Action plan for prevention of CVD
  • Risk should be measured using the JBS2 cardiovascular risk prediction charts.
  • Pre-existing CVD patients and those with a [s40]20 per cent 10-year risk require intensive management.
  • A cholesterol target of 5mmol/l should be used. Established CVD requires intensive statin therapy. Other at-risk patients can be given 40mg simvastatin.
  • Long-term antiplatelet therapy should include aspirin, with added clopidogrel for four weeks in patients with ST elevation ACS, and three months in non-ST elevation ACS.
  • ECG and BNP measurements in patients with chronic heart failure signs indicate when an echocardiogram is required.
  • Stable LVD heart failure should be treated with beta-blockers.
  • Rate control is recommended for patients with well-tolerated AF. Beta-blockers, a rate-limiting calcium channel blocker or digoxin should be used.
  • Psychological treatment should be considered for CHD patients and those requiring coronary artery bypass surgery.

Dr Begg is a GP in Montrose, Angus

Full SIGN guidelines are available at www.sign.ac.uk

References
  • JBS2: Joint British Societies' guidelines on prevention of CVD in clinical practice. Heart 2005: 91 Suppl 5: v1-52.
  • NICE. Statins for the prevention of cardiovascular events. Technology Appraisal 94. NICE, London, 2006.
  • NICE. Clopidogrel in the treatment of non-ST-segment-elevation acute coronary syndrome. Technology Appraisal 80. NICE, London, 2004.
  • NICE. Management of chronic heart failure in adults in primary and secondary care. Clinical Guideline 5. NICE, London, 2003.
  • McMurray et al. Effects of candesartan in patients with chronic heart failure and reduced left-ventricular systolic function taking angiotensin-converting-enzyme inhibitors: the CHARM-Added trial. Lancet 2003; 362: 767-71.

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