national-clinical-guidelines-for-stroke-fourth-edition

National clinical guideline for stroke
5.5.3 Implications
The Quality and Outcomes Framework of the contract for general practice includes
incentives to ensure that people who have had a stroke are on an appropriate antiplatelet
or anticoagulant regimen. Provision of community-based anticoagulation services,
particularly for those with mobility problems will need consideration and may require
additional resource. This guideline is likely to lead to an increase in the prescribing of the
new oral anticoagulants, which are expensive but considered by NICE to be cost-effective,
particularly when used for secondary prevention where the attributable risk of stroke is
several times higher than in primary prevention.
5.6 Lipid-lowering therapy
Raised lipid levels, especially hypercholesterolaemia is a well-known risk factor for
atherothrombotic events, especially myocardial infarction. Lowering lipid levels is an
effective primary and secondary prevention treatment for vascular events, including
stroke.
Evidence to recommendations
The benefit of lipid-lowering therapy with statins has been confirmed in RCTs and
systematic reviews both for individuals with cardiovascular disease and more specifically
those with cerebrovascular disease (Amarenco et al 2006; Heart Protection Study
Collaborative Group 2002). The Heart Protection Study (HPS) investigated the effect of
simvastatin 40 mg daily in individuals at high risk of cardiovascular events and found a
relative risk reduction of 17% in vascular deaths, 27% in major coronary events and 25%
in stroke. On this evidence, treating 92 individuals with simvastatin should prevent one
major vascular event each year.
The SPARCL trial investigated the effect of atorvastatin 80 mg daily in individuals with a
history of TIA or stroke in the preceding 6 months and demonstrated a relative risk
reduction of 15% in stroke and 35% in major coronary events with treatment. In this
study population, treating 158 individuals with atorvastatin should prevent one major
vascular event each year.
Lowering low density lipoprotein (LDL) cholesterol by 1 mmol/L reduces cardiovascular
events by 21% and total mortality by 12% irrespective of baseline cholesterol level
(National Institute for Health and Clinical Excellence 2008a). This suggests that the
decision to initiate treatment should be determined by reference to an individual’s absolute
cardiovascular risk rather than their cholesterol level. The fact that even at low LDL
cholesterol levels, further reduction will achieve consistent relative risk reductions, raises
the question of whether it may be beneficial to pursue more aggressive treatment regimens.
The Cholesterol Treatment Trialists’ Collaboration (2010) compared more intensive (eg
40–80 mg atorvastatin) to less intensive (eg 20–40 mg simvastatin) statin therapy in
patients with a history of coronary heart disease by means of a meta-analysis of
individual participant data. They confirmed a 22% reduction in the risk of major
vascular events per 1 mmol/L reduction in LDL cholesterol, even at levels below 2
mmol/L, with more intensive regimens providing a 15% relative risk reduction when
compared to less intensive. The calculated absolute risk reduction achieved by intensive
70 © Royal College of Physicians 2012