Ischaemic Heart Disease and Lipid Lowering
Objectives
Epidemiology – importance & trends
Diet – trans-fats & Benecol
Risk factors – importance, modifying. Individual vs. population approaches
Management of presentations (NICE Guidelines)
Lipid options
Key message 1Pain NOW?Think ACS and get it right
Key message 2Lipids?Know is thisprimary prevention use table, Simva 40, forget
Secondary preventiontreat to “4 and 2”
______
Mr Andy Brown is a 34 year old man who comes to see you one morning and starts off with “I want to know if I should be worried about my heart”. He has just read an article in the Daily Mail that explains how big a killer it is and how important it is to talk to your GP about it....
How many people die of IHD each year?What trends are we seeing?
100,000 new diagnoses90,000 deathsRepresents 16% of deaths
Downward trend for last 10-15 years50:50smoking rates (in men)
1’ and 2’ prevention
UK has seen a 42% fall in death-rates over the last 10 years
IHD is a killer of the elderly – 60% of deaths are in over 80s, only 5% in the under 50’s
People in West Scotland are 6x more likely to die early from IHD than those in Surrey
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Mr Brown has a brother who lives in Austria. He says that the UK food industry is killing us through trans-fats and that he would live longer if he cut them out and replaced them by Benecol
What are trans-fats?
Read Wikipedia!
Part hydrogenated fats that are found in “manufactured foods” – raise LDL and lower HDL
Extend shelf-life. Soften hard fats at room temperature, cheaper than butter
Banned in increasing number of countries – UK going for “voluntary code”
1g rise in daily consumption = 10% rise in IHD rate
UK average is now about 2g per day (USA 5g) but much higher in some than in others
What is the role of plant stanols & sterols?
Reduce LDL - 1g per dayreduces LDL by 5%
No randomised control studies so no official recommendation for 1’ prevention
IF this 5% LDL drop was translated in IHD reduction, would expect reduce IHD by 10%
Probably add to stain effect but negated by Ezetimibe
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Mr Brown said that he does not smoke and he is not overweight – does his mean he will be spared from this big killer?
What RF’s are you aware of for IHD?
Organise into modifiable and non-modifiable
Population Attributable Risk, as opposed to individual risk
Consider the ‘Public Health’ perspective with the normal distribution of cholesterol levels
What is the UK average (5.8)?
Risk reduction – how to reduce the number at the top
1)Target those at the top (targeted primary prevention)
2)Move the whole population to the left (public health)
Talk though population attributable risks for IHD: (note these stats predate trans-fats)
Smoking22
BP 18
Chol esterol15
Exercise13
Alcohol1235% of UK adults exercised <30min in the last week
[Family History9]
Obesity6
What “public health” measures are you familiar with that address these?
______
He explains that his father recently had a heart attack and his brother has told him that he should have a CT to score the calcium in his heart
Has his brother got the right idea? What assessment tools are you aware of?
Invasive Coronary Angiography
Functional Perfusion Imaging (stress echo, thallium scans, cardiac MRI)
Exercise Stress Test
CT calcium scoring
Risk scoring
No evidence that coronary artery calcium scoring is better than QRisk as a screening tool
NICE Guidelines 2010 discuss a possible role in risk-stratifying:
low-risk individuals with atypical symptoms
Better PPV than exercise testing to select cases for CT angiography
Similar negative predictive value (97%)
Concerns – radiation and CT capacity
What is the history of risk scoring?
Framingham, Sheffield tables, QRisk
Qrisk maps better to UK population and data-set is updated annually
Qrisk allows “what if” scenarios and can display heart-age and age-average comparators
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Mr Brown then casually mentions that for the last few weeks he has been getting chest pains...
He describes tight pain in his chest and arm, not always brought on by exertion. Usually relieved by rest. He does not smoke, his TC last year was 5.6, his FBSL is normal
What are the three features that are used to identify angina pain?
1)Constricting pain in front of chest/ neck/ shoulders/ jaw/ arms
2)Precipitated by exertion
3)Relieved within 5 min by rest or GTN
Number present 3 = typical angina2= atypical angina1=non-anginal pain
Stable angina is unlikely if the pain is:
–continuous or very prolonged and/or
–unrelated to activity and/or
– brought on by breathing in and/or
–associated with dizziness, palpitations, tingling or difficulty swallowing.
NICE Guidelines – 2010 – Chest Pain of Recent Onset
Over 90treat as stable angina
Risk 60-90angiography
Risk 30-59functional imaging
Risk 10-29CT Calcium scoring
Under 10consider non-cardiac causes again
ICA is top of the pile – it must be the best
Cost & resource issues. Risk of harm
Subjectivity – any narrowing under 50% is not flow-limiting
Incidental post-mortem finding in 80% of 18-25 y/o at post-mortem
Functional perfusion imaging good at identifying which lesions are flow-limiting
Study when functional imaging compared to angiogram:
50% of patients undergo angioplasty with zero flow-limiting stenoses
72% of lesions angioplastied were not flow-limiting
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Mr Brown (Snr.) comes to see you a few weeks later to discuss his tablets... He had a STEMI, primary angioplasty and stenting
What medication would you expect him to be on?
AspirinClopidogrelSatin (high intensity)
ACEiB-blocker?
What (relative) risk reductions do these drugs achieve?
Statins30%
Aspirin25%
ACEi12.5%
Clopidogrel if stented
Beta-blocker – mixed evidence
Cumulative effect – who knows? (Explain statin over aspirin in primary prevention)
What about high-intensity statin therapy?
Standard statin therapy reduces risk of further events by about 30% (1’ and 2’ prevention)
High-intensity? Jury still out – number of RCTs is low
ACS – yes
MI - evidence is of reduction in events but not mortality
Achieves LDL reductions of 40% (nearer 20% with standard therapy)
Pin your scores
10Reducing dietary trans-fat consumption by 1g per day reduces IHD rates by 10%
20What proportion of IHD deaths are attributable to smoking
30Relative risk reduction from statins
40Reduction in IHD mortality rates over the last 10 years
50How severe does a stenosis need to be to be classified as rate-limiting
60What percentage of IHD deaths take place in over 80’s
70What percentage of revascularisations are on non-flow-limiting stenoses
80What percentage of 18-25 y/o Vietnam War casualties had CAD on post-mortem
90What is the likelihood of IHD in a 35 y/o male smoker with typical angina pain
Let’s look at some lipid profiles....
Mr Brown (Jnr.)
Age 34BP 120/80Never smokedFather MI aged 68yFBSL 4.9
TC 5.6HDL 1.4TG 1.7(TC:HDL 4.0)
How do you interpret this?
QRisk score is 2% but is QRisk appropriate?
Mr Black
Age 42BP 120/80Never smokedFather MI aged 57yFBSL 4.9
TC 6.6HDL 1.2TG 3.7(TC:HDL 5.5)
How do you interpret this?
QRisk score is 4.8% but is QRisk appropriate?
Mr Green
Age 47BP 120/80Never smokedFather MI aged 74yFBSL 7.9
TC 4.6HDL 1.1TG 3.4(TC:HDL 4.1)
How do you interpret this?
QRisk score is 7.4% but is QRisk appropriate?
Mr White
Age 67BP 120/80Ex-smokerHad MI aged 61yFBSL 5.9
TC 4.6HDL 1.1TG 3.4(TC:HDL 4.1)
On Simvastatin 20mg
On Simvastatin 40mg
If TC was 4.2?