Risk factor reduction

AHG symposium,2014

Dr Niels van Pelt

Cardiovascular disease- single most common

cause of death in NZ men and women...’leading

cause of death world wide and respects no

borders’(WHO)

~80% of CVD attributable to preventable risk

factors

CVD is often preventable (or at least deferred)

Steve is 57 yr old accountant. He jogs regularly

and is well

He smokes (especially if stressed at work), TC

4.65 mmmol/L, HDL 0.9, LDL 3, TG 1.7 and

TC/HDL ratio 5.2. His BP is 130/85, BMI 25 and

blood glucose is normal. Both parents have

hypertension.

A

case...

AHA/ACC published new guidelines in Circulation

2013- treatment of cholesterol to reduce

atherosclerotic cardiovascular risk in adults

They also developed a new risk calculator, using

a number of longitudinal studies, designed to be

more representative of the US population

The RAWG risk calculator assesses Steves 10

year risk at 10.9%

Framingham risk model over estimated risk in the

low risk and underestimates risk in high risk

groups (elderly, maori) in NZ

Predict database actively recruiting - will lead to a

more accurate NZ based risk assessment tool

What are the new ACC/AHA recommendations

statin therapy recommended for primary

prevention

for persons with LDL >4.9 mmol/L

for patients with diabetes if LDL >1.8 mmol/L

if the 10 year risk is >7.5% (using the RAWG

calculator) and LDL is >1.8 mmol/L

Monitoring of cholesterol levels on statins is not

recommended

Low/moderate/high intensity therapy

why changes in the recommendations?

lack of evidence of specific targets such as

LDL<1.8mmol/L

reduced adherence and concern about side effects

if treatment intensified to meet targets ( note small

risk of developing type 2 DM, increased risk of

myopathy with higher doses)

but actual number treated with statins is increased

Should Steve receive a statin?

a) Start atorvastatin now (as recommended by

ACC/AHA guideline)

b) Start a fibrate

c) Lifestyle modification (particularly smoking

cessation) and review need for statins in 6-12

months

d) Start statin and aspirin

Steve is at moderate (to high) risk at 14% 5 year

risk for MI, stroke- is any intervention required?

From June 2012-13, 588 patients<60yrs presented with first MI at MMH

30% diabetes, 40 % current smoker

The ‘average’ risk profile for MMH patients presenting with MI <60yrs is 12% five year risk-make up approx 50% of the patients

Intervention in Steve’s case is indicated

90% of ‘young’ people(<45yrs) who have a heart attack are smokers

smoking is the most important life style factor and cessation is most effective lifestyle intervention

Difficult to achieve- approx 50% smokers stop

after acute MI

Steve’s risk after 12 months of smoking

cessation

Physical activity

In healthy subjects physical activity and cardiac

fitness associated with up to 25-30% reduction

in CVD mortality

similar observations in secondary prevention

lifestyle interventions under utilised and success

in maintaining exercise variable

in established CVD <50% of people achieve

lifestyle goals- in primary prevention this is

even less

Successful lifestyle changes requires

motivated, informed person with good support

from GP and ‘health’ team’

12% relative reduction in major cardiovascular

events (primary prevention)

probably balanced by the small increase in

bleeding risk- aspirin not generally

recommended for primary prevention

Fibrates?- bezofibrate or gemfibrozil

No definite role in primary prevention, unless

diabetic patients with significant dyslipidaemia

(low HDL)

Accord study 2010 suggested small benefit in

this group

low HDL is probably not causal but associated

with other risk factors (metabolic syndrome)

Gemfibrozil significantly reduced events

(secondary prevention)

My approach with Steve

strongly encourage smoking cessation

review progress over the next 6-12 months- if stops

smoking risk is in low to intermediate range and

statins not required

if still smoking , then reasonable to reduce risk by

adding statin..if Steve concerned about long term

statin then reasonable to perform CT calcium score

to aid management

I often start atorvastatin at 20mg once a day

(moderate intensity) for primary prevention.

In secondary prevention atorvastatin 40-80mg

If side effects (myalgia) reduce dose, consider

alternate days, trial rosuvastatin

I don’t use ezetimibe

Steve’s case appeared recently in NEJM

Readers were given 3 options and polled

(n=1600)

not starting statin- 57%

starting statin and monitoring LDL-26%

starting statin and not monitoring LDL-17%

Maybe we should measure his lipoprotein a

level?

Lp(a) consists of cholesterol laden LDL particle

bound to plasminogen like glycoprotein

apolipoprotein(a)

Lp(a) levels are determined by LPA gene coding

for apolipoprotein(a)

Kringle IV type polymorphisms strongly

associated with Lp(a) levels

Elevated Lp(a) levels consistently assoc with a

modest increased risk of cardiovascular events

there are 3 factors

increased Lp(a) levels are associated with increased CVD risk

Kringle IV type 2 polymorphisms assoc with increased Lp(a) levels

Kringle IV type 2 polymorphisms assoc with increased CVD risk

Strongly suggests Lp(a) is a strong, independent risk factor

Should we measure Lp(a)?

no consistent assays and risk assoc is modest

but consider in patients who have CV events

when seemingly at low risk, those with strong

family history and those at intermediate risk

a high level (>50 mg/dl) may reclassify patients

to high risk and prompt more aggressive risk

reduction (BP, LDL)

Niacin (fibrates) reduces Lp(a) levels- but no

evidence yet that CVD events reduced

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are needed to see this picture.

Final comments

Risk assessment and risk reduction is

mandatory

Patients risk can be simply and effectively

reduced by lifestyle factors and when

appropriate drug therapy

Any statin is better than none- long term

adherence is the key

Professor Rod Jackson, School of Population Health ,

University of Auckland

NTT=59