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Case 452: Gauging the risk
Authors and Affiliations
Dr Meenal Sharma
Faculty of Health Sciences
University of Adelaide
Professor Barry McGrath
Department of Medicine
Monash University
VictoriaThis case discusses the assessment and management of risk factors in coronary heart disease.
Case Overview
Learning Objectives
The graduating student should be able to:
identify
the clinical presentation of a patient with hyperlipidemia
intepret
lipid studies
recognise
carry
hyperlipidemia as a major risk factor in cardiovascular disease
out assessment of cardiovascular risk in a patient
explain
outline
identify
the role of lipid lowering therapy in reducing cardiovascular risk
the role of non-pharmacological management
associated co-morbidities commonly seen in patients with hyperlipidemia
Other relevant areas of learning:
1. Physiology of lipid metabolism and storage
2. Pathophysiology of hyperlipidemia
3. Pathophysiology of coronary heart disease
Question 1 : MS
Question Information:
A middle-aged man comes in for routine check-up as part of his work requirements. Mr Beddoe has not
complained of any recent chest pain, shortness of breath, weight loss, fatigue or malaise. He feels that
he is not as fit as he used to be but puts this down to age and general lack of time for exercise. He has
not been to see a doctor for the past five years but remembers being told previously that his blood
pressure was a little high. You want to ask him some questions about his cardiovascular risk status.
Question:
Information about which of the following questions would be appropriate?
Choice 1: His ethnicity Score : 1
Choice Feedback:
Correct. Aboriginal and Torres Strait Islander population are classified as a high risk group for
cardiovascular disease when compared to other Australians.
Choice 2: His age Score : 1
Choice Feedback:
This is a non modifiable risk factor. Risk is known to increase with age however it must be remembered
that the Framingham risk calculator does not represent the over 70 population.
Choice 3: Any past history of angina, heart attack, mini stroke or stroke Score : 1
Choice Feedback:
This is a major cardiovascular risk factor. Patients with known vascular disease are in the high risk
group.
Choice 4: Any known elevation of his blood sugar levels Score : 1
Choice Feedback:
Diabetes is also an independent risk factor for CHD. If he has not been to a doctor for five years he is
unlikely to know the answer to this question.
Choice 5: Any known kidney problems Score : 1
Choice Feedback:
Chronic kidney disease is also a major risk factor and the Heart Protection Study (HPS) trial has shown
there is benefit in reducing cardiovascular events.
Choice 6: Any family history of heart attack, stroke, high blood pressure, diabetes or high cholesterol Score : 1
Choice Feedback:
It is important to ascertain the age of these vascular events as premature CHD (less than 60 years of
age) confers a 10 to 15% risk of a cardiovascular event in the next five years. Family history of high
cholesterol may point to familial hypercholesterolemia.
Choice 7: Any smoking history Score : 1
Choice Feedback:
Correct. Any cigarette smoked within the last 12 months is included in the Framingham equation.
Question 2 : MS
Question Information:
On questioning Mr Beddoe he tells you he is 48 years old. His health has generally been good and he is
not on any prescribed medication. He was previously told he had hypertension but he never followed up
on this and is not sure what his current blood pressure is.
His father suffered a non-fatal heart attack at age 65. His 53 year old brother had an angioplasty and
stent insertion at age 52. Mr Beddoe smokes 15 cigarettes a day and drinks a glass of wine with dinner
most nights. His diet mostly consists of take away and he does little if any exercise.
You need to consider findings that might be classified as equivalents of coronary heart disease - in
other words, defined risk factors that puts the patient at similar risk for coronary heart disease as a
history of prior coronary heart disease itself.
Question:
Which of the following are classified as coronary heart disease equivalents?
Choice 1: Diabetes mellitus Score : 1
Choice Feedback:
Correct. Diabetes is a very important cardiovascular disease risk factor due to its macrovascular
complications.
Choice 2: High density lipoprotein greater than 1.55 mmol/L Score : -1
Choice Feedback:
Incorrect. High density is a protective factor against cardiovascular disease and if present allows
removal of another an identified major risk factor from the patient profile.
Choice 3: Peripheral arterial disease Score : 1
Choice Feedback:
Correct. The presence of peripheral vascular disease is a very important indicator identified by the Adult
Treatment Panel (ATP III).
Choice 4: High homocysteine levels Score : -1
Choice Feedback:
Incorrect. Although cardiovascular events are often associated with high homocysteine levels,
controlled trials have not shown improved outcomes when targeting this risk factor.
Choice 5: Symptomatic carotid artery disease Score : 1
Choice Feedback:
Correct, this is an indicator of major vessel atherosclerotic disease.
Choice 6: Abdominal aortic aneurysm Score : 1
Choice Feedback:
Correct. An abdominal aortic aneurysm as evidenced by the ATP guidelines recognizes an increased
incidence of adverse coronary vascular events in patients with underlying aneursymal to the extent that
it is classified as a coronary heart disease equivalent.
Choice 7: Asthma Score : -1
Choice Feedback:
Incorrect. Asthma is characterized by acute inflammation of the airways as a consequence of a type I
mediated hypersensitivity reaction. Although potentially life threatening, this process has no bearing on
CHD.
Choice 8: Multiple risk factors which result in a ten year risk of CHD of greater than 20% Score : 1
Choice Feedback:
Correct. This is calculated using the Framingham equation.
Question 3 : MS
Question Information:
At this stage you cannot identify any other events from the history that would be a coronary heart
disease equivalent risk factor. You are finished having an insightful chat with Mr Beddoe in regards to
his medical history and feel that it is time for some action.
Question:
Which of the following would help define this risk?
Choice 1: Blood pressure Score : 1
Choice Feedback:
Correct. Hypertension is an important major risk factor for CHD. This is defined as a systolic blood
pressure greater than 140mmHg and diastolic greater than 90mmHg on serial readings.
Choice 2: Respiratory rate Score : -1
Choice Feedback:
Incorrect. Although part of the routine †˜ vitals†™ assessment, eliciting this sign does not influence
CVD risk.
Choice 3: Heart sounds Score : 1
Choice Feedback:
Correct. The presence of 3rd or 4th heart sounds are indicative of impaired filling against a noncompliant ventricle.
Choice 4: Carotid artery auscultation Score : 1
Choice Feedback:
Correct. Bruits would imply carotid stenosis which is due to atherosclerosis. This is a good indicator of
vascular disease and is a CHD equivalent.
Choice 5: Fundoscopy Score : 1
Choice Feedback:
Given his past history of long standing hypertension, it is important to check his eyes for any signs of
hypertensive retinopathy.
Question 4 : MS
Question Information:
Your physical examination reveals a BMI of 29. His BP is 170/95 mmHg. Cardiovascular examination
reveals dual HS and nil murmurs. The JVP is not elevated. There are no thrills or heaves. No carotid
bruits heard. Peripheral pulses are strong and there is no ankle oedema. Respiratory examination is
normal. No abnormalities are detected on abdominal examination. Thyroid examination is
unremarkable.
Rather predictably Mr Beddoe is in need of further investigations to fully quantify his cardiovascular risk.
You perform a lipid profile on Mr Beddoe. The results are shown below:
CUMULATIVE LIPID RISK REPORT FASTING
Total
Cholesterol 7.1 mmol/L
Triglycerides
0.6 mmol/L
MEASURED FRACTIONS
HDL
(protective) 2.39 mmol/L
LDL
(atherogenic) 3.87 mmol/L
Total/HDL
ratio 3.0
Question:
Which of the following would be useful in treating this patient†™s lipid profile?
Choice 1: Statins Score : 1
Choice Feedback:
Statins are generally first line therapy as they have shown to reduce cardiovascular events and overall
mortality. They are the most effective drug group in reducing LDL levels. They are HMGCo-A reductase
inhibitors. Atorvostatin is one of the more potent statins due to its long half life. Some statins including
Simvastatin is taken at night as hepatic cholesterol synthesis is greatest then.
Choice 2: Fibrates Score : 1
Choice Feedback:
This group of drugs reduce triglyceride levels by agonising the action at the PPAR-alpha receptor that
increases beta oxidation of lipids in the liver. It also increases the activity of lipoprotein lipase thereby
increasing LDL breakdown.
Choice 3: Nicotinic acid Score : 0
Choice Feedback:
This is for combined hyperlipidemia or in patients with low levels of HDL. Its main action is to decrease
peripheral breakdown of fats within adipose tissue thereby reducing availability of free fatty acids in the
circulation. It is generally not a very well tolerated drug and causes excessive flushing in many patients.
Choice 4: Ezetimibe Score : 0
Choice Feedback:
This is not used as first line therapy. It is most effective when used in combination with a statin if LDL
target levels are not being reached with statins alone or if patients are not able to tolerate high doses of
statins.
Choice 5: Diet Score : 1
Choice Feedback:
The patient should decrease their intake of saturated fats. Saturated fats should only be 10% of total
daily fat intake. Patients are also advised to increase fibre in their diet as it slows down cholesterol
absorption from gut.
Question 5 : MS
Question Information:
Based on your interpretation of Mr Beddoe†™s lipid profile and his concomitant risk factors, you
decide that some form of lipid lowering therapy must be initiated. You cannot help but recall a
pharmacology lecture you had one afternoon during your medical school years warning you about the
bad things lipid medications can do to you.
Question:
What are the side effects of the major groups of lipid modifying therapy?
Choice 1: Rhabdomyolysis Score : 1
Choice Feedback:
A rare but significant complication of statin therapy is rhabdomyolysis and thus CK should be measured
prior to initiation of therapy. The risk of myopathy is further increased if used in combination with a
fibrate. If myopathy does develop the drug should be ceased and the patient started on a different class
of lipid lowering therapy.
Choice 2: Hepatoxicity Score : 1
Choice Feedback:
This side effect is dose dependent.
Choice 3: Cancer Score : 0
Choice Feedback:
The 4S study showed no difference when comparing treatment group to placebo.
Choice 4: Memory loss Score : 1
Choice Feedback:
Correct. Some of the less well known side-effects of statins include depression, memory loss, sleep
disturbances and sexual dysfunction.
Choice 5: Myositis Score : 1
Choice Feedback:
Most patients complain of muscle aches and weakness combined with a CK elevation. Patients are at
increased risk of myositis if they are also taking macrolides, cyclosporine or anti-fungals.
Question 6 : MS
Question Information:
You are wise to the ways of the world, and duly acknowledge that sometimes for all your encouraging
and informative words, patients do not always adhere to their doctor's advice.
Question:
In what ways can you improve compliance with medication?
Choice 1: Educate the patient, sets goals and target levels Score : 1
Choice Feedback:
Correct. The adherence of a patient to his or her medications will depend on many things, including how
well they understand the purpose of the therapy. It may also help if a target range for the lipid profile
could be given to the patient.
Choice 2: Provide the most expensive lipid lowering therapy Score : 0
Choice Feedback:
The most expensive therapy is not necessarily the most effective.
Choice 3: Encourage family involvement in management Score : 1
Choice Feedback:
Correct. Positive encouragement from other family members involved the well-being of the patient is
likely to be helpful.
Choice 4: Recall systems Score : 1
Choice Feedback:
Correct. In many areas - eg the management of ocular hypertension - the outcome of management can
be improved by careful follow-up and minimising the default rate. The use of computer-based booking
systems and active follow-up practices for patients who default from appointments are types of recall
that can be used to improve the outcomes of treatment.
Choice 5: Tell the patient that it is crucial to take the medication because if he does not he could possible suffer a
heart attack or stroke Score : 0
Choice Feedback:
Incorrect. It is more appropriate to try and use positive methods to reinforce compliance with
medication.
Choice 6: Regular review and follow up, serial measurement of lipid levels (every 6-12 months) Score : 1
Choice Feedback:
Correct. Such patients should be offered regular review (every 6-12 months) with measurement of their
serum lipid levels and positive reinforcement about their compliance with medication.
Choice 7: Dosettes for older patients Score : 1
Choice Feedback:
Correct. Older patients are frequently on many medications which may need to be taken on different
days and at different times. Dosettes are an effective way of minimising confusion.
Synopsis
Lipids are fats that are absorbed via the digestive system or produced in the liver. The primary function
of triglycerides is as an energy source stored in adipocytes or fat cells and also in myocytes or muscle
cells. Defects in the the synthesis, metabolism and clearance of lipids result in dyslipidemia or
hypercholesterolaemia, which is an important risk factor for the development of atherosclerosis and
cardiovascular disease. The use of risk assessment tools, the appropriate initiation of non
pharmacological management (i.e lifestyle modification) and, subsequently, the use of the right anti lipid
medication for the individual's lipid profile allow for a significant reduction in the cardiovascular disease
risk of the patient.
The knowledge of current risk stratification guidelines, and the use of statins, fibrates and agents that
reduce absorption of triglycerides (i.e ezetimibe) must be modified to the patients individual lipid profile,
and maximized for optimal treatment and reduction of their cardiovascular disease risk.
Monash
May 2010
Support for this case has been provided by the Australian Learning and Teaching Council Ltd, an
initiative of the Australian Government Department of Education, Employment and Workplace
Relations. The views expressed in this case do not necessarily reflect the views of the Australian
Learning and Teaching Council.