Why Lp(a) Matters More Than You Think – Dr Loh Wann Jia Explains
Transcript:
Introduction
Hello, I’m Dr Loh Wann Jia. I am a Consultant Endocrinologist at Changi General Hospital, Singapore. I’m here to talk about Lp(a).
What is Lipoprotein(a) and what is the importance of testing Lp(a)?
Lipoprotein(a), or the short form Lp(a), is an inherited type of lipoprotein made in our liver. Lp(a) looks like LDL lipid particle, but with the addition of an apo(a) chain, hence its name Lp(a).
Elevated Lp(a) is a hyper cholesterol condition that affects 1 in 5 people, but depending on the ethnicity of the population, it can affect 1 in 3 or up to 1 in 10 people.
High Lp(a) is important because it is an important risk factor for heart disease, stroke and calcific aortic valve disease. The higher the level, the higher the lifetime cardiovascular risk.
Who should be tested for Lp(a)?
Elevated Lp(a) >125 nmol/L or > 50mg/dL is a cardiovascular risk factor for everyone, but we should prioritise testing individuals at high and very-high cardiovascular risk. This includes anyone with a history of heart attack, stroke, or they already have cardiovascular risk factors such as high LDL levels, familial hypercholesterolemia, diabetes, and hypertension. Also, anyone with a family history of premature cardiovascular events or a family history of very high Lp(a) should be tested. This process of cascade testing in families with high Lp(a) is a very effective way to detect individuals with high Lp(a).
What are the challenges in implementing Lp(a) in clinical practice?
Firstly, poor awareness. Many healthcare professionals and many people in general are not aware of Lp(a).
Secondly, lack of confidence. Our research showed that many doctors are not confident in managing Lp(a). A common misperception is that “nothing can be done because Lp(a) is genetically destined and effective drugs are not here yet.”
Now, this is not true. And there are multiple actionable strategies that we can already do now to reduce a person’s overall cardiovascular risk. So, that’s why I came up with the concept, LILAC-for-Lp(a), it is a framework to help doctors and patients manage Lp(a).
Please explain the LILAC approach that you have created to manage patients with elevated Lp(a)?
LILAC summarises the 5 salient points that we need to consider in managing Lp(a).
“L” stands for Lp(a) is a cardiovascular risk enhancer, so use this to improve the risk prediction of a cardiovascular disease for a patient.
“I” is improve control of all modifiable cardiovascular risk factors, this is the first actionable strategy that one can do.
And the second actionable strategy that you can discuss with your patient is “L” for lower LDL and ideally lower Lp(a) concentrations. Discuss with your patient on the appropriate LDL goals, depending on their predicted cardiovascular risk. Someone who has very high Lp(a) may need Lp(a) lowering treatment.
“A” stands for assess for conditions related to elevated Lp(a), including aortic valve stenosis, and consider Aspirin when there is a significant burden of Atherosclerosis.
And “C” is cascade testing for Lp(a) if the index case has very high Lp(a).
There are 2 common measurement units for Lp(a) reporting, nmol/L and mg/dL, which one should clinicians and healthcare providers use?
Assays can report either in mass (mg/dl) or molar (nmol/l) concentrations. It is recommended to use molar concentrations (nmol/l).
Most people carry 2 different sizes of apo(a) isoforms, which means 2 different sizes of Lp(a) particles. There are more than 40 different sizes of Lp(a) particles because of the extensive range of apo(a) protein sizes in the general population.
So let me explain the difference between mass and molar concentrations of Lp(a) using an analogy with marbles. Let’s say, person A has medium and large size Lp(a) particles, and person B has small and medium size Lp(a) particles. So let’s say 2 persons have the same mass (weight) for a certain volume, which is 50mg/dL. Actually, person B has many more Lp(a) particles, a higher nmol/L. Putting person B at a higher cardiovascular risk. This explains why a conversion factor between the two units will never be accurate. So there is no standard conversion factor, but one can use a rough estimation of 2.5. For example, 50mg/dL is around 125nmol/L.
Can you summarise a key-message that the public and patients should know about Lp(a)?
Don’t be afraid to know your blood lipid and cholesterol level. On the same note, don’t be afraid to know your blood glucose, blood pressure, and weight. All of these are potential risk factors that are unlikely to cause harm if you control them early. High Lp(a) is genetic, means it is high from an early age. So use this knowledge to start early from an early age and with healthy diet, exercise, good lifestyle, and no smoking. If your Lp(a) is very high, there are actions that you and your doctor can take now to reduce your lifetime cardiovascular risk.
Want to find out more? Click here to access more LILAC-for-Lp(a) educational videos.
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