Unless you’ve seen a lipidologist, you’ve probably never heard of the potentially lifesaving blood test for lipoprotein(a).
You only need to get this blood test once in your life, and I encourage all of my patients, if it’s a financial option, to pay the $51 for it because the results have huge ramifications for how we try to lower their heart disease risks.
Table of Contents
- What is Lp(a) and why does it matter?
- The numbers that reveal the danger
- What to do if your levels are high
- Future treatments on the horizon
- Final thoughts
- References
What is Lp(a) and why does it matter?
The evidence connecting Lp(a) to heart attacks and strokes has been slowly building in recent years. And a study published just last month gives us some updated numbers that are hard to ignore.
The study drew on a large database to identify almost 300,000 people with diagnosed heart disease. Researchers examined follow-up data for about five years to see who had a heart attack or stroke, and how those numbers relate to Lp(a) [1].
Compared to those with Lp(a) levels less than 15 nmol/L, those with levels between 15 and 79 had a 4% greater risk. With levels between 80–179, it was 15% greater. The risk jumped to 29% higher for levels from 180 to 299, and a sobering 45% greater risk above 300 [1].
What’s more, the research shows our risks increase continuously the higher our Lp(a) levels go, starting from the lowest levels. Past 300, the risk just keeps going up [1].
And it’s not just those who are already diagnosed with heart disease who are at risk. The lifetime risk for a heart attack or stroke for the overall population follows the same pattern. Based on data from the UK Biobank, higher Lp(a) levels translate into much higher lifetime risks [2].
So our Lp(a) level is a big deal. Knowing where we stand is crucial for getting an accurate picture of our overall heart disease risk.
And we might be tempted to say, “Well, I’m a healthy weight, I eat right, I don’t smoke, and my blood pressure is normal. So I probably don’t have anything to worry about here.”
But that would be a big mistake. Unlike some of the other risk factors for heart disease, our Lp(a) levels are almost exclusively driven by our genetics — not by lifestyle factors [2].
So the only way we’ll know our levels is through testing. And we’ll talk about that test in just a minute. But first, I want to explain what Lp(a) is and how scientists think it affects heart disease.
Most have probably heard of lipoproteins. That’s the “L” in the HDL and LDL we use when talking about cholesterol. Lipoproteins are like transport vehicles for cholesterol and triglycerides in our bloodstream. Cholesterol and water don’t mix naturally. Think of how oil, a fat, separates when you put it in water. Our blood is mostly water. So our bodies need a way to move cholesterol through the bloodstream. And that’s where lipoproteins come in. They transport cholesterol through the blood.
While there are a lot more LDL particles, Lipoprotein(a) appears to be particularly inflammatory and causes about 6 times as much damage compared to a regular LDL particle [3].
The numbers that reveal the danger
So how do we check our Lp(a) levels? It’s a simple blood test, as easy as checking our HDL and LDL cholesterol levels. Cost and test availability will vary depending on where you live. But in the U.S., for example, you can get tested for $51 [4].
Here in New Zealand, we can get it for even less [5].
And the great thing about this test is that you only have to get it once. That’s because, again, our Lp(a) level is mostly set by our genes. Unless we have certain acute health problems, it’s stable throughout life.
So what counts as a high level for Lp(a)? A common threshold used is above 50 mg/dL (or 105 nmol/L), while a level between 30–50 mg/dL or 62–105 nmol/L is considered elevated [6].
The 5% of the population with the highest Lp(a) concentrations have 3 times the risk for a heart attack and a narrowing of the aortic valve in the heart. They have 1.6 times the risk for a stroke and 1.5 times the risk of death from heart disease [6].
Population sampling shows us that about 1 in 5 people have elevated Lp(a) levels. But most don’t know it, because only 1–2% of us get tested [6].
I had the test done when I found out about the research on Lp(a). It turns out my levels are low, which was a relief to know.
My measurement was 93 mg/L, which is roughly the equivalent of 20 nmol/L.
What to do if your levels are high
But what if our levels aren’t low? What should we do? Here’s what current guidelines recommend.
When it comes to something like high LDL cholesterol, the standard approach is familiar. We target lifestyle changes that can lower levels first. And then we add medications to drive it down even further if necessary.
Unfortunately, things are a bit different with Lp(a). That’s because, as we already mentioned, our levels are primarily driven by our genetics. And that means there aren’t any lifestyle factors that will significantly shift our numbers. Moreover, we don’t yet have a medication specifically approved for lowering Lp(a) [2].
So here’s what the guidelines recommend instead. Focus on getting other risk factors in control as much as possible. That’s because they all work together. Think of your total risk as a function of both your Lp(a) risk and contributions from other factors [2].
So what are these other factors? Key ones include our LDL cholesterol level, blood pressure, blood sugar control, BMI, etc. So we’ll want to prioritize lifestyle modifications in areas like diet and exercise to improve these areas as much as we can.
When I work with patients in the clinic with elevated Lp(a), we shoot to get LDL-c under 40–50 mg/dL. It’s an aggressive target, but LDL is a fuel for driving plaque build up in the arteries. So we want to starve the fire of fuel. To reach this level, we’ll typically use a combination of lifestyle changes, a low-dose statin, and Ezetimibe. They’re cheap, safe, and effective. Though statins can slightly increase Lp(a) levels, they can dramatically reduce LDL-c. The end result is a lower overall heart disease risk.
A subgroup analysis from the new study we started with looked at hazard ratios for those who aggressively lowered their LDL-c levels compared to other participants in the study. The impact of this strategy was really impressive. The risk for those in the highest Lp(a) category ended up being basically the same as those in the lowest category who didn’t take LDL-c lowering medications [1].
The confidence intervals are wide here, though. So we’ll want further studies to confirm this. But for now, this new evidence supports the wisdom of trying to bring down LDL-c levels as much as we’re able.
Future treatments on the horizon
Now there is one type of medication that can directly lower Lp(a) levels, although not FDA-approved for this indication yet, and that’s PCSK9 inhibitors. They’re designed to lower LDL-c levels. They also drop Lp(a) levels by 15–30% [2].
They are quite expensive, though.
Sometimes I also consider using aspirin with patients whose Lp(a) levels and other risk factors are high.
Fortunately, we do have some medications specifically targeting Lp(a) on the horizon. For instance, in early trials, we have seen an average decrease in Lp(a) levels of 97% with olpasiran. The change was sustained over 6 months. So far, the safety profile is good [2].
The next step for medications like this is to test them against a placebo for their impact in preventing outcomes like heart attacks and deaths from heart disease. A trial like that for olpasiran is currently underway. It’s projected to be completed late next year [7].
Final thoughts
For now, the best strategy we have is to control risk factors like LDL cholesterol. Discovering that we have elevated Lp(a) certainly isn’t something to panic about. But it is something to take into account and respond to appropriately. It may mean we need to take more aggressive measures to guard our heart health than other risk factors alone would indicate.
References
1. https://academic.oup.com/eurheartj/advance-article/doi/10.1093/eurheartj/ehaf297/8124887
2. https://pmc.ncbi.nlm.nih.gov/articles/PMC9639807/
3. https://pubmed.ncbi.nlm.nih.gov/38233012/
4. https://www.questhealth.com/product/lipoprotein-a-lpa-test-34604M.html
5. https://www.mytests.co.nz/our-tests/lipoprotein-a/
6. https://www.sciencedirect.com/science/article/pii/S0021915025001169
