Lipoprotein(a) (Lp(a)): A Cardiologist's Guide to Testing, Treatment, and Heart Risk

What Is Lipoprotein(a)?

Lipoprotein(a) (pronounced “lipoprotein little a,” abbreviated Lp(a)) is a genetically determined LDL-like particle that raises the risk of heart attack, stroke, peripheral artery disease, and calcific aortic stenosis independently of any other cholesterol value. It is the most common inherited cardiovascular risk factor in the world.

Imagine you have a troublesome relative who looks similar to someone you know well but causes far more problems. That’s the relationship between Lp(a) and the LDL cholesterol you’re probably familiar with. Both particles float through your bloodstream carrying cholesterol, but Lp(a) comes equipped with extra baggage that makes it particularly harmful to the heart and blood vessels.

Structurally, Lp(a) consists of an LDL-like core (apolipoprotein B-100 wrapped around cholesterol and triglycerides) with an additional protein (apolipoprotein(a), or apo(a)) covalently linked through a disulfide bond. Apo(a) is encoded by a single gene, LPA, on chromosome 6, and the gene contains a variable number of repeating “kringle IV-2” units. The number of those KIV-2 repeats determines apo(a) size, and apo(a) size is the single biggest determinant of how much Lp(a) your liver pumps into your blood.

Your body produces Lp(a) particles in the liver, just like other lipoproteins, but here’s the key difference: the amount you make is almost entirely determined by your genes. You inherit your Lp(a) level from your parents at birth. Unlike regular cholesterol, you cannot lower it through diet, exercise, weight loss, or most current medications. Levels are essentially fixed for life from late childhood onward. It is genuinely a single-number test you only ever need to run once.

Why Do Some People Have High Lp(a)? The Genetic Driver

Lp(a) level is 70–90% genetically determined by variation in the LPA gene and its KIV-2 repeat region. Some people inherit small apo(a) variants that produce high Lp(a) particle counts; others inherit large variants that produce very little.

Research shows that approximately 20–25% of the global population (roughly 1.4 billion people) has Lp(a) ≥ 50 mg/dL, the threshold most medical societies (including the American Heart Association, the National Lipid Association, and the European Atherosclerosis Society) flag as clinically elevated.

Median levels also vary by ancestry. People of African descent have the highest median Lp(a) (around 60–75 nmol/L, roughly 25–30 mg/dL), followed by South Asian, white, and East Asian populations. Family history almost always tracks with the lab result: if your Lp(a) is high, there is roughly a 50% chance each of your first-degree relatives (parents, siblings, children) also has elevated levels. This is why cascade screening of family members is so valuable.

In my Encinitas practice, I look hardest for high Lp(a) in patients with:

• A first-degree relative who had a heart attack, stroke, or bypass surgery before age 55 (men) or 65 (women)
• Recurrent cardiovascular events despite optimal LDL lowering
• Calcific aortic stenosis under age 65
• Unexplained elevated coronary artery calcium scores in a patient with otherwise normal lipids

How Does Lp(a) Damage Your Cardiovascular System?

Lp(a) injures the cardiovascular system through three converging mechanisms: it accelerates atherosclerosis, promotes blood clotting, and amplifies inflammation. It is unique among lipoproteins in causing all three at once.

While regular LDL cholesterol causes problems primarily by building up in artery walls (and over a lifetime, that cumulative LDL exposure translates directly into mortality risk), Lp(a) operates through several destructive pathways simultaneously.

1. Atherogenesis. Lp(a) promotes atherosclerosis more aggressively than regular LDL on a per-particle basis. The apo(a) component lets the particle bind preferentially to subendothelial proteoglycans in the artery wall, where it accumulates, undergoes oxidation, and is taken up by macrophages to form foam cells. Lp(a) is also enriched in oxidized phospholipids (OxPL), pro-inflammatory cargo not carried by ordinary LDL, which dramatically accelerates plaque progression.

2. Antifibrinolytic effect. Apo(a) shares 75–95% sequence homology with plasminogen, the body’s natural clot-dissolving enzyme. But apo(a) cannot be activated to dissolve clots; instead, it competes with plasminogen at the fibrin surface, blocking clot dissolution. The result is that when a coronary or cerebral artery plaque ruptures in someone with high Lp(a), the resulting thrombus is more likely to fully occlude the vessel and cause a heart attack or ischemic stroke.

3. Vascular inflammation. Through its OxPL cargo and direct effects on endothelial cells, Lp(a) drives a chronic low-grade inflammatory response in vessel walls, which sensitizes the entire arterial tree to plaque formation.

The combined effect makes Lp(a) a uniquely potent driver of both chronic atherosclerosis and acute events. In Mendelian randomization studies, which use genetic variation to mimic a randomized trial, every doubling of Lp(a) is associated with roughly a 22% increase in coronary heart disease risk and a 25% increase in calcific aortic stenosis risk.

Why Does Lp(a) Cause Aortic Valve Stenosis?

Lp(a) is the single strongest genetic risk factor for calcific aortic valve disease (CAVS), the most common reason for valve replacement in adults. The same OxPL-driven inflammation that builds plaque inside arteries also drives calcium deposition in the aortic valve leaflets.

The aortic valve normally opens and closes with each heartbeat, allowing blood to flow efficiently from the heart’s left ventricle into the aorta. When Lp(a) is high, inflammatory processes similar to those affecting arteries begin in the valve tissue itself. Over years, calcium accumulates in the leaflets, stiffens them, and narrows the opening. The end stage is severe aortic stenosis, which typically requires surgical replacement or TAVR (transcatheter aortic valve replacement).

Symptoms develop gradually and include exertional chest pain, shortness of breath, lightheadedness, and syncope. The Lp(a)–aortic stenosis link helps explain why some patients develop severe valve disease despite well-controlled traditional risk factors, and why a few of my Lp(a) patients end up needing valve replacement decades earlier than expected.

How Do You Test for Lp(a), and What Levels Are Dangerous?

A simple blood draw is all that is required. No fasting. The result is essentially fixed for life, so one test is usually enough. Lp(a) testing is not part of routine cholesterol screening, so it has to be ordered specifically.

Lp(a) Thresholds (Adults)

A quick word on units, because this trips up almost everyone. Lp(a) gets reported two different ways depending on which lab runs the test. Some labs report mass units (mg/dL), which estimate the total weight of Lp(a) in your blood. Others report molar units (nmol/L), which count the actual number of particles. The two scales are not interchangeable, and there is no exact formula to convert one to the other, because Lp(a) particles vary in size from person to person. A rough rule of thumb is that 1 mg/dL sits somewhere around 2 to 2.5 nmol/L, so a level of 50 mg/dL lands near 125 nmol/L. Treat any conversion as an approximation, not a precise translation.

This is a genuine source of confusion and worry for patients. If your level came back as 75 on one report and 180 on another, you have not gotten worse. You were simply measured on two different scales. When you compare your result over time, or against a guideline cutoff, check that both numbers use the same unit before you read anything into the change. To keep things clear, throughout this article I give both numbers whenever I mention a level.

Most major societies (including the 2018 ACC/AHA cholesterol guideline, the 2022 NLA scientific statement, and the 2019 ESC/EAS guideline) now recommend isoform-independent nmol/L assays when available, because they avoid the size bias that affects mg/dL measurements.

You do not need to fast before an Lp(a) test, and the result will not fluctuate based on recent meals, exercise, or short-term lifestyle changes. This stability is what makes Lp(a) such an unusual lab. Your level today is essentially your level for life.

Who Should Get Tested for Lp(a)?

Major societies now recommend at least one Lp(a) test for almost every adult, with priority testing for higher-risk groups. The 2018 ACC/AHA cholesterol guideline calls Lp(a) a “risk-enhancing factor” worth measuring; the 2019 ESC/EAS guideline goes further and suggests universal testing once in a lifetime.

Get tested if you have any of the following:

• First-degree relative with premature ASCVD (men < 55, women < 65)
• A personal history of premature heart attack, stroke, or bypass surgery
• Recurrent cardiovascular events despite an LDL well below 70 mg/dL
• A family history of elevated Lp(a) itself
• Calcific aortic stenosis before age 65
• An unexpectedly high coronary artery calcium score without obvious risk factors
• Inability to reach LDL goals on statin therapy, or repeated statin-associated muscle symptoms raising the question of intensifying lipid-lowering therapy
• Pre-pregnancy counseling in a woman with a strong family history of premature heart disease

Many physicians, including me, increasingly test virtually every new patient I see for risk stratification. The cost is modest, the information is durable for life, and a normal result is permanently reassuring.

Can You Lower Lp(a) With Current Treatments?

Currently approved cholesterol drugs lower Lp(a) only modestly, and none have been shown to reduce cardiovascular events specifically by lowering Lp(a). That is the gap the next generation of drugs is built to close.

New data sharpens the threshold that matters most. A 2026 pooled analysis of more than 20,000 patients found that an Lp(a) above 175 nmol/L (roughly 70 mg/dL) drives heart risk that standard treatment does not erase. I cover what to do about it in my post on why an Lp(a) above 175 needs a more aggressive plan.

Current Therapies and Their Effect on Lp(a)

Statins are still essential because the LDL-lowering benefit dwarfs anything else when Lp(a) is also elevated; in fact, statin therapy may slightly raise Lp(a) on average (around 10%), but this should not be a reason to stop, because the net LDL-driven reduction in events is large. PCSK9 inhibitors lower Lp(a) about 25% as a side effect of the mechanism, and there is some signal that this contributes to their cardiovascular benefit, though the dominant driver remains LDL reduction. Inclisiran, an siRNA targeting PCSK9, behaves similarly.

Lipoprotein apheresis (a dialysis-like extracorporeal filtration that removes Lp(a) and other apoB-containing lipoproteins from blood weekly or every other week) is reserved in the United States for patients with established cardiovascular disease and Lp(a) above 60 mg/dL (about 150 nmol/L) despite maximally tolerated lipid therapy. It is expensive, inconvenient, and available only at specialized centers, but it can reduce event rates substantially in the right patient.

Niacin lowers Lp(a) about 20–30% but was abandoned for cardiovascular outcomes after the HPS2-THRIVE and AIM-HIGH trials showed no event reduction and meaningful side effects (flushing, glucose intolerance, infection).

What New Lp(a)-Lowering Drugs Are in Clinical Trials?

Four drugs are in late-stage trials that lower Lp(a) by 70–98%. Outcomes results begin reading out in 2025–2027. Several are likely to change Lp(a) practice within the next 2–4 years.

Drugs in Phase 3 Outcomes Trials

These therapies all target apo(a) production or assembly. Pelacarsen and the two siRNAs are subcutaneous injections every 1–6 months. Muvalaplin is the first oral option, taken daily.

For the first time in cardiology, we will have drugs that lower Lp(a) by an order of magnitude greater than anything currently available. The unanswered question is whether dropping Lp(a) translates into lower heart attack, stroke, and aortic stenosis rates. That is exactly what these trials are designed to test. Mendelian randomization strongly predicts a benefit, but only randomized outcomes data will prove it.

If you have severely elevated Lp(a) and established cardiovascular disease, ask your cardiologist or local lipid clinic about enrollment in Lp(a)HORIZON, OCEAN(a), or ACCLAIM-Lp(a). I’ve referred patients from my Encinitas practice into Southern California sites for these trials.

How Do You Manage Cardiovascular Risk When Lp(a) Is High?

Until Lp(a)-specific drugs are approved, the strategy is to aggressively close every other door through which cardiovascular disease enters. That means treating LDL, blood pressure, blood sugar, and inflammation harder than you would for a patient with normal Lp(a).

Here is the approach I take in clinic for a patient with elevated Lp(a):

• Drive LDL very low. Goal LDL < 70 mg/dL for primary prevention with high Lp(a), and < 55 mg/dL for secondary prevention. I use high-intensity statins (atorvastatin 40–80 mg or rosuvastatin 20–40 mg), add ezetimibe when needed, and reach for a PCSK9 inhibitor or inclisiran if patients are still above target on dual therapy.
• Treat blood pressure to a target below 130/80 mmHg, and lower if tolerated. Elevated blood pressure amplifies Lp(a)-driven arterial damage.
• Address insulin resistance and diabetes aggressively. Maintain hemoglobin A1c < 7%. Consider SGLT2 inhibitors and GLP-1 receptor agonists for both glycemic and cardiovascular benefit.
• Stop smoking, period. The combination of smoking and elevated Lp(a) is particularly dangerous.
• Build cardiorespiratory fitness through regular aerobic exercise and resistance training; both reduce overall cardiovascular event rates.
• Adopt a Mediterranean-pattern diet. Diet does not lower Lp(a), but it improves every other lipid and vascular risk metric.
• Consider a baseline coronary artery calcium score to quantify how much plaque has already been laid down. This personalizes the urgency of intensifying therapy.
• Get a transthoracic echocardiogram at age 50 or earlier, and serially after age 60, to screen for early calcific aortic stenosis.
• Refer for clinical trial enrollment when an Lp(a) outcomes trial is recruiting in your region.

Can Diet or Exercise Lower Lp(a)?

No. No diet, exercise pattern, weight-loss program, or supplement has been shown to meaningfully lower Lp(a). This is one of the hardest conversations I have with motivated patients.

Saturated-fat restriction, the Mediterranean diet, ketogenic eating, plant-based eating, intermittent fasting, omega-3s, niacin supplements, red yeast rice, coenzyme Q10, none of these meaningfully reduce Lp(a). Some may even raise it slightly (low-saturated-fat diets, for instance, can nudge Lp(a) up 10–20%). Weight loss has a neutral-to-slightly-favorable effect at best.

This does not mean lifestyle is irrelevant. The same Mediterranean diet, exercise habits, and weight management that fail to move Lp(a) do dramatically reduce LDL, blood pressure, diabetes risk, and inflammation, every one of which compounds with Lp(a) to drive cardiovascular events. The lifestyle changes are still load-bearing for someone with elevated Lp(a); they just work through different levers.

Be skeptical of any supplement or “natural” remedy marketed as an Lp(a)-lowering therapy. The evidence does not support those claims, and the cost is real.

Should My Family Members Get Tested for Lp(a)?

Yes. Lp(a) is autosomal codominant. If your level is high, each first-degree relative has roughly a 50% chance of also being elevated. Cascade screening of relatives is one of the highest-yield prevention strategies in cardiology.

If you have elevated Lp(a), recommend testing for:

• Your parents (and any surviving aunts, uncles, grandparents with cardiovascular history)
• Your siblings
• Your children, starting in late adolescence or early adulthood, Lp(a) reaches adult levels by approximately age 5, but most clinicians wait until age 18+ to test so that results inform adult risk-factor planning

Genetic counseling is rarely required for Lp(a) specifically (it is a single-gene Mendelian trait, not a complex genetic disorder), but families with multiple early cardiovascular deaths may benefit from a broader lipid panel evaluation that also screens for familial hypercholesterolemia.

What Lp(a) Research Is Happening Now?

Beyond the four Phase 3 drugs, Lp(a) research is moving in three directions: better assays, mechanism-specific therapies, and outcomes data in non-traditional populations.

• Standardized, isoform-independent assays are gradually replacing older mg/dL methods, which under- or overestimate Lp(a) depending on apo(a) size. The 2022 NLA and 2024 IFCC statements both call for nmol/L reporting.
• Anti-OxPL therapies (targeting the inflammatory cargo on Lp(a) rather than Lp(a) particle count itself) are in early-phase study.
• Pediatric and pregnancy data are accumulating, since Lp(a) levels reach adult values in childhood and may rise transiently in pregnancy.
• Genetic variants beyond LPA (including KIV-2 copy number, SNP profile, and apo(a) size polymorphism) are being mapped to refine individual risk prediction.

This is one of the fastest-moving subfields in cardiology. I expect that in 2 to 4 years, the conversation with a patient who has Lp(a) above 70 mg/dL (about 180 nmol/L) will look nothing like the conversation today.

Lp(a): The Bottom Line

Lipoprotein(a) represents both a challenge and an opportunity in modern cardiovascular medicine. The challenge is that it is the most prevalent genetic cardiovascular risk factor we know of, and current drugs do not specifically address it. The opportunity is that once-in-a-lifetime testing now lets us identify the 20% of adults who carry this risk and intervene early on everything else.

Knowing your Lp(a) does three things. It identifies premature cardiovascular risk that traditional cholesterol numbers miss. It prompts cascade screening of relatives. And it lets you ask the right question of your cardiologist when the next generation of Lp(a)-lowering drugs is approved.

If you have not been tested, ask. If you have been tested and your level is high, partner with a cardiologist who treats every other risk factor aggressively and keeps an eye on the trial landscape. The drugs that will rewrite this article are already in late-stage testing.

Frequently Asked Questions About Lipoprotein(a)

Is Lp(a) the same as LDL?

No. Lp(a) shares the LDL-like core structure (apoB-100 + cholesterol + triglycerides) but adds a covalently bound apolipoprotein(a) protein. That apo(a) is what makes Lp(a) more thrombotic, more inflammatory, and more atherogenic per particle than LDL. A standard lipid panel does not measure Lp(a), it must be ordered separately.

How often should I get my Lp(a) tested?

Usually just once in your lifetime is enough. Lp(a) is 70–90% genetically determined and remains stable from late childhood through old age. If your level was normal a decade ago, it is almost certainly still normal today. Repeat testing makes sense only when an Lp(a)-lowering therapy is started.

Does insurance cover Lp(a) testing?

Most US commercial insurance covers Lp(a) when ordered with an appropriate clinical indication (family history of premature ASCVD, personal history of CV events, etc.). Medicare coverage is more variable. Out-of-pocket cost is typically $25–$100.

Can I donate blood if my Lp(a) is high?

Yes. Elevated Lp(a) does not disqualify you from blood donation. The recipient inherits no risk from your level.

Does pregnancy raise Lp(a)?

Lp(a) rises modestly in the second and third trimesters and returns to baseline postpartum. Pre-pregnancy testing is valuable in women with a strong family history of early cardiovascular disease.

Can statins lower Lp(a)?

No. Statins do not lower Lp(a), they may slightly raise it (about 10% on average). Statins remain essential because their LDL-lowering benefit far outweighs any small Lp(a) increase. Never stop a statin because of Lp(a).

What is the difference between pelacarsen, olpasiran, lepodisiran, and muvalaplin?

All four target Lp(a) but through different mechanisms. Pelacarsen is an antisense oligonucleotide (ASO). Olpasiran and lepodisiran are small interfering RNAs (siRNAs). All three are subcutaneous injections given every 1–6 months and lower Lp(a) by 80–98%. Muvalaplin is the first oral small molecule; it blocks the assembly of apo(a) onto apoB and lowers Lp(a) about 70%. None is yet FDA-approved; all are in or completing Phase 3 outcomes trials.

If my Lp(a) is high, what should I do this week?

Three things. First, schedule an evaluation with a cardiologist or lipid specialist to design an aggressive overall risk-factor plan. Second, ask first-degree relatives (parents, siblings, children over 18) to get tested. Third, ask whether you qualify for enrollment in an ongoing Lp(a) outcomes trial, particularly if you have established cardiovascular disease.

References

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