Lp-PLA2 (lipoprotein-associated phospholipase A2) is an enzyme in your blood that signals inflammation inside your artery walls. Unlike general inflammation markers that rise with infections, injuries, or autoimmune flares, Lp-PLA2 is vascular-specific, meaning elevated levels point directly to the kind of inflammation that drives heart attacks and strokes. It’s increasingly used alongside cholesterol panels to give a more complete picture of cardiovascular risk.
How Lp-PLA2 Damages Arteries
Lp-PLA2 travels through the bloodstream attached to LDL cholesterol particles. When LDL becomes oxidized inside artery walls, Lp-PLA2 breaks down those oxidized particles into two byproducts: lysophospholipids and oxidized fatty acids. Both are actively harmful. They trigger the artery lining to produce adhesion molecules and inflammatory signals that attract white blood cells called monocytes into the artery wall.
Once inside, monocytes gorge on oxidized LDL and become foam cells, the building blocks of arterial plaque. Over time, this cycle of oxidation, enzyme activity, and immune cell recruitment creates a growing mass with a soft, unstable core of dead cells and lipids. Lp-PLA2 essentially links two dangerous processes: the oxidation of LDL cholesterol and the inflammatory response that makes plaques grow and become fragile.
Why It Matters for Plaque Rupture
Not all arterial plaques are equally dangerous. Some are stable, with a thick fibrous cap holding everything in place. Others are vulnerable, with a thin cap covering a large necrotic core. These thin-cap plaques are the ones most likely to rupture, triggering a blood clot that blocks an artery and causes a heart attack or stroke.
High levels of Lp-PLA2 and its byproducts concentrate heavily in these vulnerable plaques. Studies examining ruptured plaques and thin-cap plaques consistently find elevated Lp-PLA2 inside them, while stable plaques contain almost none. This is what makes the enzyme such a useful risk marker: it doesn’t just indicate that plaque exists, it suggests the plaque is the dangerous, rupture-prone kind.
How Much It Increases Cardiovascular Risk
A large meta-analysis found that people with the highest Lp-PLA2 levels had a 46% greater risk of coronary heart disease and a 58% greater risk of ischemic stroke compared to those with the lowest levels. When researchers looked at incremental increases rather than top-versus-bottom comparisons, every one-standard-deviation rise in Lp-PLA2 activity was linked to a 12% increase in coronary heart disease risk.
These numbers hold up after adjusting for traditional risk factors like cholesterol, blood pressure, and smoking. That’s the key point: Lp-PLA2 adds predictive information beyond what a standard lipid panel tells you. Someone with “normal” cholesterol but elevated Lp-PLA2 may carry more risk than their basic lab work suggests.
How Lp-PLA2 Differs From CRP
High-sensitivity C-reactive protein (hs-CRP) is the most commonly used inflammation marker in cardiovascular risk assessment. It works, but it has a limitation: CRP rises in response to virtually any inflammatory process in the body. A cold, a sprained ankle, arthritis, gum disease, or obesity can all push CRP higher, making it harder to interpret as a cardiovascular signal specifically.
Lp-PLA2 doesn’t have that problem. Because it’s produced primarily within arterial plaques and circulates bound to LDL, elevated levels reflect what’s happening inside your blood vessels rather than systemic inflammation elsewhere. Some clinicians use both markers together. When both are elevated, the case for aggressive cardiovascular risk management is strongest.
The PLAC Test and What Results Mean
The blood test for Lp-PLA2 is commonly called the PLAC test. It measures either the mass (amount) or activity (how actively the enzyme is working) of Lp-PLA2 in your blood. No fasting is required. Quest Diagnostics, one of the major labs offering the test, uses a straightforward two-tier classification for activity levels:
- Optimal: 123 nmol/min/mL or below
- High risk: above 123 nmol/min/mL
Your doctor may order this test if your standard risk factors give a mixed or borderline picture. For example, if your cholesterol is moderately elevated but you have no family history of heart disease, or conversely if your cholesterol looks fine but you have a strong family history, Lp-PLA2 can help clarify which direction your actual risk leans.
Lowering Lp-PLA2 With Statins
Statins are the most studied treatment for reducing Lp-PLA2. The reductions vary by drug and dose. Rosuvastatin lowered Lp-PLA2 activity by about 33% in the JUPITER trial, the largest reduction observed. Simvastatin reduced it by 25% in the Heart Protection Study. High-dose atorvastatin (80 mg) brought it down by 20% within 30 days, while a moderate dose of pravastatin achieved a 16% reduction over 12 months.
These reductions matter beyond just changing a number on a lab report. In the Long-term Intervention with Pravastatin in Ischemic Disease study, the drop in Lp-PLA2 activity partly explained the reduction in coronary events seen with statin therapy. In other words, lowering Lp-PLA2 appears to be one of the mechanisms through which statins protect the heart, separate from their LDL-lowering effect.
The Role of Diet and Exercise
Lifestyle changes can also move Lp-PLA2 in the right direction. In a controlled study of patients with abnormal lipid levels, an intensive diet and exercise program significantly lowered Lp-PLA2 compared to usual care. The diet that produced these results emphasized roughly 50% of calories from carbohydrates, 30% from fat (heavily favoring unsaturated fats over saturated), under 200 mg of dietary cholesterol per day, and 20 to 30 grams of fiber daily. Participants in the intervention groups achieved Lp-PLA2 mass levels around 311 to 327 ng/mL, compared to about 402 ng/mL in the usual-care group.
While most of the lifestyle research has been done in specific patient populations, the dietary pattern that works resembles what cardiologists already recommend: plenty of fiber, minimal saturated fat, and limited cholesterol intake. Adding regular exercise to this dietary approach appears to amplify the benefit. If your Lp-PLA2 is elevated, these changes are a reasonable first step, particularly if you and your doctor decide statin therapy isn’t yet warranted.