The Heart-Attack Risk Hiding in Your Immune Cells

Every test I have shown you in this series reads a single moment. The calcium score, the angiogram, the ultrasound probe inside my own artery. Each one is a photograph. Last time I said the real disease is a process, something that runs for years, and that learning to read the process instead of the picture is where this goes next.

CHIP (clonal hematopoiesis) is the purest version of that idea I know. It is a disease that is not a lump or a blockage or anything a scan can photograph. It is a spelling error in your bone marrow, one rogue blood cell quietly out-breeding its neighbors over a decade or two, and the damage it does happens everywhere and nowhere you could point a camera. There is no picture of it. So I went looking for the one blood test that could actually see it.

Both my hematologist and my cardiologist told me there was no real reason to run it due to low likelihood for my age, that there is little that can be done about it, and that insurance typically doesn't cover it. While I disagree and am awaiting an appointment to get a second opinion from yet another cardiologist, I may ultimately end up conceding for now and not pursue arguments for further testing. However, of all potential drivers of cardiovascular disease, this one has been the most interesting to research as it is a great case study for understanding the biological mechanisms at play with aging, and how they interconnect.

The Bottom Line

As we age, a single blood stem cell can pick up a mutation and start quietly out-competing the ones around it, building a private little dynasty inside your marrow. That is clonal hematopoiesis, CHIP for short. Some of those rogue clones do something nasty: their white cells run hot and inflame the inside of your arteries from within. This is not classic autoimmune disease at all, it is something entirely different.

This is also not a fringe theory. The mechanism is real, and for the inflammation part of it, genuinely causal, proven in mice and in a large human drug trial. But the size of the effect is modest and depends heavily on which mutation you carry. It is a risk multiplier, not a verdict. Most people who have it never have a heart attack, and most heart attacks happen in people who don't.

At my age I do consent that the odds of carrying it are low, the test runs hundreds to over a thousand dollars out of pocket, insurance may not cover it, and there probably is not a lot else I would do differently if it came back positive. So I may have to shelve it if my next appointment is also a no, or try to find an alternative way to get an order and pay out of pocket. I am not telling you to get this tested. But, in the process of studying this, what I am telling you is that this one obscure disease is the clearest window I have found into how I have started thinking about how to connect all of chronic disease, as well as the interventions we hope might influence things, to the core of the biological aging process, including cardiovascular disease.

Vocabulary that matters

• Clone, or clonal expansion: one cell's descendants quietly taking over more than their fair share of your blood.
• Somatic mutation: a DNA typo you pick up during life, in one cell. You are not born with it and you do not pass it on.
• CHIP (clonal hematopoiesis of indeterminate potential): a detectable blood clone carrying a known mutation, with no blood cancer and no anemia. Just a clone, sitting there.
• Variant allele fraction, or VAF: how big the clone has gotten, as a percentage of your blood cells. By convention, once it reaches 2 percent, we start calling it CHIP.
• IL-1 beta and the inflammasome: the specific inflammatory alarm the rogue clone's cells blare. It is the bridge that carries a blood mutation over to the artery wall.

Why a blood mutation I'd never heard of got under my skin

My story does not add up. At 36, a CT angiogram of my heart was clean. At 44, I had an 80 percent blockage in my right coronary artery, the kind that puts you on a table with a stent going in. My LDL was borderline, not wild. My blood pressure only ever flirted with the low end of high. My Lp(a), the mostly-genetic risk factor, sits near zero. My inflammation markers have always been quiet. I did not have insulin resistance and experimented with a continuous glucose monitor several times a year and it was also flat. No family history. Never smoked. By the standard math, I am not the guy this happens to.

When your numbers don't explain your disease, "idiopathic" is the word medicine reaches for. It means "we don't know why." I have never been able to accept that word about my own heart, and CHIP is one of the very few suspects that could quietly build focal damage in someone who looks low-risk on paper. It is the kind of thing you go looking for when the usual explanations have run out.

And I had a second reason to go looking, one that has nothing to do with my arteries. Before I ever worked a shift in an emergency room, I spent three years in a cancer lab studying epigenetics — the layer of switches that decides which of your genes get read and which stay silent, without changing the underlying DNA at all. CHIP, it turns out, sits at the exact crossroads of everything I have spent a large chunk of my life trying to understand. The two mutations that most often drive it, in genes called DNMT3A and TET2,²³⁴ are not random damage. They are that epigenetic switchboard, the cell's own on/off control for which genes get read.⁶ One writes the marks that silence a gene, the other strips them off. Jam those genes in a single blood stem cell and one typo fans out into four different worlds at once: it drives heart disease, like mine; it is a pre-cancerous state, the first step on the road to blood cancers;¹ it is a textbook case of the exact epigenetic breakdown I used to study at the bench; and underneath all of it, it is aging itself, made visible. One obscure mutation, standing on the precise spot where cardiology, oncology, epigenetics, and the biology of aging all collide. Of course it got its hooks in me.

I should say plainly why that lab work matters here, because it is not a credential I am waving. I was not studying melanoma because I wanted to cure melanoma. I was studying epigenetic alterations, transcriptional regulation, cellular identity, metabolic rewiring, and genomic instability. It took me years to realize those are not cancer topics. They are hallmarks of aging. Cancer is simply where the machinery breaks loudly enough to study. Aging is the same machinery breaking slowly, in everyone, all the time. I spent three years staring at the loud version without understanding that I was looking at the quiet one.

That is the pattern of my whole career, if I am honest about it. Fifteen years in the supplement industry taught me how health claims get built from the boardroom outward, and then I hit the ceiling of what that world could tell me. Cancer epigenetics taught me how a cell changes its own instructions, and I hit that ceiling too. Bioinformatics taught me to look for patterns across systems instead of memorizing facts inside one. The emergency room taught me what disease actually looks like when it walks through a door. Each time, the honest move was to admit the discipline I was standing in could not answer the question, and to cross into the next one. CHIP is the first thing I have studied that required all of them at once.

So I did. And here is the part that still gets me. I work for the hospital. I read the primary literature. I argued my own way onto the scan that found the blockage in the first place. And I still could not get this one looked at. Both hematology and cardiology gave me the same answer: no real indication. And with the way it bills, insurance was never likely to cover it anyway.

I want to be fair about why, because it is not laziness and they are not wrong. It is that the system had already decided my case was closed. The emergency was handled: the stent is in. The obvious lever was pulled: my ApoB, the cholesterol number that actually drives the plaque, is crushed. Mission accomplished. And when the system files your case under "accomplished," nobody goes digging for the mechanism underneath. However, my case was an outlier, and a voice in the back of my head keeps telling me I need to search for more answers. What if lowering ApoB isn't enough to keep this from happening again?

What CHIP actually is, and how likely I am to have it

Start with what it is. Clonal hematopoiesis just means a chunk of your blood is descended from one mutated stem cell instead of the usual sprawling mix. Add a known leukemia-associated driver gene, subtract any actual blood cancer or anemia, and you have CHIP.¹ It is common, and it climbs steeply with age: detectable in about 1 percent of people under 50, roughly 1 in 10 over 65, and up past 18 percent in the very old.²³ I am 45. At the standard testing threshold, my odds of carrying it sit down around that 1-in-100 floor. Low. Worth saying plainly, because it is the first honest strike against CHIP as my answer.

But here is the wrinkle that makes CHIP such a good teacher, and it is the first place the whole thing starts to bend the way I want you to see. Whether you "have" CHIP depends entirely on how hard someone looks. The 2 percent line is not biology. It is the detection floor of a standard sequencing machine. When researchers used error-corrected sequencing, which reaches down to clones a hundred times smaller, they found clonal mutations in 95 percent of healthy people in their fifties.⁴ Read that again. Look hard enough and almost everyone middle-aged is already carrying a rogue clone. We just drew a line at 2 percent and named the far side of it a condition. "Do I have CHIP" turns out to be less a fact about my blood and more a question about the sensitivity of the test.

Does it actually cause heart disease

Short answer: yes, and I am going to keep the two halves of that honest, because this is exactly where health content usually cheats.

The association is real. People with CHIP carry roughly double the risk of coronary disease, and the studies find this holds even after you account for the traditional risk factors.⁵⁶ That "independent of the usual risk factors" part is what made me sit up, because the usual risk factors are exactly what look clean on me. And in younger people with early heart attacks, the group I actually belong to, the association runs stronger, closer to four times the risk.⁵

Now the honesty. Those are relative risks, and the absolute reality is far more modest. Most people who carry CHIP never have a cardiac event, and most heart attacks happen in people who don't carry it. It is a multiplier sitting on top of a baseline, not a diagnosis that explains a disease. And the risk is not one uniform thing: it runs higher with some mutations, and is genuinely murkier with the single most common one, which behaves differently from one study to the next.⁶ I am not going to pretend to be a CHIP expert. I am a clinician-scientist who can read the papers, and the papers themselves are still arguing about the gene-by-gene detail. That uncertainty is the point here, not a footnote.

How we know it is not just a coincidence

Here is where CHIP earns its place, because you can actually watch the mechanism work. Researchers took mice bred to develop atherosclerosis and gave them bone marrow engineered to carry one of these mutations. The plaques got markedly bigger. The mutant immune cells were running an inflammatory alarm called the NLRP3 inflammasome, pouring out IL-1 beta, and when the researchers blocked that alarm, the extra plaque protection came back.⁷ One mutation, one inflammatory signal, more plaque, and you can turn it off.

Then it got confirmed in people, in about the cleanest way cardiology has ever managed. A large trial called CANTOS took a drug that blocks that exact signal, IL-1 beta, and gave it to more than ten thousand heart-attack survivors. It cut their rate of major cardiac events by about 15 percent. And it did that without lowering their cholesterol at all.⁸ That last part is the whole ballgame. It means the inflammation itself was doing damage, on its own, separate from lipids. You could prove, in humans, that quieting one inflammatory pathway prevents heart attacks. And CHIP is one of the cleanest natural sources of that exact inflammation.

The one-sentence version of the whole disease

Strip out the jargon and here is the entire arrow, start to finish. One DNA typo, in one blood stem cell. The gene it lands on happens to be one of the cell's own off-switches for inflammation. So the clone's descendants, your white blood cells, run hot. They travel to the artery wall, the same wall where cholesterol is already causing trouble, and they pour accelerant on the fire.

The way I would explain it to a patient at the bedside: it is like one bad hire quietly cloning himself until a big chunk of your security staff are all the same guy, and that guy never got the memo to stand down. Everywhere they go, they escalate. That is CHIP in an artery.

Now notice what we just did

Stop and look at the move we just made, because it is the actual reason I am writing about a disease I probably don't even have.

We took something that sounds impossibly exotic, a somatic driver mutation in a blood stem cell, and we made it make sense by ignoring the name and following the mechanism. We didn't ask "what is the diagnosis." We asked "what is the broken machine, and what does it break next." And the second we did that, a disease almost no one has heard of turned into a story you can follow.

That move is a lens, and it is the one I have quietly been using this entire series. Here is the lens, said plainly: the chronic diseases we treat as a hundred separate enemies are, underneath, a small number of shared root mechanisms wearing different masks. Inflammation. Damaged DNA. Cells that have stopped listening to one another. The mask is the diagnosis on your chart. The mechanism is what is actually happening. Treating each disease one at a time while ignoring the machinery underneath all of them is like mopping up water in one room after another while the roof keeps leaking.

CHIP is the perfect place to learn this, because it is the leak made visible. You can trace one water stain, a single DNA change, all the way up to the hole in the roof. Most of the machinery of aging is diffuse and hard to point at. CHIP you can sequence, measure, and follow from one mutation to a heart attack. That is why I led with the hardest possible example instead of an easy one. If you can see the mechanism under CHIP, you can see it under almost anything.

There is a name for this, and I have been too coy about it for too long. It is called the hallmarks of aging — a map, in its current form published in 2023, of about a dozen root mechanisms that drive nearly every age-related disease we have.⁹ I have been quietly citing that one paper at the bottom of these posts for months without ever telling you what it was. I am done doing that, because CHIP is the single cleanest way I know to show you what it means.

CHIP does not touch one hallmark. It lights up several at once, and you have already met all of them in this post. The somatic mutation itself is genomic instability — the accumulated DNA damage of aging, finally made visible in a clone big enough to sequence. The genes it lands on, DNMT3A and TET2, are epigenetic alteration — the cell's own control switches for which genes get read, jammed in place.⁶ And the inflammatory alarm those cells blare is chronic inflammation, what the field calls inflammaging: the hallmark that a growing body of aging science treats as a connecting thread running far beyond the artery, into the long list of age-related diseases we file in separate folders and treat as separate enemies.⁹¹³

That is the entire thesis of what I am building here, compressed into a single disease. These are not a hundred different enemies. They are a small handful of the same broken machines, showing up in different tissues wearing different masks. CHIP just happens to be the one where you can watch a single typo travel the whole distance — from a spelling error in your bone marrow to the wall of your artery — without ever losing sight of it. From here on, I am going to name these machines out loud.

Why there is no test for someone like me

Here is the thing I did not expect to find. It is not that the guidelines say "don't test a younger patient with unexplained, fast-moving heart disease." It is that they don't mention him at all. The current cardiology position is simple: no cardiology society recommends screening people without symptoms for CHIP, full stop.⁶ The way almost everyone with CHIP actually gets diagnosed is by accident, when a hematologist or oncologist sequences their blood for some other reason, usually a cancer workup.⁶ There is no door marked "premature heart disease, come get sequenced." I am not the kind of accident this gets found in.

So when hematology and cardiology told me there was no indication, they weren't blowing me off. They were describing a real gap. The science has gotten far enough to say CHIP matters, especially for people who look exactly like me. The system has not built the part where you act on that. The silence is the story.

Four specialties, one mutation, four different answers

Here is what I did not understand until I had been turned down twice.

Hand the exact same finding to four different doctors and you get four different diseases.

A hematologist sees a small clone in the marrow sitting under the threshold that would make it a blood cancer. Nothing to treat. Watch it.

An oncologist sees a pre-malignant state, the first step toward a leukemia that will probably never come. Real, but not enough risk to act on.

A cardiologist sees a cardiovascular risk factor with no screening pathway and no approved treatment. Which means, correctly, no indication.

A geroscientist sees something else entirely: aging itself, finally big enough to sequence. A single cell's accumulated damage, expanded into a clone you can actually measure.

Every one of those readings is correct. Not one of them is the whole thing. And critically, not one of those specialties owns the problem, so the patient standing in the middle of it falls into the gap between them. That is not a story about four doctors being wrong. It is a story about a mutation whose consequences cross boundaries that medicine drew for its own convenience, decades before anyone knew this mutation existed.

I want to be careful here, because there is a lazy version of this argument that I am not making. Specialists are not the problem. Specialization is the reason medicine works at all. When my artery closed, I did not want a generalist with a systems-level worldview. I wanted an interventional cardiologist who had done that exact procedure a thousand times, and I got one, and I am here because of it. Depth is not the enemy.

But depth has a cost, and the cost is that nobody's map covers the whole territory. Each specialty is looking at a real part of the elephant. The mechanism does not care where we drew the lines. One mutated stem cell in the marrow produces inflammatory cells that end up in an artery wall, and the same clone raises the odds of a blood cancer, and the same underlying process is what we call aging. The biology is one continuous thing. The medical system that has to interpret it is cut into departments with separate journals, separate conferences, separate billing codes, and separate ideas about what counts as a real indication.

I learned this in the least academic way possible, by working in an emergency room.

The ER is the one place in medicine that is structurally forbidden from thinking in specialties. The patient arrives undifferentiated. No label, no department, no chart that tells you which bucket they belong in. Chest pain is a heart attack or a pulmonary embolism or a dissection or a panic attack or an ulcer, and you have to hold all of it at once and reason across every system in the body before anyone gets to hand the patient to a specialist. That is not a bedside manner. That is a way of thinking, and it is the only part of clinical medicine organized the way biology actually is.

I did not choose that job by accident, and I did not choose cardiology at Duke by accident either. But the ER is where I learned the habit this whole article is built on: when the label does not explain what you are seeing, stop arguing about the label and go find the mechanism.

That is what the hallmarks of aging give you. Not a new specialty to add to the list. A layer underneath all of them, where the shared machinery lives. The specialties are still necessary. They are just downstream.

What I actually changed, and why I stopped chasing the test

Not a supplement. Not a hack. A decision, and it is the honest-broker payoff of this whole post: I put the suspect in the file instead of the trash, and I stopped trying to run the test for now.

Walk through the math with me, because it is the same calibration this brand is named for. My odds of carrying it at 45 are low. The test runs a few hundred to over a thousand dollars out of my own pocket, with no established reason to run it and no reimbursement behind it.¹⁰ And here is the one that actually settles it. Even if it came back positive, the recommended move would be to drive my LDL and blood pressure down hard and control my risk factors,⁶ which is exactly what I am already doing. There is no approved treatment aimed at CHIP itself; the people writing the guidelines say so plainly.¹¹ A positive result would not hand me a single new lever.

That is what Calibrated actually looks like. It is not testing everything and fearing everything, which is the influencer move. It is weighing a real suspect honestly, deciding the answer would not change what I do, and choosing to spend my attention elsewhere. The door stays open. If the math changes, if the price drops or an actual treatment shows up, I will revisit it. For now, shelving it is the disciplined call, not the lazy one.

One thread is worth flagging, because it is the "what could you even do about it" question, and it has a live answer. There is a century-old gout drug, colchicine, that works on this exact inflammatory switch. It is now FDA-approved to lower cardiovascular risk,¹² and early work hints it might even slow the rogue clones themselves, though the human evidence is genuinely split and the effects look small.⁶ It is one of the interventions moving through the Calibrated Age evidence pipeline right now, and it deserves an honest workup rather than a name-drop in passing. That is a post of its own, and it is coming. I mention it now only because some circles do recommend this as a treatment when CHIP is discovered, despite the split evidence.

One last thing, because I keep landing here. The point of this year was never to collect diagnoses. It was to learn to see. CHIP is a suspect I am likely giving up chasing, and it still taught me the most useful thing I have learned since the stent: read the mechanism, not the label, and see what dots can get connected back to core aging mechanisms that are consistent across all disease. That habit is worth more to me than any single test result.

The Final Signal

• What's real. A rogue blood clone can genuinely inflame your arteries from the inside. The mechanism is causal for the inflammation arm, proven in mice and in a human drug trial.
• What's overstated. That it is a common answer for early heart disease. At my age it is a low-probability suspect, and the risk it carries is a modest multiplier, not a verdict.
• What I changed. I learned to read disease as a broken mechanism instead of a label on a chart, and I calibrated my way to not chasing a test I could not act on.
• What the system gets wrong, and right. There is no pathway to order this for someone in my situation, and no treatment if it were positive. That gap is real. But given the odds and the absence of any different action, the restraint is not crazy. Both things are true at once.
• Why nobody owns it. Hematology, oncology, cardiology, and geroscience each read this same mutation as a different disease, and each of them is right. Specialists are not the problem; specialization is why medicine works. The problem is that the biology is one continuous process and the system reading it is cut into departments. When no specialty owns a mechanism, the patient standing on top of it falls through the gap.
• What's next. I keep saying "chronic inflammation" like it is one thing in one artery. It is not. Next I want to pull that single hallmark out of my own chest and show you it is the same fire burning in diseases we treat as completely unrelated — and then get to the only question that actually matters: what, if anything, actually turns it down?

References

1. Steensma DP, Bejar R, Jaiswal S, et al. Clonal hematopoiesis of indeterminate potential and its distinction from myelodysplastic syndromes. Blood. 2015;126(1):9-16. PMID: 25931582 [Finding: The paper that named CHIP. Defines it as a blood-cell clone driven by a leukemia-associated mutation, without anemia or blood cancer. Note: the 2 percent size threshold comes from the sequencing studies, not this paper.]
2. Genovese G, Kähler AK, Handsaker RE, et al. Clonal hematopoiesis and blood-cancer risk inferred from blood DNA sequence. N Engl J Med. 2014;371(26):2477-2487. PMID: 25426838 [Finding: In 12,380 people, clonal mutations were found in about 10 percent of those over 65 but only about 1 percent of those under 50. Prevalence rises steeply with age.]
3. Jaiswal S, Fontanillas P, Flannick J, et al. Age-related clonal hematopoiesis associated with adverse outcomes. N Engl J Med. 2014;371(26):2488-2498. PMID: 25426837 [Finding: Detectable clones were rare under 40 and climbed with age, reaching 9.5 percent at 70 to 79 and 18.4 percent in the very old. CHIP also tracked with higher all-cause mortality.]
4. Young AL, Challen GA, Birmann BM, Druley TE. Clonal haematopoiesis harbouring AML-associated mutations is ubiquitous in healthy adults. Nat Commun. 2016;7:12484. PMID: 27546487 [Finding: Standard sequencing detects clones in about 10 percent of 70-year-olds. Error-corrected sequencing, which reaches far smaller clones, found them in 95 percent of healthy people in their fifties. Prevalence depends on how hard you look.]
5. Jaiswal S, Natarajan P, Silver AJ, et al. Clonal hematopoiesis and risk of atherosclerotic cardiovascular disease. N Engl J Med. 2017;377(2):111-121. PMID: 28636844 [Finding: Across four case-control studies, CHIP carriers had roughly a 1.9-fold higher risk of coronary heart disease, and about 4-fold in early-onset myocardial infarction. This is an association, though the paper pairs it with causal mouse data.]
6. Oren O, Laffin LJ, Singh A, Nissen SE, Carraway HE. Clonal hematopoiesis of indeterminate potential and heart disease: what every internist needs to know. Cleve Clin J Med. 2026;93(5):289-295. doi:10.3949/ccjm.93a.26003 [Finding: A current clinician review from a dedicated CHIP cardiology clinic. States no cardiology society recommends routine CHIP screening in asymptomatic adults, that risk is heterogeneous across driver genes, and that management if positive is intensive risk-factor control, with off-label colchicine or vitamin C only as small-effect, emerging options.]
7. Fuster JJ, MacLauchlan S, Zuriaga MA, et al. Clonal hematopoiesis associated with TET2 deficiency accelerates atherosclerosis development in mice. Science. 2017;355(6327):842-847. PMID: 28104796 [Finding: Mice given marrow engineered to carry a CHIP mutation developed markedly larger plaques, driven by NLRP3-inflammasome IL-1 beta signaling. Blocking that pathway was protective, arguing the mutation plays a causal role.]
8. Ridker PM, Everett BM, Thuren T, et al. Antiinflammatory therapy with canakinumab for atherosclerotic disease (CANTOS). N Engl J Med. 2017;377(12):1119-1131. PMID: 28845751 [Finding: In 10,061 heart-attack survivors, a drug blocking IL-1 beta cut major cardiovascular events by about 15 percent at the effective dose, with no reduction in cholesterol. Human proof that reducing inflammation alone prevents events.]
9. López-Otín C, Blasco MA, Partridge L, Serrano M, Kroemer G. Hallmarks of aging: an expanding universe. Cell. 2023;186(2):243-278. PMID: 36599349 [Finding: The framework paper cataloguing the twelve shared root mechanisms of aging, including genomic instability, epigenetic alterations, and chronic inflammation. This post uses it to name three of those hallmarks that CHIP engages at once.]
10. Vanner RJ, Zeng AGX, Kim RH, Chan S, Bankar A. Clinical decisions in clonal hematopoiesis: a contemporary review for clinicians. Haematologica. 2026;111(5):1584-1609. PMID: 41641651 [Finding: A targeted CHIP sequencing panel runs about $200 to $1,000 out of pocket, and CHIP clinics run on grant funding because there is no established reimbursement model. The clinical value of testing remains unsettled.]
11. Rhee J-W, Bolton KL, Gupta D, et al. Clonal hematopoiesis and its cardiovascular implications: a scientific statement from the American Heart Association. Circulation. 2026;153(11):e940-e952. PMID: 41664921 [Finding: The AHA's position statement. Notes that no CHIP-specific therapy has yet proven efficacy for treating or preventing cardiovascular disease.]
12. LODOCO (colchicine) 0.5 mg tablets. Prescribing information. AGEPHA Pharma, FDA NDA 215727. Approved June 2023. FDA label [Finding: In 2023 the FDA approved low-dose colchicine to reduce the risk of heart attack, stroke, and cardiovascular death. This is the cardiovascular indication for an old anti-inflammatory drug, distinct from its off-label use against CHIP clones.]
13. Jaiswal S, Ebert BL. Clonal hematopoiesis in human aging and disease. Science. 2019;366(6465):eaan4673. PMID: 31672865 [Finding: A landmark review establishing clonal hematopoiesis as a common feature of human aging whose consequences reach beyond blood cancer into the non-malignant diseases of aging and immune dysfunction. Frames CHIP as a visible window into the somatic mutation and selection that occurs across all aging tissues.]