Knife Down

Lily Johnston, MD MPH
  • 0.0 (0)
  • MEDICINE

 "Knife Down" is what a surgeon says in the OR when she puts her scalpel down so no one gets hurt — and it’s the mission here: put the knife down, long before anyone needs to use it. Knife Down is a podcast about how to actually invest in your health so you can live longer, stronger, and with less time in doctors’ offices. The core focus is the world’s leading cause of death—cardiovascular disease—and what to do about it before it shows up as a catastrophe. Hosted by a vascular surgeon on a mission to put herself out of business, the show translates cutting-edge science on prevention, metabolic health, and longevity into real-world strategies you can use in clinic or at your kitchen table. Expect evidence, nuance, and zero wellness hype—plus the occasional dark joke about the state of modern medicine.

  1. 2 HR AGO

    Is Ezetimibe the Secret to Preventing Dementia? Surgeon Reacts to Nick Norwitz MDPhD ​

    A common cholesterol drug might protect your brain from Alzheimer's — but I read the actual study, and there's a red flag nobody is talking about. Nick Norwitz covered this story. I went further — I pulled the original paper published in Aging Biology and read every line. Here's what I found.Researchers ran a hypothesis-free screen of FDA-approved drugs to find compounds that could disrupt the 14-3-3/hexokinase protein interaction — a mechanism implicated in the protein aggregation that drives Alzheimer's disease and other dementias.  Six drugs emerged from the screen. Ezetimibe was one of them, and it stood out for one reason: it can cross the blood-brain barrier. That's where the excitement starts. But it's also where you need to slow down. Because buried in the study design, I found something that changes everything.  As a vascular surgeon who has spent years watching patients lose their brains — and their lives — to preventable disease, this is the kind of detail I can't ignore. It's exactly why I won't be prescribing this for dementia prevention in my practice.This video is for anyone who heard the ezetimibe-for-dementia claim and wanted the full picture — not the highlight reel. Sign up for more information on my own practice here: https://corsighthealth.com/ High Quality 3rd-party tested supplements at Fullscript (10% discount): https://us.fullscript.com/welcome/ljohnstonmd/store-start Other tools for optimal health (note these are affiliate links): Home BP Cuff: https://amzn.to/49Cq7rh Sonicare Toothbrush: https://amzn.to/3KllfMS WaterPik: https://amzn.to/4894Xi8 Apple Watch with sleep & HR monitoring: https://amzn.to/3XaUn5d Oura Ring with sleep, cycle, and recovery monitoring: https://amzn.to/4riyhLS Intake Breathing Nasal Support: https://amzn.to/48dfQQ1 Personal Blender: https://amzn.to/4pyNGGl True Nutrition Protein: https://oken.do/q2xzqeqw Glass Meal Prep Containers: https://amzn.to/4ocEPJ2 Sleep Mask: https://amzn.to/48fSJV5 Air Purifier: https://amzn.to/4puzTQZ ___________________________ 🧬 About Dr. Lily Johnston    Dr. Johnston is a double board-certified vascular and general surgeon in San Diego, specializing in metabolic and cardiovascular prevention. She’s the founder of CorSight Health and a passionate advocate for reimagining how medicine approaches chronic disease.    #MetabolicHealth #CardiovascularPrevention #HeartHealth #Longevity #InsulinResistance #DrLilyJohnston #DrLily #WomenInMedicine #Surgeon #VascularSurgeon #PreventiveMedicine #PADPrevention #HeartAttackRisks #HealthPortfolio #California #SanDiego #Arizona #Virginia #Minnesota

    43 min

  2. 4 MAY

    Is Lower LDL Actually Better? New Research Has an Answer

    Is lower LDL cholesterol actually better for your heart? In this video, I break down the brand-new results from the EZ-Pave study to answer the question that keeps my patients up at night: How low should your cholesterol really go?  As a vascular surgeon, I see the end-stage results of heart disease every day.  We’ve heard the "lower is better" mantra for decades, but new research is finally providing the hard evidence we need to settle the debate.  Study link: https://www.nejm.org/doi/full/10.1056/NEJMoa2600283  We’re looking at how LDL cholesterol levels impact actual cardiovascular events and whether adding medications like ezetimibe truly changes the outcome for your heart health. If you’ve been skeptical about statins or confused by conflicting health trends, this breakdown of the latest science is for you. My mission is to put myself out of business by giving you the truth about prevention before you ever need to see me in the operating room.  For educational purposes only. Not medical advice. Always consult your healthcare provider before changing any treatment plan.  Sign up for more information on my own practice here: https://corsighthealth.com/ High Quality 3rd-party tested supplements at Fullscript (10% discount): https://us.fullscript.com/welcome/ljohnstonmd/store-start Other tools for optimal health (note these are affiliate links): Home BP Cuff: https://amzn.to/49Cq7rh Sonicare Toothbrush: https://amzn.to/3KllfMS WaterPik: https://amzn.to/4894Xi8 Apple Watch with sleep & HR monitoring: https://amzn.to/3XaUn5d Oura Ring with sleep, cycle, and recovery monitoring: https://amzn.to/4riyhLS Intake Breathing Nasal Support: https://amzn.to/48dfQQ1 Personal Blender: https://amzn.to/4pyNGGl True Nutrition Protein: https://oken.do/q2xzqeqw Glass Meal Prep Containers: https://amzn.to/4ocEPJ2 Sleep Mask: https://amzn.to/48fSJV5 Air Purifier: https://amzn.to/4puzTQZ ___________________________ 🧬 About Dr. Lily Johnston    Dr. Johnston is a double board-certified vascular and general surgeon in San Diego, specializing in metabolic and cardiovascular prevention. She’s the founder of CorSight Health and a passionate advocate for reimagining how medicine approaches chronic disease.    #MetabolicHealth #CardiovascularPrevention #HeartHealth #Longevity #InsulinResistance #DrLilyJohnston #DrLily #WomenInMedicine #Surgeon #VascularSurgeon #PreventiveMedicine #PADPrevention #HeartAttackRisks #HealthPortfolio #California #SanDiego #Arizona #Virginia #Minnesota

    24 min

  3. 27 APR

    The Truth About Aspirin and Heart Attack Prevention

    I've seen daily aspirin save lives from heart attack — and cause fatal bleeds. As a vascular surgeon, here's my honest take on heart health. The answer isn't yes or no — it depends entirely on who you are. In this video I break down the three groups you need to know: ✅ Who SHOULD take daily aspirin — if you've already had a heart attack, stroke, or stent, aspirin for secondary prevention of heart disease is still one of the most evidence-backed interventions we have. ❌ Who SHOULD NOT — the 2022 USPSTF guidelines quietly changed the recommendations for primary prevention. If you haven't had a cardiovascular event, daily aspirin may be doing more harm than good. ⚠️ The gray zone — two situations where the answer gets complicated: elevated coronary artery calcium (CAC) scores and high Lp(a) (lipoprotein a). Both raise your cardiovascular risk in ways the standard guidelines don't fully account for. This is the conversation your doctor should be having with you — but often doesn't have time for.   I'm a vascular surgeon teaching the prevention side of medicine — the part most doctors don't have time to cover. Subscribe for more evidence-based answers on heart disease, metabolic health, and longevity.   Sign up for more information on my own practice here: https://corsighthealth.com/ High Quality 3rd-party tested supplements at Fullscript (10% discount): https://us.fullscript.com/welcome/ljohnstonmd/store-start Other tools for optimal health (note these are affiliate links): Home BP Cuff: https://amzn.to/49Cq7rh Sonicare Toothbrush: https://amzn.to/3KllfMS WaterPik: https://amzn.to/4894Xi8 Apple Watch with sleep & HR monitoring: https://amzn.to/3XaUn5d Oura Ring with sleep, cycle, and recovery monitoring: https://amzn.to/4riyhLS Intake Breathing Nasal Support: https://amzn.to/48dfQQ1 Personal Blender: https://amzn.to/4pyNGGl True Nutrition Protein: https://oken.do/q2xzqeqw Glass Meal Prep Containers: https://amzn.to/4ocEPJ2 Sleep Mask: https://amzn.to/48fSJV5 Air Purifier: https://amzn.to/4puzTQZ ___________________________ 🧬 About Dr. Lily Johnston    Dr. Johnston is a double board-certified vascular and general surgeon in San Diego, specializing in metabolic and cardiovascular prevention. She’s the founder of CorSight Health and a passionate advocate for reimagining how medicine approaches chronic disease.    #MetabolicHealth #CardiovascularPrevention #HeartHealth #Longevity #InsulinResistance #DrLilyJohnston #DrLily #WomenInMedicine #Surgeon #VascularSurgeon #PreventiveMedicine #PADPrevention #HeartAttackRisks #HealthPortfolio #California #SanDiego #Arizona #Virginia #Minnesota

    24 min

  4. 20 APR

    Ask Me (Almost) Anything With Dr Johnston | Live Q&A

    We hit all the high points today! Nutrition, exercise, lipids, dental health, hormones, and more. We had amazing participation and it was wonderful to have a chance to interact with everyone in real time. Thanks SO much for taking some of your precious weekend to talk cardiovascular health, heart scans, CAC scores, and all the other nerdy prevention things with me. Hope you enjoyed it! If you want me to do more of these in the future, please say so in the comments! Water filters that remove microplastics: Clearly Filtered Pitcher: https://a.co/d/0e2GGJ1c LifeStraw 18-cup Water Filter Dispenser: https://a.co/d/0a7rPQKM Other Ways To Minimize Plastics and Air Pollutants: Glass Meal Prep Containers: https://amzn.to/4ocEPJ2 Air Purifier: https://amzn.to/4puzTQZ Dental Hygiene Tools I Use: Sonicare Toothbrush: https://amzn.to/3KllfMS WaterPik: https://amzn.to/4894Xi8 High Quality 3rd-party tested supplements at Fullscript (10% discount): https://us.fullscript.com/welcome/ljohnstonmd/store-start Other tools for optimal health (note these are affiliate links): Home BP Cuff: https://amzn.to/49Cq7rh Apple Watch with sleep & HR monitoring: https://amzn.to/3XaUn5d Oura Ring with sleep, cycle, and recovery monitoring: https://amzn.to/4riyhLS Intake Breathing Nasal Support: https://amzn.to/48dfQQ1 Personal Blender: https://amzn.to/4pyNGGl True Nutrition Protein: https://oken.do/q2xzqeqw Sleep Mask: https://amzn.to/48fSJV5 ___________________________ 🧬 About Dr. Lily Johnston    Dr. Johnston is a double board-certified vascular and general surgeon in San Diego, specializing in metabolic and cardiovascular prevention. She’s the founder of CorSight Health and a passionate advocate for reimagining how medicine approaches chronic disease.

    1hr 43min

  5. 13 APR

    Can You Unclog Arteries? A Vascular Surgeon Reacts to Dr Kevin Ham ​

    Plaque reversal is one of the most debated topics in preventive cardiology, so in this video I react to Dr. Kevin Ham’s CAST protocol for plaque reversal: Causes, Adding Cures, Strengthening the Body, and Training the Mind and Body. Overall, I think this is a thoughtful framework and I agree with much of it. But as a vascular surgeon who treats advanced atherosclerosis, I also add some nuance around what “plaque reversal” really means, what may be missing from this conversation, and where I’d want more granularity in a real-world cardiovascular prevention plan. We talk about the causes of plaque buildup, metabolic health, lifestyle change, cardiovascular risk reduction, and the difference between improving risk factors versus actually changing plaque biology. I also share where I think protocols like this can be helpful—and where they risk oversimplifying atherosclerosis. If you’re trying to understand plaque reversal, atherosclerosis, heart disease prevention, metabolic health, LDL, ApoB, inflammation, insulin resistance, and cardiovascular risk, this video will help you think more clearly about the problem. Let me know in the comments: Do you think “plaque reversal” is a useful term, or does it create more confusion than clarity? #PlaqueReversal #Atherosclerosis #HeartDisease #CardiovascularHealth #MetabolicHealth #Prevention High Quality 3rd-party tested supplements at Fullscript (10% discount): https://us.fullscript.com/welcome/ljohnstonmd/store-start Other tools for optimal health (note these are affiliate links): Home BP Cuff: https://amzn.to/49Cq7rh Sonicare Toothbrush: https://amzn.to/3KllfMS WaterPik: https://amzn.to/4894Xi8 Apple Watch with sleep & HR monitoring: https://amzn.to/3XaUn5d Oura Ring with sleep, cycle, and recovery monitoring: https://amzn.to/4riyhLS Intake Breathing Nasal Support: https://amzn.to/48dfQQ1 Personal Blender: https://amzn.to/4pyNGGl True Nutrition Protein: https://oken.do/q2xzqeqw Glass Meal Prep Containers: https://amzn.to/4ocEPJ2 Sleep Mask: https://amzn.to/48fSJV5 Air Purifier: https://amzn.to/4puzTQZ ___________________________ 🧬 About Dr. Lily Johnston    Dr. Johnston is a double board-certified vascular and general surgeon in San Diego, specializing in metabolic and cardiovascular prevention. She’s the founder of CorSight Health and a passionate advocate for reimagining how medicine approaches chronic disease.

    21 min

  6. 13 APR

    I'm a Vascular Surgeon — Stop Getting Repeat CAC Scans. Here's Why

    If you’ve had a positive calcium score (CAC score), you’ve probably asked the obvious next question: when should I repeat it? In this video, I explain why I generally do not order another calcium score if the first one is positive—and what I prefer to use instead to follow atherosclerosis over time. We walk through what a coronary artery calcium score actually measures, why it’s really just the tip of the iceberg, and why a higher repeat score does not necessarily mean your treatment failed. I also explain the difference between calcified plaque and soft, lipid-rich plaque, why that distinction matters for heart attack and stroke risk, and why serial CAC testing often adds less useful information than people think. I also cover:  • why calcium scores can be helpful as a one-time risk assessment tool  • why I’m more cautious about relying on CAC in younger patients  • when I will repeat a calcium score  • why I prefer more informative tools like CCTA and CIMT for tracking disease over time If you’re trying to understand calcium score progression, plaque stabilization, soft plaque, coronary artery disease, heart disease prevention, stroke prevention, ApoB, Lp(a), statins, and cardiovascular risk, this video is for you. Let me know in the comments: If your first calcium score was positive, would you want to repeat it—or would you rather use a different test to follow your risk? #CalciumScore #CACScore #HeartDiseasePrevention #Atherosclerosis #CardiovascularHealth #CIMT #CCTA Sign up for more information on my own practice here: https://corsighthealth.com/ High Quality 3rd-party tested supplements at Fullscript (10% discount): https://us.fullscript.com/welcome/ljohnstonmd/store-start Other tools for optimal health (note these are affiliate links): Home BP Cuff: https://amzn.to/49Cq7rh Sonicare Toothbrush: https://amzn.to/3KllfMS WaterPik: https://amzn.to/4894Xi8 Apple Watch with sleep & HR monitoring: https://amzn.to/3XaUn5d Oura Ring with sleep, cycle, and recovery monitoring: https://amzn.to/4riyhLS Intake Breathing Nasal Support: https://amzn.to/48dfQQ1 Personal Blender: https://amzn.to/4pyNGGl True Nutrition Protein: https://oken.do/q2xzqeqw Glass Meal Prep Containers: https://amzn.to/4ocEPJ2 Sleep Mask: https://amzn.to/48fSJV5 Air Purifier: https://amzn.to/4puzTQZ ___________________________ 🧬 About Dr. Lily Johnston    Dr. Johnston is a double board-certified vascular and general surgeon in San Diego, specializing in metabolic and cardiovascular prevention. She’s the founder of CorSight Health and a passionate advocate for reimagining how medicine approaches chronic disease.    #MetabolicHealth #CardiovascularPrevention #HeartHealth #Longevity #InsulinResistance #DrLilyJohnston #DrLily #WomenInMedicine #Surgeon #VascularSurgeon #PreventiveMedicine #PADPrevention #HeartAttackRisks #HealthPortfolio #California #SanDiego #Arizona #Virginia #Minnesota

    10 min

  7. 13 APR

    Is Your Candle Slowly Poisoning You? Vascular Surgeon Reacts to Joe Rogan

    Joe Rogan got half a million people talking about what's happening inside their blood vessels. As a vascular surgeon, I've spent my career trying to do exactly that. So when a celebrity does it for me, I pay attention (and thank my lucky stars ;). In the clip, Dr. Shauna Swan joins Joe Rogan to discuss the surprising hazards linked to everyday household products. In my reaction, I go through the actual studies behind the microplastics- and forever chemicals-cardiovascular disease conversation: what the data show, where the evidence is genuinely alarming, and where the certainty online is running about three years ahead of the science. Because both things are true. What we cover: — Microplastics found inside arterial plaques — and what that study actually says — PFAS (forever chemicals), phthalates, and other endocrine disruptors — Why association isn't causation and why that matters for your next doctor's appointment — What to actually do with genuine scientific uncertainty The signal is real. The panic is premature. You deserve to know the difference. If this video has you wondering whether you already have plaque — that's exactly the right question. Here's where to go next: https://youtu.be/-lt_2swYFhY?si=bRiZyDVY5QAxVvu8 📚 Studies referenced:     1. Marfella R, Prattichizzo F, Sardu C, Fulgenzi G, Graciotti L, Spadoni T, et al. Microplastics and Nanoplastics in Atheromas and Cardiovascular Events. N Engl J Med. 2024;390(10):900–10. doi:10.1056/nejmoa2309822    2. Dunder L, Salihovic S, Varotsis G, Lind PM, Elmståhl S, Lind L. Plasma levels of per- and polyfluoroalkyl substances (PFAS) and cardiovascular disease - Results from two independent population-based cohorts and a meta-analysis. Environ Int. 2023 Nov;181:108250. doi: 10.1016/j.envint.2023.108250. PMID: 37832261. Sign up for more information on my own practice here: https://corsighthealth.com/ High Quality 3rd-party tested supplements at Fullscript (10% discount): https://us.fullscript.com/welcome/ljohnstonmd/store-start Other tools for optimal health (note these are affiliate links): Home BP Cuff: https://amzn.to/49Cq7rh Sonicare Toothbrush: https://amzn.to/3KllfMS WaterPik: https://amzn.to/4894Xi8 Apple Watch with sleep & HR monitoring: https://amzn.to/3XaUn5d Oura Ring with sleep, cycle, and recovery monitoring: https://amzn.to/4riyhLS Intake Breathing Nasal Support: https://amzn.to/48dfQQ1 Personal Blender: https://amzn.to/4pyNGGl True Nutrition Protein: https://oken.do/q2xzqeqw Glass Meal Prep Containers: https://amzn.to/4ocEPJ2 Sleep Mask: https://amzn.to/48fSJV5 Air Purifier: https://amzn.to/4puzTQZ ___________________________ 🧬 About Dr. Lily Johnston    Dr. Johnston is a double board-certified vascular and general surgeon in San Diego, specializing in metabolic and cardiovascular prevention. She’s the founder of CorSight Health and a passionate advocate for reimagining how medicine approaches chronic disease.    #MetabolicHealth #CardiovascularPrevention #HeartHealth #Longevity #InsulinResistance #DrLilyJohnston #DrLily #WomenInMedicine #Surgeon #VascularSurgeon #PreventiveMedicine #PADPrevention #HeartAttackRisks #HealthPortfolio #California #SanDiego #Arizona #Virginia #minnesota

    9 min

  8. 30 MAR

    GLP-1 Drugs Cut Heart Attack Risk — And It Has Nothing to Do With Weight

    SELECT trial explained: does semaglutide reduce cardiovascular risk because of weight loss, or is something else going on? In this video, I break down the SELECT trial and the follow-up analysis examining whether the cardiovascular benefit of semaglutide was directly mediated by weight loss. The answer matters, because the data suggest the reduction in major adverse cardiovascular events was not simply a function of people losing more weight. I’m a board-certified vascular surgeon focused on cardiometabolic prevention, and in this video I walk through what the SELECT trial actually showed, what the subsequent analysis adds, and why this changes how we think about GLP-1 receptor agonists, obesity, heart disease, and prevention. If you’ve been wondering whether semaglutide’s heart protection is just about the number on the scale, this is where we separate mechanism from marketing. In this video, I cover:  • The SELECT trial design and main cardiovascular outcomes  • How semaglutide affected heart attack, stroke, and cardiovascular death risk  • The follow-up mediation analysis on weight loss  • Why the cardiovascular benefit does not appear to be explained by weight loss alone  • What this may mean for inflammation, metabolism, and vascular protection  • How I think about semaglutide clinically in the bigger picture of cardiometabolic health If you care about semaglutide, GLP-1 drugs, cardiovascular disease prevention, obesity medicine, insulin resistance, plaque, and the real mechanisms behind cardiometabolic risk reduction, you’re in the right place. Question for you: when you think about semaglutide, do you mainly think “weight loss drug,” or has the cardiovascular data changed your view? Sign up for more information on my own practice here: https://corsighthealth.com/ High Quality 3rd-party tested supplements at Fullscript (10% discount): https://us.fullscript.com/welcome/ljohnstonmd/store-start Other tools for optimal health (note these are affiliate links): Home BP Cuff: https://amzn.to/49Cq7rh Sonicare Toothbrush: https://amzn.to/3KllfMS WaterPik: https://amzn.to/4894Xi8 Apple Watch with sleep & HR monitoring: https://amzn.to/3XaUn5d Oura Ring with sleep, cycle, and recovery monitoring: https://amzn.to/4riyhLS Intake Breathing Nasal Support: https://amzn.to/48dfQQ1 Personal Blender: https://amzn.to/4pyNGGl True Nutrition Protein: https://oken.do/q2xzqeqw Glass Meal Prep Containers: https://amzn.to/4ocEPJ2 Sleep Mask: https://amzn.to/48fSJV5 Air Purifier: https://amzn.to/4puzTQZ ___________________________ 🧬 About Dr. Lily Johnston    Dr. Johnston is a double board-certified vascular and general surgeon in San Diego, specializing in metabolic and cardiovascular prevention. She’s the founder of CorSight Health and a passionate advocate for reimagining how medicine approaches chronic disease.    #MetabolicHealth #CardiovascularPrevention #HeartHealth #Longevity #InsulinResistance #DrLilyJohnston #DrLily #WomenInMedicine #Surgeon #VascularSurgeon #PreventiveMedicine #PADPrevention #HeartAttackRisks #HealthPortfolio #California #SanDiego #Arizona #Virginia #minnesota

    27 min
See All (30)

About

 "Knife Down" is what a surgeon says in the OR when she puts her scalpel down so no one gets hurt — and it’s the mission here: put the knife down, long before anyone needs to use it. Knife Down is a podcast about how to actually invest in your health so you can live longer, stronger, and with less time in doctors’ offices. The core focus is the world’s leading cause of death—cardiovascular disease—and what to do about it before it shows up as a catastrophe. Hosted by a vascular surgeon on a mission to put herself out of business, the show translates cutting-edge science on prevention, metabolic health, and longevity into real-world strategies you can use in clinic or at your kitchen table. Expect evidence, nuance, and zero wellness hype—plus the occasional dark joke about the state of modern medicine.

Information

  • Creator
    Lily Johnston, MD MPH
  • Years Active
    2k
  • Episodes
    30
  • Rating
    Clean
  • Copyright
    © 2026 Knife Down
  • Show Website
    Knife Down

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