Heart Health Education Series
Your Heart, by the Numbers
Cardiovascular disease is the number one killer in America, responsible for roughly 1 in 5 deaths. But it is also the most preventable. This guide covers the science, the risk factors, the medications, and what modern prevention actually looks like.
A Century of Heart Science
The story of cardiovascular medicine is one of the greatest in all of science. From basic observations about cholesterol to gene-targeted therapies, here are the milestones that shaped how we prevent and treat heart disease today.
Cholesterol and Atherosclerosis Linked
Nikolai Anitschkow fed cholesterol to rabbits and induced atherosclerosis, providing the first experimental evidence that dietary cholesterol could cause vascular disease. It would take decades for this insight to change clinical practice.
The Framingham Heart Study Begins
Researchers enrolled 5,209 residents of Framingham, Massachusetts in what would become the most important longitudinal study in cardiovascular medicine. Framingham would go on to identify high cholesterol, hypertension, and smoking as the major risk factors, and it coined the term 'risk factor' for medicine.
First Coronary Bypass Surgery
Rene Favaloro performed the first successful coronary artery bypass graft (CABG) at the Cleveland Clinic, giving surgeons a way to reroute blood flow around blocked arteries. This was the beginning of surgical treatment for coronary artery disease.
The Birth of Statins
Japanese biochemist Akira Endo discovered compactin, the first HMG-CoA reductase inhibitor, isolated from a fungus called Penicillium citrinum. This discovery laid the foundation for the entire statin drug class, which would go on to save millions of lives.
First Statin Approved
Lovastatin (Mevacor) received FDA approval, becoming the first commercially available statin. It validated the concept that lowering cholesterol with a medication could prevent heart disease. The statin era had begun.
The 4S Trial Proves Statins Save Lives
The Scandinavian Simvastatin Survival Study (4S) showed that simvastatin reduced coronary death by 42% and all-cause mortality by 30% in patients with prior heart attacks. This was the first definitive proof that a cholesterol-lowering drug could save lives.
PCSK9 Gene Discovered
Abifadel and colleagues identified mutations in the PCSK9 gene in families with extremely high cholesterol. Shortly after, Helen Hobbs found that people with naturally low PCSK9 activity had dramatically lower LDL and up to 88% less heart disease. A new drug target was born.
The JUPITER Trial Expands Statin Use
The JUPITER trial showed that rosuvastatin reduced cardiovascular events by 44% in patients with normal LDL cholesterol but elevated inflammation (hsCRP above 2 mg/L). The trial was stopped early for overwhelming benefit. This expanded the rationale for statins beyond just high cholesterol.
PCSK9 Inhibitors Arrive
Alirocumab (Praluent) and evolocumab (Repatha) received FDA approval. These injectable antibodies could reduce LDL cholesterol by an additional 60% on top of statins. The FOURIER trial (2017) later proved they reduce heart attacks in patients with established heart disease.
The SELECT Trial Changes the Game
The SELECT trial demonstrated that semaglutide 2.4 mg reduced major cardiovascular events by 20% in adults with established cardiovascular disease and overweight or obesity, but without diabetes. Benefits appeared within 3 months, suggesting direct vascular protection beyond weight loss. The FDA granted semaglutide a cardiovascular risk-reduction indication, making GLP-1 drugs part of cardiovascular prevention. The strongest hard-outcome evidence is currently in secondary prevention, but anti-obesity pharmacotherapy is rapidly becoming cardiovascular prevention infrastructure.
A New Era of Prevention
The 2026 ACC/AHA Dyslipidemia Guidelines reintroduced explicit LDL goals for the first time in years: under 100 mg/dL for borderline or intermediate-risk primary prevention, under 70 for high-risk primary prevention, and under 55 for very high-risk secondary prevention. The guidelines also recommend Lp(a) measurement at least once in adulthood and incorporate ApoB for selective measurement and risk refinement. Risk assessment shifted from the old pooled cohort equations to the PREVENT calculator, which estimates both 10-year and 30-year risk. Oral PCSK9 inhibitors entered late-stage trials, promising to make aggressive prevention accessible to everyone.
Understanding Cardiovascular Disease
Most people think of heart disease as “clogged arteries,” like grease building up in a pipe. The reality is more complex and more interesting. Understanding how atherosclerosis actually works will change how you think about prevention.
Risk Factors: Traditional and Emerging
We have known about the traditional risk factors for decades. But the last ten years have revealed that some of the most important risk factors were hiding in plain sight. Understanding both categories gives you a much more complete picture of your cardiovascular risk.
Traditional Risk Factors
LDL Cholesterol
Every 38.7 mg/dL reduction in LDL-C reduces major cardiovascular events by approximately 22%.
There is no lower threshold where benefit stops. The 2026 ACC/AHA guidelines reintroduced explicit LDL goals: under 100 mg/dL for borderline or intermediate-risk primary prevention, under 70 for high-risk primary prevention, and under 55 for very high-risk secondary prevention, with still lower targets considered in select patients with severe subclinical disease such as high coronary calcium burden. Lower is better, and the relationship is consistent across all populations studied.
Hypertension
Affects about 47% of U.S. adults (116 million people) based on the 130/80 mmHg threshold.
High blood pressure damages the endothelium, increases arterial wall permeability to ApoB particles, and makes the heart work harder. The SPRINT trial showed that targeting systolic blood pressure below 120 mmHg reduced cardiovascular events by 25% and mortality by 27%.
Smoking
Smokers have 2 to 4 times the cardiovascular risk of non-smokers.
Smoking damages the endothelium, increases oxidative stress, activates platelets, and raises fibrinogen. The good news: quitting reduces cardiovascular risk by about 50% within one year, and risk approaches that of never-smokers by 5 to 15 years.
Type 2 Diabetes
Diabetes confers a 2 to 4 times increased risk of cardiovascular disease.
Diabetic dyslipidemia is characterized by elevated triglycerides, low HDL, and increased small dense LDL particles. This is a pattern where ApoB is particularly important because LDL cholesterol may look 'normal' despite a dangerously elevated particle count.
Family History
A first-degree relative with premature heart disease approximately doubles your cardiovascular risk.
Premature means a male relative before age 55 or a female relative before age 65. Family history captures both genetic susceptibility and shared environmental exposures. However, it is a blunt tool. Inherited risks like elevated Lp(a) can now be directly measured.
Obesity
Increases cardiovascular risk through multiple pathways: hypertension, dyslipidemia, insulin resistance, and chronic inflammation.
Visceral (abdominal) fat is more metabolically harmful than subcutaneous fat. The SELECT trial showed that semaglutide reduced major cardiovascular events by 20% in adults with established cardiovascular disease and overweight or obesity. The FDA granted a cardiovascular risk-reduction indication, and ACC issued 2025 clinical guidance on medical weight management for cardiovascular health. Anti-obesity pharmacotherapy is becoming cardiovascular prevention infrastructure, though the strongest hard-outcome evidence today is in secondary prevention.
Emerging and Underappreciated Risk Factors
Apolipoprotein B (ApoB)
ApoB directly counts the number of atherogenic particles in your blood, giving a more accurate picture of risk than LDL cholesterol.
When LDL-C and ApoB disagree, cardiovascular risk tracks with ApoB. This discordance is common in metabolic syndrome, diabetes, and patients on statin therapy. The 2026 guidelines now incorporate ApoB for selective measurement and risk refinement, with treatment-goal relevance in selected patients. In my approach, I go further: I use ApoB as the primary treatment target, aiming for below 60 mg/dL in primary prevention and below 40 in high-risk patients. These targets are more aggressive than mainstream guideline language, but they are consistent with Mendelian randomization data and the NLA position that ApoB can outperform LDL-C for risk assessment when the two are discordant.
Lipoprotein(a) [Lp(a)]
About 20% of the global population (1.4 billion people) has elevated Lp(a), a genetically determined risk factor that most have never heard of.
Lp(a) levels are over 90% genetically determined, set at birth, and not meaningfully lowered by diet, exercise, or statins. Elevated Lp(a) doubles or triples the risk of heart attack, stroke, and aortic stenosis. The 2026 guidelines give a Class I (strongest) recommendation for universal once-in-a-lifetime Lp(a) testing. New drugs targeting Lp(a) are in late-stage trials.
High-Sensitivity CRP (hsCRP)
A biomarker of systemic inflammation. Levels above 3 mg/L indicate higher cardiovascular risk.
The JUPITER trial showed that statin therapy in patients with normal LDL but elevated hsCRP reduced cardiovascular events by 44%. The CANTOS trial proved that inflammation is a causal driver of heart disease by showing that an anti-inflammatory drug reduced events without lowering cholesterol. hsCRP is closely linked to insulin resistance.
Insulin Resistance
Increasingly recognized as a central driver of cardiometabolic risk, often present years before a diabetes diagnosis.
Insulin resistance produces the 'atherogenic triad': elevated triglycerides, low HDL, and increased small dense LDL particles. It directly promotes endothelial dysfunction, vascular inflammation, and blood clotting. Simple markers like the triglyceride-to-HDL ratio can help identify it early.
The Evolution of Lipid Management
The way we think about cholesterol management has changed dramatically. We have moved from simply checking total cholesterol to targeting the actual particles that cause disease. Here is how the field evolved, and what tools we have today.
My ApoB Targets
I use ApoB as the primary treatment target, not just LDL cholesterol. My targets are more aggressive than the 2026 guidelines because the data support going lower. For primary prevention: ApoB below 60 mg/dL. For high-risk patients: ApoB below 40 mg/dL. These targets reflect the Mendelian randomization evidence that people with lifelong lower ApoB levels have dramatically less heart disease, with no lower threshold for benefit.
Current Medications
We have more effective tools for lowering ApoB and LDL than at any point in history. Here are the medications I use and what the evidence shows.
Statins
Statins block the enzyme HMG-CoA reductase in the liver, reducing cholesterol production. This causes the liver to pull more LDL particles out of the blood. High-intensity statins (atorvastatin 40-80 mg, rosuvastatin 20-40 mg) reduce LDL cholesterol by 50% or more and ApoB by about 35-45%.
- The 4S trial proved statins save lives: 42% reduction in coronary death and 30% reduction in all-cause mortality
- True muscle damage (with elevated CK) occurs in less than 1% of patients. The SAMSON and StatinWISE trials showed that most 'statin side effects' are driven by expectation, not the drug itself
- Statins have anti-inflammatory and plaque-stabilizing effects beyond just lowering cholesterol
- Small increase in new-onset diabetes risk (about 0.1% per year), but the cardiovascular benefit far outweighs this
Ezetimibe (Zetia)
Ezetimibe blocks cholesterol absorption in the intestine by inhibiting the NPC1L1 protein. It reduces LDL cholesterol by an additional 15-25% when added to a statin and reduces ApoB by about 15%. It is inexpensive, well-tolerated, and the logical first addition when a statin alone is not enough.
- The IMPROVE-IT trial showed that adding ezetimibe to a statin after a heart attack reduced cardiovascular events over 7 years
- Achieved LDL of 53.7 mg/dL in the trial, the first major proof that going that low is beneficial
- Available as a generic and can be combined in a single pill with simvastatin (Vytorin)
- Very few side effects; most patients tolerate it without issues
PCSK9 Inhibitors
PCSK9 is a protein that destroys LDL receptors on the liver. By blocking PCSK9 with monoclonal antibodies (evolocumab or alirocumab), more LDL receptors stay on the liver surface, clearing more LDL and other ApoB particles from the blood. These are injectable medications given every 2 to 4 weeks.
- Reduce LDL cholesterol by 50-60% on top of a statin, and ApoB by 40-55%
- Also lower Lp(a) by about 20-30%, which no other common medication does well
- The FOURIER trial showed a 27% reduction in heart attacks. The VESALIUS-CV trial (2025) showed a 25% reduction in coronary death, heart attack, or stroke in patients without prior events
- Extensive safety data show no significant concerns, even at achieved LDL levels below 20 mg/dL
Bempedoic Acid (Nexletol)
Bempedoic acid works upstream of statins in the cholesterol synthesis pathway. The key advantage: it is activated by an enzyme found only in the liver, not in muscle. This means it does not cause the muscle-related side effects that some patients experience with statins.
- The CLEAR Outcomes trial showed a 13% reduction in major cardiovascular events and a 23% reduction in heart attacks in statin-intolerant patients
- Reduces LDL cholesterol by 18-25% alone, or about 38% when combined with ezetimibe (Nexlizet)
- Does not cause muscle pain because the drug is not active in skeletal muscle tissue
- Modest increase in gout risk (3.1% vs. 2.1%) due to a small increase in uric acid
Inclisiran (Leqvio)
Inclisiran is a small interfering RNA (siRNA) that silences the PCSK9 gene in the liver. Instead of blocking the PCSK9 protein after it is made (like the monoclonal antibodies), inclisiran prevents the protein from being made in the first place. It is given as an injection at baseline, 3 months, then every 6 months.
- Reduces LDL cholesterol by about 50% on top of statin therapy and ApoB by about 40%
- Only needs to be given twice a year, administered in the doctor's office, which eliminates adherence concerns
- Cardiovascular outcomes trial (ORION-4) is ongoing and expected to report in 2026-2027
- The 2026 guidelines note it is 'reasonable to use' when PCSK9 monoclonal antibodies are not tolerated or accessible
Icosapent Ethyl (Vascepa)
Icosapent ethyl is purified EPA (eicosapentaenoic acid) at prescription strength (4 grams per day). Its cardiovascular benefit appears to come from direct anti-inflammatory, anti-thrombotic, and plaque-stabilizing effects rather than just lowering triglycerides.
- The REDUCE-IT trial showed a 25% reduction in cardiovascular events in statin-treated patients with elevated triglycerides
- Over-the-counter fish oil supplements are NOT equivalent and have NOT shown cardiovascular benefit
- The STRENGTH trial (EPA plus DHA combination) showed no benefit, reinforcing that it is high-dose pure EPA that works
- Small increase in atrial fibrillation risk (5.3% vs. 3.9%)
Advanced Cardiovascular Diagnostics
Modern imaging lets us see atherosclerosis before it causes symptoms. Each test has a specific role, specific strengths, and specific limitations. Understanding what each test can and cannot tell you helps you make better decisions with your doctor.
Coronary CT Angiography (CCTA)
A contrast-enhanced CT scan that directly visualizes the coronary arteries, identifying both calcified and non-calcified (soft) plaque, measuring the degree of narrowing, and characterizing plaque composition. This is the test that gives us the most complete picture of what is happening in your coronary arteries.
Key Points
- Sensitivity of 95-99% for detecting significant coronary disease. A normal CCTA essentially rules out obstructive blockages
- Unlike a calcium score, CCTA detects soft plaque. Soft plaque is the dangerous, non-calcified plaque that is more likely to rupture and cause a heart attack. A calcium score can be zero while soft plaque is already building up
- The SCOT-HEART trial showed that CCTA-guided management reduced coronary death or heart attack by 41% compared with standard care over 5 years
- AI-powered analysis is transforming what we can learn from a CCTA. Cleerly uses AI to quantify total plaque volume, soft plaque volume, and percent stenosis from a standard CCTA scan, giving us a detailed plaque 'report card' that tracks over time. HeartFlow creates a 3D model of your coronary arteries and uses computational fluid dynamics to calculate fractional flow reserve (FFR) non-invasively, telling us whether a blockage is actually restricting blood flow without needing a catheterization
- These AI platforms turn a single CCTA scan into something far more powerful than what we could get just five years ago
Limitations
- Higher radiation dose than CAC scoring (about 3-5 mSv with modern scanners)
- Requires iodinated contrast (risk of allergic reaction; not ideal for patients with severe kidney problems)
- Motion artifacts can occur in patients with fast or irregular heart rates
- More expensive than a calcium score. AI analysis from Cleerly or HeartFlow adds additional cost, though increasingly covered by insurance
My approach: CCTA is my preferred advanced imaging test when I need to go beyond a calcium score. It gives us what CAC cannot: the soft plaque load. I use Cleerly's AI analysis to quantify total plaque burden and track it over time in selected patients. This approach is ahead of routine guideline practice for asymptomatic screening, but it is increasingly supported. ACC's 2025 quantitative plaque analysis statement endorses AI-powered plaque quantification when plaque is already visible on CCTA, and SCOT-HEART showed that CCTA-guided management improves outcomes. The direction of travel in cardiovascular imaging is clearly toward plaque burden and plaque phenotype, not just risk-factor proxies. I use this selectively in patients where the results will change management, not as a broad population screening tool.
Coronary Artery Calcium (CAC) Score
A non-contrast CT scan that detects and measures calcified plaque in the coronary arteries. The Agatston score is calculated based on the density and area of calcium deposits. A score of 0 means no detectable calcification. A score above 100 indicates moderate plaque. Above 400 indicates extensive disease.
Key Points
- Best used in asymptomatic adults aged 40-75 with intermediate risk, where the decision to start a statin is uncertain
- A CAC of 0 is a powerful negative predictor. It is associated with very low short-term risk and may reasonably defer statin therapy for about 5 years
- Any score above 0 confirms that subclinical atherosclerosis is present and favors more aggressive treatment
- Adds significantly to risk prediction beyond traditional calculators like the Framingham score or pooled cohort equations
Limitations
- Does not detect non-calcified ('soft') plaque. A young patient with aggressive disease may have significant plaque and a CAC of 0. This is the biggest limitation and why I often follow up with a CCTA
- Not useful for patients with symptoms (CT angiography or stress testing is more appropriate)
- Low radiation dose (about 1 mSv, equivalent to a mammogram). Cost: $100-400, often not covered by insurance
My approach: I use CAC scoring as an initial risk stratification tool in patients with borderline risk, elevated Lp(a), or family history of premature heart disease. A CAC above 0 in a patient with elevated ApoB strengthens the case for aggressive treatment. But I always remind patients that a CAC of 0 does not mean zero plaque. It means zero calcified plaque. If the clinical picture is concerning, I move to a CCTA to look for soft plaque.
Carotid Intima-Media Thickness (CIMT)
An ultrasound measurement of the combined thickness of the inner layers of the carotid arteries (the large arteries in the neck that supply blood to the brain). Increased thickness is a marker of subclinical atherosclerosis throughout the body.
Key Points
- Higher CIMT is associated with increased risk of heart attack (26% increase per standard deviation) and stroke (31% increase)
- UK Biobank data from 2025 confirmed the association between higher CIMT and coronary heart disease risk
- Non-invasive, no radiation, and repeatable over time to monitor treatment response
- Detecting actual carotid plaque (not just wall thickness) appears to be even more predictive
Limitations
- Measurement standardization remains challenging; results depend on the operator's skill
- Adding CIMT to traditional risk models shows only modest improvement in discrimination
- The 2013 ACC/AHA guidelines recommend against routine CIMT for first event prediction
My approach: I use CIMT selectively as part of a comprehensive vascular assessment, often alongside CAC scoring. The combination of elevated CIMT, detectable carotid plaque, and elevated ApoB provides a compelling case for aggressive treatment, even in patients with 'borderline' traditional risk scores. CIMT can also track plaque regression or stabilization over time.
Stress Testing
Functional tests that assess whether the heart gets enough blood flow during physical stress. Options include the exercise treadmill test (ECG monitoring during exercise), stress echocardiography (ultrasound imaging during stress), nuclear perfusion imaging (radiotracer to map blood flow), and stress cardiac MRI.
Key Points
- Exercise treadmill testing has moderate accuracy (sensitivity about 68%, specificity about 77%)
- Stress echo and nuclear imaging are more accurate (sensitivity 80-90%), but nuclear imaging involves more radiation
- Stress cardiac MRI offers excellent accuracy with no radiation, but is less widely available and more expensive
- Useful for evaluating symptoms and determining whether blockages are causing reduced blood flow
Limitations
- All functional stress tests only detect flow-limiting blockages, typically narrowing of 70% or more
- Most heart attacks come from plaques that are only 30-50% narrowed, too small to show up on stress testing, but unstable enough to rupture
- A normal stress test does NOT rule out significant atherosclerotic disease or future events
My approach: I use stress testing primarily for symptomatic patients. But I always remind patients that a 'normal' stress test is not a clean bill of health. It means you do not have severe blockages right now. It says nothing about the non-obstructive plaques that cause most heart attacks. That is why I focus on preventing plaque formation in the first place.
Calculate Your Cardiovascular Risk
The AHA PREVENT equations replaced the old pooled cohort equations in 2024. This calculator estimates your 10-year and 30-year risk of total cardiovascular disease, including heart attack, stroke, and heart failure. It was developed from over 6 million people across multiple U.S. cohorts and is now recommended by the 2026 ACC/AHA Dyslipidemia Guideline and the 2025 ACC/AHA Hypertension Guideline.
This is for adults aged 30 to 79 without known cardiovascular disease. If you already have heart disease, stroke, or peripheral artery disease, you are already in the highest risk category and should be on aggressive treatment. This calculator is not a substitute for a conversation with your doctor.
AHA PREVENT Risk Calculator
Results update as you enter your numbers.
Top number on your blood pressure reading.
From your labs. Leave blank if unknown (assumes 90).
What You Should Know About This Calculator
PREVENT replaces the old pooled cohort equations. It estimates total cardiovascular disease risk (not just atherosclerotic events), includes kidney function, and provides both 10-year and 30-year estimates.
Race has been removed from the model to enhance equity. Social deprivation (by ZIP code) is available as an optional variable in the full model.
The 30-year risk estimate is only calculated for ages 30 to 59, because using age as a time scale can overestimate long-term risk in older adults.
This calculator uses the base model. Enhanced models incorporating urine albumin-to-creatinine ratio (UACR) and HbA1c are available for patients with kidney disease, diabetes, or prediabetes. Ask your doctor if those apply to you.
This calculator does not account for Lp(a), ApoB, hsCRP, coronary calcium, family history, or other risk-enhancing factors. If your risk is borderline or intermediate and you have any of these, your true risk may be higher. That is where the conversation with your doctor matters most.