#247 ‒ Preventing cardiovascular disease: the latest in diagnostic imaging, blood pressure, metabolic health, and more | Ethan Weiss, M.D.
Dr. Peter Attia and preventative cardiologist Ethan Weiss discuss ASCVD risk assessment using CAC and CTA, optimal medical therapy, and the critical importance of blood pressure control and metabolic health in preventing cardiovascular disease.
Deep Dive Analysis
18 Topic Outline
Ethan Weiss's Career Transition and New Venture
Understanding Coronary Artery Calcium (CAC) Scans
CT Angiography (CTA) vs. CAC: Resolution and Insights
Peter Attia's Personal Experience with CAC and CTA
ApoB's Role in Atherosclerosis and Disease Progression
Clinical Utility of CTA and Plaque Assessment
Stenting vs. Optimal Medical Therapy for Stable Angina
Fractional Flow Reserve (FFR) and CT FFR in CAD
Fat Attenuation Index (FAI) and Pericardial Fat
Exercise, Statins, and Coronary Calcification Paradox
Addressing Statin Hesitancy and Misinformation
Revisiting Blood Pressure: Normal Ranges and Aging
Accurate Blood Pressure Measurement and Variability
Key Hypertension Trials: AllHAT, SPRINT, and STEP
Pharmacological Strategies for Blood Pressure Control
Metabolic Health and Residual ASCVD Risk Factors
Fat Storage Capacity, Location, and Lipodystrophy
Future Directions in Cardiometabolic Disease Research
7 Key Concepts
Calcium Scan (CAC Score)
A low-radiation, inexpensive CT scan that measures the amount of calcium in coronary arteries, serving as a 'satellite image' of prior injury and correlating with overall plaque burden and cardiovascular risk. It represents healed plaque and indicates a patient's risk of heart attack.
CT Angiogram (CTA)
A higher-resolution imaging tool than a CAC scan that provides more detailed information about plaque characteristics (soft vs. calcified) and vessel lumen. It offers significantly more information but involves more radiation and contrast dye, and is generally more expensive.
Fractional Flow Reserve (FFR)
A hemodynamic measurement performed in a cath lab to detect a pressure gradient across an arterial stenosis. It helps assess the severity of a blockage by comparing pressure on either side of the obstruction, providing a quantitative measure beyond visual assessment.
CT FFR
A non-invasive computational analysis applied to CTA images that estimates the fractional flow reserve. The theoretical idea is to predict the hemodynamic significance of a stenosis without requiring an invasive catheterization procedure.
Fat Attenuation Index (FAI)
A CTA bolt-on that looks at the characteristics of the fat around coronary plaques. It is hypothesized to indicate the amount of inflammation in the epicardial fat surrounding the arteries.
Lipodystrophy
A group of rare genetic diseases characterized by the inability to store fat in normal subcutaneous depots, particularly in the gluteo-femoral regions. This leads to ectopic fat accumulation in organs like the liver, pancreas, and heart, resulting in severe metabolic disease and astronomical cardiovascular risk.
Fat Mass Ratio (FMR)
A ratio, often derived from DEXA scans, that compares the distribution of fat in the upper body (e.g., abdominal/visceral fat) to the lower body (e.g., gluteo-femoral fat). A high FMR, indicating more upper body fat and less lower body fat, is strongly associated with increased cardiometabolic risk.
10 Questions Answered
A CAC scan is a low-radiation, inexpensive tool that measures calcified plaque, indicating prior injury and overall plaque burden. A CTA provides higher resolution images, showing both calcified and soft plaque, offering more detailed information about the extent of coronary artery disease, but involves more radiation and contrast dye.
Yes, up to 15% of people with a zero calcium score may still have findings on a CTA, including soft plaque or small calcifications not picked up by the less precise CAC scan. Furthermore, about 1.5-2% of those with a negative CAC may have an unstable plaque on CTA.
ApoB is considered a necessary factor for atherosclerosis, meaning if it's sufficiently low, atherosclerosis is unlikely to develop. While some argue it may be sufficient in cases like familial hypercholesterolemia (FH), it's generally understood that high ApoB significantly increases risk, but other factors can modify its penetrance.
Stenting is clearly beneficial in acute ST-elevation myocardial infarction (STEMI) and generally accepted for acute coronary syndrome (ACS) events (non-STEMI, unstable angina). For stable angina or asymptomatic plaque, optimal medical therapy is often favored over stenting, as trials have shown little to no benefit in hard outcomes for stenting in these cases.
There's some plausible evidence that high levels of cardiorespiratory fitness might be associated with increased coronary calcification, similar to statin use. However, it's unclear if this calcification carries the same risk as calcification from other causes, and the overall benefits of exercise still outweigh potential risks.
Statins are one of the most prescribed drug classes, leading to a larger denominator for reported side effects. There has also been a significant, long-standing 'propaganda campaign' to demonize statins, fostering widespread skepticism and fear despite their profound importance in modern medicine.
While blood pressure tends to rise with age in the population, 120/80 mmHg is considered the normal and aspirational target regardless of age. Clinical trials suggest that maintaining blood pressure closer to this target, even in older individuals, significantly reduces the risk of adverse outcomes.
For accurate measurement, individuals should be seated and relaxed in a quiet room, ideally by themselves, with an automated cuff. Multiple readings (e.g., three measurements five minutes apart) should be taken, and the average used, as done in trials like SPRINT.
The ALLHAT trial identified calcium channel blockers (e.g., amlodipine), ACE inhibitors (e.g., lisinopril), and thiazide diuretics (e.g., chlorthalidone) as effective first-line agents for primary hypertension, with similar outcomes.
Residual risk refers to the remaining risk of ASCVD in people who have normal lipids, don't smoke, and have normal blood pressure. This risk is strongly linked to metabolic ill-health, particularly the capacity and location of fat storage, with ectopic fat (e.g., visceral, liver, pancreas, heart) being highly problematic.
11 Actionable Insights
1. ApoB Target for Atherosclerosis Prevention
Aim for an ApoB target between 30-40 mg/dL, using pharmacological intervention if necessary, to aggressively manage and prevent atherosclerosis. Do not wait for significant stenosis or high calcium scores to initiate treatment, as ApoB is a causal agent.
2. Achieve Optimal Blood Pressure (120/80 mmHg)
Strive to maintain blood pressure as close to 120/80 mmHg as possible, regardless of age, as clinical trials show significant mortality benefits. This is crucial for long-term kidney, heart, and brain health, provided treatment does not cause harm like dizziness or kidney dysfunction.
3. Accurate Blood Pressure Measurement Protocol
To accurately measure blood pressure, use an automated cuff in a quiet room, seated and relaxed, taking three measurements five minutes apart and averaging them. This method, used in clinical trials, provides a reliable baseline, and a 24-hour ambulatory monitor can offer a comprehensive assessment.
4. Prioritize Optimal Medical Therapy for Plaque
Focus on optimal medical therapy for plaque management, regardless of plaque characteristics or volume, especially in asymptomatic individuals. Stenting without symptoms has not shown benefit over medical therapy, which should be maximized to control the disease.
5. Fat Storage Location for Metabolic Health
Understand that the location of fat storage (visceral vs. gluteo-femoral, indicated by fat mass ratio) is a critical indicator of metabolic health and cardiovascular risk, potentially more impactful than overall fat mass or smoking status. Aim to prevent fat accumulation in visceral and organ areas, as this is associated with worse outcomes.
6. Statins: Benefits Outweigh Calcification Risk
Understand that statins are a profoundly important intervention for cardiovascular health and may increase coronary calcification, but this calcification is not indicative of increased risk. The overall benefit in reducing cardiovascular events is clear, so do not let fear or misinformation prevent their use.
7. Avoid Smoking for Health
Eliminate smoking entirely, as it is an unambiguous and significant risk factor for cardiovascular disease and numerous other health problems. Not smoking dramatically improves overall health and reduces risk.
8. CT Angiogram for Detailed Plaque
Consider a CT angiogram (CTA) for a more comprehensive assessment of plaque burden, including soft plaque, which is not visible on calcium scans. Be aware it is more expensive and involves contrast and slightly more radiation than a calcium scan; inquire about the radiation dose as it can vary.
9. Calcium Scan for Initial Risk Assessment
Consider getting a calcium scan as a low-risk, inexpensive tool to assess existing plaque damage and overall heart attack risk. However, be aware that a zero score does not guarantee the absence of plaque, especially in younger individuals, and other risk factors should still be aggressively treated.
10. Tailor Blood Pressure Medication Choice
Prioritize achieving blood pressure control with first-line agents like thiazide diuretics, calcium channel blockers (e.g., amlodipine for ease of use), or ACE inhibitors/ARBs. For patients with existing atherosclerotic coronary disease or diabetes, ACE inhibitors/ARBs are often preferred due to their renal protective benefits beyond just lowering blood pressure.
11. Recognize Lipodystrophy Through Physical Exam
Be aware that visual inspection, particularly observing very skinny, muscular legs with a disproportionate pot belly, can be a crucial step in identifying lipodystrophy. Clinicians should undress patients to properly assess body fat distribution, as this condition is associated with severe metabolic and cardiovascular risk.
8 Key Quotes
ASCVD should basically be an orphan disease. There's actually no reason it needs to be the leading cause of death. It really doesn't even need to be in the top 10. It's that preventable if you start early enough and if you're maximally aggressive.
Peter Attia
The sad thing about how demonized statins have been is that it's one of the most profoundly important interventions that we have in modern medicine.
Ethan Weiss
120 over 80 is normal no matter where you are in life. And that anything above that is abnormal.
Ethan Weiss
It's very easy to convince people to be scared of something. It's a lot harder to make people unscared of something.
Ethan Weiss
I'm treating the causative risks, not the end stage problems.
Peter Attia
I think the quality of medical therapy we have today is so good that it's going to be really hard to demonstrate the value of stenting people.
Ethan Weiss
If we could just raise awareness and treat this [blood pressure], because I think we've done a really good job on the lipids... But blood pressure is one of these funny things. For whatever reason, it's just not sexy.
Ethan Weiss
I think the reality is a lot of plaque is bad.
Ethan Weiss
1 Protocols
Optimal Blood Pressure Measurement Protocol (SPRINT Study Method)
Ethan Weiss- Patient is in a quiet room, seated and relaxed, by themselves.
- An automated blood pressure cuff is placed on the person's arm.
- Blood pressure is measured three times.
- Allow a five-minute break between each measurement.
- Take the average of these three blood pressures for the final reading.