How accurate is a calcium scan compared to a CT angiogram (CTA), especially for younger individuals?

A calcium scan is a relatively imprecise measure due to thicker slices, potentially missing small calcifications or soft plaque. A CT angiogram offers much finer resolution and can detect these. Up to 15% of people with a zero calcium score may have notable findings on CTA, and 1.5-2% may have unstable plaques, particularly in younger individuals where calcium might be scarce. (Timestamp: 445)

Is ApoB a necessary and/or sufficient factor for atherosclerosis development?

ApoB is considered absolutely necessary for atherosclerosis, meaning if it's consistently bottomed out, atherosclerosis is unlikely to develop. Whether it's sufficient is debatable; while high ApoB in conditions like FH increases risk, not all individuals develop ASCVD, suggesting other genetic or environmental modifiers. (Timestamp: 932)

What are the advantages and disadvantages of a CT Angiogram (CTA) compared to a calcium scan?

A CTA provides more clarity and information, including detection of soft plaque, which calcium scans miss. However, it involves higher cost (often $700-$3000 out-of-pocket), increased radiation exposure, and potential risks from IV contrast. Radiation levels vary significantly by scanner (2-20 mSv), impacting its utility for screening. (Timestamp: 1205)

How do cardiologists assess plaque vulnerability and guide treatment for coronary artery disease?

Currently, there is no universally reliable tool to predict plaque vulnerability. While research tools like intravascular ultrasound exist, their clinical utility is unproven. Cardiologists generally focus on the overall plaque burden rather than specific plaque characteristics, treating even mild plaques aggressively with optimal medical therapy. (Timestamp: 1636)

What is fractional flow reserve (FFR) and its role in CT angiography (CT-FFR)?

FFR is a measure of pressure gradient across an arterial stenosis, traditionally performed invasively in a cath lab. CT-FFR uses computational algorithms on CTA images to estimate this pressure drop. While CT-FFR can reduce unnecessary cath lab procedures, it hasn't shown a difference in major adverse cardiovascular events (MACE) or all-cause mortality. (Timestamp: 2089)

How do statin use and intense exercise affect coronary artery calcification (CAC)?

Statins are known to increase CAC while simultaneously lowering cardiovascular event risk, indicating a beneficial plaque stabilization process. For extreme exercise, there's plausible but not confirmed evidence that increased shear forces could lead to calcification. However, more exercise is generally better, and any elevated CAC, regardless of exercise level, warrants investigation and treatment. (Timestamp: 3948)

What blood pressure target should individuals aim for, especially as they age?

Current evidence, particularly from the SPRINT trial, suggests that 120/80 mmHg is the optimal blood pressure target for most adults, regardless of age. While blood pressure tends to rise with age, treating to lower targets has been shown to reduce mortality and adverse cardiovascular events, provided such aggressive treatment does not cause harmful side effects like falls or kidney dysfunction. (Timestamp: 5107)

What is the best way to accurately measure blood pressure at home?

The most accurate method, inspired by the SPRINT trial, involves sitting quietly in a relaxed state for five minutes without distraction, then taking three measurements five minutes apart, and averaging them. While 24-hour ambulatory monitoring provides the most comprehensive data, optimizing home measurements is a practical and effective alternative. (Timestamp: 5519)

Are certain blood pressure medications preferred over others, or is blood pressure control the main goal?

The primary goal is effective blood pressure control to reach the 120/80 mmHg target. While individual patient circumstances (age, comorbidities like diabetes or existing kidney disease) might favor certain classes like ACE inhibitors/ARBs for renal protection, or amlodipine for ease of use, getting to goal with tolerable side effects is paramount. (Timestamp: 7033)

What is the 'bathtub analogy' for metabolic health and fat storage?

The 'bathtub analogy' describes the body's capacity to store subcutaneous fat. If this 'bathtub' overflows, excess fat (ectopic fat) infiltrates organs like the liver, pancreas, and heart (visceral and pericardial fat), leading to severe metabolic dysfunction and increased cardiovascular risk, regardless of overall BMI. (Timestamp: 7470)

What is lipodystrophy and how does it relate to common metabolic diseases?

Lipodystrophy is a rare genetic condition where individuals have an impaired ability to store fat in subcutaneous depots, leading to excess fat accumulating in organs and causing severe metabolic disease. This extreme phenotype provides insights into how less severe, polygenic variations in fat storage capacity (e.g., high fat mass ratio) also profoundly increase metabolic and cardiovascular risk in the general population. (Timestamp: 7640)

Key Moments

247 ‒ Preventing cardiovascular disease: the latest in imaging, blood pressure & metabolic health

Peter Attia MD

Science & Technology4 min read145 min video

Mar 20, 2023|115,167 views|1,619|460

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Key Moments

TL;DR

Experts discuss cardiovascular disease prevention: CAC/CTA imaging, blood pressure management, and metabolic health.

Key Insights

Coronary Artery Calcium (CAC) scores and CT Angiography (CTA) are valuable tools for assessing cardiovascular risk, though CTA offers more detail.

Achieving blood pressure close to 120/80 mmHg, even in older individuals, is crucial for reducing mortality and cardiovascular events.

Elevated apolipoprotein B (apoB) is a primary driver of atherosclerosis, and lowering it is essential for disease prevention.

Metabolic health, particularly the distribution of fat and the capacity to store it in subcutaneous depots, is a critical but often overlooked risk factor for cardiovascular disease.

While exercise is beneficial, excessive levels might theoretically increase coronary calcification; however, its net benefit likely outweighs this risk.

The widespread fear and misinformation surrounding statins hinder their effective use, despite their proven benefits in reducing cardiovascular events.

ADVANCEMENTS IN CARDIOVASCULAR IMAGING: CAC VS. CTA

The discussion begins by comparing Coronary Artery Calcium (CAC) scoring and CT Angiography (CTA) for assessing cardiovascular disease (CVD). CAC quantifies calcified plaque, serving as an indicator of past injury and overall plaque burden, strongly correlating with adverse outcomes. CTA provides more detailed, higher-resolution images, capable of detecting non-calcified and soft plaques that CAC might miss. While both are valuable, CTA offers a clearer picture, though it involves slightly higher radiation and cost, and is less frequently covered by insurance compared to the more accessible CAC scans.

THE CRITICAL ROLE OF BLOOD PRESSURE MANAGEMENT

Blood pressure is highlighted as a paramount, yet often neglected, risk factor for CVD, kidney, and brain health. The conversation emphasizes that 120/80 mmHg should be the target, regardless of age, as elevated blood pressure, even mildly, is detrimental long-term. While daily fluctuations are significant, consistent management towards this target, through methods like home monitoring and 24-hour ambulatory monitoring, is crucial. Clinical trials like SPRINT and STEP provide strong evidence that aggressive blood pressure control significantly reduces mortality and cardiovascular events, though careful management is needed to avoid potential harms like falls or kidney dysfunction.

APOB AS A CENTRAL TARGET IN ATHEROSCLEROSIS

Apolipoprotein B (apoB) is identified as a necessary, and potentially sufficient, factor in the development of atherosclerosis. The conversation stresses the importance of aggressively lowering apoB levels, ideally between 30-40 mg/dL, through pharmacological interventions when necessary. This aggressive stance is justified by the understanding that reducing the primary causal agent of atherosclerosis can halt or slow disease progression, as evidenced by Peter Attia's personal experience. The discussion also refutes the notion that high apoB is acceptable if linked to certain diets, emphasizing that pharmacological means can address apoB independently.

UNDERSTANDING METABOLIC HEALTH AND FAT DISTRIBUTION

Metabolic health, particularly where body fat is stored, is presented as a crucial, often misunderstood, pillar of CVD risk. The 'bathtub' analogy illustrates how exceeding one's capacity to store fat, especially viscerally, leads to deleterious effects. Individuals with lipodystrophies, lacking the ability to store fat in subcutaneous depots, demonstrate extreme metabolic disease and cardiovascular risk. Research suggests that the ratio of visceral to subcutaneous fat (fat mass ratio) is a potent predictor of risk, potentially even more so than smoking status. Addressing this imbalance is key to addressing a significant portion of CVD risk.

THE COMPLEXITY OF EXERCISE AND CORONARY THORNEY Physiology

While exercise is unequivocally beneficial, the discussion touches upon the potential for extreme levels of cardiorespiratory fitness to paradoxically increase coronary calcification. This observation, drawing parallels with statin use where increased calcification doesn't equate to increased event risk, suggests a complex interplay between physiological stress and vascular health. However, the consensus remains that more exercise is generally better, and its net benefit, even with potential for increased calcification, is substantial. The focus should remain on risk reduction through established means, even if the underlying mechanisms are intricate.

CHALLENGES AND NUANCES IN DRUG THERAPY AND CLINICAL DECISION-MAKING

The conversation highlights significant challenges in applying optimal medical therapy, particularly regarding statin usage and blood pressure pharmacotherapy. Widespread fear and misinformation surrounding statins impede their use, with many patients opting against them due to unfounded concerns. For blood pressure, while certain drug classes like thiazide diuretics, calcium channel blockers, and ACE inhibitors/ARBs are effective, individualizing treatment based on patient factors like age, comorbidities (e.g., diabetes, kidney disease), and tolerability is essential. The discussion also critiques insurance practices that often require events to occur before approving preventative therapies, underscoring the need for a proactive approach.

ASSESSING PLAQUE VULNERABILITY AND INTERVENTIONAL STRATEGIES

The limitations of current tools in precisely quantifying plaque vulnerability are acknowledged. While techniques like fractional flow reserve (FFR), both invasive and CT-derived (CT-FFR), aim to assess the functional significance of stenosis, their clinical utility, especially in asymptomatic individuals, remains debated. The consensus leans towards optimal medical therapy being the cornerstone, even for significant plaque burden, as large trials have largely failed to demonstrate a benefit of stenting in asymptomatic patients beyond medical management. Interventional cardiology is reserved for acute events or refractory symptoms, emphasizing prevention over intervention.

Mentioned in This Episode

●Tools

●Companies

●Organizations

●Books

●Studies Cited

●Concepts

●People Referenced

Common Questions

A calcium score provides a quantitative measure of calcium in coronary arteries, which correlates significantly with adverse cardiovascular outcomes. It's considered a 'satellite image' of the heart, indicating prior plaque damage and overall risk of heart attack. It's a low-radiation, inexpensive, and generally zero-risk procedure. (Timestamp: 160)

Topics

Health & Longevity Metabolic Syndrome Blood Pressure Control Atherosclerosis Prevention Calcium Scoring CT Angiography Lipid Management Hypertension Treatment Fat Distribution

Mentioned in this video

Books

JNC 8

A set of hypertension guidelines that faced controversy and was ultimately discontinued by the NHLBI due to disputes over recommendations.

JNC 7

A revised guideline for hypertension classification that lowered the definition of 'normal' blood pressure to less than 120/80 mmHg and introduced 'prehypertension'.

JNC 6

A historical guideline for hypertension classification, where 'normal' blood pressure was considered higher (120-130/80-85 mmHg) than in later guidelines.

Studies & Research

FAME 2 trial

A follow-up clinical trial to FAME, further exploring the role of FFR in guiding percutaneous coronary intervention (PCI).

SPRINT Trial

An NIH-sponsored clinical trial from 2014 or 2015 that demonstrated significant cardiovascular benefits and reduced mortality from aggressively lowering systolic blood pressure to a target of 120 mmHg.

AllHAT trial

The first NIH-sponsored blood pressure trial from the early 2000s that compared five different classes of antihypertensive medications, concluding that thiazide diuretics, ACE inhibitors, and calcium channel blockers were effective first-line treatments.

HOPE trial

A clinical trial from the mid-2000s suggesting a benefit of ACE inhibitors in people with atherosclerotic coronary disease.

FAME trial

Clinical trial that looked at the efficacy of Fractional Flow Reserve (FFR) in angiography, demonstrating benefit from stenting in cases with significant pressure drops.

COURAGE trial

A clinical trial that showed no additional benefit of percutaneous coronary intervention (PCI) over optimal medical therapy in patients with stable coronary artery disease.

ISCHEMIA trial

A trial confirming that an invasive strategy (stenting/bypass) did not improve outcomes compared to optimal medical therapy in patients with stable ischemic heart disease.

ORBITA trial

A placebo-controlled trial that found percutaneous coronary intervention (PCI) did not improve exercise capacity more than a sham procedure in patients with stable angina already on optimal medical therapy.

STEP trial

A clinical trial from the previous year that confirmed the findings of the SPRINT trial, showing that more aggressive blood pressure lowering improved outcomes, and included patients with type 2 diabetes.

Drugs & Medications

Chlorthalidone

A more potent thiazide diuretic mentioned as being used in the AllHAT trial and generally considered a strong agent for hypertension.

Hydrochlorothiazide

A commonly used thiazide diuretic, mentioned in comparison to chlorthalidone.

Lisinopril

An ACE inhibitor mentioned as an effective agent for hypertension alongside amlodipine and thiazide diuretics.

Concepts

Coronary Artery Bypass Grafting

Surgical procedure used in edge cases of revascularization, sometimes preferred over stenting for certain severe blockages, particularly in symptomatic patients.

CRISPR

A gene-editing technology mentioned in the context of Verve Therapeutics aiming to genetically reduce PCSK9.

FTG PET

A type of PET scan that can measure the amount of inflammation in plaque, used in research to gauge drug efficacy.

People

Tom Dayspring

A figure Dr. Attia met, from whom he learned about ApoB.

James O'Keefe

A cardiologist known for his views on the potential for high-intensity exercise to increase coronary calcification in some athletes.

Steve O'Reilly

Described as the 'Godfather' of the concept of fat distribution and its metabolic implications, especially in lipodystrophy.

Gerald Schulman

Researcher who conducted an experiment in mice, showing that increasing subcutaneous fat storage in insulin-resistant mice improved their metabolic health.

Companies

Verve Therapeutics

Seth Hirsh's company aimed at using CRISPR gene editing to reduce PCSK9 and eradicate cardiovascular disease.

Organizations

UCSF

University of California, San Francisco, where Dr. Attia's guest used to have his lab and is now a volunteer clinical faculty.

NIH

The primary agency of the United States government responsible for biomedical and public health research, which sponsored the SPRINT trial.

NHLBI

A division of the NIH responsible for research into heart, lung, and blood diseases, which eventually discontinued the JNC guidelines due to controversy.

Supplements

Amlodipine

A calcium channel blocker identified as a great and easy-to-use drug for hypertension due to minimal monitoring requirements, though it can cause ankle swelling.