Who is most at risk of heart disease?

Abridged from Dr Arthur Agatston writing at the Huffington Post:

Who is more likely to die from a heart attack or other cardiovascular-related event?

A. A person who is overweight, has high cholesterol, high blood pressure, and diabetes, and a calcium score of 0?

or

B. A person with no risk factors and a calcium score of over 400?

This is important to be aware of, since nearly 1 million American men and women have a heart attack every year.

The answer is B. Strikingly, it is estimated that nearly 50 percent of those who suffer fatal heart attacks don't even know they have risk factors.

Recently, a large and important study has found that even if you don't have any of the conventional risk factors for heart disease -- high blood pressure, high cholesterol, family history, prediabetes and diabetes, smoking, being overweight, high triglycerides, a sedentary lifestyle -- it doesn't necessarily mean you're home free.

The study, which was published in the journal Circulation Cardiovascular Imaging, looked at more than 44,000 individuals free of known coronary heart disease. Each person underwent a noninvasive computed tomography (CT) scan of the heart for coronary calcium and was then followed for a median of 5 years for whether or not they died of any cause.

Those with no coronary calcium and no risk factors had the lowest death rate, whereas those with a calcium score of over 400 and three risk factors had the highest death rate. Not surprising.

What's notable about this study, however, is that the individuals with no risk factors and a calcium score of more than 400 (people who are not generally candidates for aggressive prevention) had substantially higher death rates compared with individuals with three risk factors and the absence of coronary calcium (approximately 17 vs. approximately 3 per 1,000 person-years).

The authors also noted that nearly half of the individuals meeting eligibility for statin therapy based on Justification for the Use of Statins in Prevention: an Intervention Trial Evaluating Rosuvastatin (JUPITER) criteria had no CAC and experienced an extremely low event rate, with an unfavorable estimated number needed to treat for 5 years of 549 to prevent 1 CHD event compared with 42 among those with the presence of CAC.

What does this striking data mean? It suggests that people with coronary calcium (with and without other risk factors) are more likely to die, and that a selected group of patients without risk factors might benefit from further risk assessment and preventive therapies.

Atherosclerosis in abdominal aorta may predict adverse cardiovascular events

Interesting study from the University of Texas, using MRI to screen for atherosclerosis.

Accumulation of plaque tells us there is increased risk for peripheral vascular occlusion, stroke, and abdominal aortic aneurysms, but not all forms of cardiovascular events, including heart attacks and death from cardiovascular disease,“ he said. ”In contrast, thickening of the aortic walls is more likely to be predictive of all forms of cardiovascular disease.

This is a different approach to merely screening for risk factors of atherosclerosis, and one that is endorsed by SHAPE.

Advances in Molecular Imaging: Plaque Imaging

Here’s the abstract of a review we published recently in Current Cardiovascular Imaging Reports:-

Recent advances in nuclear plaque imaging aim to achieve noninvasive identification of vulnerable atherosclerotic plaques using positron emission tomography (PET) with 18F-fluorodexoyglucose (FDG) and novel tracers targeting molecular markers of inflammation and other active metabolic processes.

Nuclear imaging of atherosclerosis has been demonstrated in multiple vascular beds, including the carotid, aorta, peripheral and coronary arteries—but significant challenges remain, especially for coronary imaging. The advantage of PET over other molecular imaging modalities is its superior sensitivity, however, low spatial resolution means that images must be co-registered with computed tomography (CT) or magnetic resonance imaging (MRI) for precise anatomical localization of the PET signal.

Such hybrid techniques provide the best hope for early detection of prospective culprit lesions—which may, in the coronary vasculature, appear falsely low-risk using conventional coronary angiography or stress imaging.

Current hot topics in nuclear plaque imaging include the use of FDG-PET for therapeutic monitoring in drug development, identification of imaging biomarkers to evaluate cardiovascular risk, and the development of novel tracers against an array of biologically important markers of atherosclerosis.

The purpose of this article is to review these recent advances in nuclear plaque imaging.

The full article is available here, behind a paywall. I can send reprints as PDFs on request.

Advice for aspiring cardiologists from Harvard Professor Peter Libby

This short interview with Peter Libby from Harvard contains some good advice for those considering an academic cardiology career. Some highlights:

  • Try and continue to do some clinical cardiology alongside research
  • Research is a vocation. It is something you can't help yourself from doing.
  • Most experiments don't work
  • Be prepared for disappointment
  • Discovering something new is phenomenally exciting

Here is a link to the video

British Heart Foundation's Reflections of Research Competition

A video that we submitted to the British Heart Foundation's "Reflections of Research" competition has won in the best video category.

We made this video to highlight the variety of imaging methods that we have at our disposal to image atherosclerosis and its consequences.

Some more coverage on the Cambridge BRC website and the Addenbrooke's Hospital homepage.

Click here to view the other winning entries.

Imaging of progression of carotid atherosclerosis - case unproven

A study I recently read in the Lancet reports results of an individual patient data meta-analysis, which show that cIMT progression is not associated with incident myocardial infarction, stroke, or vascular death in the general population (hazard ratio 0·98, 95% CI 0·95–1·01, adjusted for age, sex, mean common carotid artery intima-media thickness, and vascular risk factors).

A single measure of carotid IMT may be useful for predicting risk in asymptomatic intermediate risk adults, although far less so than calcium scoring by CT according to the most recent guidelines.

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Interaction of calcification and inflammation in atherosclerosis

Cocker J Nucl Cardiol 2012 Imaging atherosclerosis with hybrid 18F fluorodeoxyglucose positron emission tomographycomputed tomography imaging What Leonardo da Vinci could not see pdf page 10 of 15

The diagram above seems a logical appraisal of the situation, published recently by Cocker and colleagues.

A proposed schematic staging inflammatory and calcification activity within atherosclerotic lesions with FDG and NaF as imaging biomarkers. During early stages of atherosclerosis, inflammation is the predominant mechanism active within plaque. During these stages, [18F]FDG may be taken up by the lesion. As inflammation peaks, the risk of plaque rupture may increase. Inflammation also contributes toward initiating calcium metabolism within lesions that results in the formation of early calcium deposits. This would be reflected by uptake of both FDG and hydroxyapatite-specific [18F]sodium fluoride (NaF). Once the density of calcium deposits exceeds a certain threshold, it becomes visible with CT. During active calcification, plaque may still be vulnerable. Eventually, the calcification and mineralization processes exceed the inflammatory activity present within plaque, which might be demarcated by only NaF uptake (in the absence of FDG), as well as calcium deposits on CT. Ongoing calcification eventually leads to forming an end- stage stable atheroma that is densely calcified with only evidence for calcium on CT. Model of plaque progression (top bar) is adapted from Koenig and Khuseyinova.