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?


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.

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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Coronary artery PET imaging with NaF - the debate continues

The paper we published in JACC with colleagues in Edinburgh continues to be discussed. A letter and our reply were recently aired on the JACC website.

It’s certainly true that we don’t fully understand the dynamics of NaF uptake into coronary atherosclerosis. And we are still working on ex-vivo experiments to determine the binding characteristics of the tracer in atherosclerosis, which will likely be similar to that expressed in bone tissue. We do know that the degree of NaF uptake correlates with cardiovascular risk, and there is only a weak relationship between NaF and FDG uptake. So it is likely telling us something different from metabolic activity of the plaque.

Whether it is predictive of future cardiovascular events, can be altered with therapy or is reproducible - time (and lots of research efforts) will tell.


Guidelines For Assessment Of Cardiovascular Risk In Asymptomatic Adults

ACCF/AHA guidelines - nice summary of current thoughts.

Similar guidelines were published recently by the European Society of Cardiology.

CT ClinImage Cardiac 4

Figure 6  2

Images above show non-invasive cardiac imaging using CT, compared (bottom) to invasive coronary angiography - 'A'. Note the distal left main stem 'soft' plaque visible on the contrast CT - 'C', invisible on the non-contrast calcium scoring CT scan in 'B'.

Dangerous plaques are missed by calcium scoring alone in maybe 5% scans in symptomatic subjects.