State of the nation in atherosclerosis imaging

Two recent reviews on imaging of atherosclerosis were just published. I had a hand in one, in Nature Cardiovascular, and the other which appears in Science is writen by experts in the field.

Mine covers PET imaging of atherosclerosis; the other describes the current state of nano-medicine and imaging in the same disease.

Schematic of atherosclerosis with illustration of various targets for PET imaging. See article for full details.

Schematic of atherosclerosis with illustration of various targets for PET imaging. See article for full details.

The guideline wars

The quickest way to start a fight at an international cardiology conference is to ask the attendees which guidelines they follow in managing their patients' cardiovascular risk.

This week, the controversy continues with the publication of a European view of the ACC/AHA 2013 guidelines.

The conclusion of the opinion piece in the European Heart Journal, perhaps predictably, is that the European approach wins.

This article discusses the potential implications of adopting the ACC/AHA guidelines on patient care in Europe and beyond and concludes with the opinion that the ESC/EAS guidelines from 2011 seem to be the most wide ranging, pragmatic and appropriate choice for European countries.

Will the British guidelines - JBS3 - clarify things for practitioners and patients?

JBS3 report on prevention of CVD and its risk calculator now launched. The report is now available here. A fabulously addictive risk calculator is also worth checking out at http://www.jbs3risk.com

Vulnerable plaque imaging comes a step closer

We published a paper in the Lancet last week.

It is the result of a scientific collaboration between Edinburgh and Cambridge Universities. Funding was provided by the British Heart Foundation and the Chief Scientist's Office in Scotland.

The project concerns using PET imaging with NaF to detect atherosclerotic plaques that are in a state of vulnerability to rupture.

Firstly, NaF successfully identified most of the plaques that had caused recent MI because they were brighter after PET imaging than bystander lesions.

We then used IVUS to clarify, in a stable angina cohort, the phenotype of NaF-avid plaques. We also confirmed using immunohistochemistry that NaF binding occurred in areas of both high calcium turnover and inflammation.

The reason that the study is exciting is that it sets the scene for this imaging to be used prospectively, perhaps in high-risk individuals with lesions in several arteries, where it might direct therapy to the most "at-risk" plaques. This might be intensive statin therapy, or even a direct plaque intervention of some type.

We still don't know whether high-risk plaque detection and treatment will alter the natural history of the disease or how cost effective such an approach might be. But it has a major advantage of being non-invasive and relatively low in radiation - about half the dose of a nuclear perfusion scan. There is also no fasting needed before scanning, and NaF is widely available.

The publication received a great deal of media coverage:

  1. The Daily Mail
  2. The Scottish Herald
  3. The Guardian
  4. BBC
  5. More BBC
  6. Even more BBC
  7. Daily Record
  8. The Express
  9. The Huffington Post
  10. The Independent
  11. More Independent
  12. Medical News Today
  13. Medscape
  14. The NHS website
  15. Pulse Today
  16. The Scotsman
  17. Scottish TV
  18. The Information Daily
  19. The Times
  20. WebMD

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.

British Cardiovascular Society Annual Meeting Preview

Imaging is a theme that runs throughout the conference. Although concentrated within the Imaging Track, there are also sessions and presentations on imaging topics within both the CS/TR and E4R Tracks.

This year, within the Imaging Track, we have sessions dedicated to several pathologies that can sometimes be overlooked, either because they are hard to diagnose or challenging to treat. Disease of the right heart fits this description. We have therefore planned a session that will show how imaging can help the clinician improve their diagnostic accuracy and risk stratification ability. We will discuss both intrinsic conditions of the right heart, as well as its secondary involvement in left-sided heart disease. A partner session will explore how to diagnose and manage pulmonary hypertension. This will include talks on its pathology and the latest diagnostic classification. Presentations on the management of pulmonary hypertension will cover both medical and surgical approaches to the disease.

Another sometimes under-appreciated condition is ‘functional’ mitral regurgitation. In this session, we will discuss its aetiology, and how multi-modality imaging can help both to diagnose and suggest when intervention is needed. We will hear about contemporary management strategies, including how new device options might fit alongside conventional surgical approaches.

We have an entire session dedicated to the pragmatic use of intravascular coronary artery imaging in the catheter laboratory. Here, we will discuss the clinical roles of intravascular ultrasound and optical coherence tomography. Bridging the research and clinical spaces, we will be joined by renowned Harvard cardiologist and entrepreneur Dr James Muller who will educate us about hybrid catheter-based imaging technologies that provide integrated anatomical and functional plaque data. Dr Muller is an expert in using near-infrared spectroscopy for identifying vulnerable plaque.

Imaging is now widely applied in multi-centre trials. In a session on Wednesday, our speakers will discuss the results of several recent large imaging trials. These will include nuclear and echo imaging within the extended STICH study, the latest multi-centre cardiac CT and MR studies, plus how imaging can help decide the best way of revascularising diabetic patients with coronary artery disease.

The ever-popular ‘Read with the Experts’ session is back once again. Do come along and test your image interpretation skills in real-life clinical scenarios presented by multi-modality imaging experts. CT, echo, MR and nuclear imaging approaches will all be on display in one of the most popular sessions of the conference.