A large international study has identified a new model for predicting outcomes for the inherited heart condition, hypertrophic cardiomyopathy (HCM), the most frequent cause of sudden cardiac death in younger people.
The findings, published in the Journal of the American Medical Association, demonstrate that incorporating clinical history, imaging and blood biomarker data into a risk assessment can improve prediction of adverse cardiac events in people with HCM.
The study, led by researchers at the University of Oxford and the University of Virginia, was funded by the National Heart, Lung and Blood Institute (NHLBI) in the USA and the National Institute for Health and Care Research (NIHR) Biomedical Research Centre: Oxford (BRC Oxford).
“Current risk prediction guidelines for hypertrophic cardiomyopathy have limitations as they can only predict sudden cardiac death, but not heart failure or other serious cardiac complications,” said Professor Stefan Neubauer from the University of Oxford’s Radcliffe Department of Medicine, one of the two chief investigators of the study.
“This is the largest prospective study of this disease that has incorporated standardised, quality-controlled assessments with cardiac MR imaging (MRI) and blood biomarkers. Our results show that these additional measurements provide powerful risk predictors of adverse outcomes in HCM,” added Professor Neubauer, who leads the BRC Oxford’s Imaging Theme.
Hypertrophic cardiomyopathy occurs when the heart muscle becomes larger and thicker than normal, which can block the outflow of the left ventricle and can lead to rapid, life-threatening heart rhythm abnormalities and to heart failure symptoms.
It is often inherited, and many people with the condition display no symptoms, highlighting the need for better risk prediction.
Researchers in this study wanted to see if integrating new methods into assessment – including contrast-enhanced cardiac MRI, blood sampling for biomarkers, genotyping and a health history questionnaire – could more accurately predict adverse events such as sudden cardiac death, heart failure, non-fatal arrythmias, and the need for device implantation or heart transplantation.
The study enrolled nearly 2,700 patients with HCM in North America and Europe at 44 sites that had expertise in HCM and cardiac MRI. The researchers collected medical history, blood tests and cardiac imaging, and followed the study participants for an average of seven years.
They determined that several predictors – such as scarring, weight and function of the heart muscle measured by cardiac MRI, history of heart failure and higher levels of a blood biomarker (NTproBNP) – were associated with fatal and nonfatal cardiac events.
Sudden cardiac death outcomes were predicted by the structure and function of the left ventricle and the same blood biomarker. In short, they showed that integrating these study methods into a risk assessment gave fuller, more accurate predictions of adverse events.
“It has taken a major effort to provide definitive data on the value of CMR imaging in guiding risk stratification in HCM, so I see this as a landmark achievement and one that will shape practice.” said Professor Hugh Watkins, Radcliffe Professor of Medicine and a study author.
Professor Helen McShane, Director of the NIHR BRC: Oxford, added: “This study is good news for those who have HCM. It demonstrates that an early assessment allows patients to understand how their condition may affect them in the future and what steps they should take to minimise the risk of serious heart complications. Congratulations to our BRC imaging experts and their collaborators on what promises to be an important advance in improving the lives of patients with this disease.”