Not all failing hearts are created equal

Many people with heart failure are not receiving effective treatment according to the results of a large international study led by researchers at The University of Auckland.

The study – which combines data from major heart-failure research groups around the world – shows that there are two different types of heart failure, and that the outcome for patients depends on the nature of their disease.

Heart failure affects approximately 2% of people worldwide, and occurs when the heart cannot generate sufficient blood flow.

“Most people experience heart failure because their heart muscle does not pump blood properly,” says lead researcher Associate Professor Rob Doughty of The University of Auckland. “For these patients the standard heart failure treatment – which is designed to improve pump function – can be very effective.”

“But our research has shown that about one in four patients have normal heart pump function. Their heart failure is caused instead by stiffening of the heart muscle, and for these people, the standard treatments targeting heart pump function will not be of benefit.”

“Previous research suggested that all patients with heart failure had a similar outlook, regardless of whether their symptoms were due primarily to pump failure or stiff heart muscle,” he says. “Because of this, doctors have assumed that all patients should be treated in the same way. Our research has shown that this is not, in fact, correct.”

People with heart failure typically feel tired, short of breath, have swelling in their legs, and are unable to cope with physical exertion. Around three in every ten New Zealanders admitted to hospital with heart failure for the first time will die within 12 months. “This rate is as high as for many different forms of cancer, but heart failure has often not been considered in this way,” says Associate Professor Doughty.

As well as having an increased risk of death, patients whose symptoms are not well managed have a reduced quality of life and return repeatedly to their doctors and to hospital. It is estimated that 1.5 to 2% of the entire healthcare budget in New Zealand and overseas is spent on patients with heart failure, in the main due to recurrent hospital admission.

“Our findings have important implications for patients as they deal with this chronic illness, and for the physicians and nurses who help them manage their condition,” he says. “By gaining a better understanding of the underlying causes of the disease, we will eventually be able to develop more effective treatments that will improve patient health and survival, as well as reducing healthcare costs.”

“This outstanding research has attracted world-wide attention,” says Professor Norman Sharpe, Medical Director of the National Heart Foundation of New Zealand. “The findings are highly relevant clinically and should lead to direct improvements in the care of patients with heart failure, which is a common but complex and difficult condition to manage.

“The work, which has been carried out over several years, has been supported by the Heart Foundation from the beginning and will be incorporated in new treatment guidelines for heart failure currently in completion through the Heart Foundation.”

The meta-analysis study, which was led by researchers from The University of Auckland and funded by the National Heart Foundation, was based on data from more than 45,000 patients who participated in 29 international studies. Using such a large dataset meant the researchers could definitely show that there were two different forms of heart failure.

“We are extremely grateful to the international research teams who granted us access to their data, and we look forward to sharing our results with them and the wider cardiology community,” says Associate Professor Doughty.

The research will be presented on Wednesday 2 September at a feature session of the European Society of Cardiology Congress in Barcelona, Spain.