A UK study has shown that nearly 40% of severe heart failure patients initially fitted with a mechanical heart pump, which was later removed, go on to recover fully. Given the shortage of donated hearts for transplant, the study authors call for the left ventricular assist devices (LVADs) to be considered as a tool that can allow patients to restore their health.
The research examined the effect of mechanical heart pumps, known as left ventricular assist devices (LVAD). The devices are used to support patients with severe heart failure while they wait for a heart transplant.
Surgeons implant the battery operated, mechanical pump which helps the main pumping chamber of the heart – the left ventricle – to push blood around the body. Fitted at the six specialist National Health Service (NHS) centres across the UK, LVADs are used for patients who have reached the end stage of heart failure.
The team report that LVAD combined with medication can fully restore heart function in patients. Dr Djordje Jakovljevic, senior research fellow in cardiovascular ageing and heart failure within the Institute of Cellular Medicine at Newcastle University, is lead author on the paper.
He said: “We talk about these devices as a bridge-to-transplant, something which can keep a patient alive until a heart is available for transplantation.
“However, we knew that sometimes patients recover to such an extent that they no longer need a heart transplant.
“For the first time, what we have shown is that heart function is restored in some patients – to the extent that they are just like someone healthy who has never had heart disease. In effect, these devices can be a bridge to full recovery in some patients.”
In the clinical trial, 58 men with heart failure were tested for their heart fitness levels. Of the men, 16 were fitted with an LVAD and then had it removed due to the extent of their recovery. Furthermore 18 still had an LVAD and 24 patients were waiting for a heart transplant. On average, a patient had a device fitted for 396 days before it was removed, though it varied from 22 days to 638 days.
The participants were compared with 97 healthy men who had no known heart disease. All were tested on a treadmill with a face mask to monitor their oxygen utilisation and heart pumping capability.
In the publication the authors report that 38% of people who recover enough to allow the device to be removed demonstrated a heart function which was equivalent to that of a healthy individual of the same age.
Jakovljevic explains: “We can consider these pumps as a tool which can lead to a patient recovering, rather than as a device which keeps people alive until a heart transplant is available.
“Our ongoing and future research is aiming to identify the markers of early heart recovery while patients are fitted with a device. These markers will inform clinical care teams to make right decisions about which patient respond well to device and when to consider potential removal or disconnection of the device while ensuring heart failure will not occur again in the future.”
Although heart transplantation offers a second chance of life for patients with advanced heart failure, a shortage of donor hearts has opened doors for developments and use of mechanical devices.
Dr Guy MacGowan, consultant cardiologist within the Newcastle upon Tyne Hospitals NHS Foundation Trust, and honorary clinical reader in heart failure at Newcastle University, is co-author of the paper. He said: “It is very difficult to get a heart transplant, especially in the UK, so any alternative treatment is important and recovery of heart function especially so. The UK has a long way to go in comparison with the number of heart transplants in other developed countries.
“Within Newcastle upon Tyne Hospitals NHS Foundation Trust, we are pioneering a new strategy to use the LVAD to enhance chances of recovery, monitor for signs of recovery, and then use a minimally invasive procedure to disconnect the device.”
Consultant cardiac surgeon within the Newcastle upon Tyne Hospitals NHS Foundation Trust and co-author, Professor Stephan Schueler, added: “In most cases the device reverses the symptoms of heart failure so that patients feel less short of breath and with less fatigue. In a smaller proportion of patients there is actually an improvement in heart function so that the pump can be disconnected or explanted.”
The average price of a LVAD is approximately £80,000 and the transplant operation costs around £69,000.
The team involved researchers at Newcastle, Cambridge, Leeds, London and Louisville (US) who are currently studying how to identify patients who will respond best to being fitted with an LVAD by identifying markers of early heart recovery.
Abstract
Background: Left ventricular assist devices (LVADs) have been used as an effective therapeutic option in patients with advanced heart failure, either as a bridge to transplantation, as destination therapy, or in some patients, as a bridge to recovery.
Objectives: This study evaluated whether patients undergoing an LVAD bridge-to-recovery protocol can achieve cardiac and physical functional capacities equivalent to those of healthy controls.
Methods: Fifty-eight male patients—18 implanted with a continuous-flow LVAD, 16 patients with LVAD explanted (recovered patients), and 24 heart transplant candidates (HTx)—and 97 healthy controls performed a maximal graded cardiopulmonary exercise test with continuous measurements of respiratory gas exchange and noninvasive (rebreathing) hemodynamic data. Cardiac function was represented by peak exercise cardiac power output (mean arterial blood pressure × cardiac output) and functional capacity by peak exercise O2 consumption.
Results: All patients demonstrated a significant exertional effort as demonstrated with the mean peak exercise respiratory exchange ratio >1.10. Peak exercise cardiac power output was significantly higher in healthy controls and explanted LVAD patients compared with other patients (healthy 5.35 ± 0.95 W; explanted 3.45 ± 0.72 W; LVAD implanted 2.37 ± 0.68 W; and HTx 1.31 ± 0.31 W; p < 0.05), as was peak O2 consumption (healthy 36.4 ± 10.3 ml/kg/min; explanted 29.8 ± 5.9 ml/kg/min; implanted 20.5 ± 4.3 ml/kg/min; and HTx 12.0 ± 2.2 ml/kg/min; p < 0.05). In the LVAD explanted group, 38% of the patients achieved peak cardiac power output and 69% achieved peak O2 consumption within the ranges of healthy controls.
Conclusions: The authors have shown that a substantial number of patients who recovered sufficiently to allow explantation of their LVAD can even achieve cardiac and physical functional capacities nearly equivalent to those of healthy controls.
Authors
Djordje G. Jakovljevic, Magdi H. Yacoub, Stephan Schueler, Guy A MacGowan, Lazar Velicki, Petar M Seferovic, Sandeep Hothi, Bing-Hsiean Tzeng, David A Brodie, Emma Birks, Lip-Bun Tan
[link url="http://www.ncl.ac.uk/press/news/2017/04/heartpumprestoreshealth/"]University of Newcastle material[/link]
[link url="http://www.sciencedirect.com/science/article/pii/S0735109717306204"]Journal of the American College of Cardiology abstract[/link]