Changing and saving lives: A multidisciplinary modelling approach to looking at interruptions in care for cardiovascular patients
The COVID-19 pandemic been an unprecedented global public health crisis. To limit direct impact of the virus, all government and public health organisations had to reorganise healthcare services and institute restrictions on travel including lockdowns. And although they reduced the number of people who died and were hospitalised with Covid, what has become more apparent over the course of the pandemic is that the interruption of care for non-Covid 19 conditions will also lead to significant morbidity and mortality.
The Newton Gateway brought together a multi-disciplinary team of mathematicians, modelling experts, and cardiologists, to look at how to lessen the impact of the Covid-19 pandemic on the care patients with cardiovascular (CV) conditions. CV disease is still the number one killer worldwide and within CVD many conditions have high mortality and the speed at which they can cause decline or death is very quick – with people often dying within a year or two.
Over a 3-day virtual symposium academics, researchers and modelling experts from institutions including Leeds Teaching Hospitals, the Universities of Leeds, Cambridge, Bristol, Newcastle, Loughborough, Edinburgh, Northumbria, and Keele discussed solutions for three main problems: first, the length of waiting lists for all CV conditions; secondly, heart failure – an increasingly urgent public health issue with many causes and an ageing population more likely to develop it; and thirdly, aortic stenosis (AS) – the most common disease of heart valves where the main heart valve through which all blood goes to the rest of the body becomes narrowed. The team identified two main issues following the pandemic: people trying to get into the CV treatment pathway, and those already in the pathway needing procedures or treatments that are curative but waiting because of delays caused by the pandemic.
The collaboration included Dr Ramesh Nadarajah, a British Heart Foundation Clinical Research Fellow at the Institute of Cardiovascular and Metabolic Medicine at the University of Leeds. “We wanted to tackle this on two fronts. Firstly, how can we understand better how many people are waiting and how to improve services to get them into the pathway and, secondly, for certain conditions that are life-threatening which need urgent treatment, how can we best work out how to get the patients who need those treatments to those treatments as quickly as possible?”
The multidisciplinary team discussed the problems and possible solutions. Mathematicians and modellers provided expertise on modelling complex situations, with cardiologists providing information, data, and expertise as to what is feasible and what isn’t within the NHS. These groups continued their collaborations after the symposium and have led to feasible, pragmatic solutions to bringing down waiting lists and reducing deaths.
During the pandemic, to provide both space and staff to care for patients suffering with COVID-19 a number of procedures for patients with aortic stenosis (AS), this severe life-threatening valve disease had to be cancelled or deferred. An estimation using nationwide data showed that between March and November 2020 approximately 5,000 patients with AS, who would normally be treated, were not treated. This was a huge concern as, when it this disease causes symptoms, fifty per cent of patients die within two years, making it an extremely urgent treatment concern. Using modelling, the team looked at what change to the care pathway could be implemented to work out how to most quickly get those patients to treatment and thus reduce the associated mortality from waiting.
There are currently two treatments available for AS: open heart surgery with valve replacement and transcatheter aortic valve implantation (TAVI). Open heart surgery has long been the treatment of choice but by its nature is higher risk for the elderly and people with more health conditions and involves intensive care. TAVI is a newer procedure where the prosthetic valve is inserted through a hole in the groin by following the blood vessels back to the heart. TAVI is the less invasive of the two approaches, with less time in hospital for the patient.
The team modelled how waiting times and mortality would be affected if capacity for these procedures of AS was increased. The Newton Gateway modelling showed that if capacity for procedures for AS was increased by twenty per cent, say by doing these procedures on more days of the week, it would take 535 days to clear the backlog, during which time an estimated 1,172 people would die waiting. The next scenario they modelled was treating fewer patients with open heart surgery and more with the less invasive TAVI procedures. The model found that if half of the surgery cases were converted to TAVI, the backlog would take 666 days to clear and over 1,400 people would die waiting.
“The conclusion was that the best approach is probably to do a bit of both – providing additional capacity for the procedures that treat AS and converting the treatment of some patients from open heart surgery to TAVI” explains Dr Nadarajah.
Modelling showed that if forty percent of valve surgeries were converted to TAVI and capacity was increased by twenty per cent per week for each type of procedure, the waiting list could be cleared within a year (342 days) with 780 deaths whilst waiting for treatment. “There is a need to acknowledge in all of this that we are living through difficult times with no perfect solution possible, but modelling allows us to find the best possible way to minimise deaths and maximise treatment,” adds Dr Nadarajah.
From this work, a paper on AS modelling to get people into treatment has been submitted for peer review publication and has been provided as a pre-print (https://www.medrxiv.org/content/10.1101/2021.11.11.21266212v1). A decision support tool, an electronic version of the model available online, for NHS and individual centres to manage waiting lists, will also be released.
The other area the team looked at was the heart failure treatment pathway. For patients with heart failure, who were normally treated in clinic and by community heart failure nurses, appointments were cancelled or virtualised during the pandemic. This meant interruptions in care and a rise in patients hospitalised with heart failure.
The main issue in the aftermath of the pandemic was identified to be how many patients are going to be waiting to get into the heart failure pathway and how to get people into the service – including what the bottlenecks are, and how to ameliorate them. There are two ways patients enter this pathway, either presenting to GPs and being referred to heart failure services with blood tests and ultrasound scans of the heart, or if they are really unwell, they go to A&E where they will be seen by a cardiologist who orders the scans and blood tests during a stay in hospital. The data enabled them to identify two backlogs: waiting to see a GP and waiting for the scans. The team believe that this issue might require more of a national policy change. The work has been sent to the British Heart Foundation, which is producing a report. It has also been sent to NHS England and will be presented to parliamentary bodies.
Dr Nadarajah who as well as a researcher, is a Cardiology Speciality Registrar states: “The prognosis for patients suffering from Heart failure has got much better and will continue to do so a there a number of really good new treatments have been developed. We can improve symptoms and life expectancy for patients, but we just need to be able to see them.”
This work clearly has massive impact that will change and save lives and it shows how we can learn from the pandemic by using the data collected to improve the ways in which the NHS provides services to patients.
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Dr. Nishant Ravikumar