Lancashire Objective Volume Evaluation of Leg Oedema in Heart Failure Second Pilot

Patients with heart failure (HF) who recently received treatment with IV diuretics for worsening congestion or outpatients with HF and peripheral oedema treated with at least 80 mg furosemide (or equivalent)/day will be recruited in the LOVE-HF-2 trial at Blackpool Victoria Hospital. The main objective of the study is to test if the Heartfelt device is sensitive to change across the full range of the individual patient's oedema. The participants will be given the Heartfelt device to use in their home. This device automatically and passively measures patient's foot and lower leg's volume without the patient having to remember to do anything. The patients will be seen face to face with a cardiologist to evaluate peripheral oedema using standard clincial technics as well as overall congestion level. The investigators aim to recruit 30 participants for the observational pilot study.

The study follows its sister pilot trial, LOVE-HF (NCT04787380).

Heart Failure is the final common pathway of most forms of cardiovascular disease. In the United Kingdom (UK), it affects around 900 000 people, causes or complicates around 5% of adult emergency hospital admissions and consumes up to 2% of total National Health Service (NHS) expenditure. An important part of discharge planning includes measures such as early follow up in order to prevent readmissions. The hallmark of heart failure is fluid retention and between 2009 and 2016, 43% to 50% of hospital admissions were associated with peripheral oedema. Therefore, early recognition of this and treatment of the congestion may prevent hospital admissions. In clinical trials, management strategies have included patient education, telemedicine and remote monitoring. The main non-invasive method for detecting fluid retention has been the use of weight as a surrogate marker.

The Heartfelt device is an invention that uses a system of cameras in a compact device in order to generate 3 dimensional images of the feet and lower legs. The volumes can then be calculated and thus, changes in amount of peripheral oedema can be estimated. In a clinical trial (NCT02993601) performed by the Heart Failure team at the Royal Brompton Hospital, there was good correlation between measurements made by Heartfelt and a water displacement method. The resolution was as good as 20mls.

By positioning the Heartfelt device in the bedroom, automatic measurements can be made whenever the subject gets in and out of bed. Images are only taken of the specified subject. Data is censored so that the part of the body which is 50cm above the floor is not stored. Encrypted, anonymised data is transmitted over the internet to the company's secure servers. Personal identifiable data (participant name, address, age...) is stored on an encrypted hard drive, along with linkage information (device serial numbers) to associate the participant identifiable data with the data captured in the home. Therefore, data collection is not only secure but entirely passive, which is a major advantage compared with previous non-invasive methods and it is applicable to a very wide range of compliant and non-compliant patients.

The LOVE-HF trial (NCT04787380) demonstrated that the number of days with missing data collected by the Heartfelt device was significantly lower than that of the weighing scales, providing a promising tool for home patient monitoring.

Being able to demonstrate that the device can provide a measure of oedema that is clinically relevant over the full range of individual patient's oedema is the main objective of this study as this will further adds to the validation of the device.

Eligibility Criteria:
Inclusion criteria:

Patients with HF who recently (\< 6 months) received treatment with IV diuretics for worsening congestion or outpatients with HF and peripheral oedema (any degree) who are treated with at least 80 mg furosemide (or equivalent) orally per day Patients with HF older than 18 years Patients who took part in LOVE-HF can also be approached.

The research team will try to include as many patients as possible in the month following discharge, however we will not exclude consideration of a small proportion of patients within 6 months of decompensation. This has the extra advantage of demonstrating the value of the device beyond 1-2 months of decompensation.

Exclusion Criteria:

1. Inability to provide informed consent\*
2. Participant has bandages to lower limbs everyday
3. Participant has an amputation of the foot
4. Participant is a regular wheelchair user
5. Participant is of no fixed abode
6. Participant has a potentially reversible cause of decompensated heart failure and is awaiting urgent intervention (revascularisation/ valvular heart disease), which means the patient cannot be discharged for home-based care
7. Participant is taking part in a conflicting evaluation/study that could confound the results of this evaluation and/or impact clinical interventions and participant outcomes
8. Participant must not be pregnant, and is taking relevant birth control if of child-bearing potential\*

Note that a participant not able to comply with weighing, or questionnaires is NOT an exclusion criteria as the Heartfelt device should provide data for these participants despite their lack of ability to adhere to the usual monitoring protocol, and this is seen as one of the long term benefits that the device can provide.

* This exclusion criteria (a) has been added as participants would need to be able to communicate directly with the Heartfelt team, etc.
* This exclusion criteria (h) has been requested by the insurance provider for clinical trial cover.