Monitoring Oedema in Heart Failure to Improve Function and Reduce Hospitalisation Risk

Heart failure often causes fluid build-up in the legs and lungs, leading to symptoms like swelling and breathlessness. Spotting these signs early is important to help prevent worsening health and hospital admissions. While patients are encouraged to monitor their weight and symptoms, this can be hard to keep up with.

The study will involve 300 participants from at least 15 NHS hospitals and GP practices across the UK. People will be randomly placed into one of two groups: one will receive standard NHS care (including regular weight checks and symptom monitoring), and the other will receive the same care plus the Heartfelt device. The trial is partly blinded: participants may see technical messages (e.g. if the device goes offline), but only the group using the device will trigger clinical alerts.

The Heartfelt device takes daily images of the feet to track changes in size, without the need for any extra effort from the user. If important changes are spotted, alerts are sent to the clinical team so they can act quickly.

The study will look at quality of life, how often the device sends useful data, healthcare use, and how teams respond to alerts. It will also explore how easy the device is to use and whether it offers good value for money.

Patients will help shape the study to make sure the findings are relevant and useful for future care.

• Installation of Heartfelt Device (Device), also known as Remote Patient Monitoring Device: Device installed in the patient's home and capturing foot volume data which are processed in the cloud.
• Enhanced Standard care (Other), also known as Daily Weighing, Breathlessness, Dizziness, Tiredness: Patients with heart failure are advised to weigh daily and to report weight increase to their clinician. They should also report changes in breathlessness, tiredness and other symptoms associated with heart failure decompensation. At the start of the study, they will be reminded (or told) about the importance of self-checks and will be handed a patient booklet (from the British Heart Foundation) to standardise patients' knowledge.
• Questionnaires (Other), also known as 5Q-5D, Bespoke Questionnaires: Patients are presented with one or more optional questionnaires (some validated, some bespoke)
• Heartfelt device alerting system (Device), also known as Remote patient monitoring device: The Heartfelt device sends alerts on the active comparator arm to the patients directly (audio-visual alert on the device, and app alerts), carers and/or medical professionals.

Primary outcomes

• Composite Clinical Events [Over 12-months period.]: Unplanned hospital attendance (clinic, emergency, or admission) or death due to heart failure, cardiovascular, respiratory, or renal causes. Recurrent events will be included and adjudicated, providing a comprehensive measure of clinical deterioration over 12 months.
• Health-Related Quality of Life (EQ-5D-5L) [Collected at baseline, 3, 6, 9, and 12 months]: Patient-reported quality of life measured using EQ-5D-5L, collected at baseline and follow-up (3, 6, 9, 12 months), with primary analysis at 12 months. This validated instrument captures overall health status across five domains and includes a visual analogue scale. * Measured using the EQ-5D-5L index * Collected at baseline, 3, 6, 9, and 12 months. * Primary time point: 12 months. EQ-5D-5L responses will be converted to utility scores on a scale from -0.59 to 1, where 1 represents the best health state, using the UK EQ-5D-5L value set. Patients with at least two or more utility scores during follow-up will be included in the analysis.

Secondary outcomes

• Days Lost to Hospitalisation or Death [Over 12-months period.]: Total number of days lost due to hospitalisation for cardiovascular, respiratory, or renal conditions, or due to all-cause mortality.
• Daily Data Availability [Over 12-months period.]: Proportion of days with successful data capture from the Heartfelt device and weighing scales, based on device-generated records or contemporaneous self-report.
• Guideline-Recommended Medication Score [Over 12-months period.]: Adherence to guideline-recommended heart failure medications will be assessed using a guideline-recommended medication score, calculated at 3, 6, 9, and 12 months and averaged across these time points. The score is based on the number of eligible medication classes prescribed, with 1 point assigned per class (e.g., ACEi/ARB/ARNI, beta-blocker, mineralocorticoid receptor antagonist \[MRA\]). The score ranges from 0 to 3, with 3 being the optimal medication score. The score is adjusted for patient eligibility: will be calculated only for patients with heart failure with reduced ejection fraction (HFrEF).
• All-Cause Hospitalisations [Over 12-months period.]: Number of hospitalisations from any cause, analysed as recurrent events and adjusted for the competing risk of death.
• Loss of Independence or Mortality [During the 12-month trial period.]: Composite measure of new admission to a long-term care facility or all-cause mortality.
• Death and Cause of Death [During 12-months trial period.]: Classification of all deaths recorded during the trial as heart failure-related, other cardiovascular, or non-cardiovascular causes, based on clinical records.

Sex: All, ages: 18 Years to any

Inclusion Criteria: Participants are eligible if they meet all General Criteria and at least one of Pathways A, B, or C.

1\. General Criteria (all participants must meet)

* Aged ≥18 years, AND
* Diagnosis of heart failure (any aetiology or LVEF classification), AND
* Documented or patient-reported moderate to severe leg oedema, AND
* Lives in the UK with a home environment suitable for installation of the Heartfelt device

Pathway A: High risk patient with daily diuretics

* Currently prescribed ≥40 mg/day of furosemide (or equivalent loop diuretic, eg. bumetanide or torsemide) for at least one month, AND
* Any cardiorespiratory admission** in the last 12 months (Includes outpatient IV diuretics, subcutaneous loop diuretics, or escalation to combination therapy with a loop diuretic and a thiazide or thiazide-like diuretic (eg: metolazone, bendroflumethiazide, indapamide etc).

Pathway B: High risk patient without daily diuretics

* Patients prescribed SGLT2 inhibitor (eg; dapagliflozin or empagliflozin) , AND
* Patients prescribed oral furosemide ≥40mg/day but advised to take it only as needed AND either:

  a) at least two admissions* caused or complicated by worsening heart failure in the previous 12 months, OR b) a measurement of plasma NT-proBNP exceeding 1,000 ng/L (pg/mL) in the previous 12 months Pathway C: Implanted Haemodynamic Monitoring Devices (minimum n=10 participants)
* Uses an implantable device designed to monitor congestion (e.g. CardioMEMS, HeartLogic, or equivalent)
* Enrichment criteria: Patients must also meet a minimum total score of 4 from the characteristics below.

  1. NYHA class III and IV (score: 2)
  2. ≥80 mg/day Furosemide or equivalent loop diuretic (score: 2)
  3. <3 Number of times the patient has weighed themselves in the last 2 weeks (score: 2)
  4. Help for essential daily activities required (score: 2)
  5. GRMT score <5 (score: 2)
  6. Use of a walking stick, walker or mobility scooter (score: 2)
  7. >2 Number of HF events in last 12 months (score: 2)
  8. Aged over 75 (score: 1)
  9. Health issues limiting daily activities (score: 1)
  10. Help getting to medical appointment required (score: 1)
  11. Problematic / not tolerated uptitration of medications:

      MRA (score: 1) SGLT2i (score: 1) Other (score: 1)
  12. English as a second language (score: 1)
  13. eGFR 20-45 (score: 1)
  14. Patient unable to regularly attend appointments for any reason (score: 1)
  15. >3 Number of co-morbidities (score: 1)

Exclusion Criteria:

* Amputation of both feet
* Bed-bound for more than 20h per 24h period
* Bandages to lower limbs every day
* Regular wheelchair user inside their home
* No fixed abode
* Participation in another interventional trial that may interfere with endpoints
* Life expectancy <6 months, in the opinion of the investigator
* Inability to provide informed consent due to cognitive impairment
* Language barriers that preclude understanding of trial procedures (unless translation resources are available in relevant language)
* Inability to install the device (even with assistance) allowing at least 6 months of data capture by the end of the study.
* Patients with severe aortic stenosis or awaiting a heart procedure or surgery
* Patient with end stage renal disease (eGFR <20)
* Pregnancy or lack of contraceptive measures if of child-bearing potential