The study aims at assessing the usefulness of the Heartfelt1 device in patients suffering from heart failure, who have peripheral oedema. The device is non-contact and does not requires patient compliance to work. It gives an output reading of the patient's lower leg volume. During the study, this measurement will be compared to clinical standard and gold standard measurements as well as clinical grading of peripheral oedema.
The Heartfelt-1 device is a CE (Conformité Européenne = European Conformity) mark medical device used to measure biometric parameters of the foot and lower leg. The study aims at assessing the usefulness in patients suffering from heart failure, who have peripheral oedema. Models used for the measurements of foot and lower legs have not yet been validated for this group of patients, who are likely to have feet with abnormal surface contours and appearance secondary to oedema. Peripheral oedema can be a leading indicator of heart failure de-compensation which can lead to hospitalisation of patients, and therefore the device could be a useful clinical tool to monitor patients in their home. The Heartfelt-1 device has the ability to recognise the patient's feet (amongst an average size household setting), and trigger automatically the measurements when the feet are naked (for example as the patient goes in and out of bed). This makes the device an obvious choice for patients with compliance issues with current methods of monitoring (e.g. daily use of weighing scales) and treatment (e.g. diuretics) if it could be validated in this patient group. The study has two general aims: The first is to collect a time-series of data on inpatients with peripheral oedema caused by heart failure, as they receive intravenous or oral diuretic treatment to remove excess fluid and achieve optimal body weight and fluid balance. This data will be used both to determine the attainable resolution of foot biometric measurements on a patient as their fluid status changes, and also to further develop the algorithms used in the device and make them usable on a wide range of feet/lower legs which have been deformed by oedema. The data required for this study are images taken using the Heartfelt-1 device, as well as validation measurements such as the figure of eight using a medical grade tape measure, callipers, or the water displacement method using a volumetric gauge, at multiple time-points whilst the peripheral oedema reduces. The second, on a second group of stable ambulatory (Heart Failure) HF patients with variable levels of oedema, is to evaluate the performance of the Heartfelt-1 device in determining foot biometric parameters one a wide range of patients at a single point in time. Patients with stable chronic heart failure will have their foot/lower legs measured by the Heartfelt-1 device, as well as standard medical measurement (figure of eight using a medical grade tape measure, callipers) and gold standard measurement (water displacement method using a gauge), as well as the patient's weight and a clinical grading of oedema. These will be compared and an estimate of the accuracy of the Heartfelt-1 device over this wider patient group can be extrapolated.
Study Type
OBSERVATIONAL
Enrollment
70
The patients will stand in front of the Heartfelt-1 in order for images to be captured and the volume of their lower legs measured.
The patient will be asked to stand on standard medical weighing scales, to measure their weight.
A member of the research team will assess the severity of the peripheral oedema on a scale of 1-5.
Royal Brompton Hospital
London, United Kingdom
Volume as measured by the Heartfelt-1 device
Time frame: Within 3 months after patient recruitment or before the end of the study (whichever is soonest).
Weight
Patient weight on the day
Time frame: Within 3 months after patient recruitment or before the end of the study (whichever is soonest).
Distance measurements
Distance measurements on the foot / lower leg of the patient
Time frame: Within 3 months after patient recruitment or before the end of the study (whichever is soonest).
Circumference and "figure of eight"
Lower leg / foot circumference and "figure of eight" measurement
Time frame: Within 3 months after patient recruitment or before the end of the study (whichever is soonest).
Volume of the lower leg/foot
As measured using the water displacement method.
Time frame: Within 3 months after patient recruitment or before the end of the study (whichever is soonest).
Medical grading of oedema
Medical grading of peripheral oedema on a scale 1-5
Time frame: Within 3 months after patient recruitment or before the end of the study (whichever is soonest).
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At the point study participants are recruited, their age, sex, diagnosis, aetiology of heart failure, LVEF (Left ventricular ejection fraction), medical and device therapy, time since diagnosis, BNP (B-type Natriuretic Peptide), CRP (C-Reactive Protein), renal function (EGFR), Haemoglobin, albumin and urinalysis will be assessed unless recent (less that 6 months old) results are available. The number of Heart failure hospital admissions in the last 2 years, LACE score, co-morbidities will also be noted.
This will involve filling a gauge with lukewarm water (27-35oC +-2oC) up to the appropriate level. The appropriate level is determined by the water stabilising after some has flown out of the gauge into the waste bucket. Once the water level is stable the patient, who is sitting on a chair will be gently plunging the foot (naked) in the gauge until their foot is flat on the bottom on the gauge. The water flowing out of the gauge into the measuring bucket will be collected until the flow of water stops. Four small marks with non-toxic /non-permanent pen will be made on the lower leg of the patient to indicate where the water level was at. The water which has been collected in the measuring bucket will be weighted with precision scales to determine the volume of water displaced by the insertion of the foot. The patient's foot will then be dried.
This will involve making 4 marks on one of the foot/lower leg (small cross) using non-toxic / non- permanent pen. The measurement will consist of making 6 measurements between those marks using callipers, and reporting the distance on a calibrated tape.
The measurements taken using a medical tape measure will involve the circumference of the ankle to be measured as well as the circumference at the level of the arch of the foot. The medical tape used will be a CE marked disposable medical measuring tape to minimise the risk of infection. The measurements will be done on both feet.