Clinical insight of remote dielectric sensing-guided congestive heart failure management in outpatient clinic

Abstract

Management of congestion by assessing the degree of systemic/pulmonary congestion and adjusting the dose of diuretics is of great importance to improve mortality and morbidity in patients with congestive heart failure, whereas it is sometimes challenging particularly in the outpatient clinic, where careful and daily assessment of congestion is impossible. We had a patient with congestive heart failure due to cardiac amyloidosis, whose congestion was successfully managed by referencing repeated non-invasive quantification of pulmonary congestion using a recently-introduced remote dielectric sensing system as well as appropriate adjustment of diuretics doses at once per month outpatient clinic. Remote dielectric sensing might be a promising supportive tool to guide the management of congestion in the outpatient clinic.

Learning objective

Remote dielectric sensing system, which is a novel non-invasive wearable device to quantify the degree of pulmonary congestion easily and quickly within a minute, would be a promising supportive tool to guide titration of the dose of diuretics in patients with congestive heart failure in outpatient clinic follow up.

Introduction

Management of congestion is of great importance to improve mortality and morbidity in patients with congestive heart failure [1]. However, it is sometimes challenging particularly in an outpatient clinic setting given the lack of gold standard to quantify the degree of congestion and limitations in times and materials to carefully assess congestion.

Remote dielectric sensing system (ReD™, Sensible Medical Innovations Ltd., Netanya, Israel) is a recently-introduced novel wearable device to quantify the degree of pulmonary congestion non-invasively and quickly within a minute by employing low-power electromagnetic signals [2], accompanying accumulating evidence with mild to moderate correlations with other modalities (Fig. 1) [3], [4]. ReDS-guided management of congestion might be a promising strategy to adjust diuretics dose and improve patients' quality of life, particularly in the outpatient setting, where careful and daily assessment of congestion is impossible.

Fig. 1.

Remote dielectric sensing system consisting of monitor and sensor unit application.

Provided and permitted to use by Sensible Medical Innovations Ltd.

We had a patient with congestive heart failure, whose congestive symptom was successfully managed by ReDS-guided adjustment of diuretics dose.

Case report

Before referral

A 76-year-old man was diagnosed with wild-type cardiac amyloidosis 3 years previously by endomyocardial biopsy. He had persistent atrial fibrillation for 20 years. One year ago, he had chronic subdural hematoma, which was surgically treated. He received percutaneous left appendage closure to terminate direct oral anti-coagulation. Following the discharge, he was referred to our outpatient clinic for further management of his chronic congestive heart failure.

On referral to the outpatient clinic

His body height was 165 cm and his body weight was 71.8 kg. Blood pressure was 109/63 mmHg and pulse rate was 77 bpm. He had slight pitting edema in his bilateral lower extremities. Estimated glomerular filtration ratio was 39.7 mL/min/1.73m² and plasma B-type natriuretic peptide was 201 pg/mL. Chest X-ray showed 0.56 of cardiothoracic ratio without obvious bilateral congestion (Fig. 2A). Electrocardiogram depicted atrial fibrillation and complete right bundle branch brock. Transthoracic echocardiography demonstrated 52 mm of left ventricular end-diastolic diameter, 52 % of left ventricular ejection fraction calculated by modified Simpson's method, 57 mm of left atrial diameter, 20/13 mm of interventricular septum/posterior wall thickness, and 17/22 mm of inspiratory/respiratory inferior vena cava diameter. He had received aspirin 100 mg, rivaroxaban 5 mg, enalapril 2.5 mg, furosemide 40 mg, and tolvaptan 15 mg. He did not receive tafamidis given his frailty.

Fig. 2.

Chest X-ray on referral to outpatient clinic (A) and at 5-months follow-up (B).

ReDS-guided follow-up

He gradually complained of dyspnea on exertion assigned to New York Heart Association class II and progression of pitting edema in bilateral lower extremities (Fig. 3). However, his body weight remained almost unchanged. Given the lack of obvious evidence of congestion, we did not adjust the dose of diuretics until the 4-month follow up, when we up-titrated the dose of furosemide and initiated dapagliflozin 10 mg.

Fig. 3.

ReDS-guided outpatient clinic management.

BNP, B-type natriuretic peptide; ReDS, remote dielectric sensing; BP, blood pressure; sBP, systolic blood pressure; dBP, diastolic blood pressure; BW, body weight.

At the 5-month follow up, he expressed partial improvement in his symptoms. His chest X-ray displayed no obvious pulmonary congestion (Fig. 2B). However, ReDS system displayed his ReDS value as 35 % (manufacture-recommended reference range: 20 % and 35 %) [2]. We initiated Kampo Goreisan for further aquaresis. We decided to measure ReDS values at each visit (once per month) to carefully follow the degree of pulmonary congestion and adjust the dose of diuretics.

At the 6-month follow up, ReDS value decreased to 28 % and he complained of slight thirst. His body weight decreased by 3.0 kg per month. We decreased the dose of furosemide from 60 mg to 50 mg.

At the 7-month follow up, ReDS value remained almost unchanged, and we decreased the dose of tolvaptan to 3.75 mg. At the 8-month follow up, ReDS value decreased to 25 %, indicating relatively hypovolemia, and we further decreased the dose of furosemide to 20 mg. Plasma B-type natriuretic peptide was 198 pg/mL and estimated glomerular filtration ratio was 41.2 mL/min/1.73m², both of which remained almost unchanged. At the 9-month follow up, ReDS value increased slightly to 27 %, and we increased the dose of furosemide slightly to 30 %.

Discussion

Assessment of congestion

Accurate assessment of congestion is challenging given the lack of gold standard to non-invasively and practically quantify its degree [1]. Distribution of congestion is another concern. For example, some patients have pulmonary congestion dominantly and others have systemic congestion without obvious pulmonary congestion. Of them, pulmonary congestion, which our patient predominantly had, would be one of the critical triggers of dyspnea symptoms that should be assessed and managed immediately.

A previous study demonstrated that physical examination had a limitation in estimating hemodynamics status [5]. The most challenging parameter to be estimated was pulmonary artery wedge pressure (i.e. pulmonary congestion). Our patient had worsening heart failure symptoms, whereas several clinical parameters including chest X-ray, body weight, and physical examination remained almost unchanged. Of note, more intensive tests including computed tomography and right heart catheterization are challenging to be utilized repeatedly in the outpatient clinic.

Nevertheless, ReDS showed clearly the existence of pulmonary congestion by displaying 35 % of ReDS values (upper limit of normal range) [2]. ReDS might be a promising tool to non-invasively and easily quantify the degree of pulmonary congestion prior to the development of clinically obvious congestive heart failure that can also be detected by other conventional modalities. As one of the limitations, ReDS system cannot distinguish any other lung-occupying lesions such as pneumonia, which requires further investigations including computed tomography for the differential diagnosis.

Assessment of hypovolemia

Another counterpart concern is the assessment of hypovolemia during diuretics therapy, which would be challenging to be accurately assessed by referencing symptoms, vital signs, physical examination, and laboratory data alone, particularly in its early stage [6]. In our patient, ReDS value indicated relative hypovolemia despite the lack of any other obvious signs of hypovolemia.

Thus, ReDS might be a promising tool to assess congestion and hypovolemia, particularly in patients with left-sided heart failure with pulmonary congestion at their early stages prior to obvious signs and symptoms, letting us adjust the dose of diuretics, as we did. The CHAMPION trial demonstrated that the frequent adjustment of diuretics dose under implantable pulmonary artery pressure monitoring CardioMEMS, which is not reimbursed in Japan, was associated with reduced heart failure hospitalization [7]. Clinical implication of ReDS-guided adjustment of diuretics dose to manage congestion in the outpatient clinic remains a future concern that should be validated in the next study.

Declaration of competing interest

All authors have no statements.