Background:

Virtual consultations have increased exponentially, but a limitation is the inability to assess vital signs (VS). This is particularly useful in patients with heart failure (HF) for titrating prognosis-modifying medication. This issue could potentially be addressed by a tool capable of measuring blood pressure (BP) and heart rate (HR) accurately, remotely, and conveniently. Mobile phones equipped with transdermal optical imaging technology could meet these requirements.

Objective:

To evaluate the accuracy of a transdermal optical imaging-based app for estimating VS compared to clinical assessment in patients with HF.

Methods:

A prospective cohort study included patients evaluated in an HF outpatient unit between February and April 2022. BP and HR were simultaneously assessed using the app and clinical examination (BP with an automated sphygmomanometer and HR by brachial palpation). Three measurements were taken by both the app and clinic for each patient, by two independent blinded physicians.

Results:

Thirty patients were included, with 540 measurements of BP and HR. The mean age was 66 (± 13) years, 53.3% were male. The mean left ventricular ejection fraction was 37 ± 15, with 63.3% having previous hospitalizations for HF, and 63.4% in NYHA class II-III. The mean difference between the app measurement and its clinical reference measurement was 3.6 ± 0.5 mmHg for systolic BP (SBP), 0.9 ± –0.2 mmHg for diastolic BP (DBP), and 0.2 ± 0.4 bpm for HR. When averaging the paired mean differences for each patient, the mean across the 30 patients was 2 ± 6 mmHg for SBP, –0.14 ± 4.6 mmHg for DBP, and 0.23 ± 4 bpm for HR.

Conclusion:

The estimation of BP and HR by an app with transdermal optical imaging technology was comparable to non-invasive measurement in patients with HF and met the precision criteria for BP measurement in this preliminary study. The use of this new transdermal optical imaging technology provides promising data, which should be corroborated in larger cohorts.