A wireless optical handheld device for carotid waveform measurement and its validation in a clinical study

Abstract

Objective: Here we introduce Vivio, a wireless optical tonometer, and compare its pulse waveform measurement capabilities to the AtCor SphygmoCor. Approach: Pulse waveform data from both devices was captured on a heterogeneous cohort of 29 participants (15 males, 14 females), including 16 healthy individuals free from cardiovascular diseases and 13 patients with one or more cardiovascular diseases. These participants were a subgroup of the Huntington Medical Research Institutes (HMRI) iPhone Heart Study. Main results: Carotid pulse waveforms captured by Vivio were comparable to those captured using the AtCor SphygmoCor tonometer. The point-by-point root-mean-square error between averaged waveforms captured by either device on the same participant was 6.3% with a standard deviation of 2%. The harmonic content of the pulse waveforms captured by either device was also similar. Data collected by Vivio displayed good to excellent agreement across a wide range of pulse waveform features such as left ventricular ejection time, reflected wave arrival time, the ratio of systolic to diastolic time intervals, and heart rate. A comparison between augmentation index (AI) measured by Vivio and tonometry showed a correlation of 0.82 (p < 0.01). Bland–Altman analysis of this data yielded a bias of −2.5% and limits of agreement spanning −15.1%–10.1%. Significance: The Vivio has the potential to enhance the availability of noninvasive pulse waveform data, thereby expanding the tools available for the diagnosis and monitoring of cardiovascular disease. When used in combination with advanced waveform analysis methods, Vivio can impact mobile healthcare resulting in improved patient health, quality of life and the overall reduction of healthcare costs.