Abstract 18846: A Noninvasive Smartphone Assessment of Aortic Arch Pulse Wave Velocity and Total Arterial Compliance

Introduction: Several clinical studies including a large multiethnic population (Dallas Heart Study) have shown that total arterial compliance (TAC) and aortic arch pulse wave velocity (PWV _aa ) are predictors of cardiovascular disease (CVD) events. Dallas Heart Study also showed that PWV _aa predicts brain white matter hyperintensity volume independent of cardiovascular risk factors. Recently, Intrinsic Frequency (IF) analysis of carotid pressure waveform from the Framingham Heart Study was used to predict heart failure (HF) events and CVD (Hypertension, 2021 PMID: 33390053).

Aim: Our goal was to show the IF method can determine PWV _aa and TAC when applied on carotid pulse waveforms obtained from a standard iPhone camera.

Methods: The clinical cohort consisted of 120 individuals (40% women) with ages from 20-92 yrs (mean 53 ± 18), including 54 healthy and 66 patients with CVD (22 HF). Phase-contrast magnetic resonance imaging (PC-MRI) and carotid pressure tonometry data were used to compute TAC. PWV _aa values were obtained using PC-MRI flow in ascending and descending aorta (not achieved in 1 patients). A custom Apple iPhone 5S application was used to obtain carotid pulse waves by holding the camera against the neck. IF parameters of iPhone waveforms (calibrated by cuff brachial pressures) were used in machine learning algorithms (IF-iPhone). The models of TAC and PWV _aa were developed using 100 participants (99 for PWV _aa ) and blindly tested on an additional 20 individuals.

Results: In blind tests, iPhone-IF models showed Pearson correlations of r=0.89 and r=0.84 with the measured values of TAC and PWV _aa , respectively (Fig.1).

Conclusions: Assessment of PWV _aa and TAC can be accurately achieved using an unmodified smartphone (iPhone). PWV _aa evaluation with an iPhone can be used to identify, predict, and quantify risk of vascular brain damage. A Noninvasive iPhone-based method can be used in a clinical or home setting to routinely assess TAC in the general population or in HF.