PROJECT SUMMARY/ABSTRACT
Advanced heart diseases lead to a reduced blood supply from the heart and consequently fatigue and deficits in
performing physical activity. In the proposed research, we will assess the lack of physiological reserve in older
adults with advanced heart disease, focusing on motor and cardiac function, to develop a novel, objective, quick,
and accurate frailty score. We designed this approach to enhance candidate selection of older adults going
through invasive therapies for advanced heart diseases. Although our approach is generic, to reduce between-
subject variability we focus on transcatheter aortic valve replacement (TAVR) for older adult with aortic stenosis.
Therapeutic options continue to grow for TAVR; however, it can be difficult to identify candidates with frailty level
that prohibit them from tolerating the stress from aggressive therapy and those with potential reversible frailty. It
is thus critically important to introduce meaningful routine objective frailty assessment into clinical care of cardiac
patients. Frailty assessment is, however, not common in cardiology because current assessment tools are
burdensome for older adults with advanced heart disease and impractical to implement in busy clinical
environments. More importantly, no disease-specific tool is available to identify heart disease-related frailty.
In continuation of our research program in the field of sensor-based frailty assessment, within our
multidisciplinary team of engineers, cardiologists, and geriatricians, we propose the multimodal upper-extremity
function (UEF) test for identifying frailty among older adults with advanced heart disease. UEF incorporates a
synchronized system of motion sensors and electrocardiography (ECG) to measure motor performance and
heart rate (HR) during a rapid 20-second elbow flexion task. Using our previously established UEF motion
tracking component, we can precisely measure the level of deficits in motor performance (slowness, weakness,
inflexibility, and fatigue), which are not detectable using eyeball assessment. Using the ECG setup, minimizing
the motion artifact using this localized task, we accurately track HR response to the physical demand, as well as
recovery behavior after the task. HR behavior during the task and recovery (HR dynamics) provide a measure
of cardiac reserve associated with frailty in heart disease. We will further quantify dysregulation between HR
response and motor demand as a novel measure of resilience. Based on our preliminary data, we expect a
weaker and delayed HR response to physical activity as well as an impaired motor function due to frailty.
The proposed research will be a four-year study at the University of Arizona Cardiovascular program. In the first
arm, we will establish a new HR score and merge it with our previously validated UEF motor score to develop a
multimodal frailty score among older adults with advanced heart disease (n=120). In the second arm, in a
longitudinally setting we will validate the UEF multimodal frailty score for predicting TAVR complications for
advanced heart disease (n=75). Accomplishing these aims, we will promote HR dynamic assessment for risk
stratification of older adults with advanced heart disease, with huge potentials for other comorbid conditions.
