Caltech Smartphone App Helps Identifies Heart Problems in Childhood Cancer Survivors

Researchers at Caltech, in collaboration with the Beckman Research Institute at City of Hope, USC, and other institutions, have developed a mobile app that can accurately detect cardiac dysfunction in childhood cancer survivors, according to a new study.

Vivio works by holding your phone up to your neck for a minute or two for an accurate reading and can essentially accomplish the same as 45-minute scan from an ultrasound machine.

Vivio collects pulse waves and phonocardiogram data from the carotid artery and sends it wirelessly via app to a smartphone or tablet. Using a specialized algorithm along with the app, medical practitioners can calculate left ventricular ejection fraction (LVEF), which is one key measure of heart health, upon which physicians base diagnostic and therapeutic decisions.

LVEF measure how much blood is being pumped out of the left ventricle of the heart with each contraction and is expressed in a percentage. A normal LVEF ranges from 55 to 70 percent. An LVEF of less than 40 percent may confirm a diagnosis of heart failure. An LVEF of less than 35 percent increases the risk of an arrhythmia that can cause sudden cardiac arrest or death.

To test device accuracy, researchers at the Childhood Cancer Survivorship Clinic (CCSC) at City of Hope conducted a cross-sectional study. It compared LVEF using the Vivio wireless device, two-dimensional (2D) echocardiography, and gold-standard cardiac magnetic resonance (CMR) imaging in childhood cancer survivors exposed to anthracycline, who risk potential cardiac dysfunction from the exposure, which can often develop at a time when they are least engaged in long-term survivorship care, a report in HospiMedica said.

In all, 191 consecutive cancer survivors participated in the study, with a median anthracycline dose of 225 mg/m² (milligrams per square meter). The researchers found that echocardiography overestimated mean LVEF by 4.9 percent compared with CMR. However, no difference was seen between mean LVEF readings from Vivio and CMR.

Also, when compared with CMR, the detection of cardiac dysfunction via echocardiography was weak, but Vivio-based measurements had considerably better sensitivity. The study was published on June 21 in Clinical Cancer Research.

Last year, Caltech researchers worked with medical practitioners to test the app on 72 volunteers between 20-92 years old at an MRI facility. Using Vivio, doctors simply held iPhones against the volunteers’ necks for one to two minutes. Afterward, the volunteers immediately received an MRI examination, and data from both tests were compared. The measurements made by Vivio had an error of ±9.9 percent compared that of an MRI. In comparison, the error for echocardiography was roughly ±10.2 percent.
“In a surprisingly short period, we were able to move from invention to the collection of validating clinical data,” said Caltech’s Dr. Mory Gharib after the trials.

Gharib, Hans W. Liepmann Professor of Aeronautics and Bioinspired Engineering and head of the Gharib Research Group at Caltech, is the senior author of a separate on the study that was published in the July 2017 issue of Critical Care Medicine.

“What is exciting about this study is that it shows our technique is as accurate as echocardiography at estimating LVEF when both are compared to the gold standard of cardiac MRI,” he said. “This has the potential to revolutionize how doctors and patients can screen for and monitor heart disease both in the U.S. and the developing world.”