Where did the idea for WatchPAT come from?

The story of Itamar Medical and the WatchPAT device begins with the company co-founder Prof. Peretz Levie, a psychologist specialising in sleep medicine who, while serving as the dean of medicine at the Israel Institute of Technology in Haifa, began researching the link between cardiovascular physiology and sleep apnoea. Together with his postdoc fellow Dr. Bob Schnell, he identified that blood volume changes in the fingers have repeatable and distinct patterns during various sleep stages and dramatic vasoconstriction during sleep events such as apnoeic events – the ceasing and resuming of breathing during sleep. It showed that blood volume changes, both amplitude and frequency, are directly impacted by activation of the sympathetic autonomic nervous system.

Prof. Levie and Dr. Schnell built a device using a non-invasive sensor mounted on the finger that allowed them to measure the changes in blood flow in the finger in a very sensitive way using photo-plethysmography (PPG) applied under unified pressure field to avoid venous pooling and other artifacts - and they named it Peripheral Arterial Tonometry or PAT.

The first investor was Dr. Yaron, who was quickly joined by a heart surgeon, Prof. Daniel Goor, and ex ALZA pharmaceutical CEO, Martin Gerstel.

The company quickly focussed on sleep medicine, developing and manufacturing a new product that would test and diagnose several forms of sleep apnoea – the WatchPAT, a non-invasive home sleep apnoea testing (HSAT) device that uses the PAT technology to diagnose sleep apnoea. Recognising the potentials of PAT to accurately detect apnoeic events, and the dire need to address the almost one billion people impacted by sleep apnoea worldwide, the WatchPAT was conceived, and developed as a more cost-effective, accessible, and less intrusive HSAT solution than was already available. WatchPAT‘s first FDA clearance was at 2001 and CMS have included it in CPT 959800 in 2009. It made it to the AASM guidelines in 2017 and Blue Cross Blue Shields Street Evidence in 2019.

What is the device itself made from?

The materials we have used are of considerable importance when speaking about our WatchPAT One device in particular. In developing this product - the first and only fully disposable HSAT device - our designers had several key challenges to address.

The designers were required to find a balance between several contradicting properties –creating a cost-effective single-use product that would be capable of competing at the same level of performance with our multiuse devices.

As such, our designers shifted their focus to DfC (design-for-cost) practices of which the materials selected are a large factor. Because the device is required to adhere to medical grade standards, the variety within material selection is very limited, and several aspects need to be considered, including:

• The material properties have to ensure that the device doesn’t have an impact on the clinical properties of interest for the sleep study.
• The material selection is restricted to those that are biocompatible in nature.
• The material’s elasticity properties cannot have a negative impact on the user’s blood flow.
• The acoustic properties of the material used in the device’s acoustic sensor component, which is placed on the user’s chest, needed to be closely considered to ensure accuracy.

A specific thermoplastic elastomer (TPE) has therefore been used to manufacture the device’s wrist straps, paired with a special latching method, to accommodate the need for unobstructed blood flow, and the device enclosure has been manufactured using acrylonitrile butadiene styrene (ABS), a common thermoplastic polymer typically used in injection moulding applications.

As a whole, the industrial design of the device needed to strike a balance between the ease of use, safety, and durability of the product.

More importantly, the entire user interface such as LCD screen, users bottoms, connectors for disposable components that need replacement and large memory, all of which are very expensive components, were replaced with a Smartphone Bluetooth interface and a dedicated app. This is revolutionary and required the creation of an entire HIPPA compliant, and data secure, digital back bone.

Tell us about the PAT technology. What’s so special about it?

The Peripheral Arterial Tone (PAT) signal is a special physiological signal acquire by PPG under unified pressure field that mirrors change in the autonomic nervous system (ANS) caused by respiratory disturbances during sleep. This signal measures arterial function and the changes in blood volume that are driven by the ANS.

The PAT signal is unique because it can be used to easily, and non-invasively measure the volume of blood in the arteries, at the fingertip, to determine when an apnoeic event takes place. When an apnoea occurs during sleep, it triggers the body to initiate a “fight or flight” event in response - the blood vessels contract rapidly in the peripheral organs, like the fingers, thereby significantly increasing blood flow to the bigger muscles and lungs.

This is precisely how Itamar Medical’s WatchPAT devices work. Using the sophisticated algorithms that we have developed, our device is able to detect these apnoeic events through the dramatic reduction of blood volume at the tip of the finger combined with other signals such as heart rate, actigraphy, oximetry, snoring level, chest and body motions and determine the presence and the degree of sleep apnoea with a device as simple as a watch with a finger probe and single chest sensor and without any facial or nasal interface.

What makes this device different from others in its field?

The WatchPAT device differs greatly from other leading commercially available HSATs on the market as we are the only company utilising the PAT technology, and the benefits of PAT are very clear and simple. PAT enables us to create a truly non-invasive at home sleep testing solution – there aren’t any nasal tubes and/or facial or chest straps required, no bulky devices that sit on a patient’s chest, and nothing that needs to be worn on or attached to a patient face as we do not need to measure airflow in order to determine sleep apnoea indices with this technology. All of this adds up to make the device far more usable, comfortable, and convenient for patients to use and allows them to successfully set up the device by themselves - with a 99% completion rate - fall asleep, and remain asleep throughout the night, to complete their study.

Another considerable advantage of the PAT device is its comprehensiveness and accuracy. Our WatchPAT devices calculates apnoea-hypopnea index (AHI) and respiratory disturbance index (RDI) using the patient’s True Sleep Time rather than the recorded time used in most commercially available HSAT’s. This reduces the risk of misdiagnosis and misclassification. The device’s clinically validated Sleep Architecture provides data on sleep staging, including sleep efficiency, sleep latency and REM latency, as well as the added value of REM related sleep apnea detection with REM and non-REM AHI. WatchPAT has also been clinically proven to detect all types of apnoea events with high accuracy – its Central PLUS Module enables specific identification of Central Sleep Apnoea (CSA) and Percent of Sleep Time with Cheyne-Stokes Respiration. Additionally, the device offers highly accurate auto scoring, generating comprehensive automated reports which are made available for analysis in just seconds after the study is complete.

Lastly, and most pertinent to the industry today during COVID-19, is our industry-first WatchPAT One device. This device is the first and only fully disposable HSAT solution on the market which allows patients to receive the device, use it at home, and then discard and dispose of it immediately after completing the test. We introduced this product to offer greater patient convenience - removing the need for them to return the device for analysis – as well as to eliminate the risk of exposure to infection, which has been a huge advantage valuable during this pandemic. The WatchPAT One connects to a simple smartphone app, transmitting the patients sleep data to our cloud platform for analysis, and, within one night - provided the patient has had a minimum of four hours sleep – a diagnosis can be made. This is done all from a patient’s own bed and we believe that this device is the future of sleep medicine.

How do you see the market for sleep apnoea devices developing in the near future?

Digital health is a very exciting market to watch and be a part of at the moment. This space is growing rapidly which is largely driven by the popularity of wearable devices, smart watches, and health and wellness focussed smartphone apps that have popularised health, fitness, and sleep tracking. These technologies are bringing awareness to the importance of sleep and the value and convenience of the digital solutions available and in development. People are now more readily accepting of seeking medical care virtually and in the comfort of their homes, especially since the onset of the pandemic, as digital solutions allow them to avoid hospital and clinic visits, and unnecessary exposure to risk. We are witnessing an at-home digital health revolution that is enabling a new level of care, and it is great to be a part of.

Clinical and institutional acceptance and endorsement is key to advancing the market and development of HSAT devices - the value, importance, and convenience of HSAT solutions are being strongly exemplified today, and I foresee this trend enduring post-pandemic as more and more patients, physicians, and payers continue to recognise the significance of these solutions/devices.

The alarming prevalence and disease burden of undiagnosed sleep apnea has also increasingly been brought to light in the last five years, pushing payers to recognise the economic value in the HSAT market. Currently, it is estimated that 54 - 60 million people in the U.S suffer from sleep apnoea, with roughly 80% of these cases going undiagnosed and even more untreated. And, according to a recent report by the AASM, the economic burden of undiagnosed sleep apnea in the U.S amounts to approximately $149.6 billion annually – roughly $30 billion of which is due to increased health care and medication costs related to comorbid health risks like cardiovascular disease. Thus, by diagnosing and treating sleep apnoea payers and healthcare systems can save about $100.1 billion annually (according to the AASM) and improve patient outcomes. This is likely to continue to spur the development of the sleep apnoea device market even further moving forward.

Have you got any plans for further development?

We are constantly working on further developing our product offerings and nurturing new and existing partnerships, and the industry today is experiencing a number of interesting and exciting developments that we plan to leverage and lean into.

Prior to the COVID-19 pandemic, the ratio of in-lab vs at-home sleep testing was 70:30. During the pandemic however, as social distancing and lockdowns force lab-closures and hinder patient access to in-person care, this ratio has flipped, with 70% of sleep tests being conducted using Home Sleep Apnoea Tests (HSAT) and just 30% being conducted in-lab via the traditional polysomnography (PSG) tests. Moving forward, while we expect many sleep experts to revert to and continue using in-lab PSG testing, we also expect physicians to continue utilising HSATs far more frequently than in the past, shifting the ratio to an even 50:50 split. Thus, the migration to home-based care and the adoption of broader telehealth solutions have been greatly accelerated by the pandemic, creating an opportunity for expansion in the HSAT market.

Looking ahead, Itamar Medical has adopted a three-pronged strategy, focusing on commercialisation and expansion across three core channels: Core Sleep, Cardiology, and Direct to Consumer. Within these channels, we aim to continue our efforts in educating the healthcare community on the serious implications and comorbidities of sleep apnoea and increase access to and the adoption of our HSAT devices. The development of new key partnerships and collaborations with industry vendors plays a large role in these plans, further enabling us to continue our mission to address and improve the outcomes for the estimated 80% undiagnosed and untreated sleep apnoea patients.

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