The aorta is the main human artery that carries blood from the heart to the different parts of the body. When the region of the aorta below the level of the kidneys expands to more than 50% of its original diameter, it is described as an abdominal aortic aneurysm (AAA). Patients with AAA typically do not know that they suffer from this disease, until diagnosed by chance or during rupture. Therefore, seven European countries have started AAA screening programs. In current clinical routine vascular specialized doctors Clinicians decide whether the AAA needs to be repaired, solely based on AAA size or rarely abdominal symptoms if present. This one-size-fits-all criterion that has been in practice contains inefficient and high-risk clinical management components, especially since small AAAs <55 mm in diameter form a significant percentage of the ruptured cases.
AAA has an average global prevalence of 6%, which amounts to roughly 0.5 million patients in Switzerland alone. There are approximately 200’000 death per year worldwide due to AAA rupture. Due to the aging society the overall incidence shows an increasing tendency.
Maximum AAA diameter is an imperfect measure of AAA rupture risk, since some large AAAs remain intact throughout a patient’s lifetime, while some small AAAs rupture (early). Patients with small AAAs are often kept under surveillance and are advised to follow-up with their clinician every 6 months to 24 months, depending on AAA size and risk profile (blood lab values, nicotine consumption, blood pressure, AAA geometry etc.). During the time between follow-ups, these patients do not know the status of their AAA, and live in constant anxiety of rupture and consequently, sudden death. Thus, there is a critical need among AAA patients for a device to monitor the status of their AAA while they are outside the hospital using a reliable marker.
With the envisioned solution caring physicians and patients can track AAA growth remotely and at home. If they have a high rupture risk, the caring physician can bring arguments for a repair or closer management (3 instead of 1 year follow-up scheme). A patient with a low risk profile can confidently choose to continue with surveillance with much less anxiety. Through SmartLyf, health costs and mortality rates, and emergency operations are supposed to be reduced.
The goal of the project SmartLyf was to set the basis to build a novel real-time monitoring platform, which forecasts biomechanics-based AAA rupture risk information using simple wearable devices. With a smartphone app, patients can track AAA growth at home. If they have a high rupture risk, the caring physician can bring arguments for a repair.
A clinical trial could be set-up with a specific adapted ergometer able to be used in the MR-scanner to gather 3D geometric- and 4D-flow images of the AAA for biomechanical analysis under patient rest and stress. Furthermore, common available wearables with PPG sensor and data transfer technology were implemented to extract relevant vital signs from the raw-data to determine a correlation between biomechanical and vital sign data in order to define a reliable biomarker for an Abdominal Aortic Rupture Risk Index (AAARI).
Switzerland Innovation Park Biel/Bienne implemented the following in the project:
- App-system conceptualization, system architecture design for wearable data
- Software App Engineering (front and backend)
- Prototype Android APP / GUI design development
- IoT – PPG sensor & data analytics, processing, exchange
- Design verifications
The project was carried out including the University of Bern respectively the University Institute for Diagnostic Interventional and Paediatric Radiology (DIPR) of the Inselspital in Bern under vice chair Prof. Dr. med. Hendrik von Tengg-Kobligk (firstname.lastname@example.org) together and the ARTORG Center for Biomedical Engineering Research and the SwissHealthTech Center des Switzerland Innovation Park Biel/Bienne within an Innosuisse project (IP-LS 39833.1) without implementation (industry) partner.