Following the announcement of CE mark approval for the Aktiia cuffless blood pressure monitor bracelet, Gregoire Wuerzner (Lausanne University Hospital and University of Lausanne, Switzerland) clinical advisor to Aktiia and President of the Swiss Society of Hypertension, discusses the potential advantages of continuous blood pressure monitoring compared to current techniques.
How does the Aktiia bracelet work, and what features set it apart from the established methods for monitoring blood pressure?
Aktiia’s Optical Blood Pressure Monitoring (OBPM) algorithms leverage optical sensors worn on the wrist and provide blood pressure values using photoplethysmography (PPG) to analyse the changing diameter of the arteries occurring at each heartbeat. This optical measurement is repeated automatically, so users are not aware of the measurements, thus removing the possible stressing effect of measurement itself. They do not have to interrupt their day and sleep time to take a measurement.This is different from the oscillometric method of measuring blood pressure that involves inflating a cuff on the upper arm that analyses pulse waves during constricted blood flow.
Aktiia takes over 100 blood pressure measurements per week, which is much more than people using a traditional blood pressure cuff, who easily forget to measure their blood pressure. Because Aktiia is monitoring your blood pressure 24/7 people and physicians for the first time are able to see the patients complete blood pressure pattern over hours, days, weeks and even months. This greater level of insight should help individuals better understand the impact of their daily activities such eating, working and sleeping on their blood pressure. It will also probably allow the physician to provide more tailored treatment plans.
What is the advantage to using a cuffless blood pressure monitoring system over ambulatory blood pressure monitoring?
Ambulatory blood pressure monitors are useful in that they are able to provide a physician a look at patients 24-hour blood pressure pattern such as white coat hypertension and dipping of blood pressure at night. While this is superior, in terms of cardiovascular risk assessment to a single in-clinic reading, it is still prone to a number of issues that include:
Aktiia’s cuffless approach has made significant improvements in each of these areas, including:
Is the system easy to fit, and do patients need to be trained to wear it?
Extensive time and energy has gone into the design of the Aktiia system. While it is a serious medical technology that took 15 years to develop and has been validated in five clinical studies, the user experience is comparable to high quality consumer technology products.The user is guided by the companion mobile application through a set-up process that only takes a few minutes. Once set-up, the user doesn’t have to interact with the bracelet, except once every eight or nine days to recharge it or for reinitialisation once a month.They will be able to open the app on their iPhone or Android smartphone and see their data automatically appear. With a simple tap of a button in the app, they can easily share their data with their doctor or family member.
To ensure the accuracy of the measurements, the bracelet includes an accelerometer that makes sure the conditions for measurement are optimal for an accurate reading. The user doesn’t have to change their behavior or spend time thinking about what body position they need to be in or what time of the day is appropriate for the best reading. Aktiia’s technology does this all for the wearer automatically.
During our validation study, one of the most frequent questions from our participants were when and where they could get the device.
How comparable is the data to ambulatory blood pressure monitoring?
Both ambulatory blood pressure monitors and Aktiia are able to gather data over a 24-hour period. While today’s ambulatory blood pressure monitors are only used during these 24 hours, they provide a snapshot of the circadian profiles of blood pressure of patients. Aktiia offers the same capability, but over longitudinal periods, providing day and night BP readings over weeks and months. This type of data has never been acquired before in patients, and is the most impactful breakthrough of cuffless technologies. When it goes to the comparison of the accuracy between ambulatory blood pressure monitors and Aktiia’s devices, both undergo the same standards of clinical validation: the so-called ISO 81060-2. They have however not been compared head to head yet in terms of accuracy or in terms of association with target organ damage or cardiovascular risk.
Is there a benefit to being able to draw on 24/7 blood pressure data? Is there a drawback? Does having access to this data potentially tell us anything new about hypertension or the way it is treated?
There are three main benefits to 24/7 blood pressure monitoring that are well established in a number of clinical studies. They include:
Could the cuffless system replace traditional methods of blood pressure monitoring over time?
Yes. Accurate and validated Cuffless products like Aktiia are big step forward and represent the future of how blood pressure will be monitored outside a physician’s office.