The Promises and Challenges of Continuous Blood Pressure Monitoring: Comparing Apple and Samsung

If you've read my latest blog post, I am passionate about the benefits of 'Continuous Wearable Cuffless Noninvasive Blood Pressure Monitoring CWCNBPM.' Wow, that's a mouthful! It will take years before this becomes the standard. The technology is being commercialized, though adoption in the medical community will lag.

Wearable technology has made significant strides in recent years, promising to revolutionize various aspects of health monitoring, including continuous blood pressure monitoring. Apple and Samsung, two giants in the tech industry, have been at the forefront of integrating blood pressure monitoring features into their smartwatches. While the potential benefits are immense, both companies have faced considerable challenges in achieving accurate and reliable continuous blood pressure monitoring. This article delves into the promises and challenges of these technologies, comparing Apple's and Samsung's approaches and exploring the hurdles all companies face in this space, particularly in gaining FDA approval in the United States.

The Promise of Continuous Blood Pressure Monitoring

Continuous blood pressure monitoring offers several advantages over traditional methods. Providing real-time data enables constant feedback and awareness of the events and times when your blood pressure is high. This allows users to monitor their condition more closely, make necessary lifestyle adjustments, or seek medical attention. The convenience of wearable devices also encourages regular use, leading to better health outcomes. It also helps to measure the total load on the cardiovascular system due to hypertension. It will make diagnosing nocturnal, morning, and dipping hypertension patterns easier, which are crucial to optimizing medication management.

Apple Watch Blood Pressure Monitoring: Challenges and Innovations

Apple has been working on integrating blood pressure monitoring into its Apple Watch for several generations. Rumor has it that this is the year it finally gets released in the Apple Watch Series 11 and Watch Ultra 3 editions. Coupled with a cellular-enabled version of the Apple Watch and Apple Health integration, the Apple Watch can prove a very valuable tool in the fight against hypertension.

However, this journey has not been without obstacles.

• Accuracy Issues: Ensuring accurate blood pressure readings without using an inflatable cuff has been challenging. Like many other devices, the Apple Watch relies on photoplethysmography (PPG) sensors, which measure blood flow using green and red/infrared LEDs. While PPG sensors are effective for heart rate monitoring, they are limited in accurately measuring blood pressure.

• Multi-Site PPG Readings: Studies suggest that using multiple PPG sensors could improve accuracy, but Apple has yet to implement this approach. A single-site PPG sensor is limited and lacks a well-defined context, such as wrist positioning relative to veins and skin color variations. I imagine the Apple AirPods will soon support PPG, increasing blood pressure measurement accuracy.

• Inflatable Strap Patent: Apple has patented a concept for an inflatable strap that acts as a sensing chamber, like a traditional blood pressure cuff. However, this technology has not yet been brought to market. Omron has released such a device, but it has led to dissatisfaction with the price and size of the device.

• Hypertension Alerts: Apple's current solution is rumored to alert users when their blood pressure appears elevated instead of providing direct blood pressure readings. This approach is less precise but aims to offer helpful health insights. In the short run, it may circumvent FDA requirements.

Samsung Galaxy Watch Blood Pressure Monitoring: Challenges and Innovations

Samsung introduced blood pressure monitoring on its Galaxy Watch3 in 2020, offering a promising solution. However, Samsung has also faced several challenges.

• Calibration Requirements: The Galaxy Watch's readings require frequent calibration with a traditional blood pressure cuff. Users must recalibrate the watch every 30 days, which can be inconvenient.

• Measurement Stability: Accuracy decreases over time, especially two weeks after calibration. This variability can affect the reliability of the readings.

• FDA Approval: Although the Samsung Galaxy Watch's blood pressure feature has been approved for use in Europe, it has not yet received FDA approval for blood pressure monitoring. This lack of regulatory clearance means the device may not meet specific standards required for medical use.

• User Experience: Some users have reported inconsistencies in blood pressure readings, with higher variability depending on the day and time of measurement. This can lead to less confidence in the accuracy of the readings.

The Overall Challenges of Continuous Noninvasive Wearable Blood Pressure Monitoring

While Apple and Samsung have made significant progress, they are not alone in facing the challenges of continuous noninvasive wearable blood pressure monitoring. Several overarching issues affect all companies working in this space:

1. Accuracy and Reliability: Achieving accurate and reliable blood pressure measurements without using an inflatable cuff is complex. Wearable devices must account for various factors, such as wrist positioning, skin color, and individual physiological differences.

2. Calibration: Frequent calibration with traditional blood pressure cuffs is often required to maintain accuracy. This can be cumbersome for users and may reduce adherence to regular monitoring.

3. Technological Limitations: Current sensor technologies, such as PPG, have inherent limitations in measuring blood pressure. Multi-site PPG readings and advanced algorithms are being explored to overcome these challenges, but these solutions are not yet widely implemented.

4. Regulatory Approval: Gaining regulatory approval is a significant hurdle. Different countries have varying standards and requirements for medical devices, complicating the approval process. In the United States, the FDA's stringent criteria for medical device approval pose additional challenges.

Why the FDA Has Not Yet Cleared Such Devices for Use in the USA

The FDA has not yet cleared any continuous noninvasive wearable blood pressure monitoring devices for use in the USA due to several reasons:

• Stringent Standards: The FDA has rigorous standards for medical devices to ensure safety and efficacy. Wearable blood pressure monitoring devices must demonstrate high accuracy and reliability, which has proven challenging given current technological limitations.

• Clinical Validation: The FDA requires extensive clinical validation to approve medical devices. Companies must conduct thorough clinical trials to prove their devices' accuracy and reliability under various conditions.

• Post-Market Surveillance: Even after approval, the FDA mandates post-market surveillance to monitor the device's performance in real-world settings. This ongoing scrutiny ensures that the device meets safety and efficacy standards.

Other Solutions

Another device approved for use in Europe is the Aktiia device. Their device will perform several measurements throughout the day when it detects the user is still. It then uploads the data to the Aktiia servers, where the blood pressure is calculated. The Aktiia device has been in R&D for over 20 years, and the company was spun out six years ago. It won't be long till a ring-type monitor is approved in Europe and the USA.

It is already possible to purchase a variety of rings and watches sold in China that claim to monitor blood pressure accurately. One such device is the Huawei Watch D2.

I can't help but wonder why the accuracy of the Aktiia and Samsung Galaxy watches is sufficient to be cleared for sale in Europe but not the USA. Cardiowell looks forward to integrating continuous blood pressure monitoring soon.

Conclusion

Continuous blood pressure monitoring has the potential to revolutionize hypertension management by providing real-time data and insights. However, significant challenges remain, including ensuring accuracy, addressing calibration requirements, overcoming technological limitations, and navigating regulatory hurdles. Apple, Samsung, and other companies in this space are making strides in developing reliable solutions. However, work must be done before these devices gain widespread acceptance and regulatory approval, particularly in the United States.

As technology advances and companies invest in research and development, we can expect improvements in accuracy and reliability. Ultimately, overcoming these challenges will unlock the full potential of continuous blood pressure monitoring, leading to better health outcomes for individuals with hypertension.