Why I Stopped Working on "Cuffless" Blood Pressure Monitoring

This month marks two years since I joined Cardiex—a journey that has brought me closer to the frontier of cardiovascular health technology. As I reflect on this milestone, I also want to share why I made the pivotal decision to sell Blumio to Cardiex and transition away from cuffless blood pressure monitoring.

When Oliver Shay & I founded Blumio, our mission was simple: to make blood pressure monitoring as effortless and accessible as possible. Cuffless solutions promised convenience, but as we dove deeper, it became evident that blood pressure alone was not the full picture of heart health. Sure, blood pressure is a critical vital sign, but the true insights into cardiovascular well-being come from understanding arterial health—an area in which traditional and cuffless blood pressure monitoring often fall short.

One of the biggest challenges with cuffless blood pressure monitoring was calibration. Unlike a cuff-based device, cuffless monitors need to be calibrated regularly using an external, traditional blood pressure cuff to maintain accuracy. This calibration dependency introduces a significant limitation in making the technology fully autonomous and accessible. For users, the need for periodic recalibration undermines the convenience that cuffless monitoring was meant to provide, especially in varied environments, such as during physical activity or at rest.

Even more problematic was that calibration wasn’t a one-size-fits-all solution. Individual variability in physiology—such as differences in arterial stiffness or vascular tone—made it difficult for cuffless systems to maintain accurate readings without constant recalibration. This complexity made it increasingly clear that while cuffless blood pressure had promise, the technical hurdles were significant and ongoing.

This realization led me to Cardiex, where I could work on calibration-free parameters like Augmentation Index (AIx), Pulse Pressure Amplification (PPA), and Subendocardial Viability Ratio (SEVR) which are pushing the boundaries of heart health assessment. These parameters offer a much deeper understanding of the cardiovascular system and are far more predictive of long-term heart health than blood pressure alone.

I’m especially excited about working with these arterial health parameters because they offer real, actionable insights into cardiovascular function. AIx, PPA, and SEVR reflect how the heart and arteries interact in ways that traditional blood pressure monitoring simply can’t capture. These measures go beyond just reading numbers—they help us understand how well your heart is performing under stress and how resilient your cardiovascular system really is. This focus on arterial health has allowed me to lead the CONNEQT Pulse through FDA clearance and secure its listing on the Validated Device Listing (VDL). These milestones underscore the shift from monitoring blood pressure to truly understanding and improving heart health.

Here’s why these parameters matter:

? AIx (Augmentation Index): AIx reflects arterial stiffness and the burden it places on the heart, giving us a more accurate understanding of cardiovascular strain. A 4,561-subject study (published in American Journal of Hypertension ) demonstrated that AIx can serve as a valuable predictor of cardiovascular risk, particularly in younger individuals.

? PPA (Pulse Pressure Amplification): PPA is a measure of how much the pressure in your arteries increases as blood moves from the heart to the rest of the body, and it tends to decrease as arteries become stiffer with age or health issues. A 5,608-subject study (published in Nature) found that PPA below a threshold of 1.3 is associated with higher risks of cardiovascular and coronary complications, making it a significant factor for risk stratification beyond traditional blood pressure measures.

? SEVR (Subendocardial Viability Ratio): SEVR measures how well the heart muscle itself is perfused, highlighting the risks of ischemia and other heart-related issues that traditional blood pressure monitoring simply cannot detect. A review (published in Journal of AHA) highlights the significant clinical value for predicting cardiovascular events and mortality across various diseases, such as hypertension, diabetes, chronic kidney disease, and aortic stenosis, while also showing promise as a tool for assessing myocardial perfusion and arterial stiffness in clinical practice.

As these parameters show, what matters most isn’t just the pressure in your arteries but how your arteries are responding to that pressure. Cardiovascular health is about resilience and adaptability. Understanding the interplay of arterial stiffness, vascular efficiency, and myocardial health paints a far more comprehensive picture of your heart’s well-being.

What's even more exciting is we demonstrated that these calibration-free parameters—AIx, PPA, and SEVR—can be accomplished using photoplethysmography (PPG), a non-invasive optical method. This breakthrough enables us to capture critical arterial health metrics through everyday wearables, without the need for constant recalibration. It further showcases how these technologies can provide accessible and accurate cardiovascular insights, revolutionizing how we monitor heart health.

When I joined Cardiex and integrated Blumio’s technology into the company’s portfolio, it was a natural fit. Cardiex’s expertise in arterial health allowed us to shift focus from cuffless blood pressure monitoring to something much more transformative for healthcare: a suite of calibration-free, AI-powered insights that offer a window into the very heart of arterial health.

At the end of the day, technology should be about providing real, actionable insights that improve lives. And I’m proud to say that our work at Cardiex is doing just that. I’m excited about what the future holds as we continue developing innovative solutions that focus not only on measuring blood pressure but on truly understanding cardiovascular health.

Here’s to two years—and the many more exciting developments to come.