Mobile Blood Pressure Testing
Blood pressure (BP) is widely believed to be one of the most important indicators of an individual’s well being and is used regularly used to assess individuals for their risk of many chronic health conditions, such as heart disease. However, one of the biggest barriers standing between individuals regularly checking their blood pressure is accessibility: buying an at-home BP test kit requires an initial investment; plus, going to free BP testing locations can be seen as a hassle, especially if someone has not been diagnosed with high BP and does not believe they have a need to monitor it. This often leads to the insidious development of BP problems that are not realized until the problem is present, and as we know, prevention is easier than reversal.
A group of scientists out of the University of California, San Diego is looking to change this barrier to accessibility. This research, published in Nature Biomedical Engineering, examined the efficacy of a postage stamp-sized patch at measuring central BP (BP in the aorta). This patch is hydrophobic and capable of enduring twisting and stretching, making it a promising candidate for future skin integration applications (i.e. making it a semi-permanent component in the body).1,2 It works by sending out ultrasonic waves (in a manner similar to sonar) that measure the changes in blood volume and tissues in the vessels in the neck, tracking the changes to produce a central blood pressure reading. This method is advantageous over prior methods which involved insertion of a catheter (tube) into an artery in the torso that caused patients discomfort and increased their risk of developing an infection.
Not only does this technology have the potential to be more accessible than standard BP testing, it may also be more accurate than standard BP testing, which uses peripheral BP (e.g. your upper arm). First, while changes in the peripheral vasculature can result in noticeable complications like intermittent claudication, the changes that result in major problems such as heart attacks occur in organs that are supplied by the central arteries. While ideally we would be able to estimate the BP in these central vessels, especially the aorta, from a reading taken in a peripheral vessel, this relationship has proven to be irregular and unpredictable, rendering it a less than ideal measure of an individual’s status.3 As technology such as the one described above becomes more available to the general public, central BP readings may become the norm, especially if central BP proves to allow for more accurate cardiovascular risk stratification than peripheral BP measurements.
This technology is indicative of a larger trend that is seeing the miniaturization of technology to a scale where it can non-invasively measure many different health markers. I would imagine similar technology will soon be able to monitor kidney health (via glomerular filtration rate), heart health (via stroke volume & ejection fraction), and a whole host of other markers. Blood pressure is only the surface of what this technology will be able to do, but until additional uses are invented, this could be a great option to help monitor your blood pressure and work to keep it under control.
P.S. While high BP can lead to many complications that have the potential to limit one’s ability to move, I want to highlight the potential effect it can have on bone density. A 2011 study found a direct association between urinary calcium excretion and blood pressure.4 When coupled with earlier research which found a correlation between bone mineral density loss and urinary calcium excretion,5 it stands to reason that anything that increases urinary calcium excretion (high BP) may lead to an increased rate of loss of bone density. While I have found no study that proves this theory, it would seem prudent to follow standard guidelines for BP, and hopefully receive excellent bone health as a side benefit.
References
- Wang C, Li X, Hu H et al. Monitoring of the central blood pressure waveform via a conformal ultrasonic device. Nature Biomedical Engineering. 2018;2:687-695.
- https://www.technologyreview.com/s/612148/stretchy-stick-on-patch-can-take-blood-pressure-readings-from-deep-inside-your-body/
- McEniery CM, Cockcroft JR, Roman MJ, Franklin SS, Wilkinson IB. Central blood pressure: current evidence and clinical importance. Eur Heart J. 2014;35926):1719-1725.
- Kesteloot H, Tzoulaki I, Brown IJ et al. Relation of urinary calcium and magnesium excretion to blood pressure. Am J Epidemiol. 2011;174(1):44-51.
- Asplin JR, Donahue S, Kinder J, Coe FL. Urine calcium excretion predicts bone loss in idiopathic hypercalciuria. Kidney Int. 2006;70(8):1463-1467.a