Evaluation of the Accuracy of Cuffless Blood Pressure Measurement Devices: Challenges and Proposals

Abstract

Several novel cuffless wearable devices and smartphone applications claiming that they can measure blood pressure (BP) are appearing on the market. These technologies are very attractive and promising, with increasing interest among health care professionals for their potential use. Moreover, they are becoming popular among patients with hypertension and healthy people. However, at the present time, there are serious issues about BP measurement accuracy of cuffless devices and the 2021 European Society of Hypertension Guidelines on BP measurement do not recommend them for clinical use. Cuffless devices have special validation issues, which have been recently recognized. It is important to note that the 2018 Universal Standard for the validation of automated BP measurement devices developed by the American Association for the Advancement of Medical Instrumentation, the European Society of Hypertension, and the International Organization for Standardization is inappropriate for the validation of cuffless devices. Unfortunately, there is an increasing number of publications presenting data on the accuracy of novel cuffless BP measurement devices, with inadequate methodology and potentially misleading conclusions. The objective of this review is to facilitate understanding of the capabilities and limitations of emerging cuffless BP measurement devices. First, the potential and the types of these devices are described. Then, the unique challenges in evaluating the BP measurement accuracy of cuffless devices are explained. Studies from the literature and computer simulations are employed to illustrate these challenges. Finally, proposals are given on how to evaluate cuffless devices including presenting and interpreting relevant study results.

Blood pressure and its variability: classic and novel measurement techniques

“…Cuffless BP devices are a rapidly evolving group of novel technologies. These devices use several different parameters and techniques to assess BP levels, including pulse transit time, pulse wave analysis, photoplethysmography and applanation tonometry, and have different intended uses (such as wearable devices for occasional use or for short-term continuous monitoring in an intensive care unit) 55 , 56 . Cuffless BP technologies embedded in wearable devices and smartphones can obtain multiple or even continuous measurements during routine activities for days, weeks or months, without the discomfort of cuff-induced limb compression.…”

Wearable Photoplethysmography for Cardiovascular Monitoring

“…Studies are now assessing the accuracy and potential clinical utility of such devices [ 167 ]. Standards have been developed for the validation of wearable, cuffless BP devices [ 168 ], [ 169 ] although further work is required to refine validation standards to account for the issues presented by PPG-based devices [ 170 ].…”

“…Validation studies provide insight into the clinical applications in which PPG monitoring could be beneficial and allow for an appreciation of the limitations of PPG monitoring. Studies to validate wearable PPG-based devices should be designed to contribute to regulatory approvals required for medical device certification [ 274 ] and should follow standard validation protocols where available [ 170 ].…”

Updates in hypertension: new trials, targets and ways of measuring blood pressure

“…Standardized blood pressure measurement encompasses proper patient positioning (back supported, feet flat on the floor, cuff correctly placed on a bare upper arm with the arm elevated and supported at the level of the heart), cuff size, lack of conversation and use of a validated automated blood pressure measurement device or a well calibrated manual device. Cuffless blood pressure devices are an emerging technology that may allow for continuous, unintrusive blood pressure monitoring in a variety of settings by indirectly estimating blood pressure using pulse transit time, pulse arrival time, tonometry and/or pulse wave analysis [11,12]. Cuffless devices are distinct from cuffed automated blood pressure devices, which use oscillometric technology to detect the mean arterial pressure and then calculate the SBP and DBP [55].…”

“…These studies encompass several key areas of hypertension research: optimal hypertension targets in older adults [3 ▪▪ ], the safety and effectiveness of potassium-based salt substitution [4,5 ▪▪ ], the use of thiazide-like diuretics in advanced chronic kidney disease [6 ▪▪ ] and under- recognition of primary aldosteronism [7 ▪ ,8]. We will also summarize evolving global trends in hypertension [9 ▪ ], evidence examining strategies for intensification of antihypertensive treatment in older patients [10] and use of cuffless blood pressure devices [11,12]. Each of the selected studies brings forward innovative ideas in approaching hypertension management and lays the groundwork for future research to further optimize our approach to hypertension management…”