Aim: Cardio-ankle vascular index (CAVI) is a marker of arterial stiffness independent of blood pressure (BP) at the time of measurement. This work sought to evaluate the association of CAVI with left ventricular hypertrophy (LVH), a marker of long-standing hypertension (HTN) in the pediatric population. Methods: CAVI values from 236 children being evaluated for HTN were compared with their BP grade (normal, elevated, stage I HTN, and stage II HTN) in accordance with clinical guidelines. CAVI values were correlated to the presence of LVH and lipid profiles. One hundred seven of the studied patients had transthoracic echocardiograms available for comparison, and 126 had available lipid results. CAVI means between the groups were compared using analysis of variance. Results: There was no significant difference in CAVI values between the BP groups [median/interquartile range: normal BP (4.95/4.4–5.7), elevated BP (5.1/4.5–5.6), stage I/II HTN (5.0/4.3–5.5)]. Mean CAVI value was higher in the group that had LVH (5.53, standard deviation = 1.4 vs. 5.1, standard deviation = 1; P = 0.13) but was not statistically significant. However, higher mean CAVI value in children ≥ 15 years was significantly associated with the presence of LVH (5.9, standard deviation = 1.8 vs. 5.2 standard deviation = 0.8; P = 0.018). Conclusions: In post-pubertal children, CAVI may be a good predictor of LVH from long-standing HTN. This tool could prove useful in screening for the presence of atherosclerotic changes and provide opportunity for intervention/improved long-term outcomes.

Background Optimal clinical care, diagnosis and treatment requires accurate blood pressure (BP) values. The primary objective was to compare BP readings taken while adhering to American Heart Association (AHA) guidelines to those typical of routine clinical care. Specifically studied: the combined effect of feet flat on the floor, back supported, and arm supported with cuff at heart level, while adhering to other guideline recommendations. Methods In this prospective, randomised, three-group cohort study, a modified cross-over design was applied in a primary care outpatient office setting in Columbus (OH, USA). Eligible participants were adults (aged >= 18 years) with an arm circumference of >= 18 cm and <= 42 cm who did not have a renal dialysis shunt or a previous or current diagnosis of atrial fibrillation. 150 recruited volunteers meeting the inclusion criteria were randomly randomised into the three groups. Group methodologies were BP readings taken on a fixed-height exam table followed by readings taken in an exam chair with adjustable positioning options (Group A), readings taken in the reverse order, chair then table (Group B), and both sets of readings in the exam chair (Group C). A rest period occurred before each set of readings. Group C was included for the purpose of obtaining an independent estimate of the order effect. The order in which the two types of readings (table vs chair) were taken was randomised. The primary outcome was the difference between the mean of three BP readings taken on the table and the mean of three readings taken in the chair. Findings Between September and October, 2022, 150 participants were enrolled in the study; all 150 of whom completed testing: 48 in Group A, 49 in Group B, 53 in Group C. The mean systolic/diastolic BP (SBP/DBP) of readings taken on the table (Group A first readings, Group B second readings) were 7.0/4.5 mmHg higher than those taken in the chair (Group A second readings, Group B first readings); both statistically significant, p < 0.0001. These findings show that AHA-recommended positioning-feet flat on the floor, back supported, arm supported with the BP cuff at heart level-results in substantially lower BP values than improper positioning. The mean SBP/DBP of the first set of readings taken on the chair were 1.6/0.6 mmHg higher than for the second set of readings (Group C, included to estimate order effect). Interpretation The observed benefit of proper positioning is sufficient to change the BP classification of several million patients from having hypertension to not having hypertension and therefore avoiding medication and/or intense follow-up.

Objective: Automated cuff blood pressure (BP) devices are widely used for ambulatory, home, and office BP measurement. However, an automated device, which is accurate in the general adult population may be inaccurate in some special populations. A 2018 Collaborative Statement by the US Association for the Advancement of Medical Instrumentation, the European Society of Hypertension, and the International Organization for Standardization (ISO) considered three special populations requiring separate validation (age <3 years, pregnancy, and atrial fibrillation). An ISO Task Group was appointed to identify evidence for additional special populations. Method: Evidence on potential special populations was identified from the STRIDE BP database, which performs systematic PubMed searches for published validation studies of automated cuff BP monitors. Devices that passed in a general population, but failed in potential special populations were identified. Results: Of 338 publications (549 validations, 348 devices) in the STRIDE BP database, 29 publications (38 validations, 25 devices) involved 4 potential special populations: (i) age 12–18 years: 3 of 7 devices failed but passed in a general population; (ii) age more than 65 years: 1 of 11 devices failed but passed in a general population; (iii) diabetes type-2: 4 devices (all passed); (iv) chronic kidney disease: 2 of 7 devices failed but passed in a general population. Conclusion: Some evidence suggest that the automated cuff BP devices may have different accuracy in adolescents and in patients with chronic kidney disease than in the general population. More research is needed to confirm these findings and investigate other potential special populations.

ObjectiveAssess the accuracy and precision of the Aktiia initialization oscillometric upper-arm cuff device (Aktiia SA, Neuchatel, Switzerland) for home blood pressure (BP) monitoring in the general population according to the American National Standards Institute / Association for the Advancement of Medical Instrumentation/International Organization for Standardization (ANSI/AAMI/ISO) 81060-2:2013 standard. MethodsThree trained observers validated BP measurements performed using the Aktiia cuff versus BP measurements performed using a standard mercury sphygmomanometer. Two ISO 81060-2 criteria were used to validate the Aktiia cuff. Criterion 1 evaluated, for both SBP and DBP, whether the mean error between BP readings performed by the Aktiia cuff and auscultation was <=+/- 5 mmHg, and whether the SD of the error was <= 8 mmHg. Criterion 2 assessed whether, for the SBP and DBP of each individual subject, the SD of the averaged paired determinations per subject of the Aktiia cuff and of the auscultation met the criteria listed in the table of Averaged Subject Data Acceptance. ResultsMean differences between the Aktiia cuff and the standard mercury sphygmomanometer (criterion 1) were 1.3 +/- 7.11 mmHg for SBP and -0.2 +/- 5.46 mmHg for DBP. The SD of the averaged paired differences per subject (criterion 2) was 6.55 mmHg for SBP and 5.15 mmHg for DBP. ConclusionAktiia initialization cuff complies with the requirements of the ANSI/AAMI/ISO guidelines and can be safely recommended for BP measurements in the adult population.

The International Standards Organization 81060-2:2018 is the current global Standard for the validation of automated sphygmomanometers. It specifies the requirements for clinical studies on the general population, as well as additional requirements for special populations, which might have physiologic characteristics that affect the accuracy of blood pressure measurements. This paper summarizes the statistical methodology behind the sample size required to test automated sphygmomanometers in these special populations and specifically addresses the pregnant patient population.

Objective The objective of this report was to describe the validation of the A&D UM-212BLE automated oscillometric sphygmomanometer to the ISO 81060-2, 2018 protocol. The device is specifically designed for enhanced office and out-of-office programmability. Methods A combined pediatric (n = 35) and adult (n = 50) population was studied at Clinmark LLC in Louisville, Colorado, USA. Same-arm sequential testing was performed following the ISO 81060-2, 2018 requirements. Five cuffs were tested with a total arm circumference range from 12 to 50 cm. Reference readings were done by two blinded observers performing simultaneous auscultation. Results For validation of Criterion 1 the mean ± SD (mmHg) of the device minus the reference differences were 3.94 ± 6.89 for SBP and 2.09 ± 6.68 for DBP. Both passed the Standard limits for Criterion 2; the systolic(S)SD achieved was 5.56 (5.70 permitted) and the diastolic(D)SD was 6.01 (6.62 permitted). All other Standard requirements were met. Conclusions The UM-212BLE passed all requirements. The features that make this device clinically superior include settings for automated office BP, variable pressure inflation, dual measurement modes (oscillometry, auscultation), the wide range of cuffs tested, automated irregular heartbeat detection, and full validation in a pediatric population. The inclusion of all of these features makes the UM-212BLE a highly attractive device for both office and out-of-office BP estimation.

Objectives To assess the accuracy of the Midmark IQvitals® Zone™ wireless vital signs monitor LINEAR deflation algorithm to the requirements of the ANSI/AAMI/ISO 81060-2 Standard and the British Hypertension Society (BHS) Protocol.Methods The Standard and BHS testing each call for ≥ 85 subjects with requirements for gender, blood pressure (BP), and arm circumference. The testers performing auscultation were blinded. Statistical calculations as per requirements were performed.Results The mean ± SD for the 81060-2 Criterion 1 were 1.98 ± 6.90 mmHg for systolic and 0.54 ± 5.79 mmHg for diastolic BP. The Criterion 2 SD values were 5.60 mmHg for systolic and 5.26 mmHg for diastolic BP. All of these values passed the Standard requirements. The overall BHS rating was AA.Conclusions The Midmark LINEAR algorithm is validated based on the results. Use of the algorithm results in shorter cuff deflation times, thus improving patient comfort. The LINEAR algorithm has multiple features to improve BP measurement accuracy in critical patient populations.### Competing Interest StatementDr. Alpert is an expert consultant to Midmark Corporation.### Funding StatementThis study was funded by Midmark Corporation.### Author DeclarationsI confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.YesThe details of the IRB/oversight body that provided approval or exemption for the research described are given below:The Salus Institutional Review Board gave ethical approval for this work.I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals.YesI understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).YesI have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable.YesAll data produced in the present study are available upon reasonable request to the author.

Abstract In 2020 the ANSI/AAMI/ISO published Amendment 1 to the 81060–2 Standard. The purpose was to try to address issues relating to the distribution of subjects with respect to limb size ranges. It also required a new plot showing the limb circumferences on the x‐axis and the device minus reference errors on the y‐axis (Alpert plot). The study reported here showed inadequacies of the Amendment if significantly overlapping cuffs were to be tested. The innovative approach led to the testing of 135 subjects. Requirements for blood pressure (BP), arm circumference, and gender were fulfilled. The standard same arm sequential protocol was used. Criterion 1 calculations gave a mean ± standard deviation (SD) device minus manual BP values of 0.22 ± 7.90 mmHg for systolic BP and ‐0.68 ± 7.36 mmHg for diastolic BP. The maximum allowed mean value for either measurement is 5.0 mmHg. The SD values for Criterion 2 were 6.03 mmHg for systolic BP (maximum allowed 6.95) and 6.47 mmHg for diastolic BP (maximum allowed 6.90). All results passed the Standard requirements. This study demonstrated inadequacies of Amendment 1 and led to the development of an Amendment 2, still in the process of finalization. The new Amendment corrects the issues with significantly overlapping cuffs and “wide‐range” cuffs. The A&D UA‐651 Plus/UA‐651SL Plus BP monitors and the five cuffs not only passed the requirements of 81060–2:2018 and Amendment 1 but also a revised and more rigorous protocol with more subjects involved. These devices and cuffs can be used with confidence.

BACKGROUND:The purpose of this document is to provide clinicians with guidance, using expert consensus, to help summarize evidence and offer practical recommendations. METHODS:Expert Consensus Documents are intended to provide guidance for clinicians in areas in which there are no clinical practice guidelines, especially for new and evolving tests such as arterial stiffness measurements, until any formal guidelines are released. RESULTS:This expert consensus document is intended as a source of information for decision-making and to guide clinician-patient discussions in various clinical scenarios. CONCLUSIONS:The goal is to help clinicians and patients make a more informed decision together.

aDepartment of Pediatrics, University of Tennessee Health Science Center, Memphis, Tennessee bMarshfield Clinic Research Institute, Marshfield Clinic Health Systems, Marshfield, Wisconsin cSunTech Medical, Inc., Morrisville, North Carolina, USA *Bruce S. Alpert retired. Received 12 October 2021 Accepted 10 November 2021 Correspondence to Bruce Alpert, MD, 1350 Poplar Ridge Dr., Memphis, TN 38120, USA, Tel: +1 901 229 3719; e-mail: [email protected]

Objectives Assess the accuracy of the Midmark IQvitals Zone Vital Signs Monitor STEP deflation algorithm according to the ANSI/AAMI/ISO 81060-2 Standard. Methods A total of 85 subjects completed the testing protocol. All standard requirements for gender, blood pressure (BP) values, and arm circumferences were met. Manual auscultation was performed by testers blinded to the device; the manual BP values were compared to the device readings. Results: The Standard Criterion 1 data analyses showed mean +/- SD device minus manual BP values of 1.22 +/- 6.3 mmHg for SBP and -1.67 +/- 6.09 mmHg for DBP. The SD values for criterion 2 were 5.06 mmHg (SBP) and 4.98 mmHg (DBP). Conclusions The device passed all Standard requirements. The Midmark IQvitals Zone device has features to improve accuracy and reduce or eliminate transcription errors and inaccuracy from improper patient positioning.

Objective: Cuffless wrist-based blood pressure (BP) monitors have a great potential to make ambulatory monitoring more appealing to patients and provide clinicians with better BP profiling. Investigators must be vigilant to validate these devices properly, as little guidance has been published. We propose a protocol that addresses ambulatory environment challenges, such as body posture changes and variable arm position. In addition to reporting the accuracy, we suggest reporting the number of successful automated measurements – the acceptance rate. Design and method: We tested the Aktiia Bracelet, a cuffless automated device that records optical signals at the wrist and requires an initial calibration, with the proposed protocol on 10 healthy volunteers. We simultaneously recorded the signals from the Aktiia Bracelet and a reference volume-clamp device positioned on the contralateral arm during the following interventions: sitting, lying supine, standing with both arms positioned at heart level; sitting with the Aktiia bracelet wrist positioned 30 cm lower than heart level; isometric leg extension inducing large BP changes. We calculated the mean and standard deviations of the error between Aktiia bracelet and the reference, as well as the acceptance rates in different measurement scenarios. Results: The figure illustrates the mean and standard deviation (STD) of the error between Aktiia bracelet and the reference, as well as the acceptance rate (Acc) for the diastolic BP (DBP). The dashed area illustrates the expected hydrostatic bias. The mean and the standard deviation of the error fell within ISO81060-2 limits. Aktiia bracelet readings were not affected by the hydrostatic bias intervention, even though one could expect an error of more than 20 mmHg. The maximum of the accepted measurements was achieved when patients were lying supine (67%) and sitting (52%). Thus, the user can expect a high density of measurements during night-time. However, when standing, the acceptance dropped (27%). Conclusions: This protocol provides more realistic testing of cuffless wrist-based BP monitors and suggests a way to improve the validation of this new family of devices.

Abstract Objective: The auscultatory blood pressure (BP) measurement technique, relying on the K1 and K5 Korotkoff sounds, is the current reference to validate new devices in the standard sitting position. There are few data to tell whether it should also be used for device validation in other body positions, since the K1 and K5 sounds can be affected by changes in vascular tone. In this study, we recorded the BP responses to body position changes by the auscultatory method, and we compared them to data from simultaneous recordings by a volume-clamp method. Design and method: Systolic (SBP) and diastolic (DBP) were estimated on the left upper arm by two independent blinded observers, and on the ipsilateral middle finger by a volume-clamp device (Nexfin, BMEYE, The Netherlands) in the supine followed by the standing position, and in the standing followed by the supine position. The auscultatory readings were repeated if readings differed more than 4mmHg between the two observers. A first auscultation was performed before the position change, and a second one 150 s after the position change. Because volume-clamp measurements were not available during upper-arm cuff inflation, the mean of volume-clamp values in a 30 s window prior to auscultation onset were used for the analyses. Results: Sixty-seven participants, between 21 and 65 years old, participated in this study. As illustrated in the figure, volume-clamp reported a consistent mean DBP increase of 9.3 mmHg when moving from supine to sitting, and a consistent mean DBP decrease of 10.4 mmHg when moving from sitting to supine. These results agree with those previously reported using simultaneous invasive and volume-clamp measurements. On the contrary, auscultation detected no consistent body position-related change in the DBP readings. Neither auscultation nor volume-clamp detected consistent body position-related changes in SBP readings. Conclusions: Compared to volume-clamp, auscultation was not able to detect any consistent changes in BP during orthostatic challenge. Our study suggests that the use of Korotkoff sounds to estimate BP in body positions other than sitting and relaxed may not be appropriate.

The auscultatory BP estimation technique, relying on K1 and K5 Korotkoff sounds, is the current reference to validate automated devices in the sitting position. With a growing need for automated 24-h BP monitoring, we will have to perform device validation in positions other than sitting and to evaluate the possibility of bias related to posture change. There have been few data to assess whether auscultation is adequate for this purpose. The origins of Korotkoff sounds are not fully understood; they are known to be affected by changes in vascular tone, which depend on extrinsic and intrinsic factors [1]. A recent review of 62 studies reported systematic differences between auscultation and invasive measurements that did not fall within the requirements of current standards [2].

Most automated sphygmomanometers use oscillometric algorithms. Motion, either patient-based or environmental, will affect the ability of a device to record an accurate blood pressure (BP). Members of the Association for the Advancement of Medical Instrumentation (AAMI) Sphygmomanometer Committee have been studying this problem for more than a decade. The AAMI TIR44 was the first publication to address the challenges of motion tolerance. The concepts described in TIR44 have led to the development of a draft of ISO 81060-4, a new standard for testing devices for which the manufacturer wishes to claim motion tolerance. The current ISO 81060-2 addresses both stress testing and 24-hour ambulatory BP monitoring. Recent publications have reported on testing of devices in response to voluntary and involuntary patient motion. The ISO 81060-4 will address testing in the presence of patient transport by ground, fixed-wing, and rotary (helicopter) ambulances. The protocol will utilize noise profiles recorded under those three conditions. The profiles will be digitally stored on a library with free access. The proposed testing will be performed using patient simulators introducing the noise library files into known BP oscillometric envelopes. The specifications of the data capture and playback devices are specified, as is the evaluation statistical testing. The authors expect that the final draft will be published in 2020.

: The Lancet Commission on Hypertension identified that a key action to address the worldwide burden of high blood pressure (BP) was to improve the quality of BP measurements by using BP devices that have been validated for accuracy. Currently, there are over 3000 commercially available BP devices, but many do not have published data on accuracy testing according to established scientific standards. This problem is enabled through weak or absent regulations that allow clearance of devices for commercial use without formal validation. In addition, new BP technologies have emerged (e.g. cuffless sensors) for which there is no scientific consensus regarding BP measurement accuracy standards. Altogether, these issues contribute to the widespread availability of clinic and home BP devices with limited or uncertain accuracy, leading to inappropriate hypertension diagnosis, management and drug treatment on a global scale. The most significant problems relating to the accuracy of BP devices can be resolved by the regulatory requirement for mandatory independent validation of BP devices according to the universally-accepted International Organisation for Standardization Standard. This is a primary recommendation for which there is an urgent international need. Other key recommendations are development of validation standards specifically for new BP technologies and online lists of accurate devices that are accessible to consumers and health professionals. Recommendations are aligned with WHO policies on medical devices and universal healthcare. Adherence to recommendations would increase the global availability of accurate BP devices and result in better diagnosis and treatment of hypertension, thus decreasing the worldwide burden from high BP.

Objective The objective of this study was to compare the systolic (S) and diastolic (D) blood pressure (BP) estimations from a new optical device at the wrist with invasive measurements performed on patients scheduled for radial arterial catheterization in the ICU. Optical signals were automatically processed by a library of algorithms from Aktiia SA (OBPM – optical blood pressure monitoring algorithms). Methods A total of 31 participants from both sexes, aged 32–87 years, were enrolled in the study (NCT03837769). The measurement protocol consisted of the simultaneous recording of reflective photoplethysmographic signals (PPG) from the cuffless optical device and the reference BP values recorded by a contralateral radial arterial catheter. From the 31 participants, 23 subjects whose reference data quality requirements were adequate were retained for further analysis. The PPG signals from these patients were then automatically processed by the Aktiia OBPM library of algorithms, which generated uncalibrated estimates of SBP and DBP. After the automatic assessment of optical signal quality, 326 pairs of uncalibrated SBP and DBP determinations from 16 patients were available for analysis. These values were finally transformed into calibrated estimations (in mmHg) using arterial catheter SBP and DBP values, respectively. Results For SBP, a mean difference (±SD) of 0.0 ± 7.1 mmHg between the arterial catheter and the optical device values was found, with 95% limits of agreement in the Bland-Altman method of –11.9 to + 12.2 mmHg (correlation of r = 0.87, P < 0.001). For DBP, a mean difference (±SD) of 0.0 ± 2.9 mmHg between arterial catheter and the optical device values was found, with 95% limits of agreement in the Bland-Altman method of –4.8 to + 5.5 mmHg (correlation of r = 0.98, P < 0.001). Conclusion SBP and DBP values obtained by radial artery catheterization and those obtained from optical measurements at the wrist were compared. The new optical technique appears to be capable of replacing more traditional methods of BP estimation.

Double-blinded auscultation is the current reference to validate new devices in the sitting position. There are few data to tell whether it should be used for device validation in other body positions, as the Korotkoff sounds can be affected by changes in vascular tone. In this study, we recorded the BP response to orthostatic posture change (standing to supine) in 75 subjects, aged between 21 and 65 years old. Systolic (SBP) and diastolic (DBP) were measured on the left upper arm by auscultation by two independent blinded observers before and 150s after posture change. In case the observers did not agree, i.e. readings differed more than 4 mmHg, the measurement was repeated. Beat-to-beat BP values were measured on the ipsilateral middle finger with Nexfin (BMEYE, The Netherlands). Because Nexfin measurements were not available during upper-arm cuff inflation, the mean of the values in a 30s window prior to auscultation onset was used for the analysis. The distribution of the BP responses to posture change was characterized in terms of median, 10 th and 90 th percentiles (see Table). The response was considered consistent if these percentiles were on the same side of zero. Neither auscultation nor Nexfin detected any consistent posture-related changes in SBP when going from standing to supine. Nexfin detected a consistent decrease in DBP. Auscultation detected no consistent posture-related change. Compared to volume-clamp, auscultation was not able to detect any consistent changes in DBP during orthostatic challenge. Our study suggests that the use of Korotkoff sounds to estimate BP in body positions other than sitting may not be appropriate.