Lelièvre, M

Introduction: Blood pressure (BP) is a complex physiological marker. Cuffless devices, often based on photoplethysmography (PPG), enable frequent or continuous BP monitoring without arterial occlusion, enhancing comfort and usability in both inpatient and outpatient settings. Various devices have received regulatory clearance, but they are not yet included in clinical guidelines due to evolving validation standards. Aim: To evaluate accuracy of the Biobeat WP613 device for continuous BP monitoring using invasive intra-arterial pressure (IAP) monitoring in ICCU patients. Methods: This prospective, single-center study enrolled adults undergoing cardiac surgery at Chaim Sheba Medical Center (June 2020–January 2023) who had radial artery catheters for standard BP monitoring. Severe shock patients were excluded. Demographics and Fitzpatrick skin tone were recorded. ClinicalTrials.gov NCT04071015. Post-op, patients were simultaneously monitored with the standard IAP system and the Biobeat device. Continuous BP and HR were collected for up to five days. Data analyzed post hoc. Tested device The WP613 (Biobeat, Israel) is FDA-cleared, chest-worn, PPG-based device that uses multi-wavelength light and a sensor to monitor vital signs. It wirelessly transmits data to a cloud based algorithms to measure BP, cardiac output, stroke volume, and more. It also records a single-lead ECG and has a 5-day battery life. Results: A total of 96 patients were enrolled, with 88 included in the final BP analysis after excluding 8 due to technical issues. Of those, 80 received inotropic support. The average age was 63.2±12.2 years, with 33% female. Monitoring lasted an average of 25.6±17.2 hours, yielding over 78000 readings for each BP parameter and over 92000 HR readings (Fig 1) . Patients represented the full range of skin tones, classified using the Fitzpatrick scale I–VI. The Biobeat device showed excellent correlation with IAP monitoring: r=0.959 for SBP, 0.973 DBP, and 0.962 HR. Bland-Altman showed minimal bias (e.g., 0.1±4.8 for SBP) (Fig 2) . Correlation remained strong across BP ranges and skin tones. Heatmaps and representative cases confirmed close tracking between Biobeat and IAP (Fig 3) . Conclusion: The tested cuffless device (Biobeat) offers a high level of accuracy and agreement for BP and HR compared to data obtained by IAP monitoring in post-cardiac surgery patients. Further studies are needed to validate these findings in various populations and clinical settings.

Introduction: Photoplethysmography-based (PPG) devices represent a significant advancement in noninvasive cardiovascular monitoring. These cuffless technologies enable assessment of hemodynamic parameters with improved comfort, usability and compliance. Modern PPG systems have expanded their capabilities to include advanced metrics such as systemic vascular resistance (SVR) and cardiac output (CO). Many antihypertensive drugs lower blood pressure by reducing SVR through vasodilatation of the systemic and renal vasculature. Limited data is available on SVR during ambulatory monitoring. PPG devices become more common as they allow us to assess SVR in real life, in ambulatory blood pressure monitoring (ABPM) patients. Aim: To evaluate and compare SVR using the Biobeat (WP613) device across patient groups. Methods: Adults from the Hypertension Clinic at University of Miami, Florida, from Aug. 2023–Jan. 2025 underwent 24-h ABPM monitoring using Biobeat device. Patient data was matched with Biobeat. PPG data was available every 15 minutes; The raw data included SBP and DBP, the heart rate, stroke volume, CO and SVR. Results: A total of 539 patients underwent PPG ABPM during the study period. The median was 62 (IQR 54, 71) years, with 57% females (Tab 1) . Patients were defined as hypertensive per AHA 2017 guidelines [SBP≥130 and DBP≥80 mmHg]. Overall, 265 patients were classified as having normal BP, 95 as having isolated systolic hypertension, and 179 as having mixed hypertension. Within the Mix-HTN group, 42 patients had isolated diastolic hypertension and the remaining 137 systolic and diastolic hypertension (Fig 2) . In subgroup analysis (Fig 3); SVR was significantly different between the groups: lowerst in No/C-HTN and highest in Mix-HTN. particularly among the mixed-hypertension group, SVR was higher in the Systolic and Diastolic HTN compared to the Isolated diastolic HTN group. Among the No/C-HTN group, 60 patients were not hypertensives and 205, were hypertensives on at least 1 drug. The SVR was not statistically significant between these 2 subgroups, suggesting that SVR may be a helpful target biomarker used to up-titrate antihypertensives. Conclusion: PPG devices offer a valuable enhancement to conventional ABPM by providing additional physiological measurements such as SVR that can help differentiate between various hypertension phenotypes and potentially provide personalized therapy that target the driver of hypertension.