CART BP Pro-Guided Blood Pressure Management for Uncontrolled Hypertension

Hypertension remains one of the most prevalent chronic conditions worldwide and is a major contributor to cardiovascular morbidity and mortality. Although multiple antihypertensive medications are widely used, a substantial proportion of patients remain inadequately controlled. Office blood pressure measurements alone may not adequately reflect the true blood pressure burden or nocturnal blood pressure patterns. Ambulatory blood pressure monitoring provides a more comprehensive assessment of blood pressure variability and control but is limited by patient discomfort and practical constraints. Recently developed wearable cuffless blood pressure monitoring devices have the potential to provide continuous and convenient blood pressure assessment in real-world settings.

CART BP Pro is a wearable ring-type device that uses photoplethysmography-based technology to estimate continuous ambulatory blood pressure. Compared with conventional cuff-based ambulatory blood pressure monitoring, the device allows more comfortable long-term monitoring and may facilitate improved hypertension management.

This study is designed as a multicenter, prospective, open-label randomized controlled trial conducted at Korea University Anam Hospital, Korea University Guro Hospital, and Korea University Ansan Hospital. Adult patients with uncontrolled hypertension despite ongoing antihypertensive therapy will be enrolled and randomized to either CART BP Pro-guided management or usual care. In the intervention group, antihypertensive treatment adjustments will be guided by blood pressure information obtained from the CART BP Pro device. In the control group, treatment decisions will be based on conventional office blood pressure measurements according to standard clinical practice. The main blood pressure and safety assessment targets 24 weeks, with an allowable assessment window of 16-32 weeks. An optional extended follow-up to 48 weeks may be performed for additional observational analysis.

The study aims to determine whether CART BP Pro-guided blood pressure management improves ambulatory blood pressure control compared with usual care in real-world clinical practice.

Assessment timing and selection Randomization is Day 0. The target assessment is Day 168, with an allowable window of Days 112-224, inclusive. If multiple valid CART assessments are available, the assessment closest to Day 168 is selected; ties are resolved using the earlier assessment. Baseline CART monitoring is not required and its availability is not an eligibility condition for the primary analysis. Standardized upper-arm cuff office BP is assessed in both groups within the same follow-up window; an available office BP outcome is not discarded solely because CART monitoring is missing.

Recording calculation and quality control Monitoring targets 24 hours. The designated 24-hour window begins at the documented recording start and is divided into 24 consecutive 1-hour intervals. For each interval with at least one valid BP report, the interval mean is calculated. The time-weighted 24-hour estimate is the sum of available hourly means divided by the number of evaluable intervals, not by 24 when intervals are missing. Empty intervals are not set to zero or filled for this calculation. This is an estimate based on observed time intervals, not a reconstruction of unobserved BP.

For the primary analysis, recordings must have a recording duration of at least 20 hours, at least 17 evaluable hourly intervals, and no within-recording unobserved gap longer than 4 hours. Recording duration and within-recording gaps are determined from documented recording/device application and removal times when available. Time confirmed to occur after device removal is not counted as a within-recording signal-loss gap. When application/removal times are unavailable, the first-to-last valid-report span within the designated window is used as a duration proxy, with its limitation documented; early return is not inferred solely from the last BP report. Gaps while the device remains worn, including the start or end of the worn period when known, are distinguished from post-removal non-observation. Exact duplicate reports are removed, and timestamp conflicts or apparent technical errors are reviewed under documented data-cleaning rules. The same operational QC rules apply to both groups and all sites. These are study-defined criteria, not externally validated CART recording-quality standards.

Sleep and awake periods Period-specific BP outcomes use the participant sleep diary. In the export, a sleep label denotes asleep and a blank denotes awake. Sleep labels, unusually long sleep periods, and discrepancies are checked against the diary. Short or poor sleep alone is not a primary-recording QC failure. If the diary indicates sleep but no BP was captured during that period, timing and technical completeness are reviewed. The evaluability of sleep-period BP and dipping outcomes is considered separately from the 24-hour primary outcome. Follow-up sleep duration is not a covariate in the primary treatment-effect model.

Analysis and sensitivity analyses The primary observed-data analysis compares eligible follow-up CART SBP outcomes according to original randomized assignment, regardless of subsequent treatment changes. ANCOVA includes randomized group, pre-randomization office SBP, and study site. The study uses non-stratified block randomization; site is a baseline adjustment variable, not a randomization stratum. Post-randomization visit counts and medication intensification are not included as primary-model covariates. Participants without an evaluable primary outcome are not described as having an observed outcome. Missing-outcome counts and reasons, and recording QC failures, are reported by group and site; observed-data analysis does not by itself remove selection bias from missing outcomes.

Two recording-quality sensitivity analyses repeat the outcome comparison: (1) stricter recordings with at least 20 hours duration, at least 20 evaluable hourly intervals, and no within-recording gap longer than 3 hours; and (2) a relaxed recording criterion requiring at least 17 evaluable hourly intervals without the additional primary duration/gap restrictions. Separate missing-outcome sensitivity methods will be specified in the statistical analysis plan; they are distinct from the recording-quality comparisons and do not change measured values into imputed observations.

Secondary and exploratory outcomes The office SBP component of office BP change and office BP below 130/80 mmHg are key secondary efficacy outcomes. Additional secondary outcomes include 24-hour DBP, awake/asleep SBP and DBP, and the proportion with CART-derived 24-hour mean BP below conventional ABPM reference thresholds. BP load is retained as an exploratory outcome rather than deleted. Applying conventional ABPM thresholds to CART-derived values does not validate device-specific diagnostic thresholds. Safety observation continues from randomization through the designated final study assessment visit; actual observation duration is reported. Medication dose reduction alone is not an adverse event; the associated symptom or clinical abnormality, if present, is the event and the dose reduction is an action taken.

Registry clarification The operational recording-quality and endpoint-calculation details are clarified in this November 2026 registry update during the ongoing study. This update does not establish that these details were included at study initiation or replace the protocol/SAP amendment and ethics-review process.