Feasibility and Effectiveness of a Ring-Type Blood Pressure Device (CART-BP) Compared With 24-Hour Ambulatory Blood Pressure Monitoring in HFrEF (RING-HFrEF)

Feasibility and Effectiveness of a RING-type Blood Pressure Measurement Device (CART-BP) Compared With 24-Hour Ambulatory Blood Pressure Monitoring Device in Patients With Heart Failure With Reduced Ejection Fraction (RING-HFrEF)

This study aims to evaluate the feasibility and diagnostic accuracy of the CART-BP ring-type wearable blood pressure monitoring device in comparison with 24-hour ambulatory blood pressure monitoring (ABPM) in patients with heart failure with reduced ejection fraction (HFrEF, LVEF ≤ 40%). As a multi-center, prospective, exploratory study, 100 patients will be enrolled at two tertiary hospitals in South Korea. The agreement between the two devices in 24-hour mean, daytime, and nighttime blood pressure measurements will be assessed per ISO 81060-2:2018 criteria.

Study Overview

• Status: Recruiting
• Conditions: Heart Failure With Reduced Ejection Fraction; Hypertension

Detailed Description

Hypertension is a major risk factor and exacerbating cause of heart failure. Accurate blood pressure monitoring in HFrEF patients is critically important, as reduced left ventricular stroke volume and altered peripheral vascular hemodynamics may affect the accuracy of photoplethysmography (PPG)-based blood pressure measurement.

The CART-BP device uses PPG technology in a ring form factor to enable continuous, non-invasive blood pressure monitoring. This study will simultaneously measure blood pressure using CART-BP and standard 24-hour ABPM over a 24-hour period. Agreement will be assessed using ISO 81060-2:2018 Criteria 1 and 2. An interim analysis will be conducted after 40 participants are enrolled to assess preliminary agreement and determine whether to continue to the full enrollment of 100 participants.

• Study Type: Observational
• Enrollment (Estimated): 100

Contacts and Locations

• Study Contact: Name: In-Cheol Kim; Phone Number: 82-53-258-4629; Email: kimic@dsmc.or.kr

Study Locations

• South Korea
  • Daegu, South Korea, 42601
    • Recruiting
    • Keimyung University Dongsan Medical Center
    • Contact: Hyemin Kwon; Phone Number: 82-53-258-6691; Email: irbdsmc@naver.com

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

Heart Failure with Reduced Ejection Fraction patients

Description

Inclusion Criteria:

1. Age ≥ 19 years (male or female)
2. Diagnosed with heart failure and currently under treatment
3. Left ventricular ejection fraction (LVEF) ≤ 40% confirmed by echocardiography performed within 1 year prior to enrollment
4. Able to undergo both 24-hour ambulatory blood pressure monitoring and ring-type blood pressure measurement
5. Voluntarily provided written informed consent to participate in this clinical study

Exclusion Criteria:

1. Office blood pressure: SBP < 90 mmHg, or DBP < 50 mmHg, or SBP > 180 mmHg, or DBP > 100 mmHg
2. Unable to perform 24-hour ambulatory blood pressure monitoring
3. Unable to wear or use the ring-type blood pressure device
4. Variability in three consecutive resting cuff blood pressure measurements ≥ 20 mmHg (SBP) or ≥ 10 mmHg (DBP)
5. Insufficient valid ABPM readings: < 25 daytime or < 12 nighttime measurements per ESH criteria; or < 25 daytime or < 12 nighttime valid readings from the ring-type device
6. Pregnant, suspected pregnancy, or breastfeeding
7. Judged by the investigator to be legally or mentally unfit to participate in the clinical study

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort
Heart failure with reduced ejection fraction; Heart failure with reduced ejection fraction with or without hypertension

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Agreement between CART-BP and ABPM in 24-hour mean systolic and diastolic blood pressure	Agreement between the CART-BP ring-type device and the 24-hour ABPM for mean 24-hour systolic blood pressure (SBP) and diastolic blood pressure (DBP), evaluated according to ISO 81060-2:2018 Criteria 1 and 2 (Opposite arm simultaneous method, section 5.2.4.2.2)	24 hours

Secondary Outcome Measures

Outcome Measure	Time Frame
Agreement in daytime mean SBP and DBP between CART-BP and ABPM	24 hours
Agreement in nighttime mean SBP and DBP between CART-BP and ABPM	24 hours
Agreement in blood pressure dipping pattern between CART-BP and ABPM	24 hours
Blood pressure variability (standard deviation) agreement between devices	24 hours
Measurement adherence rate of ABPM (target: ≥ 80% valid readings in total enrolled patients)	24 hours
Measurement adherence rate of CART-BP (target: ≥ 80% valid readings in total enrolled patients)	24 hours

Collaborators and Investigators

• Sponsor: Keimyung University Dongsan Medical Center

Study record dates

Study Major Dates

• Study Start (Actual): October 23, 2025
• Primary Completion (Estimated): October 22, 2026
• Study Completion (Estimated): October 22, 2026

Study Registration Dates

• First Submitted: May 29, 2026
• First Submitted That Met QC Criteria: May 29, 2026
• First Posted (Actual): June 4, 2026

Study Record Updates

• Last Update Posted (Actual): June 4, 2026
• Last Update Submitted That Met QC Criteria: May 29, 2026
• Last Verified: November 1, 2025

More Information

Terms related to this study

• Keywords: HFrEF, ambulatory blood pressure monitoring, ABPM, wearable device, ring-type blood pressure, photoplethysmography, PPG, blood pressure validation
• Additional Relevant MeSH Terms: Vascular Diseases; Cardiovascular Diseases; Hypertension
• Other Study ID Numbers: 2025-10-039-005

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No