Skip to content

Back to digital biomarkers

Digital Biomarker

eVO2peak

CPET-level cardiopulmonary insight without the stress test — a continuous, FDA-cleared estimate of peak oxygen uptake derived from ECG and vital-sign dynamics during activities of daily living.

  • FDA-cleared · 510(k) K252204
  • Validated against CPET
  • Continuous & at-home

Overview

An objective, high-fidelity measure of cardiopulmonary functional capacity.

CPET is the gold standard for measuring peak VO2 in patients with cardiovascular disease, but it requires specialized resources and a strenuous exercise protocol that many patients cannot safely complete. eVO2peak replaces that test with a continuous, at-home estimate built from routine activity.

  • Estimation of peak VO2 from ECG and vital-sign dynamics during activities of daily living — no strenuous activity required of the patient.
  • Generates an eVO2peak estimate from each sliding 7-day window of patch data, enabling daily trend analyses.
  • Replaces the 6-minute walk test, a low-resolution CPET substitute used ubiquitously in trials.
  • Provides additional insight between standard CPETs, enabling a better understanding of trends and variability.

Validation cohort

262

Participants

Healthy participants, patients undergoing standard-of-care CPET, and patients with heart failure. eVO2peak correlated with CPET peak VO2 across a wide range of peak VO2 values.

eVO2peak vs. CPET-derived VO2 Peak

Scatter plot of estimated vs. CPET peak VO2 showing tight clustering along the line of unity across the validation cohort.
Estimated vs. actual peak VO2 across the 262-participant cohort, clustering tightly along the line of unity.

Bland–Altman agreement plot.

Bland-Altman plot showing the difference between actual and estimated peak VO2 stays within plus or minus 1.96 standard deviations across the full range.
The difference between actual and estimated peak VO2 stays within ±1.96 SD across the full range.

Clinical outcomes

Early changes in eVO2peak predict outcomes in heart failure.

In patients with HF, changes in eVO2peak within three weeks of hospital discharge were associated with subsequent risk of unplanned hospitalization, ER visit, or death. Bicycle CPET modality.

  • p = 0.0208

    Associated with adverse events post-discharge

    Changes in eVO2peak within three weeks of hospital discharge were associated with subsequent risk of unplanned hospitalization, ER visit, or death.

  • p = 0.0034

    Decline tracks with worse outcomes

    Patients experiencing adverse clinical outcomes tended to show decreased — vs stable or increased — eVO2peak from weeks 1 to 3 post-hospitalization.

Event vs. no-event groups (p = 0.0034)

Mean change in eVO2peak from weeks 1 to 3 post-hospitalization, comparing patients with and without a subsequent event
Event vs. no-event groups (p = 0.0034). Patients without subsequent events trended upward.

Survival by Δ eVO2peak at week 3

Event-free survival curves stratified by change in eVO2peak after hospital discharge
Event-free survival stratified by change in eVO2peak.

CPET vs eVO2peak

Continuous, at-home insight in place of a strenuous lab test.

Many patients cannot safely perform maximal exercise tests. eVO2peak is derived from routine activity, making it suitable for the populations most often excluded from CPET-based endpoints.

Standard CPET

Lab-based stress test

  • Requires specialized clinic equipment and trained staff.
  • Strenuous exercise protocol — not safe for many patients.
  • Often unsuitable for elderly, advanced HF, pulmonary disease, or frail populations.
  • Typically yields 2–3 measurements over the course of a study.

eVO2peak

Continuous at-home estimate

  • Derived from routine activity — no strenuous exertion required.
  • Suitable for elderly populations, advanced HF, pulmonary disease, and frail patients.
  • Dozens of objective functional measurements per participant.
  • Supports improved endpoint sensitivity, smaller sample sizes, and earlier signal detection.

Active trials

Assessed in Kardigan clinical trials across multiple cardiovascular disorders.

eVO2peak is currently in use as a digital endpoint across three Kardigan-initiated programs, plus Prolaio’s own OCORO Heart Study.

Observational

OCORO Heart Study

Decentralized, at-home cardiovascular cohort capturing continuous real-world data.

NCT07420907

Phase 2/3

KINSHIP-DCM

Symptomatic genetic and familial dilated cardiomyopathy.

NCT07210723

Phase 2/3

KATALYST-AV

Moderate calcific aortic valve stenosis.

NCT07001800

Phase 2

KARDINAL

Uncontrolled hypertension.

NCT06864104

More from the library

Other validated biomarkers.

FDA Cleared

Multivariate Change Index

Composite signal that flags meaningful physiologic change across multiple vitals at once, surfacing decompensation days earlier than any single biomarker.

View

FDA Cleared

AFib Burden

Continuous quantification of atrial fibrillation episodes and time spent in AFib, enabling stroke-risk stratification and treatment-response tracking.

View

FDA Cleared

Heart Rate Variability

Beat-to-beat HRV measurement that captures autonomic-function shifts in heart failure, diabetes, and stress states.

View

See all biomarkers

Partner with us

Bring this biomarker into your cardiovascular trial.

Talk to our team about fitting a Prolaio digital endpoint to your protocol — from concept through regulatory submission.

Talk to our research team