Cardiopulmonary Function Assessment Scores (CPET)

CPET Composite Risk Index (HFREF & HFPEF) Calculator

Clinical calculation support · Verify results before clinical use

CPET Parameter Summary

Enter the patient's cardiopulmonary exercise test values. The count below reflects the original code's thresholds only; it is not a validated prognostic score.

—Flags
Peak oxygen uptake, as reported by the CPET laboratory.
mL/kg/min
Enter the slope value reported on the CPET interpretation.
unitless
Heart rate decrease from peak exercise to 1 minute of recovery; follow the laboratory's protocol.
bpm
Use the ratio convention reported by the laboratory (for example, 0.70 rather than 70%).
ratio
—Flags
Threshold count from original code

Enter all four values

No count is shown until every field contains a valid value.

Clinical caution: This count must not be interpreted as low, intermediate, or high risk. The thresholds and four-variable combination have not been established here as a validated composite model.

About this calculator

The original PHP code counted one flag for each of four thresholds: Peak VO₂ <14 mL/kg/min, VE/VCO₂ slope >34, 1-minute heart rate recovery <12 bpm, and VE/MVV ratio >0.7. It then assigned low, intermediate, or high risk categories.

Those risk categories are not retained because the supplied code does not demonstrate that this four-variable rule is a validated prognostic model. The current page displays a descriptive threshold count only, not an estimate of mortality or clinical outcome.

Thresholds used for the descriptive count

  • Peak VO₂ <14 mL/kg/min
  • VE/VCO₂ slope >34
  • Heart rate recovery at 1 minute <12 bpm
  • VE/MVV ratio >0.7, when entered as a ratio

These thresholds are preserved from the original implementation for transparency. Their applicability to an individual patient and the exact measurement conventions require clinical confirmation.

Evidence and limitations

Wilson JR, et al. A Composite Cardiopulmonary Exercise Test Risk Score in Heart Failure with Reduced and Preserved Ejection Fraction.

JACC: Heart Failure. 2016;4(11):882–892.

https://doi.org/10.1016/j.jchf.2016.07.002
Validation of a Cardiopulmonary Exercise Test Score in Heart Failure.

The published validation model describes a weighted score using VE/VCO₂ slope, heart rate recovery, oxygen uptake efficiency slope, end-tidal CO₂ pressure, and peak VO₂. This differs from the four-variable equal-weight count in the supplied PHP file.

Read the open-access article
Clinical disclaimer: This tool provides a descriptive count of entered CPET thresholds and is not a validated prognostic calculator. It does not replace the complete CPET report, clinical assessment, guideline-based risk stratification, or specialist interpretation. Do not use the count alone to make treatment, transplant, or advanced heart failure therapy decisions.
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