Exploring maximality criteria of cardiopulmonary exercise testing in healthy subjects and patients with chronic respiratory disease: a practical clinical framework.

BACKGROUND

Incremental cardiopulmonary exercise testing (CPET) is used to assess exercise capacity and identify mechanisms of exercise limitation. Identification of test maximality is essential for correct interpretation, yet no consensus exists on the defining criteria. This study evaluated the performance of different V̇O2 plateau definitions and the contribution of secondary maximality criteria in patients with chronic respiratory disease and healthy controls.

STUDY DESIGN AND

METHODS

We retrospectively analyzed 395 CPETs (84 healthy, 135 COPD, 99 ILD, 77 pulmonary hypertension), comparing consensus-based visual identification of a V̇O₂ plateau by three pulmonologists with three commonly used plateau definitions. Additionally, five secondary maximality criteria were evaluated, using strict and liberal thresholds.

RESULTS

The relative V̇O2 plateau definition showed strong agreement with visual assessment (κ = 0.75-0.93), while absolute thresholds were discordant (κ = 0.02-0.31). Overlap between maximality criteria was high in healthy individuals but low in disease groups, suggesting that evaluating multiple criteria in parallel is necessary. However, combining more than two secondary criteria in healthy subjects and more than three in patients on top of V̇O2 plateau provided minimal additive value.

CONCLUSION

CPET maximality assessment depends strongly on the criteria applied, potentially altering CPET interpretation and clinical decision-making.