Comparison of oxygen uptake during arm or leg cardiopulmonary exercise testing in vascular surgery patients and control subjects

Background: Cardiopulmonary exercise testing by cycle ergometry (CPET(leg)) is an established assessment tool of perioperative physical fitness. CPET utilizing arm ergometry (CPET(arm)) is an attractive alternative in patients with lower limb dysfunction. We aimed to determine whether oxygen uptake obtained by CPET(leg) could be predicted by using CPET(arm) alone and whether CPET(arm) could be used in perioperative risk stratification.

Methods: Subjects underwent CPET(arm) and CPET(leg). To evaluate the ability of VO₂ obtained from CPET(arm) to predict VO₂ from CPET(leg), we calculated prediction intervals (PIs) at lactate threshold θ(L) and peak exercise in both groups. Receiver operating characteristic (ROC) curves were used to risk stratify patients into high and low categories based on published criteria.

Results: We recruited 20 vascular surgery patients (17 males and three females) and 20 healthy volunteers (10 males and 10 females). In both groups, PIs for at and peak were wider than clinically acceptable (patient group - VO₂ at θ(L) CPET(arm) ranged from 55% to 108% of CPET(leg) and from 54% to 105% at peak; healthy volunteers - 37-77% and 41-79%, respectively). The area under the ROC for CPET(arm) VO₂ in patients was 0.84 [95% confidence interval (CI): 0.66, 1.0] at θ(L), and 0.76 (95% CI: 0.54, 0.99) at peak.

Conclusions: Although a relationship exists between VO₂ values for CPET(arm) and CPET(leg), this is insufficient for accurate prediction using CPET(arm) alone. This however does not necessarily preclude the use of CPET(arm) in perioperative risk stratification.