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

Abstract

BackgroundCardiopulmonary exercise testing by cycle ergometry (CPETleg) is an established assessment tool of perioperative physical fitness. CPET utilizing arm ergometry (CPETarm) is an attractive alternative in patients with lower limb dysfunction. We aimed to determine whether oxygen uptake ( Vċo2) obtained by CPETleg could be predicted by using CPETarm alone and whether CPETarm could be used in perioperative risk stratification. MethodsSubjects underwent CPETarm and CPETleg. To evaluate the ability of Vċo2 obtained from CPETarm to predict Vċo2 from CPETleg, 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. ResultsWe recruited 20 vascular surgery patients (17 males and three females) and 20 healthy volunteers (10 males and 10 females). In both groups, PIs for Vċo2 at θ∧L and peak were wider than clinically acceptable (patient group— Vċo2 at θ∧L CPETarm ranged from 55% to 108% of CPETleg and from 54% to 105% at peak; healthy volunteers—37–77% and 41–79%, respectively). The area under the ROC for CPETarmVċo2 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. ConclusionsAlthough a relationship exists between Vċo2 values for CPETarm and CPETleg, this is insufficient for accurate prediction using CPETarm alone. This however does not necessarily preclude the use of CPETarm in perioperative risk stratification.