A PRACTICAL EQUATION TO PREDICT PEAK OXYGEN UPTAKE IN PATIENTS WITH INTERMITTENT CLAUDICATION 503

Abstract

Measurement of peak oxygen uptake (VO2) in peripheral arterial occlusive disease (PAOD) patients is desirable because it gives an accurate estimate of functional capacity. However, not all facilities have access to the equipment necessary for its assessment. Thus, the ability to predict peak VO2 in a heterogeneous cohort of 206 PAOD patients (age = 69.1 ± 6.4 yrs; Mean ± SD) from resting and exercise measures was examined. Resting ankle/brachial systolic pressure index (ABI = 0.66 ± 0.23) in the more severely diseased leg, body mass index (BMI = 26.2 ± 4.1), and a medical history were taken prior to a progressive treadmill protocol (2 mph, 0% grade with 2% increase every 2 min). Maximal claudication pain time (MCPT = 411 ± 202 sec), maximal heart rate (MHR = 109 ± 18 b/min), and ABI immediately following exercise (0.30 ± 0.27) were recorded. Peak VO2 (13.1 ± 2.8 ml/kg/min) was predicted by MCPT, BMI, race(Caucasian = 1, African-American = 2), MHR, and gender (male = 1, female = 2) from the following regression equation: Peak VO2 (ml/kg/min) = 12.6 + (0.0071 × MCPT) - (1.7 × race) + (0.030 × MHR) - (0.096 × BMI) - (0.96 × gender); R = 0.68, R2 = 0.47, adjusted R2 = 0.46, SEE = 2.03, p < 0.0001. In conclusion, peak VO2 can be estimated to within ± 2 ml/kg/min in PAOD patients from readily obtained variables in clinical settings where its measurement is not routinely performed.