Conference: 2012 International PHA Conference and Scientific Sessions
Release Date: 06.22.2012
Presentation Type: Abstracts
D Rancourt, MC Cohen, D Atherton and JA Wirth
Maine Medical Center, Portland ME, USA
BACKGROUND: Survival in patients with pulmonary arterial hypertension (PAH) correlates with exercise capacity as measured by cardiopulmonary exercise testing and six minute walking distance testing. It is not know whether exercise performed by recumbent exercise stress ergometry (ESE) demonstrates similar clinical correlates. The purpose of this study was to determine if exercise performance measured during recumbent ESE correlated to PAH disease severity or PAH progression.
METHODS: Participants underwent recumbent exercise stress ergometry testing using a standardized protocol. We used a Philips IE 33 Ultrasound (Philips Corporation, Andover, MA) and a recumbent bicycle ergometer (Medical Positioning, Kansas City, MO) for exercise in incremental stages. A sonographer, exercise technician and cardiologist were present for testing. Continuous EKG, HR, BP, Sp02, and wattage were recorded at 25W intervals (3 minutes per stage) during exercise and each minute during recovery). Tests were symptom limited and considered diagnostic at a RatePressure product (RPP) of 20,000 following safety limits per ACC/AHA guidelines. Subjects were subsequently monitored for 12 months and evaluated for evidence of PAH clinical worsening (CW). The baseline exercise parameters from the ESE studies in the CW and non-CW groups were analyzed using Students t-test or Fisher exact test and considered statistically significant at the p <0.05 level.
RESULTS: We studied 20 patients with WHO FC I-II PAH. All subjects exercised per protocol without any serious adverse events. The targeted RPP was reached by 72% of patients and the others were symptom-limited. The rate of symptom-limited tests was similar in the stable PAH (5/17) and CW PAH (1/3) subject groups (p = 1.0). Stable PAH subjects achieved a higher median RPP (22181 vs. 20860), maximum workload (125 watts vs. 50 watts) and duration of exercise (15 min vs. 6 min) than PAH subjects who had CW, although none of these differences reached statistical significance, PAH subjects with CW demonstrated a higher HR at peak exercise (136 bpm vs. 116 bpm), slower HR recovery and lower maximum SBP (164 vs. 156) although none of these parameters met statistical significance.
CONCLUSION: Exercise characteristics of WHO Functional Class I-II PAH patients by recumbent exercise stress ergometry demonstrates similar patterns to exercise performed by other methods reported in the literature. However, exercise characteristics of WHO Functional Class I-II PAH patients obtained using ESE are not strong predictors of subsequent PAH clinical deterioration.