Conference: 2012 International PHA Conference and Scientific Sessions
Release Date: 06.22.2012
Presentation Type: Abstracts
Godara, G, Cohen MC, Atherton D, Hacobian M, and Wirth JA.
Division of Pulmonary & Critical Care Medicine and Department of Cardiac Services. Maine Medical Center, Portland, ME 04102 USA
BACKGROUND: Prognosis in PAH is associated with right ventricular (RV) dysfunction and reduced exercise. We investigated RV morphometric and function parameters using recumbent exercise stress echocardiography (ESE) in otherwise stable PAH subjects (WHO FC I-II) to assess whether exercise RV parameters correlated with eventual clinical worsening events.
METHODS: Subjects with WHO FC I-II PAH due to a variety of etiologies were enrolled. We used a Phillips IB 33 ultrasound and recumbent bicycle ergometer for exercise in incremental stages of 25 watts every 3 minutes. Heart rate and blood pressure were recorded in each stage and the test was considered complete at a rate-pressure product (RPP) of 20,000. Tests were terminated early if subjects developed limiting symptoms. Echocardiographic values for RV diameters (basal diameter - BD, mid-ventricular diameter - MD, and longitudinal diameter - LD), RV areas (RV end diastolic area - RVEDA, and RV end systolic area - RVESA) and fractional area change (FAC) were obtained at rest and during exercise. Following the index ESE, test subjects were followed 1 year for evidence of clinical worsening (CW), defined as death, hospitalization, lung transplantation, or a sustained decline in 6 minute walk test by at least 20%. The CW and stable PAH subject groups were subsequently compared with respect to RV ESE characteristics. Statistical differences were considered significant at p < 0.05.
RESULTS: Twenty subjects with PAH (WHO FC I-II) established by Dana Point criteria were enrolled. There were no statistically significant differences in baseline clinical characteristics or exercise performance measures between the groups. During the one year follow up period, 3/20 subjects developed CW. We observed CW PAH subjects had significantly larger RV diastolic diameters, RVEDA and RVESA than the stable PAH subjects at rest (p < 0.05) and during exercise (p < 0.01). RV FAC did not change significantly in the stable PAH subjects during exercise (1.3 % increase, p=0.53), but decreased significantly during exercise in the CW PAH Subjects (l8.3% decline, p=0.033).
CONCLUSION: PAH subjects at risk for clinical worsening demonstrated significant larger RV sizes and a significant decline in RV FAC during exercise. RV size and functional measurements at during exercise provide important prognostic information in patients with PAH. Measurements obtained during exercise had higher predictive value than those obtained at rest.