PURPOSE: To determine the variability in pulmonary vascular resistance (PVR) in patients with pulmonary hypertension.
METHODS: We performed a retrospective review of our systemic sclerosis database to identify patients with pulmonary hypertension diagnosed since 2008. We reviewed hemodynamic measurements including mean pulmonary artery pressure, pulmonary capillary wedge pressure, cardiac output and PVR. The variability of PVR was assessed for each patient by considering the standard deviation and coefficient of variation of the repeated measures during a single right heart catheterization.
RESULTS: There were 26 patients that met criteria. The group's aggregate mean, median and first and third quartiles for PVR were 3.9, 2.5, 2.1, and 5.3 Wood units, respectively. The mean, median and first and third quartile values for the individual standard deviation from the aggregate PVR were 0.54, 0.43, 0.22, and 0.74 Wood units, respectively. The coefficient of variation mean, median and first and third quartile values for individual coefficient of variation from the aggregate PVR were 0.18, 0.14, 0.10, and 0.19 Wood units, respectively.
CONCLUSIONS: Our results suggest that changes in PVR must exceed 14 to 18% in order to be clinically significant for patients with pulmonary hypertension associated with systemic sclerosis.
CLINICAL IMPLICATIONS: The baseline individual variability of PVR should be considered prior to use of PVR as an outcome measure in pharmacological studies.
DISCLOSURE: The following authors have nothing to disclose: Nathan Hatton, Tracy Frech, Allen Sawitzke, Theodore Liou, Boaz Markewitz
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