Mixed Venous Oxygen Saturation Is a Better Prognosticator Than Cardiac Index in Pulmonary Arterial Hypertension.

Background: European Society of Cardiology (ESC) and European Respiratory Society (ERS) guidelines include thermodilution cardiac index (TDCI) and mixed venous oxygen saturation (SvO2) as two of the three hemodynamic determinations used in risk assessment of patients with pulmonary arterial hypertension (PAH). SvO2 may be a better measurement than TDCI to assess prognosis in patients with either idiopathic or heritable PAH.Research Question: What is the concordance between TDCI and SvO2 ESC/ERS risk group allocation and their prognostic value in patients with PAH?Study Design and Methods: In this retrospective study, we assessed the correlation between SvO2 and TDCI in patients with idiopathic and heritable PAH. We determined concordance in the ESC/ERS risk group allocation and association with survival, both at baseline and follow-up.Results: A total of 158 patients (mean age, 58 ± 17 years; 72% women) with idiopathic (91%) and heritable (9%) PAH were included. There was moderate association between TDCI and SvO2 (r = 0.50; 95% CI, 0.37-0.62). Weighted kappa revealed a fair agreement between TDCI and SvO2 (κ = 0.30; 95% CI, 0.18-0.42), with concordance in risk group allocation in 49% of patients. During a median follow-up of 45 months (interquartile range, 23-105), 62 patients (39%) died. Using Kaplan-Meier analysis, survival was impacted by the SvO2 (log rank = 0.002) but not by the TDCI risk group allocation (log-rank = 0.51). Using the Cox proportional hazard model, adjusted for age and sex, SvO2 (but not TDCI) was associated with mortality (hazard ratio per 1% change, 0.94; 95% CI, 0.91-0.97; P < .001).Interpretation: When using the cutoffs proposed by the ESC/ERS guidelines, we noted poor concordance in risk score allocation between TDCI and SvO2. In patients with idiopathic or heritable PAH, SvO2 measurements are superior to TDCI in predicting long-term mortality. [ABSTRACT FROM AUTHOR]

Copyright of CHEST is the property of American College of Chest Physicians and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)