SESSION TITLE: DVT/PE/Pulmonary Hypertension Posters
SESSION TYPE: Original Investigation Poster
PRESENTED ON: Wednesday, October 30, 2013 at 01:30 PM - 02:30 PM
PURPOSE: Conflicting data exist about the utility of diffusing capacity for carbon monoxide (DLCO) in prediction of severity/presence of pulmonary hypertension (PH). One reason for this might be that corrections for lung volume and hemoglobin (Hb) concentration have not been rigorously applied in such analyses. The purpose of this study is to determine whether correcting DLCO for hemoglobin (Hb) and alveolar volume (VA) predicts the presence and severity of PH.
METHODS: Retrospectively, we evaluated consecutive patients with age >18 years and absence of systolic heart failure (EF<55%), who had right heart catheterization, pulmonary function test (PFT), and complete blood count performed between 2002-2012, and within 6 months of each other. Pulmonary artery systolic pressure (PASP), mean pulmonary artery pressure (mPAP), pulmonary vascular resistance (PVR), six minute walking distance (6MWD), and Pro-BNP levels were correlated against percent -predicted DLCO (DLCO%), with or without correction for VA and Hb.
RESULTS: A total of 62 subjects were identified, predominantly females (81%) with mean age of 59 years. Hb ranged from 8 to 17 gm/dl and averaged 8.1±2.0 gm/dl. PASP and mPAP were significantly but weakly correlated with DLCO% (R= -.303 and -.307, respectively), but PVR, and proBNP were not. Correcting DLCO for hemoglobin with the Marrades equations (AJRCCM 1997) did not improve the correlation, but correcting with the Coates equations (Clin Sci 1972) improved the correlation slightly (r=-.312 for PASP, P=0.016 and -.318 for mPAP, P= 0.013), and approached statistical significance for PVR (r=-.688, P=0.010) and 6MWD (r =-.343,P=0.037). Correcting DLCO for alveolar volume did not significantly improve the correlations.
CONCLUSIONS: In patients with precapillary pulmonary hypertension, the severity of PH is weakly inversely correlated with percent predicted DLCO, and this correlation is not substantially improved by correction for alveolar volume or hemoglobin. The Coates equations demonstrated better Hb-correction than did the Marrades equations.
CLINICAL IMPLICATIONS: Corrected diffusing capacity is a weak surrogate for prediction of severity of PH, however reduced corrected diffusing capacity warrants further invasive diagnostic evaluation.
DISCLOSURE: The following authors have nothing to disclose: Amit Chopra, Aanchal Gupta, Josanna Rodriguez, Thomas Aldrich
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