Tidal CO2 prognostic for chronic thromboembolic pulmonary HTN

(HealthDay)—End-tidal carbon dioxide (ETCO₂) levels are prognostic for patients with chronic thromboembolic pulmonary hypertension (CTEPH), according to a letter to the editor published online Aug. 14 in the Annals of the American Thoracic Society.

Manuel J. Richter, M.D., from the Kerckhoff Heart and Thoracic Center in Bad Nauheim, Germany, and colleagues retrospectively analyzed data from the Giessen Pulmonary Hypertension Registry for 151 patients with inoperable CTEPH. Baseline ETCO₂ levels obtained at rest were available for all patients.

The researchers found that 27.2 percent of the patients died during a mean follow-up of 64.8 ± 40.2 months. The median ETCO₂ at baseline was 27 mm Hg, which was substantially decreased. ETCO₂ was related to overall survival as a continuous variable in univariate analysis (hazard ratio, 0.91). Significantly impaired pulmonary hemodynamics and a more advanced functional class were seen for patients with inoperable CTEPH who had ETCO₂ <29 mm Hg compared with ≥29 mm Hg. There was a significant correlation for ETCO₂ dichotomized at 29 mm Hg with overall survival (hazard ratio, 0.37). Five-year overall survival was significantly better for patients with inoperable CTEPH and ETCO₂ ≥29 mm Hg versus <29 mm Hg (89.3 versus 73.2 percent).

"ETCO₂ emerged as a clinically relevant prognostic factor not only in pulmonary arterial hypertension but also in inoperable CTEPH, mirroring the presence of ventilation/perfusion mismatch as a pathophysiological hallmark in both disease entities," the authors write.

Several authors disclosed financial ties to the pharmaceutical industry.

Copyright © 2017 HealthDay. All rights reserved.