Pulmonary Arterial Hypertension-Specific Drug Therapy in COPD Patients with Severe Pulmonary Hypertension and Mild-to-Moderate Airflow Limitation

Abstract

Background: Patients with severe pulmonary hypertension (PH) associated with chronic obstructive pulmonary disease (COPD) present a poor outcome. Specific PH treatment could improve the clinical and hemodynamic status of these patients but may worsen arterial blood gases. Objectives: Our study retrospectively included 28 patients with severe precapillary PH (mean pulmonary arterial pressure >35 mm Hg) associated with mild-to-moderate COPD [forced expiratory volume in 1 s (FEV₁) >50% predicted]. All patients underwent specific pulmonary arterial hypertension (PAH) treatment as mono-, bi- or triple therapy. Methods: Our single-center study was conducted based on retrospective data of 537 right heart catheterizations (RHCs) performed on patients with COPD from January 2004 to June 2014. An echocardiography, comprehensive blood tests, pulmonary function tests, and a high-resolution computed tomography were performed before the RHCs. All patients underwent RHC with a Swan-Ganz catheter. Results: Compared to baseline, patients treated with specific PAH drugs showed a significant increase in cardiac index at long term (2.5 ± 0.7 liters/min/m² at baseline vs. 3.2 ± 0.6 liters/min/m² at 6/12 months; p = 0.003) as well as a decrease in pulmonary vascular resistance in the long term (8.4 ± 4.2 Wood units at baseline vs. 5 ± 1.7 Wood units at 6/12 months; p = 0.008). There was a slight decrease in arterial oxygen tension (Pa<smlcap>O</smlcap>₂) after 3 months of treatment (-2.4 ± 7.21 mm Hg; p = 0.066). During a median follow-up of 3 years, 12 patients (42.8%) died (including all causes of death). Conclusions: This preliminary report suggests that the use of specific PH therapy in severe PH associated with mild-to-moderate COPD can improve pulmonary hemodynamic parameters, with worsening of Pa<smlcap>O</smlcap>₂, which had no clinical significance and did not lead to specific PAH therapy withdrawal in any patient.