Background Mild elevation in pulmonary artery pressure (PAP) is common in patients with lung disease. In COPD, 2 groups are defined; PH proportionate to degree of underlying lung disease and PH out of proportion (mPAP ≥ 40 mm Hg) occurring in a minority.
Aim To characterise survival and prognostic factors in patients with PH associated with lung disease.
Methods Single centre retrospective review of cardiac catheters performed 2001–2010 identified incident cases of PH associated with lung disease.
Results 155 patients had a primary diagnosis of PH associated with lung disease, 96 with COPD (57 PH out of proportion to COPD, 39 PH proportionate to COPD), 31 PH in interstitial lung disease (PH-ILD) and 28 PH with sleep disordered breathing / alveolar hypoventilation. Survival is shown in Abstract P39 Figure 1. Right heart pressures were most raised in patients with PH out of proportion to COPD compared to PH-ILD and PH in proportion to COPD with mRAP 12.3, 8.5 and 8.2 mm Hg (p<0.05) and mPAP 49.4, 38.6 and 32.3 mm Hg (p<0.01) respectively. In patients with PH associated with sleep disordered breathing/alveolar hypoventilation mRAP was 11.6 and mPAP 37.8 mm Hg. Cardiac index and PVR were similar in PH out of proportion to COPD and PH-ILD but markedly reduced in both groups when compared to PH in proportion to COPD (p<0.01). Baseline shuttle walking distance was most reduced in PH out of proportion to COPD with mean 67 m compared to 133 m in PH-ILD and 156 m in PH in proportion to COPD (p<0.05). In COPD, airflow obstruction was less severe in patients with out of proportion PH than COPD with proportionate PH (FEV1 63% vs 51% respectively) but TLCO was more severely affected (26% vs 38%).
Conclusions The survival of patients with PH in association with lung disease is dependent on the underlying aetiology. Whereas patients with PH associated with sleep disordered breathing/alveolar hypoventilation have a good prognosis, patients with PH in the setting of ILD and PH out of proportion to COPD have a poor prognosis.