Baseline characteristics and survival of patients with pulmonary hypertension in interstitial lung disease in the "HYPID" study

Abstract

Background. Pulmonary hypertension (PH) in patients with interstitial lung disease (ILD) is frequent and associated with a shorter survival.

Objective. To study the clinical, pulmonary function, haemodynamic characteristics, and survival in a large cohort of patients with ILD-PH at right heart catheterization.

Methods. A prospective multicenter observational study (HYPID) was initiated in July 2010 in French expert centers for rare pulmonary diseases and/or PH (NCT01443598).

Results. Out of 220 patients included (mean age 63 ±10 years; 135 males), ILD was idiopathic pulmonary fibrosis (n=37), combined pulmonary fibrosis and emphysema syndrome (n=51), systemic sclerosis with ILD (n=38), sarcoidosis (n=33), and other ILD (n=61). NYHA class was I-II in 19% of patients, III in 59%, IV in 20%, N/A in 2%. Six-min walk distance was 282 ± 147m. Hemodynamic characteristics were mean pulmonary arterial pressure (mPAP) 39 ± 10 mmHg, cardiac index (CI) 2.7 ± 0.7 L/min/m², and pulmonary vascular resistance (PVR) 542 ± 265 dyn.s.cm-5. mPAP was ≥35 mmHg in 59% of the cases and ≥40 mmHg in 40% of the cases. PVR poorly correlated with FVC (r=0.516, p=0.028) or PaO2 (r=0.593, P=0.007). mPAP poorly correlated with FVC (r=0.587, p=0.007) and PaO2 (r=0.593, P=0.007). The median time to death or transplant was 3.85 years, with no significant difference between patients with mPAP < or ≥ 35 or 40 mmHg.

Conclusion. Hemodynamic characteristics do not correlate with pulmonary function in ILD-PH. Preliminary data suggest that the level of mPAP (< or ≥ 35 or 40 mmHg) does not impact survival.