Increase of pulmonary artery wedge pressure above 15 mm Hg in patients with pre-capillary pulmonary hypertension

Aims

Daily practice shows that patients with pre-capillary pulmonary hypertension (PH) may develop a secondary elevation of their pulmonary artery wedge pressure (PAWP) above the 15 mm Hg limit. This phenomenon has not been precisely described yet. We aimed at identifying factors present at initial diagnosis that could predict this secondary elevation of PAWP, its possible causes and impact on survival.

Methods and results

We included 90 patients followed between 2004 and 2011 in our center. At the end of follow-up (3.0 ± 1.6 years), patients were divided into two groups according to the successive PAWP measurements (always ≤ 15 mm Hg or > 15 mm Hg on at least one right heart catheterization (RHC)). Demographical, biological, echographic and hemodynamical data at first RHC were compared. Possible causes for PAWP > 15 mm Hg were searched. A Kaplan–Meier method was used to assess differences in survival. One third of our cohort developed an elevation of PAWP above 15 mm Hg and patients with idiopathic pulmonary arterial hypertension were at smaller risk (OR 0.20 [0.05–0.82]; p = 0.026). We did not identify any other baseline predictive factors. We highlighted several possible causes and factors that may unmask an underlying left ventricular diastolic dysfunction. Survival was not different between both groups (p = 0.42).

Conclusion

Secondary elevation of PAWP in pre-capillary PH was frequent but less observed in idiopathic PH. We detailed many possible causes that can be sought, many of which may be related to an underlying left ventricular diastolic dysfunction.