Assessment and Prognostic Relevance of Right Ventricular Contractile Reserve in Patients with Severe Pulmonary Hypertension
Background—This study sought to analyze a new approach to assess exercise-induced systolic pulmonary artery pressure (PASP) increase by means of stress-Doppler echocardiography as a possible measure of right ventricular (RV) contractile reserve in patients with severe pulmonary hypertension (PH) and right heart failure.
Methods and Results—In this prospective study, patients with invasively diagnosed pulmonary arterial hypertension or inoperable chronic thromboembolic PH and impaired right ventricular pump function despite a stable targeted PAH medication underwent a broad panel of non-invasive assessments including stress echocardiography and cardiopulmonary exercise testing. Based on the assumption that exercise-induced PASP is a measure of right ventricular contractile reserve patients were classified into 2 groups according to an exercise-induced PASP increase above or below median. Patients were followed for 3.0±1.8 years. Uni- and multivariate analysis were employed for analysis of factors predicting survival. Of 124 patients, 66 were below the median exercise-induced PASP increase of 30 mmHg (low PASP), and 58 patients were above (high PASP). These groups were not significantly different concerning medication and resting hemodynamics. Low PASP was associated with a significantly lower 6-minute walking distance, peak VO2/kg and 1-, 3-, and 4-year survival rate (92%, 69% and 48% respectively vs. 96%, 92% and 89%). In the multivariate Cox model analysis adjusted for age and sex PASP increase during exercise and peak VO2/kg remained as independent prognostic markers (hazard ratio 2.56 for peak VO2/kg and 2.84 for PASP increase).
Conclusions—Exercise-induced PASP-increase is of high clinical and prognostic relevance in PH-patients and may indicate right ventricular contractile reserve. Stress Doppler echocardiography may be a useful tool for prognostic assessment in PH-patients.
- Received January 29, 2013.
- Revision received July 30, 2013.
- Accepted August 9, 2013.