Abstract
Background and aim: Right ventricular (RV) function is closely related to functional capacity and survival in pulmonary hypertension (PH). Our prospective cardiac magnetic resonance imaging (CMR) study attempted to quantify the contribution of increased RV afterload to the decreased right ventricular ejection fraction (RVEF) in PH patients.
Material and methods: 72 patients with precapillary PH (aged 59±15 years; 35F) underwent right heart catheterization and CMR on a 1.5 T scanner (Siemens) with electrocardiographic gating (delay ±48h). The main diagnoses were chronic thromboembolic PH (n=41) and pulmonary arterial hypertension (n=18). RVEF was calculated by using contiguous 6 mm RV short axis cines (balanced SSFP).
Results: Patients had increased mean pulmonary artery pressure (45±12 mmHg) and pulmonary vascular resistance (9±4 wu) and decreased RVEF (30±15%). The RVEF was more strongly related to RV end-systolic volume (RVESV = 78±36 mL/m2; r = -0.80) than to RV end-diastolic volume (RVEDV = 109±35 mL/m2; r = -0.53) (each P < 0.001). The combined influences of mean pulmonary artery pressure and pulmonary artery pulse pressure explained 27% of RVEF variability. The combined influences of pulmonary vascular resistance and pulmonary arterial compliance explained 37% of RVEF variability.
Conclusion: The classical indices quantifying RV afterload explained less than 40% of RVEF variability in PH, thus suggesting that other factors (e.g., decreased contractility, tricuspid insufficiency, cardiac remodeling) played a major role in right heart dysfunction.
- © 2011 ERS
