Impaired global right ventricular longitudinal strain predicts long-term adverse outcomes in patients with pulmonary arterial hypertension

Background: New 2-dimensional strain echocardiography enables quantification of right ventricular (RV) mechanics by assessing global longitudinal strain of RV (GLSRV) in patients with pulmonary arterial hypertension (PAH). However, the prognostic significance of impaired GLSRV is unclear in these patients.  Methods: Comprehensive echocardiography was performed in 51 consecutive PAH patients without atrial fibrillation (40 females, 48 ± 14 years old) with long-term follow-up. GLSRV was measured with off-line with velocity vector imaging (VVI, Siemens Medical System, Mountain View, CA, USA).  Results: GLSRV showed significant correlation with RV fractional area change (r = -0.606, p < 0.001), tricuspid annular plane systolic excursion (r = -0.579, p < 0.001), and RV Tei index (r = 0.590, p < 0.001). It showed significant correlations with pulmonary vascular resistance (r = 0.469, p = 0.001) and B-natriuretic peptide concentration (r = 0.351, p = 0.012). During a clinical follow-up time (45 ± 15 months), 20 patients experienced one or more adverse events (12 death, 2 lung transplantation, and 15 heart failure hospitalization). After multivariate analysis, age [hazard ratio (HR) = 2.343, p = 0.040] and GLSRV (HR = 2.122, p = 0.040) were associated with adverse clinical events. Age (HR = 3.200, p = 0.016) and GLSRV (HR = 2.090, p = 0.042) were also significant predictors of death. Impaired GLSRV (≥ -15.5%) was associated with lower event-free survival (HR = 4.906, p = 0.001) and increased mortality (HR = 8.842, p = 0.005).  Conclusion: GLSRV by VVI showed significant correlations with conventional echocardiographic parameters indicating RV systolic function. Lower GLSRV (≥ -15.5%) was significantly associated with presence of adverse clinical events and deaths in PAH patients.