Role of serial quantitative assessment of right ventricular function by strain in pulmonary arterial hypertension

The aim of this study was to assess whether serial quantitative assessment of right ventricular (RV) function by speckle-based strain imaging is affected by pulmonary hypertension-specific therapies and whether there is a correlation between serial changes in RV strain and clinical status. RV longitudinal systolic function was assessed using speckle-tracking echocardiography in 50 patients with pulmonary arterial hypertension (PAH) before and after the initiation of therapy. The mean interval to follow-up was 6 ± 2 months. Subsequent survival was assessed over 4 years. Patients demonstrated a mean increase in RV systolic strain from -15 ± 5 before to -20 ± 7% (p = 0.0001) after PAH treatment. Persistence of or progression to a severe reduction in free wall systolic strain (<-12.5%) at 6 months was associated with greater disease severity (100% were in functional class III or IV vs 42%, p = 0.005), greater diuretic use (86% vs 40%, p = 0.02), higher mean pulmonary artery pressure (67 ± 20 vs 46 ± 17 mm Hg, p = 0.006), and poorer survival (4-year mortality 43% vs 23%, p = 0.002). After adjusting for age, functional class, and RV strain at baseline, patients with ≥5% improvement in RV free wall systolic strain had a greater than sevenfold lower mortality risk at 4 years (hazard ratio 0.13, 95% confidence interval 0.03 to 0.50, p = 0.003). In conclusion, serial echocardiographic assessment of RV longitudinal systolic function by quantitative strain imaging independently predicts clinical deterioration and mortality in patients with PAH after the institution of medical therapy.