Prognostic Value of Right Ventricular Strain Using Speckle-Tracking Echocardiography in Pulmonary Hypertension: A Systematic Review and Meta-analysis

Background: Right ventricular (RV) strain imaging using speckle-tracking echocardiography (STE) is a quantitative method of assessing RV systolic function that has shown prognostic utility in patients with pulmonary hypertension (PH). However, its prognostic value for a large and mixed PH population remains poorly defined. Methods: A systematic review and meta-analysis was performed using the MedLine, Embase, and Cochrane Library databases for publications reporting the prognostic value of RV strain calculated using 2-dimensional STE in PH patients for the clinical end point of all-cause mortality. Results: Screening of 687 publications yielded 10 that were included in the meta-analysis, representing data for 1001 PH patients, among whom 76% had pulmonary arterial hypertension with the remainder having a range of PH etiologies. The pooled free wall RV strain was -16.2% (95% confidence interval [CI], -14.3 to -18.1; I-2 = 94.1%; Q = 102.8; P < 0.001), and the global (free wall and septum) RV strain was -14.5% (95% CI, -12.9 to -16; I-2 = 84.9%; Q = 20; P < 0.001). There were 193 (18%) deaths (follow-up period range, 7.4 months to 4.2 years). From 6 publications, the pooled unadjusted hazard ratio for a binary cut off RV strain value for the primary outcome was 3.67 (95% CI, 2.82-4.77; P < 0.001; I-2 = 0; Q = 1.8; P = 0.87), whereas the pooled unadjusted hazard ratio of RV strain as a continuous variable (per 1% change) was 1.14 (95% CI, 1.11-1.8; P < 0.001; I-2 = 0; Q = 2.0; P = 0.85), and were superior to corresponding values for tricuspid annular systolic plane excursion (1.45; P = 0.071, hazard ratio = 1.00, and P = 0.82, respectively). Conclusions: RV strain performed using 2-dimensional STE provides important prognostic value within a large and mixed population of PH patients.