Right Ventricular Strain in Pulmonary Hypertension: Systematic Review, Meta-analysis, and Meta-regression

Echocardiography and cardiac magnetic resonance (CMR) are essential for assessing RV function, a prognostic marker in patients with pulmonary arterial hypertension or pulmonary hypertension (PH). Although recent evidence suggests that right ventricular global longitudinal strain (RVGLS) is superior at identifying right ventricular dysfunction (RVD) in preclinical stages, its prognostic value remains unclear. We performed a systematic review, meta-analysis, and meta-regression through a literature search. We aimed to evaluate RVGLS by echocardiography or CMR as an early RVD marker and assess its predictive value for clinical worsening and mortality. We included studies with RVGLS measurements obtained by echocardiography or CMR in PH groups I, III, and IV, as confirmed by right heart catheterization. Additionally, we utilized the precapillary-PH definition from the 6th World Symposium. We measured study heterogeneity using the I2 statistic and Tau2, using the Dersimonian-Laird method to evaluate different yet related intervention effects. We identified 22 studies for the systematic review and 12 for the meta-analysis, representing 1735 group I PH patients, a female prevalence (85.4% and 70.1%, respectively), an average age of 52.4, and a mean mPAP of 50.1 mmHg. The mean ejection fraction by CMR was 44.22 ± 4.0. The mean RVGLS of -17.8% from baseline represents a significant predictive value for the composite outcome (clinical worsening, hospitalization, and mortality) as assessed by echocardiography. Tau2 heterogeneity of 0.02, Chi2 = 26.79, def = 7, p= 0.0004, I2 = 74%. Test for overall effect: Z = 2.46, p = 0.001. The RVGLS, assessed by echocardiography with a value of -17.8%, may represent a potential threshold associated with adverse outcomes and could be an independent prognostic factor for overall mortality and composite endpoints in patients with severe PH.