Right ventricular strain in pulmonary arterial hypertension: a 2D echocardiography and cardiac magnetic resonance study.

BACKGROUND: Right ventricular (RV) strain is a potentially useful prognostic marker in patients with pulmonary arterial hypertension (PAH). However, published reports regarding the accuracy of two-dimensional echocardiography (2DE)-derived RV strain against an independent reference in this patient population are limited. The aims of this study were: (1) to study the relationship between 2DE RV longitudinal strain and cardiovascular magnetic resonance (CMR)-derived RV ejection fraction (RVEF) in patients with PAH; (2) to compare 2DE-derived and CMR-derived RV longitudinal strain in these patients; and (3) to determine the reproducibility of these measurements.
METHODS: Thirty patients with PAH underwent 2DE and CMR imaging within a 2-hour time period. 2DE RV longitudinal strain was measured from a focused RV apical four-chamber view using speckle tracking software. CMR RV longitudinal strain was measured from short-axis slices acquired using fast-strain-encoded sequence. Global peak systolic RV longitudinal strain was calculated for both 2DE and CMR.
RESULTS: RV longitudinal strain using 2DE software correlated well with CMR-derived RVEF (R = 0.69, P = 0.0006). There was moderate agreement when comparing 2DE to CMR RV longitudinal strain (R = 0.74, P = 0.0002; bias -1%, limits of agreement -9 to 7%). Inter-observer variability and intra-observer variability for RV longitudinal strain were lower for 2DE than CMR.
CONCLUSIONS: RV longitudinal strain by 2DE provides a good alternative for CMR-derived RVEF in patients with PAH. The moderate agreement in strain measurements between 2DE and CMR suggests that further software improvements are needed before these measurements can be used interchangeably in clinical practice.