Relationship between right ventricular longitudinal strain, invasive hemodynamics, and functional assessment in pulmonary arterial hypertension

Background and Objectives: Right ventricular longitudinal strain (RVLS) is a new parameter of RV function. We evaluated the relationship of RVLS by speckle-tracking echocardiography with functional and invasive parameters in pulmonary arterial hypertension (PAH) patients.

Subjects and Methods: Thirty four patients with World Health Organization group 1 PAH (29 females, mean age 45 ± 13 years old). RVLS were analyzed with velocity vector imaging.

Results: Patients with advanced symptoms {New York Heart Association (NYHA) functional class III/IV} had impaired RVLS in global RV (RVLS_global, -17 ± 5 vs. -12 ± 3%, p < 0.01) and RV free wall (RVLS_FW, -19 ± 5 vs. -14 ± 4%, p < 0.01 to NYHA class I/II). Baseline RVLS_global and RVLS_FW showed significant correlation with 6-minute walking distance (r = -0.54 and r = -0.57, p < 0.01 respectively) and logarithmic transformation of brain natriuretic peptide concentration (r = 0.65 and r = 0.65, p < 0.01, respectively). These revealed significant correlations with cardiac index (r = -0.50 and r = -0.47, p < 0.01, respectively) and pulmonary vascular resistance (PVR, r = 0.45 and r = 0.45, p = 0.01, respectively). During a median follow-up of 33 months, 25 patients (74%) had follow-up examinations. Mean pulmonary arterial pressure (mPAP, 54 ± 13 to 46 ± 16 mmHg, p = 0.03) and PVR (11 ± 5 to 6 ± 2 wood units, p < 0.01) were significantly decreased with pulmonary vasodilator treatment. RVLS_global (-12 ± 5 to -16 ± 5%, p < 0.01) and RVLS_FW (-14 ± 5 to -18 ± 5%, p < 0.01) were significantly improved. The decrease of mPAP was significantly correlated with improvement of RVLS_global (r = 0.45, p < 0.01) and RVLS_FW (r = 0.43, p < 0.01). The PVR change demonstrated significant correlation with improvement of RVLS_global (r = 0.40, p < 0.01).

Conclusion: RVLS correlates with functional and invasive hemodynamic parameters in PAH patients. Decrease of mPAP and PVR as a result of treatment was associated with improvement of RVLS.