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.