Background/objectives Speckle tracking echocardiography (STE) has added to the assessment of right ventricular function by providing off-line measurements of strain and strain rate. Worsening right ventricular function is associated with poorer outcomes in idiopathic pulmonary arterial hypertension (IPAH). Global right ventricular free wall (RVFW) longitudinal strain and strain rate have been reported as markers of prognosis. Differences in degree of regional RVFW deformation will affect the global RVFW analysis. We assessed whether RVFW segmental analysis using STE identified specific regional associations with proven prognostic markers.
Method Using our database, we identified newly diagnosed cases of IPAH between January 2012 and May 2016. 25 cases had echocardiograms accessible for retrospective analysis. Using 2D-STE software (EchoPAC, GE Healthcare), we measured longitudinal strain and strain rate of the RVFW basal, mid and apical segments. Data on established prognostic markers, NT-proBNP, cardiac index (CI), WHO functional class (FC), six-minute walk distance (6MWD) and mixed venous saturations (SvO2) were retrieved from the patient database. All data was anonymised for analysis.
Results Basal peak systolic longitudinal strain rate (PSLSR) of the RVFW correlated very strongly with NT-proBNP (r = 0.82, p < 0.001) and moderately with CI: (r = −0.53, p < 0.007), WHO FC (r = 0.52, p < 0.008) and SvO2 (r = −0.50, p < 0.02). Basal late diastolic longitudinal strain rate (LDLSR) correlated strongly with SvO2 (r = 0.61, p < 0.002), and moderately with NT-proBNP (r = −0.58, p < 0.005), CI: (r = 0.57, p < 0.004), 6MWD (r = 0.5, p < 0.02), and WHO FC (r = −0.49, p < 0.02). Mid PSLSR and LDLSR moderately correlated with SvO2 (r = −0.53 and 0.56), NT-proBNP (r = 0.5 and −0.5) and CI (r = −0.48 and 0.42), (all p < 0.04). The apical segment showed no significant correlations. Peak systolic longitudinal strain demonstrated only one significant segmental correlation between the mid-segment and NT-proBNP (r = 0.44, p < 0.05).
Conclusion We have demonstrated that analysing RVFW longitudinal segments provides significant regional correlations with known prognostic markers in an IPAH population group. We have shown the significant advantage of longitudinal strain rate over strain in its strength and consistency of correlation with these markers. We have acknowledged basal and mid segments as significant regions of interest. This study shows that further exploration of right ventricular function in pulmonary hypertension by RVFW segmental analysis is indicated.