Left-Right Ventricular Interactions in Pediatric Aortic Stenosis: Right Ventricular Myocardial Strain before and after Aortic Valvuloplasty

Assessment of Biventricular Myocardial Function with 2-Dimensional Strain and Conventional Echocardiographic Parameters: A Comparative Analysis in Healthy Infants and Patients with Severe and Critical Pulmonary Stenosis

Our aim was to compare the global longitudinal and regional biventricular strain between infants with severe and critical pulmonary stenosis (PS), and controls; to compare pre- and post-procedural strain values in infants with severe and critical PS; and to assess the correlations between echocardiographic strain and conventional parameters. We conducted a retrospective single-center study. The comparisons of echocardiographic variables were performed using separate linear mixed models. The overall mean right ventricle (RV) regional strains measured before intervention in PS patients was significantly different when compared to the control group (p = 0.0324). We found a significant change in the left ventricle, RV, and inter-ventricular septum strain (IVS) values from basal to apical location (p < 0.05). IVS strain values showed a higher decrease in mean strain values from basal to apical in PS patients. There was no significant difference in means of baseline and post-interventional strain values in PS patients (p > 0.05). Following the strain analysis in patients with PS, we obtained statistically significant changes in the RV global-4-chamber longitudinal strain (RV4C). The RV4C, which quantifies the longitudinal strain to the entire RV, can be used in current clinical practice for the evaluation of RV function in infants with severe and critical PS. The longitudinal and segmental strain capture the pathological changes in the IVS, modifications that cannot be highlighted through a classical echocardiographic evaluation.

Characterization of Left Ventricular Dysfunction by Myocardial Strain in Critical Pulmonary Stenosis and Pulmonary Atresia After Neonatal Pulmonary Valve Balloon Dilation

Transient left ventricular (LV) dysfunction occurs in some infants born with critical pulmonary stenosis (PS) or membranous pulmonary atresia with intact ventricular septum (PAIVS) after pulmonary valve (PV) balloon dilation (BD). The cause for this is not well understood. We sought to characterize this LV dysfunction by investigating regional differences in this cohort using myocardial strain imaging. Patients who underwent neonatal (<2 weeks age) PV BD for critical PS or PAIVS from Jan, 2007 to March, 2014 with echocardiographic images suitable for strain analysis were identified; infants with ≥moderate post-BD LV dysfunction (ejection fraction <40%, n = 8) were matched 1:1 with controls who underwent PV BD but did not develop LV dysfunction. Longitudinal and circumferential global and segmental strain were analyzed before and after PV BD. For the 8 LV dysfunction cases, LV global longitudinal strain worsened after PV BD (-16% pre- vs -8% post-PV BD, p = 0.008) with similar impairment in global LV circumferential strain (-17% vs -8%, p = 0.008); there was no significant change in RV global or segmental longitudinal strain pre- vs post-PVBD. No significant pre/post-BD differences in global or circumferential strain were found in control pts. Segmental analysis of longitudinal and circumferential LV strain before and after balloon dilation in cases demonstrated decreased strain in all segments, but more pronounced and statistically significant in septal segments as compared with the free wall. In conclusion, transient LV dysfunction post-PV BD for critical PS/PAIVS is characterized by impaired global longitudinal and circumferential LV strain, with the most significant reductions in strain at the interventricular septum; longitudinal RV strain remains unchanged. These findings suggest that the mechanism of LV dysfunction post-PV BD is adverse ventricular-ventricular interactions specifically involving the interventricular septum.