Abstract 19743: Assessment of Myocardial Mechanics Utilizing Speckle-Tracking Echocardiography in a Swine Model of Right Ventricular Pressure-Overload
Introduction: Quantitative assessment of right ventricular (RV) function by echocardiography remains a challenge due to the complex geometry of the RV. The objective of this study was to assess the utility of speckle-tracking echocardiography (STE) compared to conventional transthoracic two-dimensional (2DE) in a RV pressure-overload swine model after treatment with cardiac or mesenchymal stem cells.
Methods: Neonatal swine underwent pulmonary artery banding (PAB) to induce RV dysfunction. After banding, pigs received intramyocardial injection into the RV free wall with human c-kit+ cardiac stem cells (hCSCs) alone (n=5), human mesenchymal stem cells (hMSCs) alone (n=5), a combination of hCSCs/hMSCs (n=5) or placebo (phosphate-buffered saline, n=5). Standard 2DE was performed pre-operatively, post-banding and at 4 weeks. Offline blinded analysis using vendor-independent software was performed measuring longitudinal strain and strain rate from the apical 4-chamber view.
Results: The mean RV:systemic pressure ratio at baseline and post-banding was 0.34±0.04 vs. 0.76±0.05, respectively (P<0.0001). Compared to baseline, mean post-banding values for peak global longitudinal strain (pGLS) and strain rate were significantly decreased (P<0.0001 and P=0.0002, respectively). At four weeks post-banding, pGLS was higher in all cell-treated pigs relative to placebo (hMSCs, P=0.002; hCSCs, P<0.0001; hCSCs/hMSCs, P=0.014). Strain rate was higher than placebo at four weeks post-banding in the hMSCs alone and hCSCs alone groups, and approached statistical significance in the combination hMSCs/hCSCs. Fractional area of change demonstrated significant improvement in cell-treated pigs compared to placebo, however no significant changes were detected in other traditional measurements, such as TAPSE or tricuspid tissue Doppler indices.
Conclusion: In a neonatal model of RV pressure-overload, we were able to detect significant changes in underlying myocardial mechanics which conventional RV functional indices did not detect. STE may be more sensitive than traditional echocardiography in assessing RV function in neonatal pressure-overloaded lesions.
Author Disclosures: N. Pietris: None. B. Wehman: None. O.T. Siddiqui: None. R. Mishra: None. G. Bigham: None. S. Sharma: None. S.B. Murthi: None. S. Kaushal: None.
- © 2014 by American Heart Association, Inc.