Abstract 14906: The Effect of Shunt Type on Non-invasive Pressure-Volume Loop Measures of Cardiac Mechanics After Stage 2 Palliation: Insights From the Pediatric Heart Network Single Ventricle Reconstruction Trial Public Use Dataset
Introduction: The early survival benefit of the RV to pulmonary artery shunt (RVPAs) over the modified Blalock-Taussig shunt (mBTs) dissipates over time in children with single RV after the Norwood procedure. The objective of this study was to determine if single beat non-invasive pressure-volume loop measures of cardiac mechanics can provide insight into the mechanisms behind these findings.
Methods: Core-lab echocardiogram measures prior to superior cavopulmonary connection (SCPC) and post-operatively at 14 months of age were obtained from the publically available Pediatric Heart Network Single Ventricle Reconstruction trial database. End-systolic elastance (Ees), a measure of contractility, was calculated as (0.9 * SBP/end-systolic volume). Arterial elastance (Ea), a measure of afterload, was calculated as (0.9 * SBP/stroke volume). Ventriculo-arterial coupling was expressed as the ratio of Ea/Ees. Ees and Ea were indexed to BSA. Only patients with paired ventricular volume data pre-SCPC and at 14 months were included in the analysis.
Results: Data from 185 patients were analyzed. Differences between patients with RVPAs vs. mBTs prior to SCPC and at 14 months are reported in the table. There was a greater increase in median Ees (25.5% vs. -4.1%, p < 0.01) and Ea (27.3% vs. 2.2%, p < 0.01) in the mBTs group compared to RVPAs after SCPC. There was no difference in change in Ea/Ees between shunt groups, p = 0.31.
Conclusion: Patients in the RVPAs group displayed greater contractility compared to mBTs patients prior to SCPC. However, at 14 months, there is a trend toward greater contractility in the mBTs group. This was contributed to by a lack of improvement in contractility in the RVPAs group compared to the large increase in contractility in the mBTs group after SCPC. Investigation of the relationship between these changes in contractility and the differences in mid- and long-term mortality between shunt groups is warranted.
Author Disclosures: S.M. Chowdhury: None. A.M. Atz: None. C.L. Taylor: None. S.C. Zyblewski: None. S.M. Bradley: None. M.N. Kavarana: None. E.M. Graham: None.
- © 2016 by American Heart Association, Inc.