Serial assessment of right ventricular function and deformation in patients with hypoplastic left heart syndrome: a cardiovascular magnetic resonance study
Authors: Kanngiesser L , Gabbert D D , Uebing A , Voges I 
Published: October 2021

Abstract

Background
In patients with hypoplastic left heart syndrome (HLHS), right ventricular (RV) dysfunction and failure is a major cause of adverse outcome. Most studies have assessed RV function and size during staged palliation but serial data about RV deformation and function after completion of the Fontan circulation are rare. We assessed RV function and deformation by analysing serial cardiovascular magnetic resonance (CMR) studies in a large cohort of HLHS patients after completion of the total cavopulmonary connection (TCPC).

Methods
CMR examinations of 105 HLHS patients (female: 31, male: 74) were retrospectively analysed. Short axis cine images were used to measure RVEF and end-diastolic myocardial mass indexed to body surface area (RVMMi). 2-dimensional CMR feature tracking (2D-CMR-FT) was performed using long-axis and short axis cine images to measure myocardial global longitudinal, circumferential and radial strain (GLS, GCS, GRS) values.

Results
From 105 patients, all had at least two CMR examinations after TCPC completion (mean age at TCPC: 2.7±0.8 years; mean interval between examinations 5.4±1.6 years). 36 patients had three examinations (mean interval between first and third scan 9.9±2.2 years). The first scan was performed at a mean age of 5.6±2.9 years. Global strain values and RVEF decreased from the first to the third examination with a significant decline in GLS from the first examination to the second examination (median and interquartile range (IQR): −18.6%, IQR −20.4 to −16.3 vs. −16.8%, IQR −19.2 to −14.7) and from the first to the third examination in 36 patients (−18.6%, IQR −20.8 to −16.1 vs. −15.9%, IQR −18.3 to −12.4) (all p-values &lt;0.004). RVEF decreased significantly from the first to the third examination (55.9%, IQR 50.2–59.8 vs. 50.4%, IQR 45.0–57.6; p&lt;0.002) and from the second to the third examination (55.1%, IQR 47.1–58.7 vs. 50.4%, IQR 45.0–57.6; p&lt;0.0004). The decrease in RVEF between the first and second scan and the changes in GCS and GRS across the examinations did not reach statistical significance. Median RVMMi increased significantly between the first and second scan (47.4 g/m2, IQR 39.0–55.3 vs. 50.2 g/m2, IQR 42.6–61.7; p&lt;0.0007) and slightly but not significantly between the first and third scan in patients with three examinations (47.4 g/m2, IQR 39.5–56.2 vs. 50.1 g/m2, IQR 45.3–60.4). Negative correlations between GCS and RVEF (r=−0.57 to −0.76; p all &lt;0.0001) as well as between GLS and RVEF (r=−0.31 to −0.59; p all &lt;0.002) at all three time points could be demonstrated.

Conclusion
Serial assessment of CMR studies in HLHS patients after TCPC completion demonstrates a significant reduction in global strain values and RVEF at mid-term follow-up. The significant reduction in GLS between the first two examinations with non-significant changes in RVEF suggest that 2D-CMR-FT might be a suitable technique for the detection of early myocardial dysfunction.

Funding Acknowledgement
Type of funding sources: None.