Clinical Investigation
Congenital Heart Disease
Changes of Right Ventricular Function and Longitudinal Deformation in Children with Hypoplastic Left Heart Syndrome before and after the Norwood Operation

https://doi.org/10.1016/j.echo.2011.08.016Get rights and content

Background

The purpose of this study was to investigate changes in right ventricular (RV) function and deformation parameters before and at steady state after the Norwood operation in neonates with hypoplastic left heart syndrome. A further aim was to delineate factors that affected these changes.

Methods

On echocardiograms before and 21 days (range, 10–35 days) after the Norwood operation, the two-dimensional speckle-tracking parameters global and regional peak systolic longitudinal strain and strain rate were retrospectively compared in 33 patients with hypoplastic left heart syndrome. In addition, RV functional assessment included RV fractional area change and tricuspid annular plane systolic excursion. The associations between postoperative echocardiographic findings and preoperative or postoperative complications, prenatal diagnosis, postoperative heart rate, oxygen saturation, and medication use as well as cardiopulmonary bypass and aortic cross-clamp times were tested.

Results

Global strain (−18.3 ± 3.6% vs −16.8 ± 3.8%, P = .02) and global strain rate (−1.6 ± 0.3 vs −1.2 ± 0.3 sec−1, P < .0001) decreased significantly. Regional strain decreased significantly in the apical and mid lateral segments, while regional strain rate decreased significantly in all but the basal septal segments. Tricuspid annular plane systolic excursion of the lateral annulus decreased significantly, while RV fractional area change remained the same. No significant associations were found between postoperative RV function and potential impact factors.

Conclusions

Two-dimensional global and regional longitudinal strain and strain rate as well as tricuspid annular plane systolic excursion were reduced in patients with hypoplastic left heart syndrome after the Norwood operation. None of the examined preoperative and postoperative patient or surgical factors was found to explain this decrease.

Section snippets

Patients

A retrospective database search identified 45 children with HLHS who underwent modified Norwood operations at our institution from February 2008 to September 2010. Of these, 33 fulfilled our inclusion criteria of (1) having echocardiographic data suitable for speckle-tracking analysis of the right ventricle available before and after surgery and (2) being hemodynamically stable at the time of preoperative and postoperative echocardiography, without the need for mechanical ventilation or

Results

Pertinent patient data are shown in Table 1. MA/AA was present in 19 patients (58%), MS/AS in six (18%), and MS/AA in eight (24%). MA/AS did not occur in our study population. Twenty-one patients (64%) were male.

The diagnosis was made prenatally in 23 patients (70%). Preoperative ventilation was necessary in five patients (15%); preoperative complications occurred in eight patients (24%) and included cardiovascular shock with necessity for resuscitation in four patients (18%), a cerebrovascular

Discussion

Our study showed that longitudinal RV deformation assessed by 2D speckle tracking and TAPSE were lower at a median time of 21 days after the Norwood operation compared with preoperative values under otherwise stable clinical conditions. The right ventricle was larger in both systole and diastole, so that RVFAC, an indicator of global function, did not change. Factors such as cardiopulmonary bypass time, aortic cross-clamp time, postoperative heart rate or oxygen saturation, the anatomic subtype

Conclusions

Longitudinal RV deformation and TAPSE were lower at a median of 21 days after the Norwood operation compared with preoperative values. No single factor among those we investigated was able to explain our findings, and thus our findings are mostly descriptive and may serve for future comparison in similar patient populations. The etiology of the decrease in longitudinal RV function remains speculative, and therefore, prospective, longitudinal studies using a specified imaging protocol should be

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Dr. Petko was supported by the nonprofit organization Kinderherzen Wollen Leben e.V. (Kiel, Germany).

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