Objective: The hybrid procedure is an alternative for initial palliation for patients with hypoplastic left heart syndrome. No echocardiographic data exist for the interstage (IS) period. The goal of this study was to describe the echocardiographic changes during this period.
Methods: A chart review was performed on patients discharged from the hospital with the diagnosis of hypoplastic left heart syndrome who underwent hybrid palliation. Echocardiograms at hospital discharge (post-hybrid), before and after any IS interventions, and before comprehensive stage II procedure were reviewed. Distal right pulmonary artery (RPA) and left pulmonary artery (LPA) velocity, slope, velocity time integral (VTI), pressure halftime (p1/2), pulsatility index (PI), and systolic/diastolic (S/D) ratio of the waveforms were recorded. Atrial septal defect (ASD) mean gradient, ductus arteriosus peak velocity, retro-aortic arch peak velocity, tricuspid regurgitation (TR), and right ventricular function were documented. Exploratory hypotheses were tested with chi-square and t tests. Stepwise logistic regression was used to identify any multiple sets of relatively independent variables.
Results: Thirty patients met inclusion criteria. Fourteen patients underwent 22 different interventions at the atrial septum, ductus arteriosus, or retro-aortic arch in the IS period. Baseline ASD gradient (P = .012) and ductus arteriosus velocity (P = .002) predicted an IS intervention. There were significant differences in LPA and RPA VTI (P = .011, .03), p1/2 (P = .038, .008), and S/D (P = .012, .033); RPA slope (P = .013); ASD gradient (P = .003); ductus arteriosus velocity (P = .021); and TR (P = .031) before and after an intervention. There were significant differences in post-hybrid versus pre-comprehensive stage II LPA and RPA VTI (P = .009, .022), PI (P = .031, .022), and peak velocity (P = .004, .037); RPA S/D (P = .025) and p1/2 (P = .029); ductus arteriosus velocity (P < .001); retro-aortic arch peak velocity (P = .035); and ASD mean gradient (P < .001). Pre-comprehensive stage II function tended to predict death (P = .085).
Conclusion: Echocardiographic parameters help predict IS course and guide clinical therapy for this patient population.