Pulmonary Artery Size and Late Functional Outcome After Fontan Operation

Neurodevelopmental and functional outcome in hypoplastic left heart syndrome after Hybrid procedure as stage I

BACKGROUND

Patients with hypoplastic left heart syndrome (HLHS) undergoing staged palliation until Fontan procedure are at risk for impaired neurodevelopmental (ND) outcome. The Hybrid procedure with bilateral pulmonary artery banding, ductal stenting, and balloon atrioseptostomy may offer a less invasive stage I procedure compared to the Norwood stage I procedure avoiding early neonatal cardiopulmonary bypass (CPB) surgery. Despite altered fetal cerebral hemodynamics, the type of stage I procedure may be a covariate influencing ND outcome and functional outcome may also be altered due to postponing neonatal CPB surgery. Within this review, we analyzed ND outcome as well as functional outcome after Hybrid procedure as stage I procedure.

METHODS

The review analyzed original publications (OPs) published before March 15, 2022, identified by Cochrane, EMBASE, OVID, Scopus, and Web of science. An OP was included if short-to-long-term neurodevelopment outcome, brain development, somatic, and cardiac outcome in patients for HLHS and variants treated by Hybrid procedure were analyzed. In addition to database searches, we reviewed all references of the analyzed OP to obtain a comprehensive list of available studies. The author, year of publication, demographic characteristics of study population, study design (prospective or retrospective), study assessment, and main findings were summarized.

RESULTS

Twenty-one OPs were included with data of patients with ND outcome and functional cardiac outcome. Overall, there is an impaired mid-term ND outcome in patients with Hybrid procedure as stage I for HLHS. Only slight differences between stage I procedures (Hybrid vs. Norwood) in two comparing studies have been determined affecting right ventricular remodeling, short- and mid-term ND outcome, reduced brain growth until two years of age, sufficient quality of life, and altered hemodynamics influencing brain volumes and cerebral perfusion pattern.

CONCLUSIONS

Despite some minor differences regarding the mid-term follow-up in patients with HLHS comparing Hybrid vs. Norwood procedure, its impact on ND outcome seems rather low. This may be explained by the large number of covariates as well as the small study populations and the different selection criteria for patients undergoing Hybrid or Norwood procedure as stage I.

Predictive Models for Pulmonary Artery Size in Fontan Patients

We developed models of pulmonary artery (PA) size in Fontan patients as a function of age and body surface area (BSA) using linear regression and breakpoint analyses based on data from 43 Fontan patients divided into two groups: the extracardiac conduit (ECC) group (n = 24) and the non-ECC group (n = 19). Model predictions were compared against those of a non-Fontan control group (n = 18) and published literature. We observed strong positive correlations of the mean PA diameter with BSA (r = 0.9, p < 0.05) and age (r = 0.88, p < 0.05) in the ECC group. The absolute percentage differences between our BSA and age model predictions against published literature were less than 16% and 20%, respectively. Predicted PA size for Fontan patients was consistently smaller than the control group. These models may serve as useful references for clinicians and be utilized to construct 3D anatomic models that correspond to patient body size or age.

The impact of additional antegrade pulmonary blood flow at bidirectional Glenn shunt on long-term outcomes

OBJECTIVES

We investigated the impact of additional antegrade pulmonary blood flow on the long-term outcomes after bidirectional Glenn shunt.

METHODS

From 2001 to 2015, 279 patients underwent bidirectional Glenn shunt as an interim palliation for a functionally single ventricle. After excluding patients with a previous Kawashima or Norwood operation, 202 patients with preexisting antegrade pulmonary blood flow before bidirectional Glenn shunt were included in this study. Antegrade pulmonary blood flow was eliminated in 110 patients (no antegrade pulmonary blood flow group) and maintained in 92 patients (antegrade pulmonary blood flow group). The impact of antegrade pulmonary blood flow at bidirectional Glenn shunt on long-term outcome was analyzed using inverse probability of treatment weighting.

RESULTS

Median age and body weight at bidirectional Glenn shunt were 8 months and 7.8 kg, respectively. Prolonged chest tube drainage or readmission for effusion after bidirectional Glenn shunt was more frequent in the antegrade pulmonary blood flow group (odds ratio, 3.067; 95% confidence interval, 1.036-9.073; P = .043). In the no antegrade pulmonary blood flow group, B-type natriuretic peptide level was decreased further until the Fontan operation (P = .012). In the no antegrade pulmonary blood flow group, oxygen saturation was lower just after bidirectional Glenn shunt, although it was increased further until Fontan operation (P < .001), despite still lower oxygen saturation before Fontan operation compared with antegrade pulmonary blood flow group (P < .001). The McGoon ratio was decreased in both groups without intergroup difference, although the McGoon ratio before Fontan operation was higher in the antegrade pulmonary blood flow group (2.3 ± 0.4 vs 2.1 ± 0.4, P = .008). Overall transplant-free survival was worse in the antegrade pulmonary blood flow group (hazard ratio, 2.37; confidence interval, 1.089-5.152; P = .030).

CONCLUSIONS

Maintaining antegrade pulmonary blood flow at bidirectional Glenn shunt was beneficial for higher oxygen saturation and larger pulmonary artery size before Fontan operation. However, it was unfavorable for overall transplant-free survival with a sustained higher risk of death or transplant until the elimination of antegrade pulmonary blood flow.

Fontan pathway growth: a quantitative evaluation of lateral tunnel and extracardiac cavopulmonary connections using serial cardiac magnetic resonance

BACKGROUND

Typically, a Fontan connection is constructed as either a lateral tunnel (LT) pathway or an extracardiac (EC) conduit. The LT is formed partially by atrial wall and is assumed to have growth potential, but the extent and nature of LT pathway growth have not been well characterized. A quantitative analysis was performed to evaluate this issue.

METHODS

Retrospective serial cardiac magnetic resonance data were obtained for 16 LT and 9 EC patients at 2 time points (mean time between studies, 4.2 ± 1.6 years). Patient-specific anatomies and flows were reconstructed. Geometric parameters of Fontan pathway vessels and the descending aorta were quantified, normalized to body surface area (BSA), and compared between time points and Fontan pathway types.

RESULTS

Absolute LT pathway mean diameters increased over time for all but 2 patients; EC pathway size did not change (2.4 ± 2.2 mm vs 0.02 ± 2.1 mm, p < 0.05). Normalized LT and EC diameters decreased, while the size of the descending aorta increased proportionally to BSA. Growth of other cavopulmonary vessels varied. The patterns and extent of LT pathway growth were heterogeneous. Absolute flows for all vessels analyzed, except for the superior vena cava, proportionally to BSA.

CONCLUSIONS

Fontan pathway vessel diameter changes over time were not proportional to somatic growth but increases in pathway flows were; LT pathway diameter changes were highly variable. These factors may impact Fontan pathway resistance and hemodynamic efficiency. These findings provide further understanding of the different characteristics of LT and EC Fontan connections and set the stage for further investigation.

Age at Fontan procedure impacts exercise performance in adolescents: results from the Pediatric Heart Network Multicenter study

BACKGROUND

Most single ventricle patients undergo Fontan procedure in a staged manner. However, optimal timing of Fontan completion after an intermediate staging surgery is controversial. Therefore, we investigated the long-term impact of age at Fontan completion on the exercise performance in adolescents.

METHODS

We analyzed National Institutes of Health/National Heart, Lung and Blood Institute Pediatric Heart Network Fontan Cross-Sectional Study dataset consisting of children and adolescents 6 to 18 years of age recruited in 2003 to 2004. Multivariate linear regression techniques were used to evaluate association of age at Fontan procedure with percent predicted VO2 maximum, percent predicted maximum O2 pulse, and heart rate reserve in patients who achieved ventilatory anaerobic threshold (VAT).

RESULTS

Of the 405 patients who had undergone only one Fontan operation and ramp cycle ergometry, 72% had prior intermediate surgery. Mean age at Fontan completion and exercise testing was 3.4±2 and 12.4±3.2 years. Three hundred twelve patients reached VAT suggesting adequate cardiopulmonary effort. In patients who reached VAT, each year increase in age at Fontan completion was associated with a decline of 1.5 (95% CI -2.5 to -0.5) points in percent-predicted VO2 maximum and a decline of 4.1 (95% CI -6.0 to -2.1) beat/min in heart rate reserve after adjusting for all pertinent variables.

CONCLUSIONS

Fontan completion at a younger age is associated with better exercise performance in adolescents.