Non-invasive assessment of liver abnormalities in pediatric Fontan patients.

Liver abnormalities are well known among long-term survivors of Fontan palliation, which remains the definite surgery for complex congenital heart disease and single ventricle physiology. Pediatric data however are scarce. We assessed the prevalence and degree of liver abnormalities in pediatric Fontan patients through non-invasive investigations suitable for longitudinal follow-up. Thirty-five patients with a median age of 11.8 years (5.2-16.6) and median time since Fontan of 6 years (1.17-13.83) were studied. Each child underwent a blood test, liver Doppler ultrasound (US), and transient elastography (TE). Healthy children were used as controls for TE measurement. AST, ALT, γGT, and direct bilirubin were abnormal in respectively 12 (34%), 5 (14%), 24 (69%), and 7 (20%) patients, while platelet count was decreased in 7 (20%). Splenomegaly was present in 7 (20%) patients. Portal vein mean flow velocity was < 15 cm/s in 19 (54%) patients indicative of portal hypertension. Twenty-two patients (63%) showed inferior vena cava collapsibility index values below 17%, indicating venous congestion. Hepatic artery and superior mesenteric artery resistance index were inversely correlated with time post Fontan (p < 0.05). TE values in Fontan patients were significantly higher than controls, with a median of 12.6 versus 4.6 kPa (p < 0.001) and were already increased shortly after Fontan completion. Conclusion: Liver abnormalities are frequently observed in pediatric Fontan patients. The non-invasive investigations used were not able to confirm liver fibrosis or differentiate hepatic congestion from fibrosis. Based on our findings, we propose a prospective screening protocol with serial measurements of laboratory, (Doppler) US, and TE parameters. What is Known: • Hepatic dysfunction is a well-known consequence of the Fontan circulation. • The natural history of Fontan-associated liver disease in the pediatric age group remains unclear. What is New: • Liver abnormalities are frequently observed in pediatric Fontan patients; however, differentiating liver fibrosis and hepatic congestion with non-invasive investigations remains challenging. Sonographic Doppler measurements may improve our insight in both Fontan-associated liver disease development and the functioning of the Fontan circulation. • A prospective screening protocol is proposed to improve our ability to detect Fontan-associated liver disease early on and understand its natural history.

Functional analysis of the anatomical right ventricular components: should assessment of right ventricular function after repair of tetralogy of Fallot be refined?

OBJECTIVE: Follow-up after tetralogy of Fallot (ToF) repair is directed to detect timely right ventricular (RV) dysfunction by following pulmonary regurgitation and global RV size, with little attention for the effective contribution of regional RV dysfunction. This study investigates the contribution of regional RV dysfunction on exercise capacity after ToF repair. METHODS: Forty-two patients were investigated with cardiac magnetic resonance imaging for regional RV dysfunction in relation to global RV function by functional quantification of the sinus and outflow part of the RV. The impact of regional and global RV dysfunction on clinical status was studied by exercise testing. RESULTS: Global RV function was lower than sinus function (ejection fraction (EF) 52±12% vs 58±10%, P<0.001), attributable to the adverse influence of right ventricular outflow tract (RVOT) dysfunction (EF 34±17%). Percent predicted peak VO2 correlated better with the RV sinus ejection fraction compared with the global RV ejection fraction (r=0.51, P=0.001 vs r=0.44, P=0.004). Multivariate analysis revealed the EF of RV sinus (ß=0.34, 95% CI 0.07-0.61, P=0.013) and the extent of RVOT akinesia (ß=-0.28, 95% CI -0.50; -0.06, P=0.015) as significant determinants of exercise capacity. Impaired exercise performance occurred in 43% of the patients, and was independently determined by the type of repair (transventricular vs transatrial: OR 6.0, 95% CI 1.31-17.3, P=0.02) by associating greater sinus and RVOT dysfunction. CONCLUSION: Functional analysis of the RV components shows that exercise capacity after repair of ToF is better predicted by systolic function of the RV sinus as the extent of RVOT dysfunction commonly leads to underestimation of global RV function. This method of differential quantification of regional RV function might be more appropriate than assessment of global RV function during the long-term follow-up of repaired ToF patients.

Assessment of a right-ventricular infundibulum-sparing approach in transatrial-transpulmonary repair of tetralogy of Fallot.

OBJECTIVE: The study aimed to evaluate the outcome of transatrial-transpulmonary repair of tetralogy of Fallot in relation to a right-ventricular outflow tract (RVOT)-sparing surgery. METHODS: Based on the surgical management of right-ventricular outflow tract obstruction (RVOTO) at repair of tetralogy of Fallot, 140 children were retrospectively divided into three groups: (1) pulmonary valve (PV)-sparing, (2) infundibulum-sparing and (3) extended trans-annular patch (TAP). Clinical and echocardiographic outcome was assessed with regards to three equally divided study time eras between January 1994 and June 2010. RESULTS: Over a 15-year study period, median age decreased from 11 (2-101) to 5 (1-11) months (p<0.001), whereas type of RVOT repair changed significantly between the first and the last era (group 1: 18-40%, group 2: 25-40% vs group 3: 57-20% (p=0.002)). Mortality was 0%. Complications were mainly related to clinical restrictive RV physiology (27%) and arrhythmia (10%). This cardiac morbidity remained constant over the eras and was associated with younger age (p=0.04), increased postoperative right ventricle/left ventricle (RV/LV) pressure ratio (p=0.01) and type of RVOT repair at the cost of TAP (p=0.03). Median follow-up of 8 years (1-16 years) showed an overall freedom from RVOT re-operation of 84% and 73%, respectively at 5 and 10 years. Most re-operations were for residual/recurrent RVOTO (12%) occurring more frequently in the latter era: 16% versus 7% in era 1 (p=0.08). Late echocardiographic evaluation revealed a strong correlation between severity of pulmonary regurgitation and increased RV/LV size ratio, which was mainly determined by increased TAP length (p<0.001) and duration of follow-up (p=0.06). CONCLUSION: In a 15-year's experience with transatrial-transpulmonary correction of tetralogy of Fallot, a valve- and infundibulum-sparing approach has been advanced by lowering the age for elective repair. This change has been performed without compromising immediate clinical outcome, despite an increased early re-operation rate for residual obstruction. However, longer follow-up will disclose whether this approach is protective against progressive and late RV dysfunction.

Midterm assessment of the reconstructed arteries after the arterial switch operation.

BACKGROUND: The arterial switch operation is the preferred treatment for transposition of the great arteries (TGA), but there are concerns on the fate of the neoarterial trunks. METHODS: Ninety-three children were reviewed for functional and morphologic assessment of both reconstructed arteries after the arterial switch operation. Longitudinal analysis focused on neoaortic valve function, neoaortic obstruction, and neopulmonary stenosis as well as on the time-related size changes of both roots, with its clinical implications. RESULTS: Within a mean follow-up of 4.8 +/- 3.9 years, aortic regurgitation of 2 or greater developed in 10% in TGA with intact ventricular septum (IVS) versus 23% in TGA with ventricular septal defect (VSD). A VSD and major pulmonary to aortic annulus size discrepancy were main precursors of early neoaortic valve dysfunction, whereas development of aortic regurgitation of 2 or greater was additionally promoted by the duration of follow-up. Presence of a VSD enhanced neoaortic root enlargement, resulting in a mean root z-score of 3.25 in TGA/VSD versus 1.96 in TGA/IVS. Root dilation was more severe in case of aortic regurgitation of 2 or greater (z = 3.38). Neoaortic obstruction occurred in 8%, mostly at the neosinotubular anastomosis, and correlated with prior pulmonary to aortic ratio greater than 1.5. Concerning the neopulmonary tract, increased flow velocity was observed in 24%, primarily at the supravalvular level. Two patients with pulmonary annulus hypoplasia (z < -2) required early reintervention. Regarding clinical outcome, freedom from reintervention at 1, 5, and 10 years was, respectively, 98%, 96%, and 96% for TGA/IVS, versus 65%, 63%, and 63% for TGA/VSD. A VSD and aortic arch obstruction were significant predictors for reintervention. CONCLUSIONS: After arterial switch operation, the neoaortic root is usually enlarged, but with a growth pattern comparable to that of a normal population. The association of a VSD and major arterial root size discrepancy predisposes to both neoaortic valve dysfunction and root enlargement. Severe root dilation appears to be closely related to significant neoaortic valve regurgitation, mainly as a result of a time-depending and reciprocal process. Neopulmonary stenosis is a frequent finding, but rarely has clinical consequences. Because the factor "time" is the principal determinant of late neoaortic valve dysfunction and root dilation, strict serial surveillance after arterial switch operation is mandatory.