Intrapulmonary shunt in the course of pediatric liver transplantation

Reliable Detection of Intrapulmonary Shunts Using Contrast-Enhanced Echocardiography in Children With Portal Hypertension or Portosystemic Shunt

OBJECTIVES

The aim of this study was to analyze if contrast-enhanced echocardiography (CEE) is as reliable as lung perfusion scintigraphy (LPS) to detect intrapulmonary shunting (IPS) in children with portal hypertension (PHTN) or congenital/surgical portosystemic shunts (PSS) and to define the number of cardiac cycles required to exclude intrapulmonary shunting.

METHODS

Inclusion criteria for this cross-sectional study were: (1) presence of PHTN or PSS diagnosed on abdominal ultrasound, (2) technically valid saline contrast echocardiography, (3) lung perfusion scintigraphy within 6 months of CEE. The number of cardiac cycles between right atrial opacification and the arrival of contrast in the left atrium were counted. We analyzed our CEE data at three and five cardiac cycles and compared them with LPS results.

RESULTS

The study population was composed of 78 children (38 girls, 49%) ages 2.1-18.8 years (mean 9.8). Sixty-nine patients had PHTN (88%), and nine had a PSS (11%). Eleven subjects (14%) presented evidence of IPS on LPS. Peripheral oxygen saturation was lower in the subjects with IPS detected on LPS (95.3 ± 1.7% vs 99.0 ± 1.4%; P < 0.01). Comparison of LPS with CEE before three and five cardiac cycles showed that CEE is highly specific (95.7%) as early as three cardiac cycles with markedly better sensitivity (72.7%) when using five cardiac cycles. Furthermore, a negative study using five cardiac cycles ruled out IPS with a 95% negative predictive value. The cardiac cycle at which the bubbles appeared in the left atrium was inversely correlated to the shunt index measured using LPS (r = -0.563; P = 0.001).

CONCLUSION

CEE is sufficient for the screening of IPS in children with PHTN or congenital/surgical PSS, obviating the need for LPS.

Time-dependent reversal of significant intrapulmonary shunt after liver transplantation

BACKGROUND/AIMS

Although the association between intrapulmonary shunt (IPS) and liver cirrhosis is clear, data of repeated contrast echocardiography (CE) before and after liver transplantation (LT) to evaluate factors associated with IPS are limited.

METHODS

Hand-agitated saline was used for CE and, by assessing left-chamber opacification, IPS was classified as grade 0 to 4. Grade 3/4 constituted significant IPS and hepatopulmonary syndrome (HPS) was defined as significant IPS with the arterial partial pressure of oxygen < 70 mmHg.

RESULTS

Before LT, 253 patients underwent CE and the frequency of significant IPS and HPS were 44% (n = 112) and 7% (n = 17), respectively. Child-Pugh score (odds ratio [OR], 1.345; 95% confidence interval [CI], 1.090 to 1.660; p = 0.006) and arterial oxygen content (OR, 0.838; 95% CI, 0.708 to 0.991; p = 0.039) were independent determinants of significant IPS, whereas direct bilirubin (OR, 1.076; 95% CI, 1.012 to 1.144; p = 0.019) was the only variable associated with HPS. Among 153 patients who underwent successful LT, repeated CE was performed in 97 (63%), which showed significant reductions in IPS grade (from 2.6 ± 1.0 to 1.2 ± 1.3, p < 0.001) and the prevalence of significant IPS (from 56% to 20%, p = 0.038). After adjustment for pre-LT IPS grade, time from LT to repeated CE presented negative linear relationship with post-LT IPS grade (r 2 = 0.366, p < 0.001) and was the only determinant of post-LT IPS grade (OR, 1.009; 95% CI, 1.003 to 1.014; p = 0.004).

CONCLUSION

Repeated CE is useful to evaluate intrapulmonary vascular change before and after LT. Reversal of IPS after successful LT is time-dependent and follow-up duration should be considered for accurate assessment of IPS after LT.

Experiences with endoscopic interventions for variceal bleeding in children with portal hypertension: a single center study

PURPOSE

The aim of this study was to compare the efficacy and safety of band ligation and injection sclerotherapy in the endoscopic treatment of children with variceal bleeding.

METHODS

The study population included 55 children, all of whom were treated at the time of endoscopic diagnosis of esophageal varices at Asan Medical Center, Seoul, Korea, between January 1994 and January 2011. The primary outcomes included initial success rates and duration of hemostasis after endoscopic management (band ligation vs. injectionsclerotherapy).

RESULTS

The mean age was 6.7±5.2 years and the mean follow-up time was 5.4±3.7 years. The most common cause of esophageal varices was biliary atresia. Of 55 children with acute variceal bleeding, 39 had band ligation and 16 had injection sclerotherapy. No differences between groups were observed in terms of the size, location, and presence of red color sign. The success rates of band ligation and sclerotherapy in the control of acute bleeding episodes were 89.7% and 87.5%. The mean duration of hemostasis after endoscopic intervention was 13.2±25.1 months. After one year, 19 of 39 patients (48.7%) treated with band ligation and 7 of 16 patients (43.8%) with injection sclerotherapy had experienced rebleeding episodes. Complications after the procedures were observed in 10.3% and 18.8% of children treated with band ligation and injection sclerotherapy.

CONCLUSION

The results of our current study suggest that band ligation and injection sclerotherapy are equally efficient treatments for the control of acute variceal bleeding and prevention of rebleeding.

Hepatopulmonary syndrome in children with cirrhotic and non-cirrhotic portal hypertension: a single-center experience

BACKGROUND

Hepatopulmonary syndrome (HPS) is defined as an arterial oxygenation defect induced by intrapulmonary vascular dilatation (IPVD) associated with hepatic disease. The prevalence and clinical characteristics of HPS in portal hypertensive children is not well characterized.

AIMS

The aim of this study was to investigate the prevalence and clinical characteristics of HPS in 40 portal hypertensive children.

METHODS

We studied 40 children (11 girls and 29 boys; mean age, 111 months ± 52 months; range, 24-216 months) with portal hypertension (24 cirrhotic, 16 non-cirrhotic) for the presence of HPS using blood gas analysis, contrast-enhanced echocardiography (CEE), and Tc99m-macroaggregated albumin scintigraphy. Clinical and laboratory characteristics of patients were recorded. HPS was considered to be present in a patient with hypoxemia and/or an elevated alveolar-arterial oxygen gradient (PAaO(2)) ≥ 15 mmHg) and positive CEE and/or scintigraphy.

RESULTS

Elevated PAaO(2) was detected in 7 of 24 patients with cirrhosis. Four of them also had IPVD with CEE. An intrapulmonary shunt in Tc99m-MAA with CEE was shown in one patient. A diagnosis of HPS was made in 16.7% of the patients with cirrhosis. Cirrhotic patients without IPVD had significantly better hepatic function and lower pediatric end-stage liver disease scores. Although, 2 of the 16 patients with non-cirrhotic portal hypertension had elevated PAaO(2,) none of them showed IPVD. One normoxemic patient in the non-cirrhotic portal hypertension group showed IPVD with CEE. None of the non-cirrhotic patients fulfilled the diagnostic criteria of HPS.

CONCLUSION

Hepatopulmonary syndrome particularly occurs in cirrhotic portal hypertensive patients with severe hepatic dysfunction.

Long-term outcomes of pediatric living donor liver transplantation at a single institution

There have only been a few studies on the long-term outcomes and prognostic factors after pediatric LDLT. We conducted a retrospective, single-center assessment of the outcomes as well as the demographic and clinical factors that influenced the poor outcomes in 113 children aged <16 (median age 21 months; 6 months-15.5 yr) who underwent 115 LDLTs, predominantly for biliary atresia (60.9%) and FHF (14.8%), between 1994 and 2006 at Asan Medical Center. Left lateral segment or left lobe grafts were implanted into most of these children (86.9%) according to routine procedures. The overall rates of graft survival at one, five, and 10 yr were 89.6%, 83.0%, and 81.5%, respectively, and the overall rates of patient survival were 92.9%, 86.3%, and 84.8%, respectively. Virus-related disease (41.2%) and chronic rejection (29.4%) were the major causes of mortality. On multivariate analysis, UNOS status 1a and 1b and chronic rejection were significant risk factors for both graft and patient loss, whereas the PELD score >25 was a significant risk factor for graft loss. Patient and graft survival may be related not only to post-operative complications, but also to the patient's preoperative clinical condition.