Liu et al. BMC Pediatrics(2024) 24:515
https://doi.org/10.1186/s12887-024-04936-3

BMC Pediatrics

RESEARCH

Open AccessPredictors of length of hospital stay after
pediatric Ebstein anomaly corrective surgery:a retrospective cohort study
Qiao Liu1, Xie Wu1, Yinan Li1, Jie Ding1, Hongbai Wang1, Dou Dou1, Ran An1, Dongyun Bie1, Yuan Jia1, Su Yuan1 andFuxia Yan1*
Abstract
Background The remarkable advancements in surgical techniques over recent years have shifted the clinical focus
from merely reducing mortality to enhancing the quality of postoperative recovery. The duration of a patient’s
hospital stay serves as a crucial indicator in evaluating postoperative recovery and surgical outcomes. This study aims
to identify predictors of the length of hospital stay for children who have undergone corrective surgery for Ebstein
Anomaly (EA).
Methods We conducted a retrospective cohort study on children (under 18 years of age) diagnosed with EA whowere admitted for corrective surgery between January 2009 and November 2021 at Fuwai Hospital. The primary
outcome was the Time to Hospital Discharge (THD). Cox proportional hazard models were utilized to identify
predictors of THD. In the context of time-to-event analysis, discharge was considered an event. In cases where deathoccurred before discharge, it was defined as an extended THD, input as 100 days (exceeding the longest observed
THD), and considered as a non-event.
Results A total of 270 children were included in this study, out of which three died in the hospital. Following
the Cox proportional hazard analysis, six predictors of THD were identified. The hazard ratios and corresponding
95% confidence intervals were as follows: age, 1.030(1.005,1.055); C/R > 0.65, 0.507(0.364,0.707); Carpentier typeC or D, 0.578(0.429,0.779); CPB time, 0.995(0.991,0.998); dexamethasone, 1.373(1.051,1.795); and transfusion,
0.680(0.529,0.875). The children were categorized into three groups based on the quartile of THD. Compared tochildren in the ≤ 6 days group, those in the ≥ 11 days group were associated with a higher incidence of adverse
outcomes. Additionally, the duration of mechanical ventilation and ICU stay, as well as hospital costs, weresignificantly higher in this group.
Conclusion We identified six predictors of THD for children undergoing corrective surgery for EA. Clinicians canutilize these variables to optimize perioperative management strategies, reduce adverse complications, improve
postoperative recovery, and reduce unnecessary medical expenses.
Keywords Ebstein anomaly (EA), Time to hospital discharge (THD), Pediatric cardiac surgery, Predictor*Correspondence:
Fuxia Yanyanfuxia@sina.com

1

1Department of Anesthesiology, Fuwai Hospital, National Center of
Cardiovascular Diseases, Chinese Academy of Medical Sciences andPeking Union Medical College, 167 Beilishi Road, Xicheng District,
Beijing 100037, China© The Author(s) 2024. Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use,sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) andthe source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in thisarticle are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not includedin the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you willneed to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. The
Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available
in this article, unless otherwise stated in a credit line to the data.

Liu et al. BMC Pediatrics(2024) 24:515

Background
Accurate prediction of hospitalization duration is crucial for hospital management and rational allocationof medical resources, which helps to improve the quality and efficiency of medical care services and avoid
unnecessary long-term care. Postoperative hospital stay
duration is one of the significant indicators in pediatriccardiac surgery and is associated with long-term neurological development after surgery [1, 2]. Even a single
additional day in the hospital can significantly impact
morbidity and hospital costs following cardiac surgery.
In clinical practice, the preoperative status and perioperative information of patients are important sources forpredicting the length of hospital stay. Previous studies [3,4] have analyzed the impact of relevant clinical variableson the length of hospital stay through scientific statisticalmodels and large data sets, helping hospital administrative departments plan personnel allocation reasonably.
Ebstein Anomaly (EA), also known as tricuspid valve displacement malformation, is a rare congenital heart disease characterized by the displacement of the posteriorand septal leaflets of the tricuspid valve to the right ventricle, resulting in an atrialized right ventricle (aRV) [5].
Patients with EA usually combined with patent foramen
ovale or atrial septal defects and exhibit varying degreesof tricuspid valve insufficiency and right heart dysfunction [6]. The primary goal of EA corrective surgery is torestore the physiological function of the tricuspid valve
and the right ventricle. Although EA is a rare and complex congenital heart disease with an incidence as low as
1 per 200,000 live births [6, 7], focusing on patients withrare diseases can still yield valuable insights. Therefore,
this study sought to identify predictors of the length of
hospital stay in children who underwent EA corrective
surgery by retrospectively collecting perioperative clinical information.
Methods
This study was designed as a retrospective cohort
study and adheres to the Strengthening the Reportingof Observational Studies in Epidemiology (STROBE)
statement (Additional File 1). All methods were compliant with our hospital regulations and the 1964 Helsinki
Declaration. The research was approved by the Ethics
Committee of the Chinese Academy of Medical Sciences
Fuwai Hospital (No.2022 − 1647), and informed consent
was waived due to the nature of the retrospective study.
We included children (age < 18 years) who underwent EA
corrective surgery in Fuwai Hospital from January 2009
to November 2021. Children combined with confounding factors that may affect the hospital stay time were
excluded: previous history of bidirectional glenn surgery,complex cardiac malformations (corrected transposition of a great artery, pulmonary atresia, single ventricle,

Page 2 of 10

endocardial cushion defect, coronary artery fistula). The
surgical indications for EA patients are as follows: severeTR, cyanosis, dyspnea, right heart failure, cardiac hypertrophy, C/R > 0.65, tachyarrhythmias, and associatedother cardiac defects [8]. Surgeons performed cardiac
surgery for EA children based on the cardiac anatomical
structure and clinical experience. The surgical technique
included modified Carpentier’s method, modified Danielson method, tricuspid valve replacement, surgical ablation or division, and radiofrequency ablation.
Children’s data was collected from admission to discharge via the institution’s electronic medical record system and checked by two independent researchers. The
preoperative information was obtained: age, gestationalage, sex, weight, height, body mass index (BMI), blood
oxygen saturation (SpO2), New York Heart Association
Classification, symptoms, medication, cardiothoracic
ratio (C/R), arrhythmia, cardiac defects, preoperativelaboratory tests, and echocardiography data. The SpO2
was obtained before surgery when the children inhaled
the air. A bluish or purplish discoloration of the skin,lips, or nail beds and a SpO2 less than 90% after inhaling air was considered cyanosis. The intraoperative data
included surgical technique, cardiopulmonary bypass(CPB) time, aortic cross-clamp (ACC) time, the minimum temperature during CPB, drugs, the intraoperative
maximum vasoactive-inotropic score (VISm), infusion
volume, transfusion, and blood loss. Clinicians used thePhilips iE33 ultrasound system (Philips Medical Systems,
Andover, MA) with S8 or S12 phased array probe to evaluate the preoperative cardiac structure of EA patients in
our hospital. The acquisition of echocardiography images
through multiple standard ultrasound windows, including the parasternal long axis, parasternal short axis, apical four chambers, and subcostal view. We collected thefollowing parameters in particular: left ventricular ejection fraction, tricuspid regurgitation (TR), right ventricular anteroposterior diameter, septal leaflets displacement,
posterior leaflets displacement, aortic valve annulus
diameter, pulmonary valve annulus diameter, left pulmonary artery diameter, and right pulmonary artery diameter. TR was characterized as none, mild, moderate, andsevere based on color flow maps. The Carpentier’s classification method was used to classify the anatomy of EA.
In addition, the left ventricular end-diastolic diameterz-score (LVEDDz) was calculated to reflect the left ventricular end-diastolic diameter.
The primary outcome was the Time to Hospital Discharge (THD), defined as the number of days from surgery to discharge. Secondary outcomes included adverse
events, mechanical ventilation time, acute kidney injury(AKI), acute hepatic injury (AHI), ICU stay time, hospital stay time, and hospitalization costs. Adverse eventswere a composite outcome referring to in-hospital death,Liu et al. BMC Pediatrics(2024) 24:515

re-exploratory thoracotomy, extracorporeal membrane
oxygenation placement, reintubation, respiratory failure,
low cardiac output syndrome (LCOS), malignant ventricular arrhythmia, and continuous renal replacement
therapy. LCOS was defined as a maximum vasoactive
inotropic score greater than 20 within 24 h after surgery[9]. Respiratory failure was defined as a postoperativeoxygenation index of less than 100 [10]. AKI was defined
as a postoperative creatinine level more than 1.5 times
the baseline level [11]. AHI was defined as postoperative aspartate aminotransferase (AST) or alanine aminotransferase more than 2 times the upper limit, excluding
increased AST within 24 h [12].
Statistical analysis

To compare perioperative information of children withdifferent hospital stay times, we divided them into threegroups based on quartiles of THD. Descriptive statistics were used to summarize the children’s characteristics. Continuous data were presented as median (25th,
75th percentile) and compared using the Mann-Whitney U test (for two groups) or the Kruskal-Wallis H test(for more than two groups). Categorical variables were
described as absolute counts with percentages and compared using the Chi-squared test. For the time-to-event
analysis, hospital discharge was considered an event. In
contrast, death before discharge was defined as a prolonged THD, input as 100 days (longer than the longest
THD), and considered as no event. Univariable and multivariable COX proportional hazard models were used toassess predictors for THD. Variables with P < 0.1 in theunivariable model and clinically relevant variables wereincorporated into a multivariable model. Collinearity
relationships between predictors were evaluated by tolerance and Variance Inflation Factor (VIF). Tolerance < 0.1
and/or VIF > 10 indicated a collinear relationshipbetween variables. Results from the Cox proportional
hazards models are presented as hazard ratios (HRs) with
95% confidence intervals (95% CIs). HR < 1 indicated alower discharge rate (longer THD), and HR > 1 indicateda higher discharge rate (shorter THD). The Kaplan‑Meiersurvival curves were used to present the relationships
between predictors and postoperative hospital stay time.
P < 0.05 was considered statistically significant. All statistical analysis was conducted in SPSS software version
25 (IBM, Armonk, NY, USA) and GraphPad Prism 7.0(GraphPad Software, Inc.).

Results
Basic characteristics

Over the past 13 years, 278 children underwent EA corrective surgeries at Fuwai Hospital. Eight children were
excluded due to previous history of bidirectional glenn
surgery(n = 4), and complex cardiac malformations

Page 3 of 10(n = 6). Consequently, 270 children were included in thisstudy. Children were classified into three groups according to the THD quartile and the perioperative information was displayed in Tables 1 and 2. The median age of
all children was 5.2(2.5,10.7) years, and 146(54.1%) weremale. The median SpO2 was 98% (95%,99%), and mostchildren combined with a heart murmur (72.6%). 19.6%(n = 53) of children had a C/R > 0.65 and 36 (13.3%) children with preoperative WPW syndrome. Most children had an atrial septal defect or patent foramen ovale.
Regarding echocardiography results, the median ejection
fraction was 65% (62%,70%), the median LVEDDz was− 1.9(-2.8, -1), the median displacement of septal leaflet and posterior leaflet were 20(14,27) and 32(12,42),
respectively. 180(66.7%) children presented with severe
TR. Intraoperative data showed that 205(75.9%) surgeries
performed modified Carpentier’s technique, the median
CPB and aortic cross-clamp times were 110 (90,139) and76 (61,96) minutes, respectively. The median VISm was
9.5(5,13), and 148(54.8%) children received transfusions.
Children in the ≥ 11 days group were younger, and had
a lower value of BMI, hemoglobin, hematocrit, and aortic annular diameter, compared to those in the ≤ 6 days
group. They also had higher VISm, longer CPB time, anda higher rate of C/R > 0.65, Carpentier C or D, glenn, andtransfusion.
Predictors of THD

The univariable analysis demonstrated that NYHA class(III/IV), C/R > 0.65, Carpentier type C or D, glenn, transfusion, higher CPB time, and VISm were associated witha lower rate of hospital discharge (i.e., longer THD). In
contrast, older age, longer height, palpitation, and dexamethasone were associated with a higher rate of hospital discharge (i.e., shorter THD). The HRs and 95% CIs
of univariable analysis were shown in Additional File 2. A
multicollinearity test was conducted and found a highly
collinear relationship between age and height. Given thatheight was correlated with age, and then we excluded
height from the multivariable analysis. Upon performing a multivariable Cox analysis (Table 3), C/R > 0.65,
Carpentier type C or D, longer CPB time, and transfusion were still significantly associated with a lower rateof hospital discharge (i.e., longer THD). In contrast, older
age and the use of dexamethasone were associated witha higher rate of hospital discharge (i.e., shorter THD).
The Kaplan‑Meier survival curves from the multivariate
Cox analysis also displayed the relationship of categoricalvariables (C/R > 0.65, Carpentier type C or D, transfusion,and dexamethasone) with postoperative hospitalization(Fig. 1).

Liu et al. BMC Pediatrics(2024) 24:515

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Table 1 The demographic and preoperative information of the study children
VariableAge (years)
Gestational age (weeks)male
Weight (kg)Height (cm)BMI (kg/m2)
SpO2(%)
NYHA class (III/IV)
Symptoms
CyanosisTachypnoea
Heart murmur
Palpitation
Chest tightness
Medication
Diuretics
Beta-blocker
ACEI
Inotropes
C/R > 0.65
WPW syndrome
ASD
PDA
PFO
WCC (109/L)
RBC (1012/L)
PLT (109/L)
Neutrophil
Lymphocyte
Monocyte
Hb(g/L)Hct (%)CK-MB (IU/L)
hs-CRP(mg/L)

Total
5.2(2.5,10.7)
40(39,40)
146(54.1%)
18.8(13,33)
110(89,141)
16.5(15.1,18.4)
98(95,99)
32(11.9%)≤ 6 days
6.2(3,13.8)
40(40,40)
33(63.5%)
22.3(14.4,53.3)
117(92,161)
17.6(16,21.4)
98(96,99)4(7.7%)

7 to 10 days
6(2.9,10.8)40(39,40)
80(55.2%)
19(13.8,35)
112(92,142)
16.4(14.9,18.1)
98(95,99)13(9%)≥ 11 days
4(1.9,6.7)40(39,40)
33(45.2%)
16(10.5,24.5)
104(83,122)
16(14.6,17.8)
96(91,99)
15(20.5%)

P value
0.022b, c
0.189
0.041c0.005b, c
0.010 b, c
< 0.001a, b
0.138
0.018b, c

46(17%)
20(7.4%)
196(72.6%)21(7.8%)9(3.3%)

5(9.6%)
4(7.7%)
36(69.2%)8(15.4%)2(3.8%)

28(19.3%)7(4.8%)
106(73.1%)11(7.6%)5(3.4%)

13(17.8%)9(12.3%)54(74%)
2(2.7%)
2(2.7%)

0.290b
0.237c0.579
0.010a, b,c0.726

105(38.9%)8(3%)
18(6.7%)19(7%)
53(19.6%)
36(13.3%)
83(37.7%)4(1.8%)
11(22.4%)
8.3(6.5,9.5)
4.8(4.6,5.2)
279(239,333)
3.1(2.5,4.2)
3.9(2.9,4.7)
0.48(0.37,0.58)
135(128,144)
39.4(36.8,42.4)
16(9,27)0.41(0.18,0.95)

22(42.3%)
1(1.9%)
1(1.9%)
4(7.6%)
8(15.4%)8(15.4%)19(38.8%)0(0%)
40(34.2%)8(6.8,9.5)
4.8(4.6,5.3)
305(259,345)
3.6(2.4,4.6)
3.6(2.8,5)0.47(0.35,0.58)
140(129,150)
41.2(38.2,44.1)
14(5.8,22.8)
0.41(0.14,1.08)

55(37.9%)4(2.8%)
11(7.6%)12(8.2%)21(14.5%)20(13.8%)
41(35%)
1(0.95)17(31.5%)
8.3(6.3,9.4)
4.8(4.6,5.1)
279(242,329)
3.1(2.7,4.2)
3.7(2.8,4.6)
0.47(0.36,0.58)
136(128,145)
39.4(36.8,42.5)
19(12,28)
0.41(0.17,0.94)

28(38.4%)3(4.1%)
6(8.2%)
3(4.2%)
24(32.9%)
8(11%)
23(42.6%)3(5.6%)
68(30.9%)
8.3(6.7,10.1)
4.8(4.5,5)279(228,319)
2.7(2.4,4.2)
4.5(3.4,4.6)
0.51(0.38,0.58)
134(126,139)
37.6(36.8,40.5)
13(3.3,25.5)
0.41(0.28,0.95)

0.352
0.465
0.195b0.574
0.007b, c
0.459
0.668
0.032b, c
0.343
0.766
0.153
0.172
0.184
0.107
0.474
0.003b, c< 0.001b, c
0.016a, c
0.902

Quantitative variables are expressed as median with interquartile range; Categorical variables are expressed as frequency (percentage). BMI, body mass index; SpO2,
peripheral oxygen saturation; NYHA class, New York Heart Association Classification; ACEI, angiotensin-converting enzyme inhibitor; C/R, cardiothoracic ratio; WPW,
Wolff-Parkinson-White; ASD, atrial septal defect; PDA, patent ductus arteriosus; PFO, patent foramen ovale; WCC, white blood cell; RBC, red blood cell; PLT, platelet;
Hb, Hemoglobin; Hct, hematocrit; CK-MB, isoenzyme of creatine kinase-MB; hs-CRP, C-reactive protein; a: the significant difference of results between the ≤ 6 days
group and the 7 to 10 days group; b: the significant difference of results between the ≤ 6 days group and the ≥ 11 days group; c: the significant difference of results
between 7 to 10 days group and ≥ 11 days groupIn-hospital outcomes

In total, 32 (11.9%) children experienced adverse events,
and the specifics are described in Additional File 3. Figure 2 visually displays the relationship between adverse
outcomes and THD, showing that as THD increased, theincidence and number of adverse events also increased.
We also summarized the other in-hospital outcomes inTable 4. Compared to children in the ≤ 6 days group, children in the ≥ 11 days group were associated with a higher
incidence of adverse outcomes, AKI, and AHI. Additionally, the duration of mechanical ventilation, ICU stay, andhospital stay, as well as hospital costs, were significantly
higher in the ≥ 11 days group.

Discussion
With the remarkable advancement of cardiac surgery
technology and perioperative management in recent
years, the survival rate of cardiac surgery has significantly increased [13]. This shift has redirected medical
focus from reducing mortality to improving the qualityof postoperative recovery and optimizing the allocationof medical resources. The mortality after cardiac surgery
has become very low, leading many medical institutions
to consider hospital stay duration as one of the crucial
clinical indicators to evaluate postoperative recovery[14]. Early discharge and rational allocation of medical
resources are currently issues of concern in the medical

Liu et al. BMC Pediatrics(2024) 24:515

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Table 2 The cardiac diagnosis and intraoperative information of the study children
Variable
Echocardiography data
LVEF (%)
TR
Mild
Moderate
SevereCarpentier typeType A
Type B
Type CType DLVEDDzRVAD (mm)SLD (mm)
PLD (mm)
ANND (mm)PVA (mm)
LPA (mm)
RPA (mm)
Surgical information
Surgical technique
Modified Carpentier method
Modified Danielson method
TVR
Glenn
Surgical ablation or division
Radiofrequency ablation
CPB time (min)ACC time (min)Tmin (℃)
Sufentanil (ug/kg)
Dexamethasone
Ulinastatin
VISm
Infusion volume (ml)Transfusion
Blood loss (ml)Total

≤ 6 days

7 to 10 days

≥ 11 days

P value65(62,70)

65(61,70)

65(62,70)

66(62,71)

0.680
0.270

20(7.4%)53(19.6%)
180(66.7%)1(1.9%)
10(19.2%)
39(75%)

13(9%)
30(20.7%)
92(63.4%)

6(8.2%)
13(17.8%)
49(67.1%)< 0.001b, c

38(14.1%)
165(61.1%)
62(23%)
5(1.9%)-1.9(-2.8,-1)
25(20,30)
20(14,27)
32(12,42)
15(13,18)
15(12,17.3)
10(8,10)
10(8,11)12(23.1%)
34(65.4%)
6(11.5%)0(0%)-1.7(-3.1,-0.9)25(19,33)
20(14,28)
32(19,45)
16(13,19)
16(12,18.8)
10(8,11)
10(8,11.8)

20(13.8%)
97(66.9%)28(19.3%)0(0%)-2(-2.6,-1.2)
25(19,30)
20(14,26)
32(22,43)
15(13,18)
15(12,17)
10(8,11)
10(8,11)6(8.2%)
34(46.6%)
28(38.4%)5(1.9%)-1.9(-2.7,-1)
25(21,30)
22(14,29)
32(20,40)
13(12,16)
14(11,17)9(7.5,10)
9(7,10)

0.909
0.768
0.973
0.781
0.001b, c
0.331
0.081
0.049b205(75.9%)63(23.3%)9(3.3%)
50(18.5%)5(1.9%)
6(2.2%)
110(90,139)
76(61,96)30(29.6,31)
2.6(1.9,4.4)
177(65.6%)
92(34.1%)
9.5(5,13)90(55,300)
148(54.8%)60(30,200)

39(75%)
13(25%)
4(7.7%)
3(5.8%)
1(1.9%)
1(1.9%)
101(89,134)
74(63,97)
30.5(29.6,31)
2.6(1.7,4.9)34(65.4%)
19(36.5%)6(5,10)100(56,300)
20(38.5%)70(30,360)

106(73.1%)
38(26.2%)
1(0.7%)
28(19.3%)
2(1.4%)
4(2.8%)
104(87,135)
71(60,92)
30(29.7,31)
2.6(1.9,4.4)
106(73.1%)
49(33.8%)9(5,13)90(55,300)
81(55.9%)70(30,200)

60(82.2%)
12(16.4%)4(5.5%)
19(26%)
2(2.7%)
1(1.4%)
129(105,147)
85(69,105)
30(29.3,31)
2.5(1.9,4)37(50.7%)24(32.9%)10(6,16)80(58,200)
47(64.4%)45(23,80)

0.288
0.210
0.726a0.005ab
0.684
0.776
0.001b, c
0.034b, c
0.378
0.954
0.042b, c
0.683
0.006b, c
0.428
0.005b
0.020cQuantitative variables are expressed as median with interquartile range; Categorical variables are expressed as frequency (percentage). LVEF, left ventricular ejection
fraction; TR, tricuspid regurgitation; LVEDDz, left ventricular end-diastolic diameter z-score; RVAD, right ventricular anteroposterior diameter; SLD, Septal leaflets
displacement; PLD, Posterior leaflets displacement; ANND, aortic valve annulus; PVAD, pulmonary valve annulus diameter; LPA, left pulmonary artery diameter; RPA,
right pulmonary artery diameter; TVR, tricuspid valve replacement; CPB, cardiopulmonary bypass; ACC, aortic cross-clamp; Tmin, the minimum temperature; VISm, theintraoperative maximum vasoactive inotropic score; a: the significant difference of results between the ≤ 6 days group and the 7 to 10 days group; b: the significant
difference of results between the ≤ 6 days group and the ≥ 11 days group; c: the significant difference of results between 7 to 10 days group and ≥ 11 days groupfield. Therefore, accurately predicting discharge time andidentifying high-risk patients with extended hospitalization can help arrange patients more effectively, improve
bed utilization, enhance healthcare service efficiency,
and optimize the rational allocation of medical resources[15]. Previous studies have employed various statistical methods to construct clinical models for predicting
hospitalization duration, including regression analysis,
machine learning, deep learning, etc [14–18]. However,these studies typically involve a wide range of diseases,

with little attention paid to specific populations of certain
heart malformations, and they often require complex statistical processes. Consequently, the use of these predictive models in clinical applications has been limited. Dueto the extremely low incidence of EA, no studies havebeen conducted to predict the length of hospital stayfor children with EA. As China’s largest cardiovascularspecialized hospital, we receive several children with EA
every year. Therefore, we attempt to establish a simple
model based on routinely available clinical variables toLiu et al. BMC Pediatrics(2024) 24:515

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Table 3 Multivariable cox proportional hazards model
Predictor

Age (years)
Height (cm)
NYHA class(III/IV)
Palpitation
C/R > 0.65
Carpentier
type C or DGlenn
CPB time(min)
Dexamethasone
VISm
Transfusion

Univariable modelMultivariable modelHR(95%CI)
P
HR(95%CI)
P
value
value
1.032(1.008,1.057) 0.009 1.030(1.005,1.055) 0.019
1.005(1.002,1.009) 0.003
0.651(0.448,0.945) 0.024
1.984(1.264,3.112) 0.003
0.494(0.357,0.682) < 0.001 0.507(0.364,0.707) < 0.001
0.477(0.356,0.638) < 0.001 0.578(0.429,0.779) < 0.001
0.638(0.467,0.871)
0.995(0.992,0.998)

0.005
0.001 0.995(0.991,0.998)

0.001

1.494(1.156,1.930)

0.002 1.373(1.051,1.795)

0.020

0.983(0.966,1.000)
0.698(0.546,0.892)

0.046
0.004 0.680(0.529,0.875)

0.003

HR, hazard ratio; CI, confidence interval; NYHA class, New York Heart Association
Classification; C/R, cardiothoracic ratio; CPB, cardiopulmonary bypass; VISm, theintraoperative maximum of vasoactive inotropic scorepredict hospitalization duration early, utilizing preoperative and intraoperative information for EA children.
In this study, univariable and multivariable COX analyses were used to identify predictors for THD in children
with EA. We found that a C/R > 0.65, Carpentier type Cor D, longer CPB time, and transfusion were associatedwith longer THD, whereas older age and the use of dexamethasone were associated with shorter THD.
Due to a failure of the delamination of tricuspid valve
leaflets during embryonic development in EA patients,
causing the posterior displacement of posterior and septal leaflets and the formation of aRV [19]. The enlargement of aRV could gradually affect the function of thefunctional right ventricle (fRV) and eventually result inright heart failure which would threaten the survival timefor EA patients. Generally speaking, the severity of EA is
inversely related to the size of fRV [20]. As the functionof the right heart deteriorates, the heart enlarges, and anincreased C/R is observed on chest radiographs [21]. Previous research has found that preoperative C/R > 0.65 is
an independent predictor of poor outcomes in EA thatmight related to the increase in hospitalization duration[7, 22]. EA has a wide range of anatomic features due tothe difference in valve leaflet displacement and the sizeof aRV. No classification method could cover the characteristics of all EA patients, Carpentier type [23] waswidely used to categorize the anomaly of EA because of
its simplicity. Despite the Carpentier type not being completely consistent with the severity of EA, Carpentier C
or D usually means a larger aRV or a small fRV comparedwith type A or B [24]. Previous studies also have foundthat Carpentier C or D are usually associated with poor
clinical outcomes which could prolong postoperative

recovery and increase hospital stay time [20, 25–27]. In
addition, CPB can cause multifaceted damage to systemicorgans, including organ ischemia, reperfusion injury,
activated systemic inflammatory response, oxidative
stress, microemboli, and changes in cellular metabolism[28]. The direct contact of the CPB artificial pipeline withendothelial tissue activates pro-inflammatory cytokines,
such as TNF-α, IL-6, TGF-β, promoting inflammatorycascade reactions and exacerbating tissue and endothelial
cell damage [29]. Under the shear force caused by CPB,
blood cells are prone to rupture, causing microemboli
composed of fibrin, cellular fragments, fat, and air, damaging the microcirculation of organs [30]. Therefore, thelonger the CPB time, the more severe the damage to thesystemic system, which is not conducive to postoperative recovery. While surgeons advocate for cardiac surgery without CPB to reduce the inflammatory response
and accelerate postoperative recovery, CPB is still indispensable for most pediatric complex cardiac surgeries.
Moreover, a longer duration of CPB may indicate complex surgical techniques, poor patient physiology, andunexpected adverse events during surgery, all of which
are related to poor prognosis and prolonged hospital staytime [31].
Blood transfusion is common during pediatric complex
cardiac surgery, especially for children with low weightand preoperative anemia. However, allogeneic bloodtransfusion, while life-saving, may also bring negative
effects, including respiratory dysfunction, kidney injury,
surgical site infection, and even death [32, 33]. Besides,
transfusions may be associated with other factors suchas anemia, intraoperative excessive bleeding, circulatory instability, and other unexpected events that would
increase the risk of prolonged THD. In our developing country, many patients are unable to undergo regular prenatal examinations due to economic constraints.
EA patients often only receive surgical treatment when
they present obvious symptoms such as severe tricuspid
regurgitation, cyanosis, dyspnea, and right heart failure[34]. Severe EA patients are extremely critical during theinfancy period and must receive surgery immediately,while mild patients only develop obvious symptoms as
they grow older [19, 35]. Therefore, younger children who
undergo EA corrective surgery usually present severe
symptoms. Prior literature has found that compared toolder children, younger children have less mature development of the circulatory and nervous systems, causing
them to be susceptible to surgical and CPB stimulation,and requiring a longer time to recover [15, 36, 37]. In
cardiac surgery, surgical trauma, direct contact between
vascular endothelial tissue and artificial pipelines, andorgan ischemia-reperfusion injury can activate systemic
immune-inflammatory responses. Dexamethasone, as a
glucocorticoid, can inhibit inflammatory response andLiu et al. BMC Pediatrics(2024) 24:515

Page 7 of 10

Fig. 1 The Kaplan‑Meier survival curves for postoperative hospitalization. Times refers to the length of hospital stay after surgery. C/R, cardiothoracic ratio

reduce the associated inflammatory mediators [38]. Studies have proved that intraoperative use of dexamethasone
can help reduce the duration of mechanical ventilationand hospital stay [39, 40].
Accurate prediction of hospitalization duration helps
to rationally allocate medical resources, improve bed
turnover, and enhance the clinical satisfaction of bothpatients and medical staff. Previous studies [41–43] havefocused on patients in some settings: neonates, ICU,
adult heart surgery, elderly stroke patients, etc. By retrospectively collecting perioperative information on thesepatients and utilizing relevant statistical methods, clinical models for predicting hospitalization duration are
constructed. In recent years, it has become increasingly
recognized that while these clinical models are effective
for large populations, their predictive power for specific disease groups may be unstable. Therefore, clinicalresearch has shifted towards focusing on patients with asingle disease, aiming to construct simpler clinical models to improve their practicality [14, 15, 37]. This study
only included children who underwent EA corrective
surgery at our center. By collecting perioperative information, we identified relevant predictive factors for THD.
In addition, we also observed that THD was associatedwith adverse outcomes (Fig. 2). Patients with one or more
adverse outcomes often require additional medical treatment, which would prolong hospitalization duration andincrease hospitalization costs. Therefore, THD can beused as an indicator to evaluate the postoperative recovery quality of patients. We identified six easily obtainableclinical variables related to THD. Clinicians can optimize
perioperative clinical practices based on these variables,such as detailed preoperative discussions, improving
intraoperative management strategies (including shortening CPB time, reducing allogeneic transfusion, reducing circulatory fluctuations, using anti-inflammatory

Liu et al. BMC Pediatrics(2024) 24:515

Page 8 of 10

Fig. 2 The incidence of adverse outcomes in different THD groups. Patients were classified into three groups according to the THD quartile. Frequency
refers to the number of patients who experienced adverse events. Percentage refers to the incidence of adverse event. Yellow represents only one adverse
event occurred, orange represents two adverse events occurred, dark orange represents three adverse events occurred, and red represents four adverse
events occurred

Table 4 In-hospital outcomes of the study of children
Variable
Adverse event
MV time (h)AKIAHI
ICU stay time (d)Hospital stay time (d)In-hospital cost (¥1000)

Total
32(11.9%)
12(7,21)72(26.7%)
62(23%)
2(1,3)
15(11,20.5)
65.9(50,86.4)≤ 6 days1(1.9%)
10(6,14)
11(21.2%)9(17.3%)1(1,2)
11(9,13.8)
60.4(48.7,72.4)

7 to 10 days
5(3.4%)
10(6,18)32(22.1%)
26(17.9%)1(1,3)
14(11,16)
58(49.1,75.8)≥ 11 days
26(35.6%)
24.1(11.5,49)
29(39.7%)
27(37%)
4(2,6)
23.4(19.29.5)
95(75.5,117)

P value< 0.001b, c< 0.001b, c
0.012b, c
0.005b, c< 0.001b, c< 0.001abc< 0.001b, c

Quantitative variables are expressed as median (interquartile range); Categorical variables are expressed as frequency (percentage). MV, mechanical ventilation; AKI,
acute kidney injury; AHI, acute hepatic injury; ICU, intensive care unit; a: the significant difference of results between the ≤ 6 days group and the 7 to 10 days group;b: the significant difference of results between the ≤ 6 days group and the ≥ 11 days group; c: the significant difference of results between 7 to 10 days group and≥ 11 days groupdrugs, etc.), and optimizing postoperative management(including infection prevention, organ protection, nutritional support, etc.). By early screening of high-riskpatients of THD, clinicians could optimize perioperative
management strategies, reduce adverse complications,improve postoperative recovery, and decrease medical
costs.
We still recognize some limitations in our study. Firstly,
this was a single-center study, which may limit the generalizability of our findings to other cardiac centers.
Secondly, we only collected in-hospital outcomes anddid not explore long-term outcomes. Thirdly, as we retrospectively collected the clinical data of EA patients,
some clinical data may be missing. Additionally, due tothe rarity of EA, the sample size was relatively small. A
prospective multicenter study with a larger sample sizeis necessary to further explore the predictors of THD forchildren with EA in the future.

Conclusions
In summary, our findings indicate that C/R > 0.65, Carpentier type C or D, longer CPB time, and transfusion
were associated with longer THD, older age and the useof dexamethasone were associated with shorter THD.
These variables are easy to obtain, clinicians can optimize
perioperative medical practices and management strategies based on them. This could help in reducing adverse

Liu et al. BMC Pediatrics(2024) 24:515

complications, improving postoperative recovery, anddecreasing medical costs.

Page 9 of 102.

Abbreviations
EA	Ebstein anomaly
THD	The Time to Hospital DischargeaRV	Atrialized right ventricle
AHI	Acute hepatic injury
AKI	Acute kidney injury
C/R	Cardiothoracic ratio
CPB	Cardiopulmonary bypass
ICU	Intensive care unit
LVEDDz	Left ventricular end-diastolic diameter z-score
SpO2	Peripheral oxygen saturation
LCOS	Low cardiac output syndrome
fRV	Functional right ventricle3.

Supplementary Information

9.

4.
5.
6.
7.
8.

The online version contains supplementary material available at https://doi.
org/10.1186/s12887-024-04936-3.
Supplementary Material 1

10.

Supplementary Material 2
Supplementary Material 3
11.
Acknowledgements
Not applicable.
Author contributions
FY, SY, YJ, and QL contributed to the conception of the study. XW, RA, DB, andDD collected the data and material. YL and HW checked the data. QL and JD
conducted the statistical analysis. QL wrote the manuscript. All authors readand approved the final submitted vision.
Funding
The authors declare that no funds were received during the preparation ofthis manuscript.
Data availability
The datasets generated or analyzed during the current study are not publicly
available due to data protection policy in our hospital but are available fromthe corresponding author on reasonable request.

12.
13.

14.
15.

16.
17.

Declarations
Ethics approval and consent to participate
The retrospective cohort study was reviewed and approved by the Ethics
Committee of the Chinese Academy of Medical Sciences Fuwai Hospital (NO.
2022 − 1647) and waived the need for informed consent.
Consent for publication
Not applicable.

18.
19.
20.

Competing interests
The authors declare no competing interests.

21.

Received: 8 November 2023 / Accepted: 8 July 2024

22.

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