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DOI: 10.1055/a-2350-7374
German Registry for Cardiac Operations and Interventions in Congenital Heart Disease: Annual Report 2022
- Abstract
- Introduction
- Materials and Methods
- Results
- Discussion
- Future Perspectives
- Limitations
- Collaborators
- References
Abstract
Background The German Registry for Cardiac Operations and Interventions in Patients with Congenital Heart Disease is a voluntary registry initiated by the German Society for Thoracic and Cardiovascular Surgery and the German Society for Pediatric Cardiology and Congenital Heart Defects. Since 2012, the registry collects data for the assessment of treatment and outcomes of surgical and interventional procedures in patients with congenital heart disease (CHD) of all age groups.
Methods This real-world, prospective all-comers registry collects clinical and procedural characteristics, adverse events (AEs), mortality, and medium-term outcomes (up to 90 days) of patients undergoing surgical and interventional. A unique pseudonymous personal identifier (PID) allows longitudinal data acquisition in case of further invasive treatment in any participating German heart center. Prior to evaluation, all data sets are monitored for data completeness and integrity. Evaluation includes risk stratification of interventional and surgical procedures and classification of AEs. Each year's data are summarized in annual reports containing detailed information on the entire cohort, all subgroups, and 15 index procedures. In addition, each participating center receives an institutional benchmark report for comparison with the national results. This paper presents a comprehensive summary of the annual report 2021.
Results In 2021, a total of 5,439 patients were included by 22 participating centers. In total, 3,721 surgical, 3,413 interventional, and 34 hybrid procedures were performed during 6,122 hospital stays. 2,220 cases (36.3%) could be allocated to the 15 index procedures. The mean unadjusted in-hospital mortality ranged from 0.4% among interventional and 2% among surgical cases up to 6.2 % in cases with multiple procedures. In-hospital mortality among index procedures accounted for 2.3% in total cavopulmonary connection, 20.3% in Norwood procedures, and 0.4% following interventional closure of patent ductus arteriosus. For the remaining seven surgical and five interventional index procedures, no in-hospital deaths were recorded. The 10-year longitudinal evaluation of 1,795 patients after tetralogy of Fallot repair revealed repeat interventional or surgical procedures in 21% of the patients. Over the same period, 31.1% of 2,037 patients, following initial treatment of native coarctation, required at least one additional hospital admission, 39.4% after initial interventional, and 21.3% after initial surgical therapy.
Conclusion The annual report 2021 of the German Registry for Cardiac Operations and Interventions in CHD shows continuously good results in accordance with previous data of the registry. Compared to international registries on CHD, it can be ascertained that in Germany invasive treatment of CHD is offered on a high medical level with excellent quality. The proven fact that patients with various malformations like tetralogy of Fallot and coarctation of the aorta require repeat procedures during follow-up confirms the urgent requirement for longitudinal assessment of all patients presenting with complex lesions.
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Keywords
congenital heart disease - outcomes - multicenter registry - pediatric cardiology - congenital heart surgery - transcatheter intervention - FallotIntroduction
Treatment of congenital heart disease (CHD) is complex and carries a significant risk of morbidity. Therapeutic concepts frequently require several consecutive interventional and/or surgical procedures. Since the quality of care has a major impact on patients' long-term outcomes and quality of life, several scientific registries have been established worldwide during the recent decades to assess the outcome and to improve the quality of treatment.[1] [2] [3] [4] [5] [6] [7] [8] [9] At the beginning of this century, cardiac surgical procedures in CHD were subject to a nationwide obligatory external quality assurance in Germany. In 2004, this obligatory quality assurance measure, according to § 136ff Social Code Book V, was suspended by the political representatives (Bundeskuratorium) for various reasons. Based on the scientific awareness that surgical and interventional treatment of CHD patients represents complementary parts of common treatment concepts the German Society for Thoracic and Cardiovascular Surgery (DGTHG) and the German Society for Pediatric Cardiology and Congenital Heart Defects (DGPK) took the initiative and the responsibility to establish a prospective multicenter registry collecting data from German heart centers on interventional and surgical therapies in patients with CHD.[10] [11] The nationwide registry started in 2012. The purpose of this report is to provide a public comprehensive update based on the Annual Report of the German Quality Assurance for CHD 2022.
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Materials and Methods
The voluntary German Registry for Quality Assurance in CHD (Nationale Qualitätssicherung Angeborene Herzfehler) is designed to collect data on the treatment and outcome of patients suffering from CHD in Germany. The structure of the Registry and the data submission have been described in detail previously.[10] [11] The structures of the registry, data acquisition, and evaluation are in accordance with the guidelines of “Good Epidemiological Practice”[12], “Good Clinical Practice,”[13] and the Declaration of Helsinki for medical research involving human subjects.[14] The Registry has been approved by the Charité's Ethics Committee (code number: EA2/011/11).
Inclusion criteria are the presence of a congenital heart defect and performance of any cardiac surgical or transcatheter procedure. The inclusion of patients is based on the intention to treat rather than on success. Since treatment of CHD extends into adulthood, patients are included irrespective of their ages. Coding of diagnoses and procedures is performed by the International Pediatric and Congenital Cardiac Code (IPCCC).[15] [16]
Each included patient receives a unique personal identifier (PID) for the generation of a pseudonym. Based on this PID, any cardiac surgical or interventional procedure whenever performed in one of the participating German cardiac centers can be assigned to an individual patient. This enables longitudinal data acquisition as well as short- mid- and long-term evaluations.
Prior to evaluation the collected data are monitored with respect to data integrity and plausibility before case closure. Participation in this voluntary registry requires informed consent either of the patient or guardian, absence of consent being the only exclusion criterion.
Based on the initial treatment, all cases are allocated to one of four groups assorted by interventional, surgical, multiple, or hybrid procedures. Interventional and surgical cases include all hospital admissions with an intention to treat the patient with a single procedure as well as those requiring subsequent additional treatment by a second or more procedures during the same admission due to an unpredicted complication. The group “multiple procedures” summarizes all patients with a predefined treatment concept, which consists of at least two procedures during one admission (e.g., arterial switch operation following balloon atrioseptostomy). Hybrid procedures are defined as combined surgical and interventional one-stage procedures. For risk stratification, the interventional cases are assigned to risk categories 1 to 4 according to the Catheterization for Congenital Heart Disease Adjustment for Risk Method,[2] while surgical cases are assigned to risk categories 1 to 5 according to the Society of Thoracic Surgeons (STS)—European Association for Cardio-Thoracic Surgery (EACTS) mortality categories.[1] Risk stratification of the two remaining groups (multiple and hybrid procedures) is not possible yet due to the lack of established risk categories for these treatment options.
Evaluation of the four groups includes analysis of procedure-related data as well as analysis of various indicators, including adverse events (AEs), in-hospital mortality, 30- and 90-day mortality. Major AEs following surgical procedures are classified according to the STS morbidity classification codes in the STS Congenital Heart Surgery Database Data collection form, Version 2.50 as cited in Jacobs et al.[17] AEs following interventional procedures are categorized in five categories according to Bergersen et al.[2] To allow a detailed and differentiated view on specific procedures in homogeneous subgroups of CHD, 15 index procedures (nine surgical and six interventional) were defined. The surgical procedures include atrial septal defect (ASD) and ventricular septal defect (VSD) closure, repair of atrioventricular septal defect (AVSD), repair of aortic coarctation (COA), arterial switch operation for transposition of the great arteries (TGA) with intact ventricular septum, repair of tetralogy of Fallot (TOF), total cavopulmonary connection (TCPC), Norwood procedure, and pulmonary valve replacement (PVR). Interventional procedures include ASD and VSD closure, treatment of aortic COA and recoarctation (ReCOA), closure of patent ductus arteriosus (PDA) and percutaneous pulmonary valve implantation (PPVI).
Longitudinal evaluation was performed for all patients following surgical TOF repair and for all patients who received surgical or interventional treatment of native COA from 2012 until 2021. These patients were analyzed for subsequent invasive treatment during the follow-up.
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Results
In 2021, a total number of 22 German centers contributed 6,122 cases (hospital stays) under the terms of quality assurance. Numbers of patients, cases, and procedures, documented in the registry in 2021, are shown in [Table 1]. Detailed data from 2,810 surgical cases and 356 cases with multiple procedures were provided by 18 centers, accounting for a total of 3,721 surgical procedures. In total, 23 departments submitted data from 2,931 interventional cases resulting in a total of 3,413 interventional procedures, while hybrid procedures accounted for only 25 (0.4%) of the reported cases including 34 procedures. In 10.1% of the patients included in 2021, more than one hospital stay for interventional or surgical treatment was recorded.
According to the data of the German Heart Foundation, published in the German Cardiac Report (Deutscher Herzbericht 2022, www.herzstiftung.de),[18] the German Registry represents 72% of institutions performing surgical and 92% of institutions performing interventional treatment of CHD. The 3,721 surgical procedures included in the German Registry represent 67.2% of operations for CHD reported in the German Heart Surgery Report 2021, which is based on a voluntary public report of 78 German heart surgery departments.[19] The 3,413 interventional procedures of the German Registry represent 73% of the procedures from 24 institutions listed in the German Cardiac Report (Deutscher Herzbericht 2022).[18]
Age and Gender Distribution
Almost 36% of cases were performed in newborns and infants, and 50% of the cases in children and adolescents. Treatment in adults with CHD accounted for 14.5% of cases ([Table 2]). The age distributions as well as the predominance of the male gender remained nearly unchanged compared to previous years.
Cases |
% |
|
---|---|---|
Newborns |
694 |
11.3 |
Infants |
1,481 |
24.2 |
Children and adolescents |
3,060 |
50 |
Adults |
887 |
14.5 |
Males |
3,307 |
54 |
Females |
2,815 |
46 |
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Key Performance Indicators
Details for interventional and surgical cases as well as for the index procedures are summarized in [Tables 2], [3], and [4]. In total, 56.4% of the interventional cases were performed in patients who had previously undergone either surgical (12.1%) or interventional treatment (7.4%) or a combination of both (36.9%). The median hospital stay of interventional cases was 2 days, and intensive care unit stay was required in 14.2% only ([Table 3]). In the majority of cases (82.5%), the procedure was performed under analgosedation without the requirement of general anesthesia and mechanical ventilation. It was noticeable that 4.7% of the cases were performed without fluoroscopy (mainly ASD closures and balloon-atrioseptostomies in TGA). The analysis of interventional index procedures revealed significant differences among the different procedures partially related to the complexity of the procedure and partially associated with the age group requiring the specific treatment. ASD closure was the most frequent intervention (442 cases) among the index procedures, 24.7% of these procedures were performed for closure of PFO. General anesthesia was required in 29.9%, fluoroscopy was avoided in 17.2% of these cases ([Table 3]). The most laborious interventional index procedure was PPVI, which was performed under general anesthesia in 51.5% of the cases. Almost half of the procedures were performed in adults (47.5%). Median procedure time (160 minutes) and median fluoroscopy time (24.4 minutes) exceeded all other procedures ([Table 3]).
Centers |
Cases |
Age (years)[a] |
Hospital stay (d)[a] |
ICU stay (%) |
GA (%) |
Fluoroscopy (%) |
Fluoroscopy time (min)[a] |
|
---|---|---|---|---|---|---|---|---|
Interventions |
23 |
2,931 |
2.0 (2.0/3.0) |
14.2 |
17.4 |
95.3 |
11.0 (5.9/19.5) |
|
ASD |
22 |
442 |
9.1 (5.4/38.3) |
2.0 (2.0/3.0) |
6.1 |
29.9 |
82.8 |
4.2 (2.4/7.5) |
VSD |
13 |
35 |
6.3 (2.3/11.3) |
3.0 (2.0/3.0) |
8.6 |
20.0 |
97.1 |
16.9 (10.0/26.5) |
COA |
15 |
61 |
4.1 (0.2/11.1) |
3.0 (2.0/7.0) |
37.7 |
27.9 |
100 |
6.2 (4.0/9.2) |
ReCOA |
12 |
23 |
16.8 (10.1/24.0) |
2.0 (2.0/3.0) |
26.1 |
0 |
100 |
9.6 (3.2/12.0) |
PDA |
22 |
274 |
1.9 (0.6/4.3) |
2.0 (2.0/3.0) |
16.4 |
8.8 |
100 |
7.0 (4.4/11.4) |
PPVI |
15 |
101 |
17.8 (14/30.3) |
5.0 (4.0/6.0) |
16.8 |
51.5 |
100 |
24.4 (16.4/38.3) |
Abbreviations: ASD, atrial septal defect; COA, coarctation; GA, general anesthesia; ICU, intensive care unit; PDA, patent ductus arteriosus; PPVI, percutaneous pulmonary valve implantation; ReCOA, recoarctation; VSD, ventricular septal defect.
a Numbers represent median and standard deviation.
Centers |
Cases |
Age (years)[a] |
Hospital stay (d)[a] |
ICU stay (d)[a] |
Ventilation period (h)[a] |
CPB (%) |
Perfusion time (min)[a] |
Cross-clamp (%) |
|
---|---|---|---|---|---|---|---|---|---|
Surgical procedures |
18 |
2,810 |
11 (8/17) |
4 (2/8) |
8 (5/30) |
74.8 |
113 (76/167) |
59.1 |
|
ASD |
18 |
172 |
4.0 (2.4/6.0) |
8 (6/9) |
2 (2/3) |
5 (3/7) |
100 |
51 (33/66) |
70.9 |
VSD |
17 |
233 |
0.4 (0.3/0.8) |
9 (8/12) |
4 (2/6) |
8 (5/50) |
100 |
93 (77/121) |
100 |
AVSD |
17 |
172 |
0.5 (0.4/2.0) |
12 (8/16) |
6 (3/9) |
12 (6/97.5) |
100 |
137 (102/182) |
98.3 |
COA |
14 |
119 |
0.0 (0.0/0.1) |
11(7/17) |
4 (3/7) |
13 (6/50) |
28.6 |
80 (55/109) |
26.1 |
TGA |
18 |
73 |
0.0 (0.0/0.0) |
21 (18/28) |
10 (8/14) |
51.5 (8/138) |
100 |
155 (134/209) |
100 |
TOF repair |
18 |
163 |
0.5 (0.4/0.7) |
12 (9/18) |
5 (3/8) |
11 (7/78) |
100 |
136 (106/169) |
100 |
TCPC |
16 |
174 |
3.8 (3.1/4.4) |
16.5 (13/24) |
5 (3/10) |
7 (5/11) |
100 |
96 (65/124) |
19 |
Norwood |
14 |
79 |
7 (5/9)[b] |
45 (34/92) |
28.5 (14/50) |
127 (48/221) |
100 |
210 (162/267) |
100 |
PVR |
15 |
99 |
17.9 (8.5/30.5) |
9 (8/13) |
3 (2/5) |
8 (6/11) |
99 |
143 (99/182) |
38.4 |
Abbreviations: ASD, atrial septal defect; AVSD, atrioventricular septal defect; COA, coarctation; CBP, cardiopulmonary bypass; ICU, intensive care unit; PVR, pulmonary valve replacement; TCPC, total cavopulmonary connection; TGA, transposition of the great arteries; TOF, tetralogy of Fallot; VSD, ventricular septal defect.
a Numbers represent median and standard deviation.
b In patients with the Norwood procedure, the median and standard deviation of age are given in days.
Due to the different nature of the treatment, surgical cases required more resources. Intensive care treatment was required in 93.5% of the cases with a median length of stay in the intensive care unit (ICU) of 4 days and in the hospital of 11 days ([Table 4]). Preceding interventional (5.7%), surgical (20.2%), or combined invasive treatment (18.4%) was common accounting for 44.3% of surgical cases. In total, 74.8% of the procedures were performed under cardiopulmonary bypass conditions, and in 54.4% of the cases, blood transfusions were required ([Table 4]). VSD closure (233 cases) was the most frequent surgical index procedure followed by TCPC (174 cases), ASD and AVSD closure (172 cases each), and TOF repair (163 cases). The surgical treatment appeared highly standardized with narrow interquartile ranges for perfusion and aortic cross-clamp times as well as for the duration of hospital stay. There were only minor differences in these parameters as compared to previous years.
The complex nature of univentricular heart treatment was apparent in the evaluation of Norwood operation and TCPC cases. The predominant diagnosis in Norwood cases was hypoplastic left heart syndrome (HLHS) with 78.5%. Fourteen patients (18%) received bilateral pulmonary arterial banding prior to the Norwood procedure. Norwood patients had the longest perfusion times (median 210 minutes), longest mechanical ventilation (median 127 hours), longest ICU stay (median 28.5 days), and longest in-hospital stay (median 45 days) ([Table 4]). Twenty percent of the patients required one and forty-four percent required two or more subsequent interventional or surgical procedures during the same hospital stay. In 2021, 14/18 units participating in this registry entered data on Norwood procedures. Concerning the index procedure, TCPC HLHS was also the most frequent main diagnosis (36.8%), followed by tricuspid atresia (16.1%). Bidirectional superior cavopulmonary anastomosis was the most frequent preceding palliative procedure (79,3%). Extracardiac conduit from inferior caval vein to the pulmonary artery without (58%) or with fenestration (28.2%) was the predominant surgical technique. TCPC cases showed short ventilation periods with a small interquartile range (median 7 hours), but relatively long and variable lengths of hospital stay (median 16.5 days) ([Table 4]).
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Key Quality Indicators
The in-hospital mortality during 2021 (2.0% in surgical and 0.4% in interventional cases) is specified in [Table 5]. Cases with multiple procedures carried a higher mortality rate of 6.2%.
Abbreviations: AE, adverse events; ASD, atrial septal defect; AVSD, atrioventricular septal defect; COA, coarctation; PDA, patent ductus arteriosus; PPVI, percutaneous pulmonary valve implantation; PVR, pulmonary valve replacement; ReCOA, recoarctation; TCPC, total cavopulmonary connection; TGA, transposition of the great arteries; TOF, tetralogy of Fallot; VSD, ventricular septal defect.
Seventy-five percent in-hospital deaths in interventional cases occurred in neonates and infants. Risk stratification according to the Catheterization for Congenital Heart Disease Adjustment for Risk Method[2] was possible in 89.1% of interventional cases. Analysis of the different age groups revealed that in neonates a higher percentage of procedures belonged to risk categories 3 or 4 (90.5%) as compared to infants (42.8%), children/adolescents (39.8%), or adults (34.7%) ([Fig. 1]). AEs were noted in 6.9% of interventional cases ([Table 5]). Irrespective of the age group, the highest rate of AE was recorded among patients of the highest risk categories ([Fig. 2]). Due to the predominance of procedures in the higher risk categories the largest percentage of AE (13,9%) was recorded in the neonatal age group. Seventy-three percent of AE resulted in minor or transient harm to the patients, while twenty-three percent were categorized as major or catastrophic occurring in 1.6% of all interventional cases ([Table 6]). No categorization was available yet in 4% of AEs. [Table 7] presents a comparison of observed AEs with data from the Congenital Cardiac Catheterization Project on Outcomes (C3PO) registry,[2] while a comparison of major AEs[2] including the categories “major” and “catastrophic” is given in [Table 6].
Adverse events |
German Registry AE/patients |
German Registry AE rate (%) |
CCCPO data set (5/2008–12/2009) AE/patients |
CCCPO data set (5/2008–12/2009) AE rate (%) |
---|---|---|---|---|
Any AE |
201/2,931 |
6.9 |
858/7,043 |
12.2 |
AE level 4 and 5 |
47/2,931 |
1.6 |
99/7,043 |
1.4 |
Abbreviation: AE, adverse events.
Risk categories |
AE/cases |
German Registry Rate of AE (%) |
3CPO Registry Rate of AE (%) |
---|---|---|---|
Category 1 |
16/240 |
6.7 |
5.2 |
Category 2 |
55/1,265 |
4.3 |
13 |
Category 3 |
63/763 |
8.3 |
19 |
Category 4 |
38/343 |
11.1 |
25 |




No in-hospital mortality was noted among patients with interventional index procedures except for 1/274 patients (0.4%) following interventional closure of PDA ([Table 5]). Freedom of AEs > 95% was reported in cases of interventional closure of ASD and ductus arteriosus as well as treatment of ReCOA ([Table 5]). Freedom of AEs was lower for interventional treatment of native COA (88.5%), PPVI (87.1%), and during interventional VSD closure (82.9%).
Classification of complexity according to the risk categories of the Society of Thoracic Surgeons-European Association for Cardio-Thoracic Surgery (STS-EACTS) mortality score[1] was possible in 91.9% of the cases. In-hospital mortality correlated with the level of complexity ranging from 0.5% in category 1 up to 18.9% in category 5 ([Table 8]). Procedures of the risk categories 4 and 5 were prevalent in the neonatal age group (50.7.6%) as compared to their proportion among infants (14.9%), children/adolescents (7.5%), or adults (7.8%) ([Fig. 3] and [4]). Due to the predominance of higher risk operations, the in-hospital mortality was higher in neonates (7.8%) as compared to infants (1%), children and adolescents (1%), or adults (1.4%).


STS-EACTS mortality risk category[1] |
German Registry Mortality/patients |
German Registry Mortality rate (%) |
STS-EACTS[1] mortality rate 2002–2007 (%) |
---|---|---|---|
Category 1 |
5/1,083 |
0.5 |
0.8 |
Category 2 |
17/735 |
2.3 |
2.6 |
Category 3 |
7/342 |
2.0 |
5.0 |
Category 4 |
10/349 |
2.9 |
9.9 |
Category 5 |
14/74 |
18.9 |
23.1 |
Abbreviation: STS-EACTS, Society of Thoracic Surgeons-European Association for Cardio-Thoracic Surgery.
In the subgroup analysis of surgical index procedures, the in-hospital mortality following the Norwood (20.3%) procedure was remarkable but similar to previous years (2020: 18.7% and 2019: 19.8%). The in-hospital mortality rate following TCPC was 2.3%, while no mortality was noticed among patients undergoing one of the remaining seven surgical index procedures ([Table 5]). A comparison of in-hospital mortality rates among five index procedures matching index procedures from the European Congenital Heart Surgeons Association (ECHSA) database[20] is provided in [Table 9].
Index procedures |
German Registry cases 2021 |
Mortality 2021 (%) |
German Registry cases 2017–2021 |
Mortality 2017–2021 (%) |
ECHSA database cases 2016–2019 |
ECHSA database mortality 2016–2021 (%) |
---|---|---|---|---|---|---|
VSD |
233 |
0 |
1,326 |
0 |
2,503 |
0.6 |
TOF repair |
163 |
0 |
865 |
0.6 |
249 |
1.2 |
TGA |
73 |
0 |
430 |
1.4 |
757 |
5.4 |
TCPC |
174 |
2.3% |
797 |
1.0 |
420 |
2.9 |
Norwood |
79 |
20.3% |
332 |
19.6 |
564 |
28.4 |
Abbreviations: ECHSA, European Congenital Heart Surgeons Association; TCPC, total cavopulmonary connection; TGA, transposition of the great arteries; TOF, tetralogy of Fallot; VSD, ventricular septal defect.
AEs were recorded in 32.5% of surgical cases ([Table 5]). Their frequency correlated with the complexity according to the risk categories of the STS-EACTS mortality score ranging from 19.2% in category 1 to 87.8% in category 5. Procedures of higher risk categories were prevalent in the neonatal age group ([Fig. 3]). Comparison of AEs in the German Registry with data in the literature has to take into consideration that many registries are reporting major AEs only.[17] [21] The reporting of the German Registry also includes minor AEs (67.4%), while 31.2% were classified as major complications according to Jacobs et al.[17]
AEs among the surgical index procedures were < 30% after ASD and VSD closure, PVR, and treatment of native COA ([Table 5]). Values between 30 and 60% were recorded in patients following AVSD repair, TOF repair, TCPC, and arterial switch operation for TGA. As expected patients after Norwood procedures showed the highest AE rate (83.5%) ([Table 5]).
The case volume in the category multiple procedures was significantly smaller (356) than in isolated surgical or interventional cases ([Table 5]). Although there is presently no risk categorization for these combinations of treatment, the fact that the majority of cases in this group were treated in the first year of life (44.9% newborns and 23.9% infants) suggests that these treatment concepts are performed preferentially in high-risk patients with complex CHD. In total, 71.9% underwent one subsequent and 28.1% required two or more subsequent procedures accounting for a total of 563 procedures (347 operations and 216 interventions). The complexity of this group is also evident in the in-hospital mortality rate of 6.2% and a rate of cases without AEs of 39.9% ([Table 5]).
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Longitudinal Observations Tetralogy of Fallot
The database included 1,795 patients following TOF repair during the 10-year period from 2012 to 2021. Palliative procedures prior to surgical repair were performed in 17.9% of the patients ([Fig. 5]). These palliative procedures included interventional (53.6%) and surgical procedures (33.3%) or a combination of both (13.1%). Following surgical repair, repeat procedures were recorded in 373 patients (21%). They were less common among patients undergoing primary repair (17%) as compared to patients with preceding palliative procedures (38%). The largest number of repeat procedures was recorded during the first year after repair: 141/1,781 patients (7.9%) required at least one additional hospital admission ([Fig. 6]). This number decreased continuously during the subsequent years resulting in 1.3% of the patients requiring repeat interventional or surgical treatment in the tenth postprocedural year.






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Longitudinal Observations Coarctation of the Aorta
From 2012 to 2021, the registry recorded 2,037 patients following primary treatment of native COA. In total, 883 patients (43.3%) were newborns, 522 infants (25.6%), 500 children and adolescents (24.5%), and 132 were adults (6.5%). Initial treatment was performed by transcatheter intervention in 30.3% and by surgery in 69.7% of the patients ([Fig. 7]). With respect to patients' age, there was a clear dominance of surgical strategies in the primary treatment of neonates (89.8%) and infants (82.2%), while interventional procedures dominated the treatment in children and adolescents (63.2%) as well as in adulthood (89.4%). Among patients who underwent interventions, balloon dilatation was the preferred method in infants (81.7%), while stent implantation was the dominant procedure in children/adolescents (68.4%) and especially in adults (96.6%). Notably, there was also a significant percentage of stent implantations (51.1%) among interventions in the neonatal period. The majority of surgical treatments (86%) was performed in the 1st year of life. Extracorporeal circulation was required in 24.7 % of the surgical procedures.


Repeat procedures requiring further hospital admissions were noted in 39.4% of patients with initial interventional and in 21.3% of patients who underwent primary surgical treatment. The requirement of hospital readmissions was highest in the 1st year of treatment (20.7%) and decreased significantly in the 3rd year to a level < 3%. However, this rate of 2 to 3% remained quite constant during the following years ([Fig. 8]).


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Discussion
Since 2012, the German Registry for Cardiac Operations and Interventions in patients with CHD collects data on interventional and surgical treatment from the neonatal age until adulthood.[10] [11] So far, these data cover an entire decade describing the results of current invasive treatment in these complex patients in Germany. The data of each year were summarized in annual reports containing detailed age and risk-related outcome data on key quality indicators for all different case groups and for 15 index procedures (www.dgpk.org, www.dgthg.org). In addition, all participating institutions received a specific center-related report allowing a benchmark of the institutional performance to the national cohort. The underlying paper presents a comprehensive summary of the Annual report 2022 of the German Quality assurance for CHD. It has to be mentioned that some selected data from the German Registry have already been included in the German Heart Report 2022 (Deutscher Herzbericht).[18]
Like in previous years, the data of this registry reflect the complexity of CHD and the complementary nature of interventional and surgical procedures: 56.4% of interventional cases were performed in patients following prior hospital admissions for surgical and/or interventional treatment, while preceding procedures were also recorded in 44.3% of the surgical cases. 10.1% of the patients required more than one hospital treatment in 2021.
The overall in-hospital mortality of surgical cases (2.0%) was slightly higher than in 2020 (1.6%) but remained within the average mortality of previous years (1.4–2.6%) in the German Registry.[10] [11] The observed mortality rates correlated with the level of complexity according to the risk categories of the STS-EACTS mortality score.[1] Comparison of the surgical mortality in the German Registry 2021 and the expected in-hospital mortality according to the STS-EACTS database[1] revealed excellent results over the entire range of mortality categories ([Table 8]). This applies as well for data concerning the surgical index procedures VSD closure, TOF repair, arterial switch operation in TGA, TCPC, and Norwood procedure. Both the mortality in the German Registry in 2021 and the average mortality over the last 5 years compare favorably to the data from the ECHSA database ([Table 9]) published in 2022.[20]
Cases with multiple procedures carried a significantly higher in-hospital mortality of 6.2% reflecting the complex nature of these patients, who were predominantly treated either in the neonatal age or in infancy (68.8%). The mortality rate was similar compared to 2020[11] and lower than the average mortality of multiple cases (6.2–10.4%) observed from 2015 to 2019.[10]
In-hospital mortality among interventional cases (0.4%) was similar compared to data from the German Registry from previous years (0.2–0.8%).[10] [11] It did not play a significant role among interventional cases, although 42.4% of the cases in 2021 belonged to the risk categories 3 and 4. The frequency of observed AEs was in the expected range ([Tables 6] and [7]) or below as compared to data published by the CCCPO registry.[2]
The structure of the German Registry provides the possibility of longitudinal assessment since readmissions for repeat interventional or surgical treatment can be assigned by the PID, even if the treatment is provided by different centers. Therefore, this report also includes data on 10 years' longitudinal evaluation of TOF patients following corrective surgery and patients following the treatment of native COA. Evaluation of children with TOF revealed two groups of patients: while the majority of patients underwent primary surgical repair (82.1%), a smaller group of patients required prior palliative procedures (17.9%). Among these palliative procedures, interventions have gained a significant share either as exclusive interventional palliations (53.6%) or as combinations of interventional and surgical palliative procedures (13.1%) confirming trends reported in the international literature.[22] After surgical repair, repeat procedures were required less frequently among patients following primary repair (17%) as compared to patients who underwent preceding palliation (38%). In our opinion, this can be explained by the fact that the latter group represents patients with a less favorable anatomic spectrum regarding the morphology of the right ventricular outflow tract and the central pulmonary arteries. This is supported by the fact that 70% of repeat interventional procedures addressed problems of the central pulmonary arteries (61%) or the right ventricular outflow tract (9%). Similar data have been reported in the literature.[23] The annual report 2021 recorded no mortality following TOF repair. This is in accordance with the results of previous years and compares very favorably with data reported from the ECHSA database in 2022 ([Table 9]).[20]
Longitudinal analysis of patients who underwent treatment of native COA revealed significant differences depending on the patients' age, which are certainly also influenced by the underlying morphology of the obstruction. While surgical strategies dominated the primary treatment in neonates and infants, interventional methods were the preferred treatment in children and adolescents as well as in adults ([Fig. 7]). The significant number of repeat procedures especially in the first year after initial treatment (20.7%) confirms the complex nature of this cardiovascular malformation ([Fig. 8]).
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Future Perspectives
The data sets covering surgical and interventional procedures are compatible with the ECHSA database to provide the possibility of future data transfer/migration and international compatibility. STAT mortality categories and Bergersen risk categories as well as AEs scores will be adjusted according to recent updates to allow continuous comparison with other databases.[7] [20] [21] [24] [25] [26] Demands on biocompatibility and longevity are particularly important for medical devices implanted in neonates, children, and adolescents for the treatment of CHD.[27] [28] To meet the future requirements of an obligatory implant registry, the German database started in 2023 to include specific details for ASD- and PDA-occluders as well as PPVI. Implementation of defined surgical devices is provided for 2024.
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Limitations
The registry is limited by its all-comers registry design and the voluntary participation of patients and institutions. Financial restrictions are due to the fact that presently the registry does not receive public funding. Financial support for the registry is provided exclusively by the participating centers, the DGTHG and the DGPK. Comparisons of in-hospital mortality and AEs of the German Registry with results of the STS-EACTS database and the CCCPO registry have to take into consideration that these data were obtained in different time periods.
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Collaborators
German Quality Assurance/Competence Network for Congenital Heart Defects
Ulrike Herberg, Majed Kanaan, Corinna Lebherz, Stefan Ostermayer, André Rüffer, Mustafa Gülgün, Vincent Kundt, Thai Duy Nguyen (Aachen); Stephan Schubert, Kai Thorsten Laser, Eugen Sandica, Alexey Ilin, Alina Georgiana Sandica, Marek Zubrzycki, Ursula Schultz-Kaizler, Yasin Essa (Bad Oeynhausen); Felix Berger, Oliver Miera, Bernd Opgen-Rhein, Joachim Photiadis (Berlin); Johannes Breuer, Martin Schneider, Nicole Müller, Boulos Asfour, Benjamin Bierbach, Lennart Dübener, Mathieu Vergnat (Bonn); Gleb Tarusinov, Aktham Tannous, Christina Rogkakou, Paul Hacke, Jochen Börgermann, Michael Scheid, Andrey Semyashkin (Duisburg); Sven Dittrich, Wolfgang Wälllisch, Oliver Dewald, Ariawan Purbojo, Johannes Rösch, Michela Cuomo, Saya Aziz (Erlangen); Brigitte Stiller, Alexej Bobrowski, Charlotte Schwab, Christoph Zürn, Daniela Kocher, Hannah Kappler, Hendryk Schneider, Lisa Marie Stelling - Fuchs, Meike Schwendt, Miriam Schwab, Simon Oberle, Thilo Fleck, Martin Czerny, Fabian Alexander Kari, Fatos Ballazhi, Johannes Kroll, Matthias Siepe (Freiburg); Christian Jux, Hakan Akintürk, Klaus Valeske (Gießen); Thomas Paul, Matthias Sigler, Heike Schneider, Matthias Müller, Ulrich Johannes Krause (Göttingen); Rainer Kozlik-Feldmann, Carsten Rickers, Lena Christine Siebel, Philipp Schneider, Roland Volker Jebens, Veronika Stark, Michael Hübler, Daniel Biermann, Jörg Sachweh (Hamburg); Philipp Beerbaum, Dietmar Böthig, Arjang Ruhparwar, Dmitry Bobylev, Elena Petena, Tomislav Cvitkovic, Valery Tsimashok (Hannover); Matthias Gorenflo, Sebastian Uhl, Matthias Karck, Tsvetomir Loukanov, Viola Deneke (Heidelberg); Hashim Abdul-Khaliq, Axel Rentzsch, Gloria Färber (Homburg); Thomas Kriebel, Michael Zimmer, Peter Follmann (Kaiserslautern); Anselm Uebing, Gunther Fischer, Jan-Hinnerk Hansen Kolja Becker, Ulrike Hoffmann, Jens Scheewe, Tim Attmann, Jill Jussli-Melchers (Kiel); Ingo Dähnert, Frank-Thomas Riede, Martin Kostelka (Leipzig); Nikolaus A. Haas, André Jakob, Christoph Funk, Felix Sebastian Oberhoffer, Guido Mandilaras, Matthias Hermann, Roxana Engmann Roxana Riley, Simone Dold, Jürgen Hörer (Großhadern, München); Hans-Gerd Kehl, Felix Kleinerüschkamp, Volker Debus, Sven Martens, Sabrina Martens, Erdal Yörük, Fadi Almuhrez, Katarzyna Januszewska, Lofti Ben Mime, Helmut Baumgartner (Münster); Matthias W. Freund, Gerrit Kopiske, Michael Schumacher (Oldenburg); Ulrich Schweigmann, Volker Ocker, Jelena Pabst von Ohain, Ioannis Tzanavaros, Janez Vodiškar (Stuttgart); Johannes Nordmeyer, Jörg Michel, Christan Scheckenbach, Vanya Icheva, Christian Schlensak, Rafal Berger (Tübingen).
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Participating Centers in 2021
Universitätsklinikum Aachen; Kinderherzzentrum/Zentrum für angeborene Herzfehler Bad Oeynhausen; Deutsches Herzzentrum der Charité, Berlin; Universitätsklinikum Bonn; Herzzentrum Duisburg; Universitätsklinikum Erlangen; Universitäts-Herzzentrum Freiburg/Bad Krozingen; Universitätsklinikum Gießen; Universitätsklinikum Göttingen; Universitätsklinikum Hamburg-Eppendorf; Medizinische Hochschule Hannover; Universitätsklinikum Heidelberg; Universitätsklinikum des Saarlandes, Homburg; Westpfalz-Klinikum Kaiserslautern; Universitätsklinikum Schleswig-Holstein, Kiel; Herzzentrum Leipzig; Klinikum der LMU Campus Großhadern, München; Universitätsklinikum Münster; Klinikum Oldenburg; Klinikum Stuttgart; Universitätsklinikum Tübingen.
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Conflict of interest
None declared.
Acknowledgment
On behalf of the German Society for Thoracic and Cardiovascular Surgery (DGTHG) and the German Society for Pediatric Cardiology and Congenital Heart Defects (DGPK), the authors would like to express their deep gratitude and respect to the heads of the departments and the teams of all participating heart centers in Germany for their continued cooperation and support to realize this registry.
Abbreviations
AE Adverse events
ASD Atrial septal defect
AVSD Atrioventricular septal defect
CHD Congenital heart disease
ECC Extracorporeal circulation
GA General anaesthesia
ICU Intensive care unit
PDA Patent ductus arteriosus
COA Native coarctation
ReCOA Re-Coarctation
PVR Pulmonary valve replacement
PPVI Percutaneous pulmonary valve replacement
TCPC Total cavopulmonary connection
TGA Transposition of the great arteries with intact ventricular septum
TOF Tetralogy of Fallot
VSD Ventricular septal defect
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References
- 1 O'Brien SM, Clarke DR, Jacobs JP. et al. An empirically based tool for analyzing mortality associated with congenital heart surgery. J Thorac Cardiovasc Surg 2009; 138 (05) 1139-1153
- 2 Bergersen L, Gauvreau K, Marshall A. et al. Procedure-type risk categories for pediatric and congenital cardiac catheterization. Circ Cardiovasc Interv 2011; 4 (02) 188-194
- 3 Bergersen L, Gauvreau K, Foerster SR. et al. Catheterization for Congenital Heart Disease Adjustment for Risk Method (CHARM). JACC Cardiovasc Interv 2011; 4 (09) 1037-1046
- 4 Jayaram N, Spertus JA, Kennedy KF. et al. Modeling major adverse outcomes of pediatric and adult patients with congenital heart disease undergoing cardiac catheterization: observations from the NCDR IMPACT Registry (National Cardiovascular Data Registry Improving Pediatric and Adult Congenital Treatment). Circulation 2017; 136 (21) 2009-2019
- 5 Overman DM, Jacobs ML, O'Brien Jr JE. et al. Ten years of data verification: The Society of Thoracic Surgeons Congenital Heart Surgery Database Audits. World J Pediatr Congenit Heart Surg 2019; 10 (04) 454-463
- 6 Herbst C, Tobota Z, Urganci E. et al. Ten years of data verification: the European Congenital Heart Surgeons Association Congenital Database Audits. World J Pediatr Congenit Heart Surg 2022; 13 (04) 466-474
- 7 Quinn BP, Yeh M, Gauvreau K. et al. Procedural risk in congenital cardiac catheterization (PREDIC3T). J Am Heart Assoc 2022; 11 (01) e022832
- 8 McCrossan BA, Karayiannis S, Shields M. et al. Incidence, predictors, and outcomes of cardiac perforation during pediatric cardiac catheterization: a retrospective observational study from the Congenital Cardiac Interventional Study Consortium (CCISC). Pediatr Cardiol 2023; 44 (04) 867-872
- 9 Jacobs JP, Krasemann T, Herbst C. et al. Combining congenital heart surgical and interventional cardiology outcome data in a single database: the development of a patient-centered collaboration of the European Congenital Heart Surgeons Association (ECHSA) and the Association for European Paediatric and Congenital Cardiology (AEPC). Cardiol Young 2023; 33 (07) 1043-1059
- 10 Beckmann A, Dittrich S, Arenz C. et al; German Quality Assurance / Competence Network for Congenital Heart Defects Investigators. German Registry for cardiac operations and interventions in patients with congenital heart disease: report 2020-comprehensive data from 6 years of experience. Thorac Cardiovasc Surg 2021; 69 (S03): e21-e31
- 11 Dittrich S, Arenz C, Krogmann O. et al. German Registry for cardiac operations and interventions in patients with congenital heart disease: report 2021 and 9 years' longitudinal observations on Fallot and coarctation patients. Thorac Cardiovasc Surg 2022; 70 (S 03): e21-e33
- 12 Hoffmann W, Latza U, Baumeister SE. et al. Guidelines and recommendations for ensuring Good Epidemiological Practice (GEP): a guideline developed by the German Society for Epidemiology. Eur J Epidemiol 2019; 34 (03) 301-317
- 13 Guideline for Good Clinical Practice. Accessed June 21, 2024 at: https://www.ema.europa.eu/en/ich-e6-r2-good-clinical-practice
- 14 World Medical Association. WMA Declaration of Helsinki—Ethical Principles for Medical Research Involving Human Subjects. Accessed January 11, 2021 at: https://www.wma.net/policiespost/wma-declaration-of-helsinki-ethical-principles-for-medical-research-involving-human-subjects/
- 15 Franklin RCG, Béland MJ, Colan SD. et al. Nomenclature for congenital and paediatric cardiac disease: the International Paediatric and Congenital Cardiac Code (IPCCC) and the Eleventh Iteration of the International Classification of Diseases (ICD-11). Cardiol Young 2017; 27 (10) 1872-1938
- 16 Jacobs JP, Franklin RCG, Béland MJ. et al. Nomenclature for pediatric and congenital cardiac care: unification of clinical and administrative nomenclature. — The 2021 International Paediatric and Congenital Cardiac Code (IPCCC) and the Eleventh Revision of the International Classification of Diseases (ICD-11). Cardiol Young 2021; 31 (07) 1057-1188
- 17 Jacobs ML, O'Brien SM, Jacobs JP. et al. An empirically based tool for analyzing morbidity associated with operations for congenital heart disease. J Thorac Cardiovasc Surg 2013; 145 (04) 1046-1057.e1
- 18 Deutscher Herzbericht. 2022 . Accessed May 14, 2024 at: https://epaper.herzstiftung.de/#0
- 19 Beckmann A, Meyer R, Lewandowski J, Markewitz A, Blaßfeld D, Böning A. German Heart Surgery Report 2021: the annual updated registry of the German Society for Thoracic and Cardiovascular Surgery. Thorac Cardiovasc Surg 2022; 70 (05) 362-376
- 20 Bertsimas D, Zhuo D, Levine J. et al. Benchmarking in congenital heart surgery using machine learning-derived optimal classification trees. World J Pediatr Congenit Heart Surg 2022; 13 (01) 23-35
- 21 Pasquali SK, Shahian DM, O'Brien SM. et al. Development of a congenital heart surgery composite quality metric: part 1-conceptual framework. Ann Thorac Surg 2019; 107 (02) 583-589
- 22 Dorobantu DM, Mahani AS, Sharabiani MTA. et al. Primary repair versus surgical and transcatheter palliation in infants with tetralogy of Fallot. Heart 2018; 104 (22) 1864-1870
- 23 Ravaglioli A, Ait-Ali L, Federici D. et al. The impact of native Fallot anatomy on future therapeutic requirements and outcomes at follow-up. Cardiovasc Ultrasound 2021; 19 (01) 23
- 24 Pasquali SK, Thibault D, O'Brien SM. et al. National variation in congenital heart surgery outcomes. Circulation 2020; 142 (14) 1351-1360
- 25 Jacobs ML, Jacobs JP, Thibault D. et al. Updating an empirically based tool for analyzing congenital heart surgery mortality. World J Pediatr Congenit Heart Surg 2021; 12 (02) 246-281
- 26 Sarris GE, Zhuo D, Mingardi L. et al. Congenital heart surgery machine learning-derived in-depth benchmarking tool. Ann Thorac Surg 2023; (e-pub ahead of print)
- 27 Foth R, Quentin T, Michel-Behnke I. et al. Immunohistochemical characterization of neotissues and tissue reactions to septal defect-occlusion devices. Circ Cardiovasc Interv 2009; 2 (02) 90-96
- 28 Foth R, Shomroni O, Sigler M. et al. Screening for potential targets to reduce stenosis in bioprosthetic heart valves. Sci Rep 2021; 11 (01) 2464
Address for correspondence
Publication History
Received: 05 June 2024
Accepted: 06 June 2024
Accepted Manuscript online:
24 June 2024
Article published online:
09 July 2024
© 2024. The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commercial purposes, or adapted, remixed, transformed or built upon. (https://creativecommons.org/licenses/by-nc-nd/4.0/)
Georg Thieme Verlag KG
Rüdigerstraße 14, 70469 Stuttgart, Germany
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References
- 1 O'Brien SM, Clarke DR, Jacobs JP. et al. An empirically based tool for analyzing mortality associated with congenital heart surgery. J Thorac Cardiovasc Surg 2009; 138 (05) 1139-1153
- 2 Bergersen L, Gauvreau K, Marshall A. et al. Procedure-type risk categories for pediatric and congenital cardiac catheterization. Circ Cardiovasc Interv 2011; 4 (02) 188-194
- 3 Bergersen L, Gauvreau K, Foerster SR. et al. Catheterization for Congenital Heart Disease Adjustment for Risk Method (CHARM). JACC Cardiovasc Interv 2011; 4 (09) 1037-1046
- 4 Jayaram N, Spertus JA, Kennedy KF. et al. Modeling major adverse outcomes of pediatric and adult patients with congenital heart disease undergoing cardiac catheterization: observations from the NCDR IMPACT Registry (National Cardiovascular Data Registry Improving Pediatric and Adult Congenital Treatment). Circulation 2017; 136 (21) 2009-2019
- 5 Overman DM, Jacobs ML, O'Brien Jr JE. et al. Ten years of data verification: The Society of Thoracic Surgeons Congenital Heart Surgery Database Audits. World J Pediatr Congenit Heart Surg 2019; 10 (04) 454-463
- 6 Herbst C, Tobota Z, Urganci E. et al. Ten years of data verification: the European Congenital Heart Surgeons Association Congenital Database Audits. World J Pediatr Congenit Heart Surg 2022; 13 (04) 466-474
- 7 Quinn BP, Yeh M, Gauvreau K. et al. Procedural risk in congenital cardiac catheterization (PREDIC3T). J Am Heart Assoc 2022; 11 (01) e022832
- 8 McCrossan BA, Karayiannis S, Shields M. et al. Incidence, predictors, and outcomes of cardiac perforation during pediatric cardiac catheterization: a retrospective observational study from the Congenital Cardiac Interventional Study Consortium (CCISC). Pediatr Cardiol 2023; 44 (04) 867-872
- 9 Jacobs JP, Krasemann T, Herbst C. et al. Combining congenital heart surgical and interventional cardiology outcome data in a single database: the development of a patient-centered collaboration of the European Congenital Heart Surgeons Association (ECHSA) and the Association for European Paediatric and Congenital Cardiology (AEPC). Cardiol Young 2023; 33 (07) 1043-1059
- 10 Beckmann A, Dittrich S, Arenz C. et al; German Quality Assurance / Competence Network for Congenital Heart Defects Investigators. German Registry for cardiac operations and interventions in patients with congenital heart disease: report 2020-comprehensive data from 6 years of experience. Thorac Cardiovasc Surg 2021; 69 (S03): e21-e31
- 11 Dittrich S, Arenz C, Krogmann O. et al. German Registry for cardiac operations and interventions in patients with congenital heart disease: report 2021 and 9 years' longitudinal observations on Fallot and coarctation patients. Thorac Cardiovasc Surg 2022; 70 (S 03): e21-e33
- 12 Hoffmann W, Latza U, Baumeister SE. et al. Guidelines and recommendations for ensuring Good Epidemiological Practice (GEP): a guideline developed by the German Society for Epidemiology. Eur J Epidemiol 2019; 34 (03) 301-317
- 13 Guideline for Good Clinical Practice. Accessed June 21, 2024 at: https://www.ema.europa.eu/en/ich-e6-r2-good-clinical-practice
- 14 World Medical Association. WMA Declaration of Helsinki—Ethical Principles for Medical Research Involving Human Subjects. Accessed January 11, 2021 at: https://www.wma.net/policiespost/wma-declaration-of-helsinki-ethical-principles-for-medical-research-involving-human-subjects/
- 15 Franklin RCG, Béland MJ, Colan SD. et al. Nomenclature for congenital and paediatric cardiac disease: the International Paediatric and Congenital Cardiac Code (IPCCC) and the Eleventh Iteration of the International Classification of Diseases (ICD-11). Cardiol Young 2017; 27 (10) 1872-1938
- 16 Jacobs JP, Franklin RCG, Béland MJ. et al. Nomenclature for pediatric and congenital cardiac care: unification of clinical and administrative nomenclature. — The 2021 International Paediatric and Congenital Cardiac Code (IPCCC) and the Eleventh Revision of the International Classification of Diseases (ICD-11). Cardiol Young 2021; 31 (07) 1057-1188
- 17 Jacobs ML, O'Brien SM, Jacobs JP. et al. An empirically based tool for analyzing morbidity associated with operations for congenital heart disease. J Thorac Cardiovasc Surg 2013; 145 (04) 1046-1057.e1
- 18 Deutscher Herzbericht. 2022 . Accessed May 14, 2024 at: https://epaper.herzstiftung.de/#0
- 19 Beckmann A, Meyer R, Lewandowski J, Markewitz A, Blaßfeld D, Böning A. German Heart Surgery Report 2021: the annual updated registry of the German Society for Thoracic and Cardiovascular Surgery. Thorac Cardiovasc Surg 2022; 70 (05) 362-376
- 20 Bertsimas D, Zhuo D, Levine J. et al. Benchmarking in congenital heart surgery using machine learning-derived optimal classification trees. World J Pediatr Congenit Heart Surg 2022; 13 (01) 23-35
- 21 Pasquali SK, Shahian DM, O'Brien SM. et al. Development of a congenital heart surgery composite quality metric: part 1-conceptual framework. Ann Thorac Surg 2019; 107 (02) 583-589
- 22 Dorobantu DM, Mahani AS, Sharabiani MTA. et al. Primary repair versus surgical and transcatheter palliation in infants with tetralogy of Fallot. Heart 2018; 104 (22) 1864-1870
- 23 Ravaglioli A, Ait-Ali L, Federici D. et al. The impact of native Fallot anatomy on future therapeutic requirements and outcomes at follow-up. Cardiovasc Ultrasound 2021; 19 (01) 23
- 24 Pasquali SK, Thibault D, O'Brien SM. et al. National variation in congenital heart surgery outcomes. Circulation 2020; 142 (14) 1351-1360
- 25 Jacobs ML, Jacobs JP, Thibault D. et al. Updating an empirically based tool for analyzing congenital heart surgery mortality. World J Pediatr Congenit Heart Surg 2021; 12 (02) 246-281
- 26 Sarris GE, Zhuo D, Mingardi L. et al. Congenital heart surgery machine learning-derived in-depth benchmarking tool. Ann Thorac Surg 2023; (e-pub ahead of print)
- 27 Foth R, Quentin T, Michel-Behnke I. et al. Immunohistochemical characterization of neotissues and tissue reactions to septal defect-occlusion devices. Circ Cardiovasc Interv 2009; 2 (02) 90-96
- 28 Foth R, Shomroni O, Sigler M. et al. Screening for potential targets to reduce stenosis in bioprosthetic heart valves. Sci Rep 2021; 11 (01) 2464















