In 2022, three major themes in pediatric cardiology have captured our attention. From fetal life to adolescence, these topics are very varied and thus illustrate the broad field of competence of our team of pediatric cardiologists.

First, despite coarctation of the aorta (CoAo) being one of the most common congenital heart diseases, its prenatal diagnosis remains challenging. Because of the subtlety of the ultrasound signs of CoAo during the morphological examination in the second trimester of pregnancy, screening is difficult. Yet, the prognosis of these patients depends on prompt management in the neonatal period. The development of fetal cardiac MRI and improved knowledge in cardio-genetics tend to improve fetal detection of CoAo.

Second, postural tachycardia syndrome (POTS) affects the quality of life of adolescent patients. Simple indicators such as heart rate and blood pressure during a head-up tilt test have a predictive value regarding treatment efficiency and prognosis in children with POTS. Recently, a new hypothesis has suggested vaccine-induced autoimmune POTS following mRNA COVID-19 vaccination.

Third, postoperative pulmonary hypertension (PH) after correction of congenital heart defects is a serious and potentially lethal complication. In recent years, PH-targeting drugs have been increasingly used in the postoperative setting. The scientific evidence of an improved outcome is discussed in the last part of this manuscript.

The year 2022 saw a gradual return to normal after the COVID-19 pandemic. This was an opportunity to optimize processes that had sometimes been undermined and to update procedures. It was also an occasion to take on new challenges: to consider acquiring new equipment for the coming years, to implement new techniques that are more sensitive, faster, and better adapted to the needs of prescribers.

In the Special Hematology Laboratory, and in particular in the specialized hemostasis sector, the automation of the ADAMTS13 protein assay was critical for the diagnosis and biological follow-up of patients with immune thrombotic thrombocytopenic purpura (iTTP). This uncommon condition can rapidly deteriorate if not diagnosed early and managed appropriately based on ADAMTS13 testing. This assay also allows identifying patients at risk of relapse who should receive preventive treatment.

The determination of erythrocyte blood groups is most often straightforward using serological techniques. However, in certain situations, it is necessary to use molecular biology techniques. The Immunohematology - Molecular Biology Laboratory has implemented a real-time PCR technique that allows for extensive erythrocyte genotyping and the detection of antigenic variants missed by serological techniques. This is an essential tool for determining blood groups in polytransfused patients and for selecting bags for individuals with a variant or deletion blood group.

It has been known for over 50 years that the HLA system plays a central role in human immunity and is at the same time one of the main obstacles to organ transplantation. The involvement of anti-HLA antibodies in early and late rejection is indisputable. In 2021, the Leuko-Platelet Immunology Laboratory has implemented a new test for a more specific identification of clinically relevant anti-HLA antibodies, which facilitates graft allocation. In 2022, the records of patients awaiting renal transplant who had anti-HLA antibodies were reviewed, and controls were performed on old sera using the new technique. This allowed the removal of "forbidden" antibody specificities in more than half of the patients, thereby increasing their chance of receiving a compatible graft. Six patients received a kidney graft carrying an HLA antigen previously listed as forbidden with the old technology and removed after revision. Currently, all these patients have displayed a functional graft without immunological complications. These results will be presented at the European Foundation for Immunogenetics (EFI) Congress in April 2023. Although transfusion is a common and beneficial therapeutic procedure for the patient, transfusion reactions can occur. The diagnosis of these reactions is sometimes confusing and difficult. The Hemovigilance Transfusion Sector has developed new decision-making algorithms based on the main symptoms presented by the patient and the blood component involved in the reaction. These algorithms are intended to guide towards a diagnosis and, in order to achieve this, to determine the controls and laboratory tests that must be carried out in each situation. These algorithms have been published in the journal of the Société Francophone de Transfusion Sanguine.

While there were already warning signs of a shortage in 2021, the supply situation for O-negative red blood cells worsened considerably in 2022. The Blood Bank, in consultation with the Medical Direction and the Transfusion Committee, had to deal with this by implementing various actions to try to stop the "hemorrhage". This is the subject of a specific procedure: implementation of very strict and closely monitored indicators, prioritization of transfusion indications, exclusive unitary distribution (outside of hemorrhagic situations), and medical decision to transfuse Rh-positive erythrocyte concentrates to Rh-negative recipients. Various very precise assessments of this situation are still underway and will soon be submitted for publication. Concerted action has been taken within the network hospitals and initiatives are also being taken at the national level.

Finally, the year 2022 also witnessed the publication of a new European directive and new EDQM (European Directorate for the Quality of Medicines) standards defining blood as a SoHO (Substance of Human Origin), similar to cells and tissues. For this reason, it was decided that the Blood Bank and the Erythrocyte Immunology Laboratory would join the Banking Department as of January 1, 2023.

The development of molecular biology led to a new diagnostic tactic for gastrointestinal infections: a syndromic approach, which led to the development of numerous multipathogen molecular polymerase chain reaction (PCR) panels. We evaluated the BD MAX™ (BD Diagnostics, USA) system and compared the results with conventional methods used in our microbiology laboratory to determine if this approach could be implemented as a routine analysis. We also highlighted the practical advantages of a multipathogen molecular panel: reduction of the number of needed technologists needed per day to perform microbiological stool analyzes, easier stock management, and complete traceability for each clinical sample of reagents, expiry date, and user. Moreover, the the BD MAX™ system is easy to use, requires minimal training, and the bidirectional connection with the Laboratory Information System enables a more reliable encoding of the results. In some laboratories, molecular panels already replace conventional methods. Some of these panels’ performances are very satisfactory and their cost are gradually becoming more affordable. Each microbiology laboratory can therefore consider the integration of a multipathogen molecular PCR panel in their routine work.