PREDICTIVE SIGNIFICANCE OF LABORATORY PARAMETERS IN CHILDREN WITH CONGENITAL DEFECT OF THE AORTIC ARCH AND CARDIORENAL SYNDROME TYPE I

Abnormalities in the aortic arch represent a wide range of congenital states characterized by impaired development of the structure, position, quantity and function of the aortic arches that arise from the disturbed gill arch embryogenesis.

Aortic arch abnormality with systemic blood flow obstruction is a frequent component of critical congenital heart defects requiring emergency surgical treatment during the newborn period. It can occur in isolation (aortic coarctation, aortic arch interruptions), but most often it is a component of complex chronical heart disease (CHD). According to the classification of the American Association of Cardiologists, it refers to acyanotic CHD, leading to ischemia of renal, mesenteric blood flow and the development of cardiogenic shock in the neonatal period in the absence of timely surgical care.

The incidence of aortic arch abnormality among the population is 1-2%. It can be diagnosed at 16-18 weeks of intrauterine development. The ratio between male and female is 2:5. 

In the course of this study, the data of patients with obstructive aortic arch anomalies were examined: aortic coarctation (7.5% of CHD), aortic arch interruption (0.5-1% of CHD), hypoplasia of the aortic arch (in 70% of cases with aortic coarctation).

The volume of surgical intervention in obstructive aortic lesions depends on the degree and extent of the aortic arch lesion and its combination with other intracardiac anomalies.  

According to the results of foreign studies, the frequency of acute kidney injury after aortic surgery in children was 36.8% of cases.

At the moment, the level of development of the cardiac surgical service allows us to speak about progress in performing reconstructive operations in the case of congenital abnormality of the aortic arch, while attention is focused on improving postoperative results, and therefore the importance of correct preoperative medical management of diagnosed CHD with systemic blood flow obstruction and the correct interpretation of laboratory and instrumental research.

In everyday practice, we use laboratory tests such as a general blood test: hemoglobin, erythrocytes, leukocytes, MCV (mean cell volume), MCH (RBC mean cell hemoglobin), MCHC (mean corpuscular hemoglobin concentration), platelets. Also biochemical blood test: creatinine, urea, glomerular filtration rate, alanine-aminotransferase, aspartate aminotransferase, bilirubin total (BILT), indirect bilirubin (BILD), C-reactive protein, immunoassay: NT-pro-BNP which can be most effective for predicting the outcome of the postoperative period. 

We conducted a post-hoc test of 402 cases of patients after correction of CHD under cardiopulmonary bypass hospitalized in the NJSC “National research cardiac surgery center” Astana, Kazakhstan for the period from January 2017 to December 2022.  The frequency of acute kidney injury was 15.6% (63 out of 402). In 9 out of 63 patients, the acute kidney injury (AKI) developed after correction of congenital aortic abnormality.

The patients were divided into two groups: group 1 included 5 patients - children who had AKI + congenital aortic abnormalities (CAA) with a recovery outcome, group 2 – 4 patients with AKI + congenital malformation of aorta with a fatal outcome.

All patients were operated during the newborn period (from 1 to 40 days of life). Operations were performed using heart-lung bypass. Congenital aortic abnormalities were in combination with other congenital heart defects.

Inclusion criteria: Children under 18 years of age with congenital aortic abnormality who underwent open heart surgery with aortic arch interruptions diagnoses, aortic coarctation, hypoplasia of the aortic arch.

Exclusion criteria: the presence of AKI and end-stage renal disease in the preoperative period.

Pediatric RIFLE – pRIFLE criteria based on changes in glomerular filtration rate (GFR) and rate of diuresis were used to diagnose AKI in children.

We evaluated the results of a general blood test: hemoglobin, erythrocytes, leukocytes, MCV, MCH (RBC mean cell hemoglobin), MCHC (RBC mean corpuscular hemoglobin concentration), platelets; also biochemical blood test: creatinine, urea, GFR, alanine-aminotransferase, aspartate aminotransferase, C-reactive protein; immunological analysis: NT-pro-BNP. 

The statistical analysis was carried out using the SPSS Statistics 28.0.1 program. According to the data obtained during the analysis of creatinine after surgery, depending on the study group, significant differences were found (p = 0,002) (method used: Student's t–test). Comparing creatinine before surgery, depending on the study group, we were unable to identify significant differences (p = 0,213) (method used: Student's t–test). 

Also, during acute kidney injury assessment of systolic arterial pressure before surgery, depending on the study group, we found statistically significant differences (p = 0,041) (method used: Mann–Whitney U–test). Comparing systolic arterial pressure after surgery, depending on the study group, it was not possible to establish statistically significant differences (p = 0,653) (method used: Student's t–test).

As a result of the evaluation of BILT after surgery, statistically significant differences (p<0.001) were established depending on the study group (method used: Student's t–test). When evaluating BILT before surgery, depending on the study group, it was not possible to establish statistically significant differences (p = 0.050) (method used: Mann–Whitney U–test).

According to the data obtained when comparing BILD after surgery, depending on the study group, we identified statistically significant differences (p = 0.001) (method used: Student's t–test). When evaluating BILD before surgery, depending on the study group, it was not possible to identify statistically significant differences (p = 0.624) (method used: Mann–Whitney U–test).

Evaluating these indicators, we were unable to see significant differences depending on the study group (before and after surgery data): urea (p = 0.328, p = 0.147), glomerular filtration rate (p = 0.502, p = 0.081), NT-pro-BNP (p = 0.248, p = 0.083, methods used: Mann–Whitney U test), hemoglobin (p = 0.325, p = 0.501), erythrocytes, MCH (p = 0.389, p = 0.638), MCHC (p = 0.109, p = 0.893), platelets (p = 0.101, p = 0.130), alanine-aminotransferase (p = 0.216, p = 0.228), aspartate aminotransferase (p = 0.624, p = 0.944), C-reactive protein (p = 0.265, p = 0.285) (methods used: Student's t–test).

Table 1 - Descriptive statistics of categorical variables

Analyzing the results of the study, we come to the conclusion that it is necessary to search for reliable possible prognostic factors to improve perioperative results. This fact encourages us to continue further study in this issue.