This is the first systematic review and meta-analysis of neurological development after congenital heart surgery and the effects of different surgical procedures (surgical repair and transcatheter repair) on neurodevelopment in patients with CHD. Our results show that the mental development of patients after congenital heart surgery is slow, although the other outcome measures are negative. Moreover, there was no significant difference in postoperative neurodevelopment (full IQ, verbal IQ and performance IQ) between the surgical methods.
Of the six articles on mental development in patients with CHD, two studies showed that the mental development and growth of patients after congenital heart surgery was delayed compared with the corresponding measures in healthy controls, and the remaining four studies showed that the mental development of patients after congenital heart surgery had no significance compared with healthy controls. The results of our meta-analysis are statistically significant. That is, the intellectual development of postoperative patients with CHD is slow, which is consistent with the conclusion of Karl 2004, Sarajuuri, 2012[22; 23]. However, the heterogeneity of the three outcome indicators (full IQ, verbal IQ and performance IQ) is more than 50%, so we want to find the source of their heterogeneity. In this regard, we carried out subgroup analysis and sensitivity analysis. We found that the CHD type in the patients in these three studies[22; 23; 25] was more serious compared to that of the patients enrolled in the other studies. Therefore, we performed a subgroup analysis based on the severity of disease in children with CHD. The analysis results of the severe group showed that the large heterogeneity, and the results of full IQ and verbal IQ were not statistically significant, but the performance IQ result were statistically significant. The analysis results of the mild group showed that there was no heterogeneity, and the results of full IQ and performance IQ were statistically significant. Further, we performed a sensitivity analysis. The results of the sensitivity analysis showed that when we did not include it in Heinrichs 2013, the heterogeneity decreased. After carefully reading Heinrichs’ study, we found that the cardiopulmonary bypass time of this study was shorter than the other three studies in severe group. As a result, we boldly speculate that the time of extracorporeal circulation also has a certain impact on brain development and neurocognitive function[36; 37], which may be due to insufficient blood supply to the brain during the long period of surgery. Therefore, we speculated that there was little influence over a short period of time but gradual deterioration after longer durations of circulatory arrest.
Four articles on surgical procedures were included in this paper, two of which showed no statistical significance[16; 17], and the other two articles did not perform a statistical analysis[24; 26]. The results of our meta-analysis showed no significant difference between surgical repair and transcatheter repair. We considered whether the condition of the patients with CHD in the included literature was relatively mild, and all cases involved atrial septal defect or ventricular septal defect, which may be the reason the results of the two surgical methods were consistent. Therefore, regardless of the type of surgical method (surgical repair or transcatheter repair), there was little effect on mental development. However, we believe that different surgical methods for severe CHD have an impact on mental development. We need more research to clarify the effects of surgical methods on neurodevelopment. Additionally, for the results of the meta-analysis about surgical procedures, we also performed a sensitivity analysis. The results of the analysis did not change after the inclusion and exclusion of each study. In other words, our results are stable and reliable.
In addition, no publication bias was found in our study. With the GRADE approach, there was low-quality or unclear-quality evidence for each of the analyzed outcomes.
Our research has the following advantages. This study is unique in providing information on nerve development after cardiac surgery and differences between different operations (surgical repair and transcatheter repair) based on longitudinal follow-up, which is of great significance for whether early intervention is needed to promote neurodevelopment after such procedures. Our findings show that the mental development of patients with CHD is retarded after surgery, meaning that it is necessary to develop intellectual training programs to solve the problems we are facing.
The present meta-analysis also has potential limitations. First, our results show that neurological development is delayed after surgery and is either caused by the operation or existed before the operation. However, the mechanism is unknown. Second, regarding surgical repair and transcatheter repair, the number of articles included in the literature is small, the sample size is not large, there are no randomized controlled trials, which makes it unclear whether the results are affected. Third, the study only concerns intelligence assessment, and there are many aspects of neurodevelopment, such as motor language execution ability, which is not covered in the present study. Fourth, the time of the postoperative evaluation is different, and the version of the scale is inconsistent, which may have a potential impact. In addition, our study did not reveal whether the time of CPB and the time of carotid artery clipping have a certain influence on postoperative neurocognitive function. Finally, patients with CHD have different disease severities. Although we conducted a subgroup analysis, the sample size of the included studies was relatively small, which may have affected the reliability of the results obtained. Additional studies are needed in the future to evaluate these potential influences.