Originally published by 2 Minute Medicine® (view original article). Reused on AccessMedicine with permission.

1. In a meta-analysis of school-aged children with congenital heart disease after cardiopulmonary bypass surgery, the summary estimate for total IQ was lower than healthy-matched controls, but still within the normal range.

2. Based on 13 studies of executive function (EF) in the same population, performance was significantly poorer compared to controls without a consistent profile of EF impairment.

Evidence Rating Level: 2 (Good)

Study Rundown:

Due to advancements in the management of congenital heart disease (CHD), the population of older children and adults with CHD has grown over the past several decades. Cognitive delays and neurological comorbidities are common in this population, but have not been well characterized. This meta-analysis included studies reporting intellectual and/or executive function (EF) measures in children aged 5-17 years with CHD who had undergone cardiopulmonary bypass. The overall estimate of total IQ across studies was 96.03, within the normal range of 85 to 115. Across the subgroup of studies that included healthy controls, CHD patients had lower IQ scores by about 10 points. CHD subtype significantly affected IQ, with children with hypoplastic left heart syndrome (HLHS) and univentricular heart disease (UVH) having significantly lower IQs than those with atrial or ventricular septal defects (ASD/VSD). EF was found to be impaired based on both parent- and self-reported inventories and on performance-based measures compared to healthy controls. This difference was observed across EF domains such as working memory, inhibitory control, and cognitive flexibility, without a predilection for one domain over others. This meta-analysis is methodologically rigorous and provides an updated rundown of the literature, but the heterogeneity of studies themselves limits detailed interpretation and application. Differences based on CHD subtype suggest that clinicians should refer to studies of neurocognitive prognosis within their patients’ subgroup.

In-Depth [systematic review and meta-analysis]:

This study of children with CHD included 74 studies reporting IQ (n=3,645) and 13 studies reporting EF measures (n=774). Studies were identified using several electronic databases with a pre-defined search protocol. EF studies that did not include a healthy control group were excluded. Patients with genetic syndromes were excluded from the analysis. The Higgin’s I2 value was 94.7% for total IQ, indicating a high degree of heterogeneity between included studies. A regression analysis for effect of age at IQ testing on IQ score was performed and revealed that scores decreased with age for patients with transposition of the great arteries (β = -1.62); in all other subgroups, there was no significant association. For behavior-rated and performance-based EF measures, I2 values were 51.3% and 64.5% respectively, indicating moderate heterogeneity. Risk of bias was assessed and reported in detail for all included studies.

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