Objectives: Impairment regarding their cognitive function is often assumed in adults with congenital
heart disease (ACHD). In particular, patients with Fontan circulation are assumed
to be at higher risk for impairments in cognitive function. Currently, there is no
data with regard to cognitive function formally assessed by standardized intelligence
tests in ACHD patients, particularly concerning specific heart defects.
This study analyses the cognitive function in ACHD patients with Fontan circulation
compared with patients with acyanotic congenital heart disease (CHD).
Methods: Twenty-eight ACHD patients (female n = 15 (53.6%), mean age at assessment 35.2 ± 13.1 years, Fontan patients n = 14, and acyanotic CHD patients n = 14) underwent the Wechsler Intelligence Scale for adults (fourth edition, German
version)—a well-established assessment of cognitive function in adults—between March
2017 and January 2018. Impairment is defined as an intelligence quotient (IQ) achieved
less than 1 standard deviation (SD) of the norm (100 ± 1 SD).
Results: Fontan patients achieved a full scale IQ (FSIQ) 102.2 ± 8.9 IQ points (IQp) which
was significantly higher than in patients with acyanotic CHD 90.9 ± 11.2 IQp (p = 0.007). Regarding the subcategories, Fontan patients achieved significant higher
IQ levels than acyanotic CHD patients in terms of verbal comprehension (107.1 ± 6.8
vs. 94.9 ± 13.1 IQp; p = 0.004) and logical thinking (102.0 ±12.2 vs. 88.9 ± 10.1 IQp; p = 0.005), but not in working memory (100.1 ± 13.8 vs. 93.4 ± 14.0 IQp; p = 0.208) and processing performance (97.1 ± 11.9 vs. 94.1 ± 13.8 IQp; p = 0.554). Both patient groups showed no significant impairment in FSIQ and subcategories
IQ levels compared with IQ norm standard (100 IQp ± 1 SD).
Conclusion: In contrast to the general assumption, adult Fontan patients showed normal intelligence
levels assessed by IQ test. Interestingly, compared with acyanotic CHD patients, they
even achieved significant higher IQ levels in FSIQ and some subcategories in this
study. Data from larger cohorts are needed to confirm these findings.