Early cerebral perfusion dynamics in neonates with transposition of the great arteries assessed by ultrafast ultrasound imaging

Background

Transposition of the great arteries (1/3,500–5,000 births) leads to parallel circulations, systemic hypoxaemia, and increased cerebral oxygen extraction. The impact of postnatal management and neonatal surgical repair on cerebral perfusion, and consequently on neurodevelopmental outcomes, remains poorly understood. Ultrafast ultrasound allows non-invasive bedside assessment of cerebral blood volume (CBV) dynamics in affected and healthy neonates.

Objectives

1) to compare CBV relative variation (ΔCBV) for patients with TGA and healthy volunteers during the first weeks of life, and 2) to assess the impact of arterial switch surgery on ΔCBV.

Methods and Results

We performed a retrospective study including 44 newborns (age range 1-59 days), 27 healthy volunteers and 17 with transposition of the great arteries, with serial cerebral blood volume measurements assessed by ultrafast ultrasound scanner and obtained from birth at regular intervals during follow-up.

In linear mixed-effects models, ΔCBV increased significantly with age in healthy neonates (β = +0.10 ΔCBV/day, p = 0.003). In contrast, only a non-significant trend was observed in TGA patients (β = +0.035 ΔCBV/day, p = 0.054). Across vascular territories, CBV trajectories differed: in TGA infants, age-related increases were non-significant in arterial (β=+0.020 ΔCBV/day, p=0.07) and venous (β=+0.032 ΔCBV/day, p=0.12) sectors but remained significant in the capillary compartment (β=+0.05 ΔCBV/day, p<0.001).

Within the TGA group, perioperative ΔCBV was summarized as median [IQR]. Median ΔCBV was 0.10 [−0.01, 0.69] preoperatively (n = 10), 0.08 [−0.27, 0.62] peroperatively (n = 16), and −0.04 [−0.22, 0.14] postoperatively (n = 15). Paired Wilcoxon analyses showed no significant difference between pre and peroperative periods (p = 0.82) nor between per and postoperative phases (p = 0.50). However, postoperative ΔCBV was significantly lower than preoperative values (p = 0.016).

Conclusion

Healthy neonates exhibited a significant age-related increase in CBV, whereas infants with TGA did not, consistent with prior reports of reduced brain volumes in congenital heart disease. In addition, a marked postoperative decline in CBV was observed. Ultrafast ultrasound imaging provides the first in vivo characterization of cerebral perfusion abnormalities in TGA neonatal patients, thereby raising questions regarding their longitudinal trajectory and the timing of potential neurological recovery.