Abstract 4368358: Practice variation in cardiovascular computed tomography (CCT) imaging protocol and utility of tracheal area ratio in airway assessment in pediatric patients with vascular ring (VR)- a multicenter study

Intro: Vascular rings (VR) are congenital anomalies where the trachea and esophagus are encircled by vascular structures and may require surgery. There are no published studies on the multicenter practice variation in the use of CCT and the quantitative assessment of tracheal narrowing. Method: 10 academic centers contributed to this retrospective study of all consecutive patients with a suspected VR and CCT between 1/2018 and 1/2024. CCT details, clinical data, VR subtype and percentage of tracheal narrowing, defined as the difference in tracheal areas above and at the VR was evaluated. Results: 455 patients (BSA median 0.3 m2 with IQR 0.23-0.46, ages 0-18 years, 53% male) were included with 284 (63%) diagnosed with right aortic arch with aberrant left subclavian artery (RAA) and 138 (30%) with a double aortic arch (DAA). Fifty-four percent of patients developed symptoms in this cohort and 57 (13%) had a confirmed genetic diagnosis. The most common symptom was stridor (52% of symptomatic) and 57% developed symptoms before 6 months of age. The most common scanner platform was Siemens (85%) with dual source (56%) and prospective gating (68%) with only 13 (3%) cases with dynamic airway evaluation. The indication to perform a CCT was to confirm echocardiographic diagnosis (67%) or after symptom onset (28%). Table 1 shows the variation in technique by center. 22% of patients had a change in suspected VR type after CCT (Gwet AC1 0.69, 95% CI: 0.63 – 0.75). Tracheal narrowing >10% was seen in 83% of patients analyzed (Table 2A). Tracheal narrowing was greater in DAA (36.3%) than RAA (22.4%, p<0.0001). Table 2B shows the correlation of tracheal narrowing with symptoms and surgery. With each unit increase in % tracheal narrowing in DAA, the odds of seeing symptoms increased by 3% (OR: 1.03, 95% CI: 1.01-1.05, p = 0.01). A threshold analysis showed the cutoff for predicting the presence of symptoms in DAA is 32.1%. There was a discrepancy noted between CCT and intra-operative diagnosis in 5 patients (1.9%). Conclusion: There is variability among centers in the use CCT for VR. Tracheal narrowing seen on CCT was common and was associated with symptoms but not surgery in the entire cohort and the DAA subgroup. For the RAA subgroup, symptoms were present in those with and without tracheal narrowing.