Abstract No. 193 ▪ FEATURED ABSTRACT Selective Lymphatic Embolization for Treatment of Lymphatic Conduction Disorders in Children

The importance of preserving the thoracic duct (TD) when treating patients with lymphatic conduction disorders has been increasingly recognized. We present our experience with selective lymphatic embolization (SLE) in these patients, with focus on technical aspects and outcomes. Clinical and lymphangiogram records of 39 patients (18 females; median age 6.5 y, IQR 9.3 y; median weight 20.5 kg, IQR 33 kg) who underwent SLE for thoracic lymphatic conduction disorders from 2015-2022 were analyzed; 36 patients presented with chylothorax and 15 with plastic bronchitis. Relevant clinical and imaging data, including technical aspects of the procedure, complications, and outcomes, were collated. Etiology of conduction disorders included palliation of single-ventricle heart disease in 28 patients (72%), vascular malformation/aneuploidy in 9 (23%), and trauma in 2 (5%). 39 procedures were performed after initial planning dynamic contrast-enhanced MR lymphangiogram. SLE of abnormal branches via microcatheter in the TD was performed in in 35 patients (90%), and an articulating steerable microcatheter was used for selection in 22 of 35 cases (63%). Initial TD access was antegrade in 24 of 35 (69%), retrograde in 1 of 35 (3%), and both in 10 of 35 (29%). A dextrose flood technique, requiring placement of 2 catheters in the TD, was used during embolization in 21 cases (54%). In 12 of 39 cases (31%), SLE was performed by direct needle puncture of target channels. Adjunct procedures included balloon occlusion of the TD confluence in 5 cases, balloon occlusion of Fontan fenestration in 4, selective coil embolization in 2, and balloon dilation of duct stenosis with resolution of pressure gradient in 3 cases. Inadvertent extension of glue into the TD was seen in 8 cases. In all cases, glue was cleared by flushing, snaring, or balloon maceration. Cerebral embolization after venous extension of glue occurred in 1 patient with a Glenn shunt, without neurologic sequela. The TD was confirmed to be patent in all cases. Median follow-up was 571 days (IQR, 324 d; range, 42-2318 d). Presenting symptoms were resolved in 32 patients (82%), improved in 4 (10%), and unchanged in 1 (3%); 2 patients were lost to follow-up. We show that selective lymphatic embolization, with appropriate attention to technique, can be performed safely, and that it is effective in the treatment of lymphatic conduction disorders. Importantly, selective techniques preserve the patency of the thoracic duct in these patients.