Transcatheter Embolization of Systemic-to-Pulmonary Collaterals – A New Approach Using Concerto™ Helix Nylon-fibered Microcoils

Background: Systemic-to pulmonary collaterals (SPC) are common in congenital heart disease (CHD). Particularly in single ventricle anatomy and Fontan circulation, SPC can both complicate the postoperative course and lead to clinical deterioration in the long term. Treatment of SPC is controversial. The aim of our study was (1) to analyze retrospectively patients who underwent SPC embolization using Concerto™ Helix nylon-fibred microcoils (CHM) and (2) to describe the interventional technique. Methods: In this a single-center retrospective observational cohort study, we analyzed clinical and imaging data of all patients who underwent transcatheter embolization of SPC using CHM from January 2016 to December 2023. Results: In 38 consecutive patients (65.8 % male, median age 41 months, range 2 – 490), a total number of 141 CHM had been implanted into 64 SPC in 49 procedures. The majority were arterial SPC (n = 59/64) originating from the thoracic aorta or its branches; 5/64 were veno-venous SPC. Primary closure succeeded in all procedures. The CHM diameters ranged from 3 to 8 mm, with 5 mm being the most commonly used diameter. The mean coil / SPC ratio was 2.6 (range 1.3 – 5.3). CHM implantation was performed via 4 French sheaths. Both detachment and stable positioning was simple and safe. Neither non-target embolization nor coil migration occurred. One complication occurred with a minor vascular injury without clinical relevance. Conclusion: CHM are easy to use and appropriate for SPC embolization in all age groups, including infants, with a low complication rate. The coils are particularly suitable for closure of collaterals with small diameter or tortuous course.