Use of a modified microvascular plug to modify fenestration flow in a rapidly failing Fontan.

We report a case of an alternative transcatheter use of the modified Medtronic microvascular plug to modify fenestration stent flow in a patient with a rapidly deteriorating clinical condition. This four-year-old boy developed severe cyanosis following fenestration stent insertion, initially placed due to prolonged drainage post-Fontan with extra-cardiac conduit. In April 2023, he underwent urgent cardiac catheterisation and had partial occlusion of fenestration stent with a modified 9Q microvascular plug. His oxygen saturations improved from 50 to 89% in room air with no re-emergence of raised cavopulmonary pressures.