Catheter systems including one or more flow restrictors are disclosed. The catheter systems may include two or more delivery branches. The delivery branches may be connected to a supply catheter section using a branching catheter connector that may include one or more flow restrictors. The flow restrictors may include a restrictor body located within a lumen with a channel located between the restrictor body and interior surface of the lumen, the channel restricting flow through the lumen past the flow restrictor. The channel may be defined by a groove formed in the restrictor body and/or the interior surface of the lumen. Methods of providing pressure relief by flowing fluid past a flow restrictor are also disclosed.