Mr Sanders was treated in hospital for an arterial blockage after experiencing chest pain at an event in Nevada on Tuesday.
An adviser for the Vermont senator said he was in "good spirits" and will be resting over the next few days.
Mr Sanders had earlier announced his campaign has raised over $25m (£20m).
Senior adviser Jeff Weaver said in a statement: "Following medical evaluation and testing he was found to have a blockage in one artery and two stents were successfully inserted."
Read More (...)