You searched for: “valvotomy
valvotomy (s) (noun), valvotomies (pl)
A medical operation performed to correct a stenosed (narrowed) passage that transports fluids: "A surgeon performs a valvotomy by making incisions or applying pressure to separate the flaps of any valves where they have joined together in order to reduce the degree of narrowing."

"Balloon valvuloplasty is now being used more often during valvotomies as a treatment for narrowed valves without opening the chest."