Deborah O'Hara underwent an operation to remove a 8.7in (22cm) tumour at Coventry's University Hospital in 2015.
A clip was inadvertently placed on one of her arteries which led to a lack of blood to vital organs. She died two days later.
Deputy coroner Emma Witting recorded a verdict of death by misadventure and said it was a "tragic loss".
At the inquest in Coventry, surgeon Anthony Blacker told the hearing it was a complicated operation over six hours and when the tumour was removed Mrs O'Hara lost five litres of blood.
In a bid to save her life, four clamps were placed on her arteries, but the move cut off the blood supply to her bowel and she died.
Bosses apologised after her family learnt about the mistake from the BBC.
Widower Andy O'Hara said there was a degree of justice in getting the cause of death recognised saying it was "another bit of closure, but there's still a lot of unanswered questions".
"I'm gutted for my family because we've lost a lovely wife, brilliant mum," he said.
University Hospitals Coventry and Warwickshire NHS Trust previously apologised to Mrs O'Hara's family after failing to tell them about the error.
An internal investigation has been carried out.
It is understood the hospital will pay compensation.
An inquest into the death of a mother-of-three after an error during surgery has recorded a verdict of misadventure.