A Sydney gastroenterologist should never have operated on a obese woman who died when her stomach developed a tear after weight-loss surgery, a coroner has found.
Margot Pegum, 68, had a balloon inserted in her stomach in April 2015, despite being at higher risk due to a previous procedure.
She died in July 2015 after suffering complications following the procedure.
On Thursday, Magistrate Elizabeth Ryan described Dr George Marinos' decision to perform the procedure as "a serious error of judgement" as she delivered her findings at Glebe Coroner's Court.
Prior to the procedure the wife and mother weighed 109 kilograms and had a body mass index of 46.
She had previously undergone surgery for a hiatus hernia and had suffered from reflux, sleep apnoea, hypertension and anxiety.
The court heard she was at greater risk due to a previous operation, and the decision to insert an IntraGastric Balloon (IGB) went against the manufacturer's instructions.
Magistrate Ryan said: "There was no evidence to support the proposition that an IGB device for a patient in Margaret's circumstances was safe or appropriate."
"In his evidence Dr Marinos accepted that his decision to proceed with IGB in Margot's case was unwise."
The coroner said the decision to perform the procedure was not easy and was made in the patient's best interests, but was ultimately wrong.
Outside court, Mrs Pegum's son James said he was devastated.
"I think family should be entitled to rely on a doctor to follow the instructions from a manufacturer," he said.
"It's very sad, in this country, when a doctor decides to move away from a manufacturer's instructions on what should and shouldn't be done."
James Pegum's pregnant wife, Ria Pegum, said the couple's baby, their second child, was due next month.
"If it's a girl we're going to call her Margot," she said.
"We'll remember her through our child, hopefully, with lots of stories.
"She was a very fun woman. So we'll always remember her with a smile."
The coroner recommended the governing body, the Australian and New Zealand Metabolic and Obesity Surgery Society develop guidelines covering IGB procedures, covering patient selection and exclusion criteria and follow-up care.
There was a second recommendation to compile a data registry to help doctors and patients make more informed decisions.
In a statement, Dr Marinos expressed his "deep and sincere regret and sympathy" for Mrs Pegum's death.
"I fully support the recommendations of the coroner that guidelines be developed around the use of these devices," the statement said.
"My team and I have thoroughly reviewed our practices to further improve patient safety and support."
