Rex Rowe said his wife Sandra was pushed by ambulance staff for nearly a mile because Nottingham's Robin Hood Marathon was routed round the hospital.
Mr Rowe said the driver of the non-emergency ambulance tried various routes before walking.
Race organisers said there was a "permanent passage" to the hospital.
About 8,000 runners took part in the annual race, which took them along Derby Road, Abbey Street and Gregory Street - around the Queen's Medical Centre (QMC).
"They closed so many roads in Nottingham, it was so stupid, it was unbelievable," Mr Rowe said.
Mr Rowe said his wife's leg had become infected and there were fears it could spread to a replacement heart valve.
He said the three-mile journey took more than an hour and a half because the NHS transfer ambulance, which did not have blue lights or a siren, was repeatedly stopped by race stewards.
"We did a major route of the Radford area, the Derby Road area and every time stopped by stewards who said 'you can't go this way'."
The retired baker said the driver pushed Mrs Rowe in a wheelchair for the last 15 minutes of the journey.
Mr Rowe, who urged the organisers to rethink the route next year, said: "Think about other people besides the runners and please do not block hospital routes."
East Midlands Ambulance Service also said it had problems, with police escorts called to help some of its ambulances get to the hospital.
In a statement, race organisers said: "At no point was it radioed in that there were concerns surrounding this patient.
"If there had been, they would have made sure she was blue-lighted immediately to the QMC.
"We will use the learnings from this year's race for planning for the future."
Steve Hunt, head of traffic and safety at Nottingham City Council, said: "The council only signed off the orders with the complete consent and approval of all the emergency services."
The husband of a patient who had to be pushed to hospital in a wheelchair has criticised the route of a marathon for blocking the ambulance.