Katie Mitchell had procedure at 15 after being diagnosed with Eisenmenger syndrome, a rare congenital disease Katie Mitchell had procedure at 15 after being diagnosed with Eisenmenger syndrome, a rare congenital disease At the age of 15, medics feared Katie Mitchell was coming to the end of her life after suffering irreversible lung damage and heart failure from a rare congenital disease. But she defied the odds thanks to a heart and lung transplant, and at the age of 53 she has become the UK’s