I am a survivor of Atrial Septal Defect closure by the Gross Atrial Well Technique, a method that was refined by the renowned Mayo surgeon, John W. Kirklin. Would anyone out there happen to know for certain in what year the Mayo moved from this procedure to exclusive use of cardiopulmonary bypass for the repair of these lesions? It must be somewhere between 1959 and 1961. If 2019 is not the sixtieth anniversary of the transition then we are certainly getting close to it. Perhaps a fellow survivor from the early period, a physician or a specialist in the history of medicine would have the answer for me. Here's hoping – and thanks in advance if you can help.