A 38-year-old woman presented with exertional dyspnea and chest compression. She had undergone repair of congenital supravalvular aortic stenosis at 8 years of age. Contrast-enhanced computed tomography showed re-stenosis in the ascending aorta, bilateral coronary arterial aneurysm, and a highly thickened left ventricular wall. Release of stenosis was necessary to avoid left ventricular functional deterioration; however, it could cause demand-supply mismatch in coronary flow due to substantial left ventricular hypertrophy. Sufficient statistical evidence was not available in this situation; therefore, computerized virtual surgery based on computational fluid dynamics (CFD) was performed to predict the postoperative hemodynamics. Consequently, root replacement with in situ Carrel patch coronary reconstruction was considered a better option than coronary artery graft bypass in the left-side coronary flow supply. The patient underwent root replacement with in situ Carrel patch coronary reconstruction as planned based on CFD without any complication and was discharged 15 days postoperatively.