Tetralogy of Fallot: factors influencing the mortality rate of total correction.

F ROM 1957 TO THE PRESENT, a total of 215 patients with tetralogy of Fallot underwent operations for total correction using extracorporeal circulation. Although the overall mortality rate was about 13 per cent. the rate decreased considerably during the 10 years. The most significant factors influencing the mortality rate were found to be the age of the patient when total correction was performed, the degree of right ventricular outflow obstruction. the associated Iesions and the surgical technic. In severe cases the best resuhs were obtained by means of a palliative operation in the early years, followed bv total correction when the child was over 6 years. The diagnosis was confirmed by cardiac catheterization and cineangiography. These findings, as well as other laboratory data, together with the clinical symptoms, postoperative course and necropsy records were carefully reviewed and augmented by follow-up data. There were 123 males and 92 females. Their ages at operation ranged from 17 months to 41 years. The severity of the disease in any given patient depended on the degree of right ventricular obstruction and associated cyanosis. The patients were grouped as “cyanotic” or “acyanotic” on the basis of cardiac catheterization and angiographic studies. The cyanotic group included those showing obstruction to right ventricular outflow, a ventricular septal defect with a right-to-left shunt and equal pressures in the right and left ventricles. The acyanotic group included those showing less severe obstruction and a balanced shunt or a left-to-right shunt at the ventricular level, with the right ventricular pressure either equal to or slightly lower than that in the left ventricle. There were 154 cyanotic and 61 acyanotic patients, Both infundibular and valvular stenosis were found in 102 patients, infundibular stenosis in 79, pure valvular stenosis in 21, pulmonary atresia in 12 and supravalvular stenosis in one. In addition to obstruction of the right ventricular