Preoperative prediction from cineangiograms of postrepair right ventricular pressure in tetralogy of Fallot.

To aid preoperative decision-making, we have related the ratio of postrepair peak pressure in the right and left ventricles (PRV/LV) to preoperative cineangiographic measurements in a retrospective study of 135 patients undergoing complete repair of tetralogy of Fallot or tetralogy of Fallot with pulmonary atresia. Postrepair PRV/LV was related to the preoperative diameter of right (DRPA) and left (DLPA) pulmonary arteries normalized to the descending thoracic aorta (DescThAo) in patients undergoing repair with transannular patching or a valved external conduit by the dquation: PRV/LV = 0.4840/(DRPA/DescThAO + DLPA/DesThAo) + 0.2007. Stenosis of the right pulmonary artery orifice and pulmonary artery arborization abnormalities incrementally increased postrepair PRV/LV. When a transannular patch was not used in classical tetralogy of Fallot, an increment of postrepair PRV/LV usually resulted, depending upon the size of the "anulus" measured intraoperatively: Incremental PRV/LV = 0.09437 . exp(-0.6344 . Z) where Z is a normalized expression in circumference terms of the diameter of the pulmonary arterial outflow tract (DPAOT) measured intraoperatively after infundibular dissection and valvotomy. DPAOT is itself related to the cineangiographically measured pulmonary valve anulus diameter (DPVA): DPAOT = 3.357 . DPVA0.5789 . BSA0.1551. In toto, these relations allow postrepair PRV/LV without transannular patching to be estimated from preoperative cineangiographic measurements. This allows preoperative predictiom in classical tetralogy of Fallot of the need for transannular patching, and in infants this can determine the choice between primary one-stage repair and two-stage repair. Prediction of postrepair PRV/LV when transannular patching or an external conduit is planned allows identification of patients in whom right and left pulmonary arteries are too small for safe complete repair, and in them an initial palliative operation should be done to enlarge the arteries.