Original Article Objective: Chronic volume overload in repair of tetralogy of Fallot (TOF) with transannular patch leads to significant late morbidity and mortality. Preserving pulmonary valve integrity offers a better long-term prognosis, despite a risk of residual stenosis. In our study we analyzed the evolution of pressure gradients in patients operated with conservative approaches, with particular regard to those babies with an immediate postoperative Prv/Plv ratio 0.70. Methods: Between January 2000 and June 2008, 24 patients with TOF underwent reparative surgery with a valve sparing procedure (median age 8.1 months, range 1.1–86.6). The intraoperative post-repair echocardiography showed a Prv/Plv ratio 0.70 in eight patients (33%, group A) and <0.70 in 16 patients (67%, group B). We realized a retrospective study of pre-, intra-, and postoperative data and of clinical and echocardiographic follow-up data. Results: There was no early or late mortality, nor functional or rhythmic disturbances. One patient required re-operation for residual stenosis at annular level at one year. After a median follow-up of 32.8 months (range 0.6–73.1), the Prv/Plv ratio decreased by 16% (p = 0.001) in all patients. In group A the reduction was 28% (p = 0.018) and in group B it was 12% (p = 0.14). Conclusions: After a valve sparing procedure there is a reduction of Prv/Plv ratio at medium-term follow-up; in our study this reduction was statistically significant in all patients and in the subgroup with higher postoperative ratios. A valve sparing strategy reduces pulmonary regurgitation, preserves RV function and decreases the incidence of late arrhythmias, which are the determinants of long-term outcome. Tetralogy of Fallot • Pulmonary valve sparing • Cardiac congenital 33 0 http://www.iscs.org.ir/journals/vol.2/no.4/52/