Tetralogy of Fallot Correction in Low Z-scores: Expanding the Use of the Valve-sparing Approach

Abstract

Objective: Sparing the pulmonary valve (PV) complex in tetralogy of Fallot (TOF) repair prevents pulmonary regurgitation and consequently, the need for valve replacement. Traditional criteria for employing a valve-sparing strategy include a PV z-score of > -2. This retrospective cohort study aimed to establish differences in outcomes between patients with low and high z-scores who underwent a pulmonary valve-sparing technique of TOF correction. Methods: From 2002 to 2012, 59 patients were subjected to a PVsparing TOF repair. Of these, 25 patients had low z-scores? -3 (Group 1), while 34 patients had high z-scores > -3 (Group 2). A retrospective review of patient outcomes and follow-up two-dimensional transthoracic echocardiograms in the immediate and intermediate postoperative periods was conducted. Results: There was no significant difference in baseline patient characteristics except in PV z-scores. Average z-scores were -4.85 for Group 1 and -1.45 for Group 2 (P-value 0.00). No significant difference in immediate postoperative outcomes was noted between groups, specifically in terms of arrhythmias, conversions, early reoperations, morbidity and mortality. There were three deaths (5%) in the series. For intermediate outcomes, Group 1 had a higher degree of residual stenosis than Group 2; however, this did not translate to an increase in late reoperation rates. In both groups, there was note of a significant decrease in residual obstruction through time (P-value 0.00). Conclusion: A pulmonary valve-sparing TOF repair can be successfully utilized even in patients with low pulmonary valve z-scores, with similarly acceptable outcomes as in those with larger pulmonary valve annuli. Key words: Tetralogy of Fallot, pulmonary valve, reoperation