Reply to the Editor

Abstract

I appreciate the interest in our recently published study by Buckberg and Hoffman in their letter to the Editor. In our study, no long-term benefits were demonstrated for limited right ventricular (RV) incision relative to conventional (longer) RV incision in transannular repair of tetralogy of Fallot (TOF) in terms of RV volume and function. Buckberg and Hoffman speculate that our finding was due to the limited contribution of the RV free wall to the overall RV function. They stressed the importance of interventricular septum in maintaining normal RV function according to the helical heart model of Torrent-Guasp. I admit the limited contribution of the RV infundibulum, in which a transannular incision is made, to global RV function. As discussed in previous paper, Geva and colleagues1Geva T. Powell A.J. Crawford E.C. Chung T. Colan S.D. Evaluation of regional differences in right ventricular systolic function by acoustic quantification echocardiography and cine magnetic resonance imaging.Circulation. 1998; 98: 339-345Crossref PubMed Scopus (185) Google Scholar have demonstrated that the infundibulum contributes only 13% of the total RV stroke volume. Bodhey and colleagues2Bodhey N.K. Beerbaum P. Sarikouch S. Kropf S. Lange P. Berger F. et al.Functional analysis of the components of the right ventricle in the setting of tetralogy of Fallot.Circ Cardiovasc Imaging. 2008; 1: 141-147Crossref PubMed Scopus (63) Google Scholar found the stroke volume of the infundibulum to account for 25% of the total RV stroke volume in healthy individuals. The fact that the RV infundibulum has limited contribution to global RV function, however, does not mean that the RV infundibulum is not important in maintaining RV function. In fact, there is good evidence leading us to speculate that RV infundibular contractility may play a key role in protection of the RV against deleterious consequences of the chronic volume overload related to pulmonary regurgitation after TOF repair.3d'Udekem d'Acoz Y. Pasquet A. Lebreux L. Ovaert C. Mascart F. Robert A. et al.Does right ventricular outflow tract damage play a role in the genesis of late right ventricular dilatation after tetralogy of Fallot repair?.Ann Thorac Surg. 2003; 76 (discussion 561): 555-561Abstract Full Text Full Text PDF PubMed Scopus (27) Google Scholar, 4Puranik R. Tsang V. Lurz P. Muthurangu V. Offen S. Frigiola A. et al.Long-term importance of right ventricular outflow tract patch function in patients with pulmonary regurgitation.J Thorac Cardiovasc Surg. 2012; 143: 1103-1107Abstract Full Text Full Text PDF PubMed Scopus (26) Google Scholar One should remember that many factors other than the length of the RV incision could also influence late outcomes of patients with repaired TOF. These factors include the width of the transannular patch, the number of coronary arterial branches sacrificed, the extent of infundibular muscle resection, and the methods of myocardial protection. Poor myocardial protection and ensuing septal dysfunction can definitely affect the long-term outcomes of patients with repaired TOF, and we cannot rule out the possibility of poor myocardial protection in the historical cohort of patients who underwent TOF repair long ago and whose late outcomes are being studied today. In the current era of improved myocardial protection, however, serious septal dysfunction is too rarely observed after operation for TOF for us to reconsider our current method of myocardial protection. Effect of right ventricular free wall ventriculotomy on right ventricular function: Is that the correct question?The Journal of Thoracic and Cardiovascular SurgeryVol. 148Issue 2PreviewLee and colleagues1 recently reviewed the effects of limited versus conventional right ventriculotomy on subsequent right ventricular (RV) dilation and dysfunction in patients with tetralogy of Fallot who develop pulmonary regurgitation (PR) after transannular repair. No long-term benefits were seen after limited right ventriculotomy. The logic behind this strategy stems from the premise that the free wall RV incision generates dysfunction, with a corresponding hypothesis that late RV function would benefit from restricting the RV incision to less than 1 cm or avoiding it with transatrial and pulmonary artery approaches. Full-Text PDF Open Archive