Stenosis of the superior limb of the systemic venous baffle following a Mustard procedure: An under-recognized problem Natalie A. Bottega ⁎, Candice K. Silversides, Erwin N. Oechslin, Kaveesh Dissanayake, Jeanine L. Harrison, Yves Provost, Louise Harris Toronto Congenital Cardiac Centre for Adults, Division of Cardiology, University of Toronto, University Health Network, Toronto General Hospital, Peter Munk Cardiac Centre, Toronto, Ontario, Canada abstract article info Article history: Received 12 February 2010 Received in revised form 26 July 2010 Accepted 19 August 2010 Available online 8 October 2010 Keywords: Mustard Atrial switch procedure Baffle stenosis Pacemaker Implantable cardioverter defibrillator Background: Patients with atrioventricular concordance and ventriculoarterial discordance (DTGA) and a Mustard procedure may develop stenosis of the superior limb of the systemic venous baffle (SLSVB). The frequency of this complication in an adult cohort was evaluated. Methods: Patients N 18 years with DTGA and a Mustard procedure with and without a pacemaker (PM)/ implantable cardioverter defibrillator (ICD) were identified through an institutional database. Subjects were included following a cardiac imaging study (computed tomography, magnetic resonance imaging, venography or cardiac catheterization) and follow-up in the PM/ICD or congenital cardiac clinics from 2001 to 2007. The primary end-point was narrowing of the SLSVB (b 10 mm) on cardiac imaging. Hemodynamically significant narrowing was defined by: azygous vein dilatation with retrograde flow or superior vena cava syndrome or the need for dilatation ± stenting of the SLSVB. Results: Narrowing of the SLSVB was observed in 49/112 patients (70 males) age 31 ± 6 years (range 18–49) and was hemodynamically significant in 15/49. Of 29 patients with a PM (23) or ICD (6) and cardiac imaging, 17 had narrowing of the SLSVB which was hemodynamically significant in 8. Non-echocardiographic imaging had a sensitivity of 88% at detecting narrowing of the SLSVB in contrast to pulse-wave Doppler, which yielded a sensitivity of 16% (61% negative predictive value, 88% positive predictive value). Conclusions: In our adult cohort of Mustard patients, narrowing of the SLSVB had a prevalence of 44% and was more likely to be detected by non-echocardiographic imaging. Baffle patency should be evaluated before transvenous device implantation. © 2010 Elsevier Ireland Ltd. All rights reserved. 1. Introduction Prior to the advent of the arterial switch procedure, patients born with atrioventricular concordance and ventriculoarterial discordance (DTGA) were palliated with an atrial switch (Mustard or Senning) procedure (ASP). These operations involve the redirection of blood flow to the appropriate ventricle with a surgically created baffle. Obstruction of the baffles can contribute to detrimental hemodynam- ics and clinical symptoms. Long-term complications associated with DTGA and an ASP include arrhythmias [1–3] and sudden cardiac death [3–5]. Perma- nent pacemakers (PM) are often required to manage symptomatic sinus node dysfunction or high-grade AV block. Although implant- able cardioverter defibrillator (ICD) use is advocated in secondary arrhythmia prevention [5], their use for primary prevention in the setting of systemic RV dysfunction remains limited [6]. The insertion of transvenous (TV) PM or ICD wires across the surgical baffle can contribute to baffle obstruction by further reducing the luminal cross-sectional area of the superior limb of the systemic venous baffle (SLSVB). Baffle patency has typically been assessed using Doppler flow velocity measurements on transthoracic echocardiog- raphy (TTE) [7–11]. However, in this era of increasing PM and ICD insertion rates in this population, the frequency of baffle obstruction and the contribution of PM or ICD wires to this complication are unknown. The primary objective of this study was to evaluate the frequency of stenosis of the SLSVB in a cohort of adults palliated with an ASP and to determine the relationship, if any, between TV devices and stenosis of the SLSVB. The secondary objective was to determine the accuracy of Doppler echocardiography compared to other cardiac imaging modalities (cardiac computed tomography (CT), cardiac magnetic resonance imaging (MRI), venography and right-heart catheteriza- tion) in detecting stenosis of the SLSVB. International Journal of Cardiology 154 (2012) 32–37 ⁎ Corresponding author. Division of Cardiology, McGill University Health Centre, Royal Victoria Hospital, MAUDE Unit H4.33, 687 Av. des Pins Ouest, Montreal, Quebec, H3A 1A1, Canada. Tel.: +1 514 934 1934x42691; fax: +1 514 934 4475. E-mail address: natalie.bottega@muhc.mcgill.ca (N.A. Bottega). 0167-5273/$ – see front matter © 2010 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.ijcard.2010.08.064 Contents lists available at ScienceDirect International Journal of Cardiology journal homepage: www.elsevier.com/locate/ijcard