Original article

When the bi-directional Glenn is an unfavourable option:primary extracardiac inferior cavopulmonary connectionas an alternative palliation

Ali Dodge-Khatami,1 Avichal Aggarwal,2 Mary B. Taylor,2,3 Douglas Maposa,4 Jorge D. Salazar1

1Division of Pediatric and Congenital Heart Surgery; 2Division of Pediatric and Fetal Cardiology; 3Division of PediatricCritical Care; 4Division of Pediatric Anesthesiology, The Children’s Heart Center, University of Mississippi MedicalCenter, Jackson, Mississippi, United States of America

Abstract The superior cavopulmonary anastomosis – bi-directional Glenn – is the standard palliation for singleventricle physiology. When upper body systemic venous anatomic concerns such as superior caval vein stenosis,hypoplasia, or inadequate collateral tributaries are present, a Glenn may be precluded or have a high risk of pooroutcome. A primary inferior cavopulmonary connection with an extracardiac conduit is an alternative palliationthat provides a generous pathway for pulmonary blood flow, with the additional benefit of including hepaticvenous return.We report a case of primary extracardiac inferior cavopulmonary connection in a patient unsuitablefor Glenn, with successful post-operative outcome and early follow-up.

Keywords: CHD; Fontan; Glenn

Received: 3 March 2015; Accepted: 19 March 2015

THE SUPERIOR CAVOPULMONARY ANASTOMOSIS, ALSO

known as the bi-directional Glenn procedure, is astandard surgical palliation for single ventricle

physiology before the completion of total cavo-pulmonary connection. Initially, used as an interimpalliation only in high-risk patients,1 the bi-directionalGlenn is now a routine stage preceding Fontancompletion in all patients, with low operative risk andexcellent short-term outcomes. Drawbacks of thesuperior cavopulmonary anastomosis include the devel-opment of pulmonary arteriovenous malformations inup to 60% of patients,2 presumably due to the absenceof a purported “hepatic factor”, thereby rendering somechildren increasingly cyanotic with time. The logicalsequence after bi-directional Glenn has therefore beenFontan completion, incorporating inferior caval veinand hepatic venous flow to the pulmonary arteries, with

near or complete separation of systemic and pulmonarycirculations, and resolution of cyanosis if the pulmonaryarteriovenous malformations regress.3 In the presence ofsystemic venous anomalies including superior caval veinor tributary stenosis, thrombosis, hypoplasia, oftenleading to a network of inadequate collateral venouschannels, or high-risk bilateral superior caval veins,4 abi-directional Glenn procedure may be a poor option. Inthese situations, an inferior cavopulmonary connectionmay provide a reliable source of pulmonary blood flow,avoid potential bi-directional Glenn failure, takedown,and a step backwards to shunted circulation, withresultant prolonged intensive care stay, morbidity, andeven mortality.4 It could theoretically accomplish onestep forwards towards eventual Fontan completion,while providing hepatic venous return to the pulmonaryarteries. The inferior vena cava-pulmonary artery shuntwas first performed in 1993 by Macé et al. as atemporizing measure, with an intracardiac lateraltunnel, and transection with reimplantation of thesuperior caval vein elsewhere in the common atrium, intwo patients with temporary contraindications to a

Correspondence to: Dr A. Dodge-Khatami, MD, PhD, Chief, Division ofPediatric and Congenital Heart Surgery, Children’s Heart Center, Professor ofSurgery, University of Mississippi Medical Center, 2500 North State Street, RoomS345, Jackson, MS 39216, United States of America. Tel: + (601) 984 4693; Fax:+ (601) 984 5872; E-mail: adodgekhatami@umc.edu

Cardiology in the Young 2015; Page 1 of 3 © Cambridge University Press, 2015doi:10.1017/S104795111500058X

Fontan completion.5 To our knowledge, we report thefirst successful primary extracardiac inferior cavopul-monary connection with satisfactory early follow-up.A 3-month-old male infant after a Norwood I

operation with Sano modification for hypoplastic leftheart syndrome presented for routine pre-Glenn evalua-tion. Ventricular function was normal with no semilunaror atrioventricular valve regurgitation. At catheterisation,pulmonary vascular resistance (2.94 Wood Units) andpulmonary artery pressures (18/13/15mmHg) werenormal, with adequate pulmonary arteries. The veno-gram demonstrated a thrombosed innominate vein andmultiple veno–venous collaterals between a smaller rightsuperior caval vein, a left remnant superior caval vein, theazygous vein, an accessory hemiazygous, and para-vertebral plexuses (Fig 1). Attempts at interventionalcatheter improvement of the situation were unsuccessful.The surgery was deferred until nearly 6 months of age toencourage further superior caval vein growth, but intra-operative findings confirmed the unfavourable upperbody venous anatomy for the planned bi-directionalGlenn. After consulting with the referring paediatriccardiologist and family, we proceeded with primaryinferior cavopulmonary connection. Through redo med-ian sternotomy, arterial inflow was accomplished via theprevious 3.5-mm GoreTex graft to the innominateartery, alongwith a low inferior caval vein and right atrialcannulation for venous return. The superior caval veinwas mobilised, and the azygous vein was doubly ligatedand transected, so that the future inferior caval vein–pulmonary artery conduit could travel unobstructedbehind the superior caval vein–right atrial junction and

avoid right pulmonary venous compression. Cardio-pulmonary bypass was initiated and the procedure wasperformed on a beating heart. After takedown of the Sanoshunt, the inferior caval vein was transected from thecommon atrium and the cardiac side was oversewn. Atube of bovine photofixed xenopericardiumwas created –with 14-mm diameter based on intra-operative inferiorcaval vein measurement – and anastomosed to the infer-ior caval vein opening. The pulmonary arteries were iso-lated, the underside opened, and anastomosed to theextracardiac conduit, working first between the aorta andthe superior caval vein and then lateral to the superiorcaval vein (Fig 2). An intra-cardiac line was placed andtunnelled to the skin for common atrial pressure mon-itoring. Weaning from cardiopulmonary bypass wasuneventful, with systemic oxygen saturations in the loweighties on a fractional inspired oxygen of 50%, pul-monary artery pressures via a femoral venous line of 14–18mmHg, and atrial pressures of 4–6mmHg. In thepaediatric cardiac ICU, low-dose intravenous heparin wastransitioned to oral Aspirin as with our standard post-Glenn protocol. Post-operative haemodynamics werestable, allowing planned early extubation, an uneventful3-day ICU stay with removal of chest drains, and dis-charge to home on post-operative day eight. The infantmaintained saturations in the low eighties on room air,had no abdominal symptoms, and was feeding and

Figure 1.Pre-operative antero-posterior angiogram showing a small stenoticsuperior caval vein and multiple systemic veno–venous collaterals.

Figure 2.Artist’s illustration of the inferior cavopulmonary connection andthe free lie posterior to the superior caval vein–common atrialjunction.

2 Cardiology in the Young 2015

growing appropriately at 5 months post-operatively. Afollow-up catheterisation (Fig 3) and CT-angiogram at4months post-operatively disclosed an open inferior cavalvein–pulmonary artery connection, no veno–venous col-lateral systems in the lower body, and no hepatic venouscongestion.

Discussion

With anatomic concerns pertaining to upper body sys-temic veins, performing the standard superior cavo-pulmonary anastomosis may be a challenging forwardstep in single ventricle palliation. When consideringoptimal staging towards Fontan completion, it is para-mount to protect the pulmonary arteries from hyperten-sion while promoting pulmonary artery growth, andshorten the duration of shunted physiology yet avoidGlenn takedown. Faced with a patient with sub-optimalupper body systemic venous anatomy, likely due to vas-cular access-induced thrombosis of the innominate vein,we attempted and successfully performed a new alter-native surgical operation – the primary extracardiacinferior cavopulmonary connection. This palliationallowed saturations equal to those expected after a stan-dard bi-directional Glenn, the post-operative course wasuneventful, of similar duration to a bi-directional Glenn,and, to date, has allowed the infant to feed and grownormally, without any evidence of morbidity. If a hepaticfactor entity exists,2 it may flow directly to the pulmon-ary arteries with the primary inferior cavopulmonaryconnection, and hopefully avoid the formation of

troublesome pulmonary arteriovenous malformationsleading to increased cyanosis.3 A bubble-contrast echo-cardiographic study or angiography will be planned inthe near future of our patient to study this potentialphenomenon. Longer follow-up is certainly warranted tounderstand the fate of this new physiology and perhapsextend its indications: whether it leads to an unplannedinter-stage re-operation, will be an ideal set-up for futureFontan completion with the superior caval vein,5 orresults in a final palliative stage not needing any furtherintervention, given the similar haemodynamics andoxygen delivery to a very largely fenestrated Fontancirculation.

Limitations to the technique and future considerationsIn the absence of a right-sided pumping chamber,creating an inferior caval vein–pulmonary artery con-nection with laminar flow, which goes against gravity, inan infant who is not yet ambulating or even crawlingmay be haemodynamically sub-optimal. The true sig-nificance of this phenomenon compared with the bi-directional Glenn, which theoretically uses gravity toflow downwards is however unknown. The use of aninterposition graft of any nature, which will not grow,may render future re-operations inevitable due to poten-tial conduit outgrowth (patient-conduit size mismatch),although many centres uniformly use small conduits atFontan completion.

Acknowledgements

The authors thank Kyle Cunningham and MichaelSchenk for their superb surgical illustration.

Financial Support

This research received no specific grant from anyfunding agency, commercial, or not-for-profit sectors.

Conflicts of Interest

None.

References1. Pridjian AK, Mendelsohn AM, Lupinetti FM, et al. Usefulness of

the bidirectional Glenn procedure as staged reconstruction for thefunctional single ventricle. Am J Cardiol 1993; 71: 959–962.

2. Bernstein HS, Brook MM, Silverman NH, Bristow J. Developmentof pulmonary arteriovenous fistulae in children aftercavopulmonary shunt. Circulation 1995; 92 (Suppl): II309–II314.

3. Knight WB, Mee RBB. A cure for pulmonary arteriovenous fistulas?Ann Thorac Surg 1995; 59: 999–1001.

4. Iyer GK, Van Arsdell GS, Dicke FP, McCrindle BW, Coles JG,Williams WG. Are bilateral superior vena cavae a risk factor forsingle ventricle palliation? Ann Thorac Surg 2000; 70: 711–716.

5. Macé L, Dervanian P, Losay J, et al. Bidirectional inferior vena cava-pulmonary artery shunt. Ann Thorac Surg 1997; 63: 1321–1325.

Figure 3.Post-operative early injection angiogram showing the inferiorcavopulmonary connection with widely patent anastomoses compatiblewith generous pulmonary artery flow.

Dodge-Khatami et al: When the bi-directional Glenn is an unfavourable option 3