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Stent Dilatation of a Right Ventricle to Pulmonary Artery Conduitin a Postoperative Patient with Hypoplastic Left Heart Syndrome

Rowan Walsh, MD,* Rajiv Jauhar, MD,† and Dipak Kholwadwala, MD*

*Schneider Children Hospital—Pediatric Cardiology, New Hyde Park, New York, NY, USA; †Long Island Jewish MedicalCenter—Cardiology, New Hyde Park, NY, USA

A B S T R A C T

A 10-day-old child with hypoplastic left heart syndrome (HLHS) underwent first-stage palliation for HLHS,Norwood procedure with a Sano modification, i.e., placement of a right ventricular to pulmonary artery (RV-PA)conduit. The patient developed progressively worsening systemic oxygen desaturation in the immediate postopera-tive period. Stenosis of the proximal RV-PA conduit was diagnosed by echocardiography. In the catheterizationlaboratory stent placement in the conduit was performed. This resulted in increased systemic oxygen saturation. Thepatient was eventually discharged from the hospital with adequate oxygen saturations.

Key Words. Stent; Desaturation; Hypoplastic Left Heart

Case

A10-day-old female with a cardiac diagnosisof hypoplastic left heart syndrome (HLHS)

underwent first-stage palliation for HLHS,Norwood procedure and a 5 mm right ventricularto pulmonary artery (RV-PA) conduit placement(Sano modification). The systemic oxygen satura-tion was 50% despite full ventilatory support and100% FiO2. Four weeks following surgery, thepatient was taken to the catheterization laboratoryfor evaluation.

Cardiac catheterization and angiographyrevealed proximal stenosis at the ventricular originof the conduit and more distal stenosis was alsopresent where the conduit coursed leftward of theaorta. Unsuccessful attempts at femoral venousaccess precluded intervention from the groin. Aright subclavian venous line was exchanged for a5F sheath but despite multiple attempts from thissite, negotiation across the conduit was not pos-sible. Therefore, a 4F coronary catheter (Glide-Cath Cobra 1) was placed retrogradely via the 4Fsheath right femoral artery and was maneuveredanteriorly into the proximal conduit. After somedifficulty, a wisper wire was then advancedthrough the coronary catheter into the conduit.A premounted coronary stent (MX Driver4 mm ¥ 15 mm) was delivered retrogradely fromthe left femoral artery without the aid of a long

sheath or guiding catheter. Accurate stent posi-tioning was verified by multiple contrast injectionsthrough the venous catheter placed into the rightventricle. The stent was then dilated to 5 mm.Initial stent placement resulted in dilatation of theproximal shunt but seemed to miss the origin fromthe muscle bound right ventricular wall. There-fore, a second stent (MX Driver 4 mm ¥ 15 mm)was placed that straddled the origin as well asreinforced the proximal shunt from kinking.

The systemic oxygen saturation increased to80% following stent placement. Angiographyrevealed improved patency and alleviation of thestenosis. There were no complications throughoutthe procedure. The patient was eventually weanedfrom mechanical ventilation. At discharge thetranscutaneous oxygen saturation was 80%. Thepatient continues to do well (Figures 1–4).

Discussion

In 2003, Sano et al. reported improvement in stageI morbidity and survival by using an RV-PAconduit rather than a modified Blalock-Taussigshunt (mBTS).1 Increasing experience with thismodification is being acquired. Higher diastolicpressures and improved coronary circulation is atheoretical advantage of the RV-PA conduit whileimproved growth of the pulmonary arteries has

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also been documented.2 However, the unknownrisk of a ventriculotomy and right ventricularvolume overload during diastole requires furtherinvestigation and long-term follow-up.

Decreased flow through the RV-PA conduitmay manifest as decreased oxygen saturation whilecomplete obstruction may lead to sudden death.3

The RV-PA conduit is an example of a modifi-cation of a surgical technique which is amenable tocardiac catheterization intervention when stenosisdevelops. The stenting of such a conduit may betampered by several conditions including difficultywith access because of prior surgery, inability toestablish stable guidewire position, and technicaldifficulty in maneuvering wires across a stenosed

Figure 1. Lateral view demonstrating proximal stenosis(arrow) of the RV-PA conduit. RV-PA, right ventricular topulmonary artery.

Figure 2. AP view of the proximal stenosis in the RV-PAconduit. AP, antero posterior; RV-PA, right ventricular topulmonary artery.

Figure 3. Stent (arrow) is seen deployed in the proximalconduit with relief of the stenosis.

Figure 4. Lateral view of the conduit with stent placed.Improved pulmonary blood flow is observed.

Congenit Heart Dis. 2008;3:146–148

Hypoplastic Left Heart Syndrome 147

conduit. Herein, we describe retrograde place-ment of premounted coronary stents through a 4Fshort sheath in the femoral artery with the aid ofright ventricular contrast injections via the venouscatheter for accurate placement of the stents.

The etiology of conduit obstruction is variable.Stenosis may occur because of kinking of theGore-tex graft particularly when a long conduithas been used. The nature of the ventricular originmay potentiate proximal stenosis of the conduitparticularly in the presence of a hypertrophiedright ventricle and fibrointimal dysplasia. Throm-bus formation should be considered in the differ-ential diagnosis of any occluded artificial conduit.

This case describes successful stent dilatation ofan RV-PA conduit in a 4-week-old patient follow-ing stage I palliation for HLHS. The antegradeapproach was unsuccessful. Because of the anteriorposition of the proximal conduit, the retrogradeapproach facilitated access to the conduit, stablewire position, and deployment of premountedcoronary stents without the use of a long sheath ora guiding catheter. Also, there was no disruption ofthe surgical anastomosis. The retrograde approachhas been previously described.4

Early systemic oxygen desaturation followingfirst-stage palliation for HLHS may indicate shuntobstruction. The surgical options for conduitobstruction include RV-PA conduit revision, con-version to a systemic-pulmonary artery shunt orcompletion of the Glenn anastomosis. The lattermay not be suitable particularly in a youngerpatient. Therefore, stent dilatation of the conduitmay allow adequate interstage recovery andprovide adequate systemic oxygen saturations untilthe second staged repair.

Early reports alluded to improved outcomes offirst-stage palliation for HLHS using an RV-PAconduit. Recent reports, however, comparingthe RV-PA conduit with the mBTS over the sametime period does not substantiate this.5,6 Early

systemic oxygen desaturation following use of anRV-PA conduit should alert the physician topossible conduit obstruction. Stent dilatationof an obstructed or stenosed conduit may allowadequate pulmonary blood flow, thus providingextra time until the next planned surgery.

Corresponding Author: Rowan Walsh, MD,Schneider Children Hospital—Pediatric Cardiology,260-01 76th Avenue, New Hyde Park, New York, NY11040, USA. Tel: (+1) 718-470-7350; Fax: (+1) 718-347-5864; E-mail: rwalsh1@lij.edu

Accepted in final form: January 23, 2007.

References

1 Sano S, Ishino K, Kawada M, et al. Right ventricle-pulmonary artery shunt in first-stage palliation ofhypoplastic left heart syndrome. J Thorac CardiovascSurg. 2003;126:504–509.

2 Rumball E, McGuirk S, Stumper O, et al. TheRV-PA conduit stimulates better growth of the pul-monary arteries in hypoplastic left heart syndrome.Eur J Cardiothorac Surg. 2005;27:801–806.

3 Nigro J, Bart R, Derby C, Sklansky M, Starnes V.Proximal conduit obstruction after Sano modifiedNorwood procedure. Ann Thorac Surg. 2005;80:1924–1928.

4 Eicken A, Sebening W, Genz T, Schreiber C, Hess J.Stenting of a stenosed Sano shunt in a neonate withhypoplastic left heart syndrome. Pediatr Cardiol.2005;26:877–878.

5 Cua C, Thiagarajan R, Gauvreau K, et al. Earlypostoperative outcomes in a series of infants withhypoplastic styndrome undergoing stage I palliationoperation with either modified Blolock-Taussig shuntor right ventricle to pulmonary artery conduit.Pediatr Crit Care Med 2006;7:298.

6 Tabbutt S, Dominquez T, Ravishankar C, et al. Out-comes after the stage I reconstruction comparing theright ventricular to pulmonary artery conduit withthe modified Blalock Taussig shunt. Ann Thorac Surg.2005;80:1582–1591.

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