pulmonary artery growth following arterial duct stenting in congenital heart disease with...

Original Studies

Pulmonary Artery Growth Following Arterial DuctStenting in Congenital Heart Disease WithDuct-Dependent Pulmonary Circulation

Giuseppe Santoro,* MD, Maria Teresa Palladino, MD, Giovanbattista Capozzi, MD,Carola Iacono, MD, Maria Giovanna Russo, MD, and Raffaele Calabro, MD

Objectives: The aim of this study was to assess the pulmonary artery (PA) growth fol-lowing arterial duct (AD) stenting in neonates with congenital heart disease (CHD) withduct-dependent pulmonary circulation. Background: AD stenting is increasinglydeemed as a reliable alternative to surgical shunt in CHD with duct-dependent pulmo-nary circulation. Allowing the stent to conform to the PA anatomy might avoid anyunbalance of lung perfusion and promote a uniform growth of the main PAs. Methods:Of the 47 neonates and infants submitted to AD stenting as palliation of CHD withduct-dependent pulmonary circulation at our Institution, 15 underwent angiographicevaluation of the PA development before surgical repair due to progressive decreaseof the systemic oxygen saturation. The Nakata and McGoon indexes as well as theleft-to-right PA diameter ratio were considered as being indicative of global and bal-anced growth. Results: Ductal stabilization was achieved with coronary stents dilatedto 3.3 6 0.4 mm (range 2.5–4). The control angiography was performed 7 6 3 months(range 3–13) after the stenting procedure. At that time, the Nakata and McGoonindexes had significantly increased from 132 6 67 to 287 6 94 mm/m2 and from 1.6 60.3 to 2.1 6 0.2 mm/m2, respectively (P < 0.0001 for both comparisons), due to uniformvascular growth (left PA z-score from 20.7 6 1.6 to 1.4 6 1.2; right PA from 20.8 6 1.4to 1.4 6 1.2, P < 0.0001 for both comparisons; final left-to-right PA ratio 0.9 6 0.1).Conclusions: Percutaneous AD stabilization with highly flexible coronary stents iseffective in promoting a significant and balanced growth of the PAs in CHD with duct-dependent pulmonary circulation. VC 2009 Wiley-Liss, Inc.

Key words: congenital heart disease; cyanosis; arterial duct; stent; pulmonary arterygrowth

INTRODUCTION

Arterial duct (AD) stenting is increasingly deemedas an effective and less-invasive alternative to surgicalsystemic-to-pulmonary shunt in congenital heart dis-ease (CHD) with duct-dependent pulmonary circulation[1–7]. This option has been advocated either in high-risk patients unsuitable for primary repair or whenevera short-term pulmonary blood flow support is antici-pated. Allowing the stent to conform to the pulmonaryartery (PA) anatomy might avoid any unbalance oflung perfusion and promote a uniform growth of themain pulmonary arteries. However, no study has so farspecifically addressed this hypothesis in patients withCHD and duct-dependent pulmonary blood flow.

Department of Pediatric Cardiology, ‘‘Monaldi’’ Hospital, 2ndUniversity of Naples, Naples, Italy

Conflict of Interest: There is no relationship with any industry for

any of the authors.

*Correspondence to: Giuseppe Santoro, MD, Via Vito Lembo, 14

84131 – Salerno, Italy. E-mail: [email protected]

Received 28 May 2009; Revision accepted 13 June 2009

DOI 10.1002/ccd.22191

Published online 29 July 2009 in Wiley InterScience (www.

interscience.wiley.com)

VC 2009 Wiley-Liss, Inc.

Catheterization and Cardiovascular Interventions 74:1072–1076 (2009)

METHODS

Patient Population

Between April 2003 and April 2009, 47 neonatesand infants with CHD and duct-dependent pulmonarycirculation (age 22 � 39 days, range 1–84; weight 3.2� 0.9 kg, range 1.2–5.5) underwent AD stenting at ourInstitution in alternative to surgical shunt. Over a mid-term follow-up, 26 of them spontaneously improvedand did not need any further therapeutic approach.Conversely, 19 infants underwent control cardiac cath-eterization in view of surgical repair and because ofprogressive decrease of systemic oxygen saturation. Infour patients the stented AD served a discontinuousPA, and they were excluded from the study. The demo-graphic data of the remaining 15 patients are summar-ized in the Table I. Seven patients had complete duct-dependency of the pulmonary circulation due to trivialor absent antegrade pulmonary blood flow, whereaseight patients showed a mild-to-moderate antegradepulmonary flow in addition to the ductal flow.

Interventional Procedure

AD stenting was performed under general anaesthe-sia following a previously described protocol [7]. Pros-taglandin infusion was stopped 6 hr before the proce-dure, to achieve a stable ductal constriction to grip thestent after its deployment. Arterial vascular access wasused both to image the AD and to perform the stentingprocedure. The AD morphology, size and length wereassessed in multiple angiographic views, and the meas-urements were made using the catheter as reference.After duct visualization, a 0.014’’ coronary guide-wire(Crosswire NT, Terumo Corporation, Tokyo, Japan;Balance Middleweight, Guidant Corporation, SantaClara, CA) was passed through the channel and anch-ored in a distal lower lobe pulmonary artery branch.Positioning and deployment of the stent were angio-graphically-guided by repeat injections through theintroducer sheath or a right coronary guiding catheter.Open-cell, highly flexible, cobalt-chromium stents(Vision, Guidant Corporation, Santa Clara, CA; Driver,

Medtronic, Minneapolis, MN) were used. The length ofthe stent was chosen to cover the entire length of theAD, whereas the diameter of the stent was chosen indi-vidually, based on the size of the patient and theexpected time for which palliation was needed. Thestent diameter was always about 75% of the proposedsurgical shunt size in the belief that it acted more as acentral shunt than a Blalock-Taussig shunt. After stentdeployment, repeat angiographies were performed inmultiple views to exclude any incomplete covering ofthe duct as well as to evaluate any potential stent-related pulmonary artery stenosis.

Angiographic Measurements

Pulmonary angiography was performed in right ante-rior oblique and four-chamber views. The left and rightPAs were measured just before their first branchingpoint. The diameter of the descending aorta was meas-ured at the diaphragm level. All values were obtainedduring ventricular systole and, if possible, from thesame angiographic frame using the catheter size as ref-erence. The cross-sectional area of the left and rightPA (Nakata index)[8], and the ratio of the sum of thediameters of both PAs to the diameter of the descend-ing aorta (McGoon ratio)[9] were considered as beingindicative of global growth of the pulmonary vasculartree. The diameter ratio of any main PA to the de-scending aorta [10], as well as the normative diametersof the right and left PAs against body surface area (z-scores) obtained from web nomograms (http://parame-terz.blogspot.com/2008/09/z-scores-of-cardiac-structur-es.html) were deemed as indexes of individual PAgrowth. Finally, the left-to-right PA diameter ratio wasconsidered as being indicative of balanced vasculargrowth.

STATISTICAL ANALYSIS

All analyses were performed using SPSS for Win-dows version 13.0 (SPSS, Chicago, IL). Results areexpressed as mean � standard deviation. Comparisonswere performed using the paired and unpaired Studentt-test. Significance was defined as a P value < 0.05.

RESULTS

Ductal stabilization was achieved with stents dilatedto a mean diameter of 3.3 � 0.4 mm (range 2.5–4, me-dian 3.4). The control angiographic evaluation was per-formed 7 � 3 months (range 3–13, median 8) after theprocedure due to progressive decrease of percutaneousoxygen saturation, from 87 � 5% (post-stent implanta-tion) to 81 � 7% (P < 0.01). The follow-up cardiac

TABLE I. Demographic and Clinical Data at Control CardiacCatheterization of Patients Submitted to ArterialDuct Stenting

Age (mos) 8.1 � 3.6 (range 3–15, median 7)

Weight (kg) 5.7 � 1.8 (range 3.6–10.6, median 5)

Cardiac malformation

Tetralogy of Fallot 2

Pulmonary atresia with intact

ventricular septuma

6

Complex CHD with pulmonary

atresia/stenosis

7

ain five cases after pulmonary valve perforation and angioplasty.

Artery Growth in Duct-Dependent Circulation 1073

Catheterization and Cardiovascular Interventions DOI 10.1002/ccd.Published on behalf of The Society for Cardiovascular Angiography and Interventions (SCAI).

catheterization was performed slightly earlier in thesubgroup without antegrade pulmonary flow (7 � 4 vs.9 � 3 months, P ¼ NS) due to a significantly lowerpercutaneous oxygen saturation (76 � 5 vs. 84 � 7%,P < 0.03). At that time, both the PAs had shown anover 100% increase of their absolute and indexed size(Fig. 1), overgrowing nearly 40% the descending aortasize (Table II). These changes resulted in a significantincrease of both the Nakata index (from 132 � 67 to287 � 94 mm2/m2, P < 0.0001)(Fig. 2a) and theMcGoon ratio (from 1.6 � 0.3 to 2.1 � 0.2, P <0.0001)(Fig. 2b). Neither distortion of the proximalPAs nor significant changes of the left-to-right diame-ter ratio (from 1.0 � 0.1 to 0.9 � 0.1, P ¼ NS) wasfound at control angiography (Fig. 3). Finally, no sig-nificant difference was found between the subgroupswith or without antegrade pulmonary flow in terms ofboth individual and global PA growth.

DISCUSSION

Over the last few years, AD stenting has gainedwide acceptance as a reliable alternative to systemic-to-pulmonary shunt in patients with CHD and duct-de-pendent pulmonary circulation [1–7]. This option isnow-a-days deemed safer and more effective than sur-gical shunt in high-risk patients unsuitable for primaryrepair [11–14], since it is possible to tailor the shuntmagnitude to the patient’s size and pulmonary anat-omy. In addition, the shorter durability of the stentedduct [2] with respect to a conventional shunt may actas a temporary bridge toward spontaneous improve-ment in patients in whom a short-term pulmonaryblood flow support is anticipated [7]. Finally, thisoption prevents from shunt-related complications andavoids any pulmonary artery distortion and differentialgrowth that may potentially increase morbidity andmortality of subsequent corrective surgery [10,15–18].However, the capability of ductal flow to promote asignificant and balanced PA growth in CHD with duct-dependent pulmonary circulation has so far never beenspecifically addressed. Conforming the stent to the sizeand angulations of the main PAs might theoreticallyprevent any unbalance of lung perfusion and vascular

Fig. 1. Individual growth of the pulmonary arteries followingthe arterial duct stenting, as assessed in terms of z-scorechanges over a mid-term follow-up.

TABLE II. Pulmonary Artery Anatomic Changes Following theArterial Duct Stenting

Pre- Post- P value

Left pulmonary artery (mm) 4.0 � 1.4 7.6 � 1.8 0.0001

z-score �0.7 � 1.6 1.4 � 1.2 0.0001

% increase 101 � 48

Right pulmonary artery (mm) 4.1 � 1.2 8.3 � 2.0 0.0001

z-score �0.8 � 1.4 1.4 � 1.2 0.0001


LPA/RPA diameter ratio 1.0 � 0.1 0.9 � 0.1 NS

% change �4 � 12

LPA/Ao diameter ratio 0.8 � 0.2 1.0 � 0.2 0.0001


RPA/Ao diameter ratio 0.8 � 0.2 1.1 � 0.1 0.0001


Nakata Index (mm2/m2) 132 � 67 287 � 94 0.0001


McGoon Ratio 1.6 � 0.3 2.1 � 0.2 0.0001


Fig. 2. Changes of the Nakata Index (a) and McGoon Ratio(b) after the arterial duct stenting.

1074 Santoro et al.


distortion, thereby resulting in uniform vascular devel-opment. This hypothesis is so far supported only byscanty data drawn from large series reporting just theglobal development of the PA tree [6,7]. However, nodata exist about the growth of the individual PAs aswell as the left-to-right balance resulting from stabi-lized ductal flow. Preliminary data from our group sug-gested a significant and uniform growth of the mainPAs following the AD stenting as well as a better out-come than after modified Blalock-Taussig shunt in neo-nates with CHD and duct-dependent pulmonary circu-lation [19]. In this study, the stented duct ensured anacceptable systemic oxygen saturation over a mid-termfollow-up despite it was dilated to a smaller diametercompared with both previous series [3–6] and conven-tional surgical shunts. At the same time, it promoted asignificant and uniform PA development that mightfoster either spontaneous improvement of duct-depend-ent pulmonary circulation or reduce the risk of furthercorrective surgical approaches. The percutaneous palli-ation appeared less durable in patients without acces-sory pulmonary flow although the stented duct was

able to promote a similar PA growth even in this subsetof patients. These results were possibly due to an opti-mal angle between the AD, stabilized with highly flexi-ble coronary stents, and the main pulmonary branches,that allowed a significant and balanced pulmonary bloodflow. However, the small size of our population pre-cluded any reliable analysis regarding the influence ofthe accessory pulmonary blood flow on the developmentof the pulmonary vascular tree. After the percutaneouspalliation, all patients underwent successful surgicalrepair (n ¼ 7 biventricular repair; n ¼ 8 bidirectionalcavo-pulmonary anastomosis) without any technicalproblem in removing the stent. Thus, AD stenting con-firms as an advisable short-term palliative option inCHD with duct-dependent pulmonary circulation, eitherin patients who are likely to achieve a biventricularrepair or in those destined to the Fontan track. In thislatter subset, the percutaneous option should be evenmore advisable than surgical palliation in that it pro-motes a similar but more uniform growth of the pulmo-nary vascular tree than a conventional surgical shunt[19], thereby hopefully influencing more favorably thelong-term outcome of univentricular physiology [20].

CONCLUSIONS

In conclusion, percutaneous AD stenting with highlyflexible chromium-cobalt coronary stents is effective inpromoting a significant and balanced pulmonary arterygrowth in CHD with duct-dependent pulmonary circu-lation over a mid-term follow-up. Thus, it could beproposed as the first-choice approach for short-termpalliation of these malformations, although its useshould be still restricted to single centers with specialexpertise and experience.

ACKNOWLEDGEMENTS

The authors gratefully acknowledge the professorShakeel Qureshi for his invaluable help in reviewingand improving the article. They would also thank Mrs.Annunziata Orefice, chief-nurse of the cardiac catheter-ization laboratory, and her colleagues for their tirelessand loving work in assisting our small patients. Finally,they would like to acknowledge our colleagues Gian-piero Gaio, Marianna Carrozza, Chaira Marrone, Car-mela Morelli, and Raffaella Esposito for their clinicalskill in curing our patients.

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pulmonary artery growth following arterial duct stenting in congenital heart disease with...

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