Case Report

Endovascular Treatment of Superior Vena Cava Obstruction After Surgical Correction of Intracardiac Total Anomalous Pulmonary Venous Connection

World Journal for Pediatric and Congenital Heart Surgery 2015, Vol. 6(2) 288-290 ª The Author(s) 2014 Reprints and permission: sagepub.com/journalsPermissions.nav DOI: 10.1177/2150135114563940 pch.sagepub.com

Altin Veshti, MD1, Edvin Prifti, MD, PhD1, Luigi Ballerini, MD2, and Vittorio Vanini, MD2

Abstract A three-month-old infant operated for obstructed intracardiac total anomalous pulmonary venous connection was readmitted because of sinus bradycardia and superior vena cava syndrome. Cardiac catheterization revealed a stenosis at the superior vena cava–right atrial junction with retrograde azygos flow. Following balloon dilatation of the stenotic area and stent implantation, the superior vena cava syndrome was rapidly relieved. At six months, an echocardiogram confirmed unobstructed flow from the superior vena cava to the right atrium. Keywords superior vena cava obstruction, collateral blood flow, stent Submitted September 4, 2014; Accepted November 19, 2014.

Introduction Recently, the causes of superior vena cava (SVC) obstruction in children and adolescents have tended to most often be iatrogenic; some being secondary to surgery for congenital heart malformations including atrial switch operations and bidirectional cavopulmonary anastomosis, implantation of pacemaker wires or after ventriculoatrial shunts for hydrocephalus, and inlying SVC catheters for long-term parenteral nutrition and fluid administration.1 Since the first description in 1996 by Fontaine and Nijiar,2 radiologically monitored endovascular interventional therapy has become a well-established treatment of central venous obstruction due to its high success and low morbidity rate.3

Case Report A 14-day old male infant with an oxygen saturation of 40% underwent echocardiography which revealed a diagnosis of total anomalous pulmonary venous connection to the coronary sinus with a 3 mm restrictive atrial septal defect. The infant underwent a successful repair, using aortic and bicaval cannulation (12F right-angle metal cannulas; Medronic, Inc, Medronic DLP, Grand Rapids, Michigan). The SVC cannula was inserted through a small, narrow, longitudinal purse string positioned on its anterior surface. The size of SVC cannula, as well as the arterial cannula, was selected

according to the weight and body surface area of the child to allow adequate venous return during the operation. A fenestration procedure was used to redirect all pulmonary venous return into the left atrium. A week later, the baby, still intubated, developed SVC syndrome. At reoperation, we noted a severe stenosis at the SVC cannulation site. Without cardiopulmonary bypass support, the superior vena cava was partially clamped and a bovine pericardial patch was used to enlarge the stenotic area. The patient was extubated within 24 hours and was discharged on the 15th postoperative day. One month later, an echocardiogram revealed a normal flow pattern of all four pulmonary veins and a residual 2 mm Hg gradient at the junction between the SVC and the right atrium. Three months later, the patient was readmitted because of a recurrent SVC syndrome with significant facial and neck edema and sinus bradycardia. A two-dimensional echocardiogram identified a gradient of 37 mm Hg at the cavoatrial junction.

1 Division of Cardiovascular Surgery, University Hospital Center of Tirana, Albania 2 Heart of Children Foundation, Bergamo, Italy

Corresponding Author: Edvin Prifti, Division of Cardiovascular Surgery, University Hospital Center of Tirana, Rr. Dibres, Tirana, Albania. Email: [email protected]

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Figure 1. A, Stenosis at the cavoatrial junction identified by balloon waist. B, Obstruction of superior vena cava at the cavoatrial junction with retrograde decompression via azygos vein. C, Similar decompression of innominate vein through the azygos vein.

Figure 2. A, Inflated balloon showed elimination of the waist. B. Free flow through stented superior vena cava.

Catheterization on emergency basis confirmed the severe stenosis close to the cavoatrial junction (Figure 1A and B). Injection of contrast into the innominate vein outlined a prestenotic dilatation of the SVC with complete obstruction close to the cavoatrial junction and collateral flow of contrast, within a dilated azygous vein (Figure 1C). Balloon dilatation of the SVC stenosis at 15 atmosphere (Figure 2A) was initially performed, but a significant residual gradient at the cavoatrial junction persisted. Then, we proceeded with the placement of a 10  5 mm stent (Intra Stent S10-26, Intra Therapeutics, Minneapolis, MN) dilated to 6 mm, allowing unobstructed flow through the SVC into the right atrium, with no detectable gradient (Figure 2B). Superior vena cava syndrome resolved within a few hours after the procedure. The child was extubated six hours later and discharged home after 48 hours. Intravenous heparin was administered for two days and aspirin during the subsequent six months. An echocardiogram performed six months later confirmed unobstructed laminar flow through the SVC. Published description of this case was approved by the institutional review board of University Hospital Center of Tirana and by the patient’s family.

Discussion Iatrogenic obstruction of the SVC after open heart surgery is a rare but serious complication. Particularly in infants, the surgeon must avoid causing stenosis of the SVC by purse string or additional wall trauma by using the smallest possible cannula that will still provide adequate systemic venous flow during cardiopulmonary bypass. Symptoms are related to (1) the rate of progression of the SVC obstruction and its extension and (2) the ratio of flow through the obstructed SVC and retrograde decompression via the azygous vein. Caval cannulation can cause an endothelial and intimal injury that can become a nidus for thrombosis. Also if the purse string in the SVC is too large, it can invaginate part of the vessel wall and cause stenosis. Superior vena cava diameter in a 14-day-old baby is about 6 mm, while a 12F venous cannula corresponds to 4 mm in diameter. The turbulence created by flow through a stenotic vessel represents a risk factor for thrombus formation more so in a laminar flow area as in the SVC. Sharoni et al1 in a retrospective review of 1,853 consecutive

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pediatric cardiac surgical procedures reported that only 0.5% of patients (all neonates) developed iatrogenic SVC due to a thrombosis at the cannulation site. In our patient, the first signs and symptoms of SVC syndrome were probably delayed because of the retrograde decompression through the azygous vein, which entered the SVC about 1 cm proximal to the atriocaval junction. As the obstruction progressed, the azygos vein flow must have become insufficient to effectively decompress the SVC. Sinus bradycardia in this patient in combination with SVC syndrome may have been due to the sinus node being exposed to a higher tension within the caval–right atrial junction. As a consequence, the patient was admitted at the intensive care unit and was initially assisted. Once the obstruction was resolved, sinus node function returned to normal. Therapeutic strategies in the presence of an SVC syndrome depend upon causes and time of detection and may include if detected early thrombolysis, long-term anticoagulation, stent implantation, bypass surgery or reconstructive surgery of the SVC, or spiral vein graft implantation.1,4 In our case, the choice of using a patch plasty of the SVC after the initial surgery seemed justified, once the cause appeared to be related to the cannulation site. Bovine pericardium was selected mostly because of its anticalcific properties.5 Unfortunately, the obstruction recurred, probably due to the shrinkage of the most distal part of the patch. At this time, balloon dilatation was selected as the procedure of choice instead of surgery due to the bad general conditions of the patient. However, dilatation alone did not produce effective reduction in the gradient at cavoatrial junction. So, during the same procedure the stent implantation was performed, resulting in the first case of SVC stent implantation in an emerging country. The use of stents within the caval system had been reported to yield acceptable results for other causes of caval obstruction.1,6 Stents placed within systemic veins reportedly are quickly and completely covered by neointima, while protruding stent wires become encased by fibrous connective tissue.7 Excellent long-term outcome in terms of patency rate in stents implanted into SVC is reported.8 The endovascular treatment of SVC syndrome with stent implantation is associated with few complications. Tzifa et al6 reviewed their experience over 22 years with SVC stenting in 63 patients. Acute complications after stenting occurred in 12 (19%) patients and included SVC tear, 9.5%; right atrial perforations, 3%; and stent malposition or embolization, 6.5%. During the 22-year late follow-up, 28% of patients developed recurrent SVC syndrome caused mostly by intra-stent neointimal proliferation.7 Smayra et al8 in a series of 30 patients with SVC syndrome undergoing 49 stent implantation reported only 7% of complications with an acceptable patency rate. In our experience, the percutaneous stenting of an obstructed SVC proved a viable option for treating this patient with SVC

syndrome, after cardiac surgery. A few technical points deserve mention. An expeditiously performed venogram can help identify the exact location of the stenotic lesion and guide the selection of a properly sized device. In our case, the stent was selected to allow for slight oversizing. Placing a longer length stent carries the risk of occlusion of one of the two branches. This could potentially lead to thrombosis of the upper extremity veins. We closely monitored the patient postoperatively for upper extremity swelling. The stent that we employed can be reexpanded up to 10 mm in diameter, which should permit over time development of additional collateral flow. Six-month follow-up in our case is too short to evaluate long-term caval patency in an infant. Nevertheless, the stent did resolve the anatomic and the hemodynamic consequences of the complication with immediate remission of symptoms. Declaration of Conflicting Interests The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding The author(s) received no financial support for the research, authorship, and/or publication of this article.

References 1. Sharoni E, Erez E, Birk E, Katz J, Dagan O. Superior vena cava syndrome following neonatal cardiac surgery. Pediatr Crit Care Med. 2001;2(1): 40-43. 2. Fontaine AB, Nijiar A. Treatment of iatrogenic superior vena cava syndrome with a vascular stent. J Vasc Interv Radiol. 1996;7(4): 607-609. 3. Nagata T, Makutani S, Uchida H, et al. Follow-up results of 71 patients undergoing metallic stent placement for the treatment of a malignant obstruction of the superior vena cava. Cardiovasc Interv Radiol. 2007;30(5): 959-967. 4. Doty JR, Flores JH, Doty DB. Superior vena cava obstruction: bypass using spiral vein graft. Ann Thorac Surg. 1999;67(4): 1111-1116. 5. Neethling WM, Hodge AJ, Clode P, Glancy R. A multi-step approach in anti-calcification of glutaraldehyde-preserved bovine pericardium. J Cardiovasc Surg. 2006;47(6): 711-718. 6. Tzifa A, Marshall AC, McElhinney DB, Lock JE, Geggel RL. Endovascular treatment for superior vena cava occlusion or obstruction in a pediatric and young adult population: a 22-year experience. J Am Coll Cardiol. 2007;49(9): 1003-1009. 7. Mullins CE, O’Laughlin MP, Vick GW III, et al. Implantation of balloon-expandable intravascular grafts by catheterization in pulmonary artery arteries and systemic veins. Circulation. 1198;77(1): 188-199. 8. Smayra T, Otal P, Chabbert V, et al. Long-term results of endovascular stent placement in the superior caval venous system. Cardiovasc Intervent Radiol. 2001;24(6): 388-394.

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Endovascular treatment of superior vena cava obstruction after surgical correction of intracardiac total anomalous pulmonary venous connection.

A three-month-old infant operated for obstructed intracardiac total anomalous pulmonary venous connection was readmitted because of sinus bradycardia ...
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