Left Modified Blalock-Taussig Shunt Research Articles

Three-dimensional-printed heart model can determine univentricular repair strategy in borderline double-outlet right ventricle

BackgroundAs double-outlet right ventricle has a wide pathophysiology spectrum, its comprehensive treatment strategy is determined based on relevant factors, such as the location and size of the ventricular septal defect, ventricular volume, and relationship of the great arteries. However, for borderline double-outlet right ventricle cases, it is occasionally difficult to decide the treatment strategy preoperatively. Recently, advances in 3D printing technology based on computed tomography have enabled the creation of 3D heart models of congenital heart disease that can precisely reproduce the anatomical structure of each patient even for complex anomalies. Herein, we describe a young patient in whom univentricular repair could be decided after confirming the 3D heart model and intracardiac structure under direct vision.Case presentationWe describe a 3-year-old girl who was diagnosed with double-outlet right ventricle and severe pulmonary valve stenosis at birth and who underwent a left modified Blalock–Taussig shunt at 2 years of age. Preoperative examination revealed a borderline condition for biventricular repair characterized by a small left ventricle volume and side-by-side relationship of the great artery. After a preoperative discussion using a 3D heart model, we concurred that an intraoperative assessment would be made as to whether biventricular repair was possible or not. After confirming the intracardiac structure under direct vision, we assessed that intraventricular rerouting was not possible owing to the high risk of subvalvular aortic stenosis as there was no tissue that could be incised between the right ventricular free wall and the primary interventricular foramen, as indicated in the 3D heart model. Thus, atrial septostomy and Glenn anastomosis were performed.ConclusionsWe report a 3-year-old girl with a borderline double-outlet right ventricle in whom a univentricular repair strategy could be decided after confirming the 3D heart model and intracardiac structure under direct vision. A 3D-printed heart model can be useful in patients whose repair strategy is difficult to judge for the borderline double-outlet right ventricle.

Intrapulmonary artery septation for unilateral absence of the pulmonary artery.

We describe a seven-month-old boy with tetralogy of Fallot and an absent left pulmonary artery. Due to the diminutive size of the left pulmonary artery, we performed a native tissue left pulmonary artery reconstruction and intrapulmonary artery septation procedure with a left modified Blalock-Taussig shunt. After confirming left pulmonary artery growth, the patient underwent tetralogy of Fallot repair, removal of septation patch, and division of the Blalock-Taussig shunt. Nine months post-surgery, we confirmed his balanced lung perfusion (R/L ratio 6:4). The intrapulmonary artery septation procedure would be suitable for both the resuscitation and reconstruction of the hypoplastic absent pulmonary artery.

Hemodynamics in a bidirectional Glenn Shunt supplemented with a modified Blalock-Taussig shunt: Computational fluid dynamics assessment

The bidirectional Glenn Shunt (BGS), superior vena cava (SVC) to right pulmonary artery (RPA) is occasionally supplemented with a left modified Blalock-Taussig shunt (mBTS) when PA growth is inadequate. Little is known about hemodynamics when BGS's low-velocity steady flow interacts with mBTS's high-velocity pulsatile flow. We employed simulations of flow in cavopulmonary pathways consisting of internal jugular, subclavian and innominate veins, SVC, RPA, LPA and mBTS, using computational fluid dynamics (CFD) to numerically solve (finite volume method) the Navier-Stokes equations subject to in vivo flow rates at the inlets and measured or calculated pressures at the outlets of the cavopulmonary system. For normal size (9 mm) PAs and a BGS alone, SVC pressure was 12.3 mmHg, RPA and LPA 12.2 mmHg; PA outlets 12 mmHg. We then compared results for the BGS with a 4 mm mBTS. I) With normal-size PAs, SVC pressure was 14.3 mmHg, RPA 13.3 mmHg and LPA 12.9 mmHg; PA outlets 12 mmHg. Wall shear stress (WSS), RPA 6.2 Pa and LPA 53.7 Pa. II) With normal size (9 mm) RPA but small (5.1 mm) LPA, SVC pressure was 15.1 mmHg, RPA 13.8 mmHg and LPA 17.4 mmHg; RPA outlet 12 mmHg and LPA 14 mmHg. WSS, RPA 13.2 Pa and LPA 71 Pa. Normal PA WSS is ~ 2 Pa. *All parameters were averaged over the cardiac cycle. The mBTS created vortices which markedly elevated WSS. High WSS can induce PA luminal cell expression of coagulatory molecules and initiate platelet aggregation. However, WSS lessened as flow velocity decreased from LPA to RPA. This is important since in vitro studies demonstrate WSS's harmful effect on PA endothelium is ameliorated under decelerating flow. In conclusion, for a BGS with a mBTS, SVC pressure became cyclic and significantly increased and thrombogenic vortices were established in the PAs.

Biventricular repair in heterotaxy patients.

Heterotaxy patients' hearts may or may not be suitable for biventricular repair depending on anatomy. Even in the subset that are amenable to surgical septation, cardiac anatomy may present multiple difficulties in achieving a satisfactory repair. However, it is also well known that heterotaxy patients are not ideal candidates for univentricular repair. From 2007 until 2012, a total of 20 patients (11 male) with heterotaxy syndrome underwent biventricular repair (left atrial isomerism: 10 and right atrial isomerism: 10) in our center. Their median age at surgery was 40 (range: 3-108) months. Ten patients had dextrocardia. Eleven patients presented with bilateral superior vena cava, three with inferior vena cava (IVC) draining into left atrium, and six with IVC interruption with azygos or hemiazygos continuation. Anomalous pulmonary venous drainage was present in eight patients. One had a common atrium. Atrioventricular septal defect (AVSD) occurred in nine (complete AVSD in seven) patients. Eight patients had double outlet right ventricle (DORV), one had d-transposition of great arteries (d-TGA), and two had congenitally corrected transposition of the great arteries (CC-TGA). Prior palliative procedures included pulmonary artery banding in three patients and left modified Blalock-Taussig shunt in one patient. Complex intra-atrial baffle constructions were required in all patients to direct pulmonary and systemic venous inflow to the appropriate ventricle. Complete AVSDs were corrected using two-patch technique. Intraventricular tunnel repair was done for DORV. Combined atrial and arterial switch was required to rectify abnormal connections in a child with congenitally corrected transposition with normal pulmonary valve, while a Rastelli + Senning was needed in two children with CC-TGA with pulmonary atresia (n = 1) and double outlet of the right ventricle (n = 1). Major early postoperative complications included intestinal gangrene in four patients for which they underwent bowel resection. Two of these patients could not be salvaged. One patient required coiling of aortopulmonary collateral for early postoperative pulmonary hemorrhage. Two patients needed a tracheostomy for prolonged mechanical ventilatory support. Five patients had a pacemaker implanted for complete heart block. There were no instances of atrial baffle stenosis. Median follow-up was 27 (range: 2-46) months. There was one late death secondary to pneumonia. Satisfactory survival outcomes can be achieved in heterotaxy patients who undergo hemodynamically acceptable biventricular repair. Borderline ventricular hypoplasia and trivial atrioventricular valve regurgitation should not be considered as discouraging factors in anatomically suitable heterotaxy patients as it is possible to adopt a two-stage repair in such patients to achieve biventricular repair at a later stage. Anticipating a higher incidence of conduction problems and gut malrotation preemptively can help reduce the morbidity.

Angiographically detectable infracardiac TAPVC in a 7-month-old patient who had single ventricle physiology and left modified Blalock-Taussig shunt, dextrocardia, and large midline liver

Angiographically detectable infracardiac TAPVC in a 7-month-old patient who had single ventricle physiology and left modified Blalock-Taussig shunt, dextrocardia, and large midline liver

Ischemic prevention for stent implantation via brachial artery in children

An 11-year-old boy received stent implantation for peripheral pulmonary stenosis through the left modified Blalock-Taussig shunt from the left brachial approach because of the hairpin-shaped route from a femoral or carotid approach. A temporary bypass between the left radial and the femoral arteries was established to prevent ischemic complication of the left forearm. There was no ischemic change of the left forearm in the physiological monitoring despite the long procedure (more than 4 hr) and brachial arterial spasms. No complications occurred after the procedure. The temporary bypass will support fewer complications in various catheter interventions through a brachial arterial approach in children.

Thrombotic occlusion of Blalock-Taussig shunt in a patient with unnoticed protein C deficiency

A 6-month-old girl with a diagnosis of double-outlet right ventricle and pulmonary stenosis had a left modified Blalock-Taussig shunt. Chest computed tomography (CT) performed on postoperative day 11 showed good patency of the shunt. However, on postoperative day 16, oxygen saturation suddenly dropped below 40%, and chest CT showed thrombotic occlusion of the shunt. Urgent thrombectomy was performed successfully. Examination of coagulation factors revealed low levels of both the amount and activity of protein C (27% and 31%, respectively). Diagnosis of heterozygous hereditary protein C deficiency was made, and the patient was placed on warfarin. She is currently in good condition.

Fontan operation through a right lateral thoracotomy to treat Cantrell syndrome with severe ectopia cordis

A median sternotomy would be very difficult for Cantrell syndrome with severe ectopia cordis. For Cantrell syndrome and tricuspid atresia after left modified Blalock-Taussig shunt with severe ectopia cordis, defect in the middle and inferior portion of the sternum, and the closing of ventriculo-peritoneal shunt, we performed extracardiac total cavopulmonary connection through a right lateral thoracotomy after establishing right modified Blalock-Taussig shunt and performing coil embolization of left modified Blalock-Taussig shunt by cardiologists.

Right ventricle-dependent coronary circulation demonstrated with 64-slice computed tomography

A 12-year-old female patient, who had emergency left modified Blalock–Taussig shunt operation during neonate and a total cavo-pulmonary shunt operation performed at the age of 5 years following a diagnosis of pulmonary atresia with intact ventricular septum (PAIVS), was under regular follow-up. At her last visit, she was admitted with exercised-induced anginal symptoms. …

Novel use of a retroaortic innominate vein in cavopulmonary anastomosis

is well recognized. 3 We present a child with tricuspid atresia and pulmonary atresia with bifurcation stenosis of confluent pulmonary arteries (Figure 1). The child also had a right aortic arch. The parallel course of the retroaortic innominate vein with the pulmonary artery was used in pulmonary artery reconstruction by creating a wide side-to-side anastomosis (Figure 2). Clinical Summary The child was given a diagnosis of tricuspid atresia and pulmonary atresia at birth. He underwent placement of a left modified Blalock-Taussig shunt at day 1 of life. He was initially doing well, and then he presented at 6 months of life with increasing cyanosis. A central shunt from the aorta to the right pulmonary artery was placed through a sternotomy at another center. At 9 months of age, when he presented with increasing cyanosis, it was found that the central aortopulmonary shunt had become blocked and that there was narrowing of the left Blalock-Taussig shunt. A narrowed patent ductus was found supplying the right pulmonary artery. The patent ductus arteriosus (PDA) was stented, with the stent extending into the right pulmonary artery. When he presented to us at 1 year and 5 months of age, he had a patent but narrowed left Blalock-Taussig shunt, a blocked aortoright pulmonary shunt and a stented PDA supplying the right pulmonary artery, which had narrowed. He had an oxygen saturation of 72% on room air. There was severe stenosis of the pulmonary artery bifurcation at the site of PDA insertion (Figure 1). He had a right aortic arch. A computed tomographic angiogram revealed that he had a retroaortic innominate vein. A bidirectional Glenn procedure with pulmonary artery reconstruction was planned. After induction, a venous cannula in the left jugular vein was placed to detect any compression of the retroaortic innominate vein. The right and left jugular venous catheters showed equal pressures of 10 mm Hg. A redo median sternotomy was performed, and the aorta and right atrium were cannulated. All the systemic pulmonary shunts were controlled, and the patient was cooled to 18°C. The retroaortic innominate vein was dissected. It was found coursing just above the left pulmonary artery behind the PDA and inserting into the superior vena cava just above its junction with right atrium. The aorta was transected to provide unimpeded visualization of the pulmonary artery bifurcation. The pulmonary artery was opened, and the previous stent was removed piecemeal. The pulmonary artery was opened across the stenosed portion into the right and left pulmonary artery. The retroaortic innominate vein was opened parallel to the pulmonary artery from its insertion into the superior vena cava and anastamosed side to side, with the pulmonary artery providing a wide, unimpeded venous drainage into the pulmonary arteries and at the same time augmenting the stenosed portion of the pulmonary artery bifurcation (Figure 2). The aorta was reanastomosed, and the patient was weaned off cardiopulmonary bypass. The oxygen saturation was 87% with a fraction of inspired oxygen of 60%, and the left and

Double Aortic Arch Associated with Common Inlet Left Ventricle

A double aortic arch is usually an isolated abnormality. We report a case with a previously undescribed combination of double aortic arch and common inlet left ventricle. The patient underwent division of the nondominant right aortic arch and the right ductus arteriosus at 2 months of age following a left modified Blalock-Taussig shunt. At 3 years of age, extracardiac total cavopulmonary connection was successfully performed via bidirectional cavopulmonary anastomosis.

Successful Fontan procedure for asplenia with pulmonary atresia and major aortopulmonary collateral arteries

Asplenia with a single ventricle and major aortopulmonary collateral arteries (MAPCAs) is a rare congenital cardiac anomaly. In this patient group achievement of the Fontan procedure depends on ample rehabilitation of the pulmonary arteries to secure sufficient pulmonary vascular beds and the prevention of progressive pulmonary vascular obstructive disease. Here we report a successful 1-stage bilateral unifocalization of the pulmonary blood supply followed by a staged Fontan procedure in a patient with a univentricular heart and MAPCAs. Clinical Summary The patient was given a diagnosis of asplenia, univentricular heart (right ventricular type), common atrioventricular orifice, pulmonary atresia, bilateral superior vena cavas, total anomalous pulmonary venous connection (intracardiac type), and MAPCAs on the basis of echocardiography and cardiac catheterization. His neonatal aortography showed a small central pulmonary artery (3 mm in diameter) and bilateral multiple MAPCAs (Figure 1, A). The patient’s arterial oxygen saturation (Sa O2) was around 80%, and his pulmonary/systemic blood flow ratio (Qp/Qs) was 1.6 with stable hemodynamics. Subsequent cardiac catheterization at 6 month of age revealed a good-sized central pulmonary artery (Figure 1, B) and 5 large MAPCAs. His SaO2 was approximately 87%, and his Qp/Qs had increased to 3.7. At 1 year of age, he underwent a primary complete unifocalization of his bilateral pulmonary arteries, total anomalous pulmonary venous connection repair for progressive pulmonary venous obstruction (Figure 2), and a left modified Blalock-Taussig shunt (polytetrafluoroethylene [PTFE],* 5 mm). The postoperative course was uneventful except for transient bilateral phrenic nerve palsy. He subsequently did well, while becoming increasingly cyanotic. A catheterization at 2 years of age revealed peripheral pulmonary stenosis, low pulmonary vascular resistance (1.2 Wood units), and normal pulmonary blood flow (Qp/Qs 1.0). The patient then underwent a bilateral bidirectional cavopulmonary shunt and take down of his left modified Blalock-Taussig shunt without cardiopulmonary bypass. This postoperative course was also uneventful, with an SaO2 of 85% and superior vena caval pressure of 10 mm Hg. Eight months after the bilateral bidirectional cavopulmonary shunt, a cardiac catheterization was performed, demonstrating good-shaped pulmonary arteries (Figure 3), low pulmonary vascular resistance (1.4 R*U), low pulmonary artery pressure (mean, 10 mm Hg), and low pulmonary blood flow (Qp/Qs 0.8). Two weeks before definitive surgical intervention, he underwent balloon angioplasty for peripheral pulmonary stenoses and coil embolization of aortopulmonary collateral arteries. At 3 years of age, a fenestrated modified Fontan procedure was performed. An 18-mm PTFE tube graft with a 4-mm PTFE tube graft anastomosed in end-to-side fashion was used for the extracardiac total cavopulmonary connection. The 4-mm PTFE tube graft was anastomosed to the common atrium as a fenestration. The patient was hemodynamically stable intraoperatively, with superior vena caval and inferior vena caval pressures of 11 mm Hg, a common atrial pressure of 4 mm Hg, and an SaO2 of 94%. The patient returned to the cardiovascular intensive care unit in stable condition and was extubated 3 hours after the operation. His postoperative course was uneventful. He was transferred to the general ward on the first postoperative day and discharged home 13 days later without any complications. Three months after the Fontan procedure, another cardiac catheterization was performed, demonstrating a spontaneously occluded tube graft fenestration, an Sa O2 of 96%, low pulmonary artery pressure (mean, 12 mm Hg), and excellent Fontan circulation.

“Bail-out” stenting for acute obstruction of a modified Blalock-Taussig shunt following selective angiography

A 3-year-old boy developed acute obstruction of a left modified Blalock-Taussig shunt following selective power injection of contrast in the shunt. Balloon dilation was ineffective due to rapid recoil of the narrowed segment, but implantation of a stent effectively abolished the obstruction. The obstruction itself may have been produced by an intimal flap caused by the power injection.

Pulmonary ventricular outflow reconstruction with a size-reduced cryopreserved pulmonary valve allograft: mid-term follow-up.

Surgical reduction of pulmonary allografts is being performed because of the shortage of allografts of suitable size for pediatric use. However, the outcome of size-reduced pulmonary allografts for pulmonary conduits is unknown. In the present study, cryopreserved pulmonary allografts harvested from adults at the time of kidney donation were size-reduced and used in 4 children, 2 with pulmonary atresia and ventricular septal defect and 2 with atrioventricular discordance, pulmonary atresia and ventricular septal defect. They all had undergone right and/or left modified Blalock-Taussig shunt operations with a 5-mm synthetic graft prior to the reparative operations. They underwent definitive repair with a size-reduced cryopreserved pulmonary allograft valved conduit and were followed up for 2-5 years. Postoperative echocardiographic and cineangiographic assessments revealed excellent function of the pulmonary bicuspidalized valves with a minimal pressure gradient and no, or only trivial, regurgitation. Although the long-term result of a cryopreserved bicuspid pulmonary valved conduit remains unknown, the remodeled bicuspid pulmonary allograft conduits showed excellent hemodynamic characteristics in mid-term follow-up and appear to be a reasonable alternative to other types of conduits when an appropriate-sized allograft is not available.

Extracardiac modification of the Fontan operation without use of prosthetic material

Extracardiac modification of the Fontan operation without use of prosthetic material

An unusual post-operative complication following modified left Blalock-Taussig shunt

A left modified Blalock-Taussig shunt was performed in a 3-year old child with Fallot's tetralogy. Intraoperative course was uneventful. Persistent hypoxia was noticed in the post-operative period in spite of a clinically functioning shunt. Angiography revealed a functioning shunt with totally blocked left pulmonary artery. A thrombus was removed from the left pulmonary artery which dramatically improved the clinical course of the patient.

Pulmonary atresia and intact ventricular septum: surgical management based on a revised classification.

Sixty patients with pulmonary atresia and intact ventricular septum (PA:IVS) presenting from 1970 to 1980 are reviewed. Three groups of patient are discussed: those with tripartite right ventricles, those with no trabecular portion to the cavity, and those with neither trabecular nor infundibular portions. The decrease in early mortality for neonates with PA:IVS since 1977 (one death in 15 patients) supports our current management policy of preoperative prostaglandin E1 infusion with transpulmonary valvotomy (for patients with an infundibular cavity) combined with a left modified Blalock-Taussig shunt using a Gore-Tex prosthesis. Tricuspid valve growth, estimated by serial angiograms in 12 patients, was greater if right ventricle-to-pulmonary artery continuity was established. Later definitive repair was attempted in nine patients, with two early deaths; five underwent right ventricular outflow tract reconstruction and four had modified Fontan procedures. Neonates with critical pulmonary stenosis are also discussed. Their neonatal mortality (nine deaths in 20 patients) was similar to that of comparable patients with PA:IVS, but their actuarial survival at 5 years (55%) was superior (36% at 5 years).