Case Report
Hybrid Stage I Palliation in a 1.1 kg, 28-Week Preterm Neonate With Posterior Malalignment Ventricular Septal Defect, Left Ventricular Outflow Tract Obstruction, and Coarctation of the Aorta
World Journal for Pediatric and Congenital Heart Surgery 2014, Vol. 5(4) 603-607 ª The Author(s) 2014 Reprints and permission: sagepub.com/journalsPermissions.nav DOI: 10.1177/2150135114535272 pch.sagepub.com
Kunal B. Karani, BA1, Farhan Zafar, MD1, David L. S. Morales, MD1, and Bryan H. Goldstein, MD1
Abstract The hybrid stage I procedure has emerged as a less-invasive alternative to the standard surgical Norwood procedure in the palliation of high-risk hypoplastic left heart syndrome and variants. This approach may also benefit patients requiring complex neonatal repair who have significant anatomic and/or perioperative risk factors that either prevent or complicate durable and robust biventricular circulation from being safely achieved. An extremely low-birth weight (1.1 kg) 28-week gestation preterm neonate with postnatal diagnosis of posterior malalignment ventricular septal defect, severe left ventricular outflow tract obstruction, aortic annular hypoplasia, and aortic arch obstruction underwent initial palliation with a hybrid stage I procedure. In this case, hybrid stage I palliation allowed for both somatic and left heart growth followed by ultimate uncomplicated biventricular repair. Keywords malalignment ventricular septal defect, hybrid stage I procedure, hypoplastic left heart syndrome, prematurity, neurodevelopmental outcomes Submitted December 11, 2013; Accepted April 16, 2014.
Introduction Since 1981, the Norwood with Blalock-Taussig shunt procedure has been employed as the primary approach to initialstaged palliation of hypoplastic left heart syndrome (HLHS) and variants.1 The Norwood procedure with right ventricle to pulmonary artery (RV-PA) shunt was later introduced as an alternative approach.2 The hybrid approach to stage I palliation (hybrid stage I), first introduced in 1992, has proved to be another successful alternative method for first-stage palliation.3 The hybrid strategy avoids neonatal exposure to cardiopulmonary bypass (CPB) or circulatory arrest, possibly improving long-term neurodevelopmental outcomes. Large centers have demonstrated similar acute and long-term survival, pre-stage II and pre-Fontan hemodynamics, and preservation of ventricular function with use of the hybrid stage I procedure in patients with standard risk HLHS, compared to conventional Norwood procedure.4 The hybrid stage I procedure has been increasingly employed as an alternative approach to the Norwood procedure for patients who have specific factors associated with increased perioperative morbidity and mortality. Despite significant improvements in survival following the Norwood procedure,
early mortality remains as high as 20% to 30%.4 It is possible that use of the hybrid procedure in patients with high-risk single ventricle will reduce overall stage I palliation-related morbidity and mortality. Meanwhile, the hybrid procedure may also be utilized in neonatal candidates in whom it is unclear whether durable and robust biventricular circulation can be achieved safely and reliably, thus allowing for interval observation of further cardiac ‘‘differentiation’’ prior to ultimate decision making regarding a definitive repair strategy is undertaken. For example, in patients with complex left ventricular outflow tract (LVOT) obstruction, a hybrid strategy to initial neonatal palliation may allow for interval growth of left heart structures without
1
The Heart Institute, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, USA Corresponding Author: Bryan H. Goldstein, Cincinnati Children’s Hospital Medical Center, MLC 2003, 3333 Burnet Avenue, Cincinnati, OH 45229, USA. Email: [email protected]
Downloaded from pch.sagepub.com at NORTHERN ARIZONA UNIVERSITY on May 28, 2015
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World Journal for Pediatric and Congenital Heart Surgery 5(4)
Abbreviations and Acronyms CHD CPB HLHS LVOT RV-PA VSD
congenital heart disease cardiopulmonary bypass hypoplastic left heart syndrome left ventricular outflow tract right ventricle to pulmonary artery ventricular septal defect
necessitating a decision regarding long-term repair strategy at the time of initial palliation. Thus, this type of patient could progress without the perioperative morbidity associated with early ‘‘forced’’ two-ventricle repair or, alternatively, without necessitating the use of a conduit to provide RV-PA continuity inherent to a Norwood/Rastelli style repair. Herein, the outcome following the performance of a hybrid stage I procedure in an extremely preterm and low-birth weight infant with posterior malaligned ventricular septal defect (VSD), complex LVOT, and arch obstruction is reported.
Case Report A 28-week gestational age 1.1 kg infant male was postnatally diagnosed with moderate posterior malalignment VSD, severe LVOT obstruction with hypoplastic aortic annulus and bicommisural valve, and hypoplastic transverse aortic arch with discrete coarctation. The aortic valve annulus measured 3.2 mm (Z score of 3.8) while the ascending aorta measured 4.9 mm, the transverse arch measured 2.4 mm (Z score 2.1) and the aortic isthmus measured 1 mm (Z score 3.2) as assessed by transthoracic echocardiography (Figures 1 and 2). The mitral valve annulus was normal, and the left ventricle was apex forming. There was a small patent foramen ovale (PFO) present. Surfactant was administered to the patient because of rapidly increasing oxygen deficiency resulting from prematurity. Routine newborn screening revealed a diagnosis of severe congenital hypothyroidism; thyroid replacement therapy was initiated. After extensive discussion between the neonatal, cardiology, cardiac intensive care, and cardiac surgical teams, the decision was made to proceed with a hybrid stage I palliation due to a number of patient factors including extreme low-birth weight, extreme prematurity as well as complexity of the necessary repair. Most in the group felt that this patient would ultimately require a Norwood/Rastelli style operation, given the nature of the LVOT obstruction. On day of life 10, a median sternotomy was performed. After dissecting out the PAs bilaterally, a 3.5-mm GORE-TEX shunt (W.L. Gore & Associates, Flagstaff, Arizona) was transected, longitudinally incised into two 2-mm wide strips, and each marked (but not cut) centrally, 2 mm in from each edge, to establish a mark-to-mark distance of 7 mm in length. These bands were placed circumferentially around the branch PAs, overlapped at the marks to establish a circumference of 7 mm (or a PA diameter of just over 2 mm), and sewn together using 6-0 Prolene. A pursestring suture was then placed in the proximal main PA, immediately distal to the sinutubular junction, and a 6F sheath was
Figure 1. Two-dimensional echo image in parasternal long-axis plane, obtained upon initial presentation, demonstrating crowded left ventricle outflow tract with presence of substantial subvalvar tissue. The aortic valve annulus was reported to measure 3.2 mm (Z score 3.8).
advanced into the main PA and secured in place. Heparin was administered. A directional catheter and 0.014-in coronary pressure guidewire were introduced and utilized to measure the distal PA pressure bilaterally. Initial bilateral mean PA pressure was 14 mm Hg without substantial pulsatility (pulse pressure < 1 mm Hg) identified. Biplane main PA angiography was performed to evaluate the banded branch PAs and ductal anatomy. Adjustments were then made to loosen the bilateral PA bands, given the lack of pulsatility seen by pressure tracing, the tight angiographic appearance of the bands, and the expected long duration of banded branch PAs in this very preterm 1.1 kg neonate. Following band adjustment, the bilateral mean PA pressure measured 25 to 28 mm Hg with a pulse pressure of 7 to 8 mm Hg, which we felt to be satisfactory. Repeat angiography demonstrated somewhat looser appearing PA bands, each slightly proximal to PA branching, with qualitatively equivalent right- and left-sided pulmonary venous return on levophase. In our practice, we rely upon the constellation of angiographic, branch PA pressure, and saturation data to achieve adequate PA band tightness and appropriate balance of pulmonary and systemic circulations. Following completion of the PA band manipulation, focus shifted to endovascular stenting of the ductus arterious. A 0.018-in floppy-tipped stiffshaft guidewire was advanced across the ductus into the descending aorta. Two 6 20 mm eV3 Prote´ge´ self-expanding Nitinol stents (ev3 Endovascular, Plymouth, Minnesota) were sequentially deployed (telescoped) in the ductus arteriosus to ensure adequate coverage across the entirety of the ductal arch. Lower extremity saturations were in the mid-high 80’s while upper extremity saturations were in the low 90’s with excellent hemodynamics. Due to the small patient size, the decision was made to leave the chest open at that time. Delayed sternal closure took place uneventfully on postoperative day 2. The atrial septum was left uninstrumented. Postoperatively, the patient was managed by the neonatal and cardiac intensive care services. Although extubated within a few weeks postoperatively, the patient developed respiratory
Downloaded from pch.sagepub.com at NORTHERN ARIZONA UNIVERSITY on May 28, 2015
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Figure 2. Two-dimensional echo image with and without color Doppler, obtained upon initial presentation, demonstrating the presence of posteriorly deviated conal septum (posterior malalignment VSD) with associated left to right shunt. The VSD was reported to measure 4 mm. VSD indicates ventricular septal defect.
distress requiring reintubation and mechanical ventilation at 2 months of life. Cardiac catheterization at that time demonstrated excellent hemodynamics (branch PA pressure means of 8 and 12 mm Hg, mean right atrial pressure of 4 mm Hg, and RV end-diastolic pressure of 6 mm Hg) without ductal arch obstruction. Although left atrial pressure was not directly obtained, the atrial septum was left uninstrumented given the paucity of evidence for left atrial or pulmonary venous hypertension in the setting of normal distal PA pressure. Necrotizing enterocolitis developed and was treated medically with intravenous antibiotics and parenteral nutrition. Ultimately, the patient was discharged to home at 4.5 months of age and 3.9 kg with no ventilatory or oxygen requirements, receiving oral medications and a combination of oral and gavage feeding. Echocardiography at discharge demonstrated excellent RV systolic function, no significant atrioventricular valve regurgitation, an unobstructed ductal arch, unobstructed ascending aorta with exclusive antegrade flow, no gradient across the crowded LVOT, and banded PAs with systolic gradients of 60 to 70 mm Hg. After an uneventful outpatient course, at approximately 8 months of age and 6.9 kg, the patient underwent an elective complete repair. Imaging at that time demonstrated substantial subaortic obstruction but an aortic valve annulus that now measured 7.3 mm (Z score 1.8; Figure 3). Therefore, the biventricular repair included aortic arch reconstruction, PFO suture closure, VSD CorMatrix patch (CorMatrix, Roswell, Georgia) closure, subaortic stenosis resection, and PA band removal with bilateral PA patch reconstruction. The LVOT was managed by resecting a large shelf of subaortic muscle; the valve was dilated with a Hagar dilator. The aorta was reconstructed
Figure 3. Left ventriculogram in left anterior oblique and cranial angulation, obtained shortly before complete surgical repair, demonstrating severe long-segment subvalvar aortic obstruction. The posterior malalignment ventricular septal defect is also visualized with contrast seen entering the right ventricle.
by resecting the PDA and ductal stent entirely, followed by homograft patch augmentation from the distal ascending aorta all the way to the proximal descending aorta. The perioperative
Downloaded from pch.sagepub.com at NORTHERN ARIZONA UNIVERSITY on May 28, 2015
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World Journal for Pediatric and Congenital Heart Surgery 5(4)
course was uncomplicated, and the patient was discharged home on the eighth postoperative day. At outpatient followup at 16 months of age, echo demonstrated a normally functioning aortic valve with trivial LVOT obstruction (peak instantaneous pressure gradient of 15 mm Hg), normal left and right ventricular function, and no residual intracardiac shunting.
Discussion To date, the dominant discussion surrounding the use of the hybrid stage I procedure relates to its role as an alternative to the Norwood operation, in patients with HLHS and related variants. Although some centers have chosen to employ the hybrid strategy as a Norwood alternative in patients with standard risk, most centers have instead opted to use the hybrid approach for high-risk Norwood candidates. In the present case presentation, we detail successful use of the hybrid stage I procedure as an initial palliative strategy in a patient with both substantial risk factors (extreme prematurity and extreme low birth weight at 1.1 kg) and not typical HLHS anatomy (severe LVOT obstruction with malaligned VSD and arch hypoplasia/coarctation). Moreover, the hybrid stage I strategy was employed as a successful bridge for an extremely high-risk Norwood candidate—or primary biventricular repair candidate—to undergo ultimately successful and uncomplicated biventricular repair. Although some have favored a single modality approach to the treatment of all HLHS and variants, individual circumstances (anatomic, physiologic, center, or even surgeon specific) frequently demand a more tailored approach.5 In our center, the treatment of HLHS utilizes the hybrid stage I approach for patients with intact or highly restrictive atrial septum, large left ventricular to coronary sinusoids, prematurity (< 32 weeks gestation), and patients with end-organ dsyfunction that does not recover in 10 days following presentation in shock. Those patients with genetic abnormalities and/or substantial extracardiac anomalies are also considered. Use of the hybrid stage I procedure as a bridge to a decision, either in patients with complex cardiac morphology such that it is unclear whether a durable and robust biventricular circulation can be achieved safely and reliably or as in the current case with complex LVOT obstruction with multiple risk factors present, is a more recent adaptation. In this particular case, the degree of prematurity, small birth weight, and presence of congenital hypothyroidism all combined to favor a less invasive approach to initial palliation or repair. Moreover, this strategy allowed for interval observation of aortic annular growth, thereby delaying the ultimate decision and allowing for a primary repair that might have not been considered feasible in the neonatal period. Performance of the procedure was not technically different from routine hybrid stage I procedures in older and larger neonates. Equipment was not altered for the case. Achieving optimal PA band diameter to generate an acutely balanced circulation and still allow for a greater degree of postoperative growth, in the setting of anatomically small branch PAs, was
the most technically challenging aspect of the procedure. Bilateral distal branch PA pressures, systemic blood pressure, differential extremity saturations, and angiographic appearance of the banded branch PAs were simultaneously integrated to allow an informed decision to be made.6 Early postoperative hemodynamics were very stable in this patient, despite the extreme prematurity and low birth weight. Differences in postoperative hemodynamics between Norwood and hybrid palliated stage I patients have been detailed elsewhere.7 Use of the hybrid stage I procedure in this case was chosen to maximize both short- and long-term outcomes. A key aspect that drove this decision was the avoidance of CPB and circulatory arrest in this 28-week preterm infant. Cardiopulmonary bypass exposure during the neonatal period, when the immature brain carries substantial risk of neurological injury, is associated with poorer long-term neurodevelopmental outcomes. Preterm infants specifically demonstrate reduced neurodevelopmental outcomes compared to other congenital heart disease (CHD) populations.8 Long-term neurodevelopmental outcomes following the hybrid stage I procedure have not yet been well defined, although limited early follow-up data have not identified a difference between hybrid and Norwood cohorts.9 Rigorous long-term comparative neurodevelopmental follow-up studies will be essential to understanding the role of hybrid stage I palliation in patients with highand standard-risk HLHS as well as in other CHD populations where the hybrid approach may offer potential benefit.
Conclusion In this case of an infant with postnatal diagnosis of posterior malaligned VSD, LVOT obstruction, and arch hypoplasia with coarctation, in addition to extreme prematurity and extreme low birth weight, a hybrid stage I strategy to initial palliation was employed, thereby acting as a bridge to a decision. The infant successfully transitioned to outpatient care followed by a complete two-ventricle repair at eight months of age. No clinically evident neurologic insults occurred during management. 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. Norwood WI, Lang P, Casteneda AR, Campbell DN. Experience with operations for hypoplastic left heart syndrome. J Thorac Cardiovasc Surg. 1981;82(4): 511-519. 2. Sano S, Ishino K, Kawada M, et al. Right ventricle–pulmonary artery shunt in first-stage palliation of hypoplastic left heart syndrome. J Thorac Cardiovasc Surg. 2003;126(2): 504-510. 3. Gibbs JL, Wren C, Watterson KG, Hunter S, Leslie Hamilton JR. Stenting of the arterial duct combined with banding of the
Downloaded from pch.sagepub.com at NORTHERN ARIZONA UNIVERSITY on May 28, 2015
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pulmonary arteries and atrial septectomy or septostomy: a new approach to palliation for the hypoplastic left heart syndrome. Br Heart J. 1993;69(6): 551-555. 4. Honjo O, Caldarone CA. Hybrid palliation for neonates with hypoplastic left heart syndrome: current strategies and outcomes. Korean Circ J. 2010;40(3): 103-111. 5. Bacha EA. Individualized approach in the management of patients with hypoplastic left heart syndrome (HLHS). Semin Thorac Cardiovasc Surg Pediatr Card Surg Annu. 2013;16(1): 3-6. 6. Zampi JD, Hirsch JC, Goldstein BH, Armstrong AK. Use of a pressure guidewire to assess pulmonary artery band adequacy in the hybrid stage I procedure for high-risk neonates with hypoplastic
left heart syndrome and variants. Congenit Heart Dis. 2013;8(2): 149-158. 7. Li J, Zhang G, Benson L, et al. Comparison of the profiles of postoperative systemic hemodynamics and oxygen transport in neonates after the hybrid or the Norwood procedure: a pilot study. Circulation. 2007;116(11 suppl): I179-I187. 8. Massaro AN, El-dib M, Glass P, Hany A. Factors associated with adverse neurodevelopmental outcomes in infants with congenital heart disease. Brain Dev. 2008;30(7): 437-446. 9. Knirsch W, Liamlahi R, Hug MI, et al. Mortality and neurodevelopmental outcome at 1 year of age comparing hybrid and Norwood procedures. Eur J Cardiothorac Surg. 2012;42(1): 33-39.
Downloaded from pch.sagepub.com at NORTHERN ARIZONA UNIVERSITY on May 28, 2015
Hybrid Stage I Palliation in a 1.1 kg, 28-Week Preterm Neonate With Posterior Malalignment Ventricular Septal Defect, Left Ventricular Outflow Tract Obstruction, and Coarctation of the Aorta
World Journal for Pediatric and Congenital Heart Surgery 2014, Vol. 5(4) 603-607 ª The Author(s) 2014 Reprints and permission: sagepub.com/journalsPermissions.nav DOI: 10.1177/2150135114535272 pch.sagepub.com
Kunal B. Karani, BA1, Farhan Zafar, MD1, David L. S. Morales, MD1, and Bryan H. Goldstein, MD1
Abstract The hybrid stage I procedure has emerged as a less-invasive alternative to the standard surgical Norwood procedure in the palliation of high-risk hypoplastic left heart syndrome and variants. This approach may also benefit patients requiring complex neonatal repair who have significant anatomic and/or perioperative risk factors that either prevent or complicate durable and robust biventricular circulation from being safely achieved. An extremely low-birth weight (1.1 kg) 28-week gestation preterm neonate with postnatal diagnosis of posterior malalignment ventricular septal defect, severe left ventricular outflow tract obstruction, aortic annular hypoplasia, and aortic arch obstruction underwent initial palliation with a hybrid stage I procedure. In this case, hybrid stage I palliation allowed for both somatic and left heart growth followed by ultimate uncomplicated biventricular repair. Keywords malalignment ventricular septal defect, hybrid stage I procedure, hypoplastic left heart syndrome, prematurity, neurodevelopmental outcomes Submitted December 11, 2013; Accepted April 16, 2014.
Introduction Since 1981, the Norwood with Blalock-Taussig shunt procedure has been employed as the primary approach to initialstaged palliation of hypoplastic left heart syndrome (HLHS) and variants.1 The Norwood procedure with right ventricle to pulmonary artery (RV-PA) shunt was later introduced as an alternative approach.2 The hybrid approach to stage I palliation (hybrid stage I), first introduced in 1992, has proved to be another successful alternative method for first-stage palliation.3 The hybrid strategy avoids neonatal exposure to cardiopulmonary bypass (CPB) or circulatory arrest, possibly improving long-term neurodevelopmental outcomes. Large centers have demonstrated similar acute and long-term survival, pre-stage II and pre-Fontan hemodynamics, and preservation of ventricular function with use of the hybrid stage I procedure in patients with standard risk HLHS, compared to conventional Norwood procedure.4 The hybrid stage I procedure has been increasingly employed as an alternative approach to the Norwood procedure for patients who have specific factors associated with increased perioperative morbidity and mortality. Despite significant improvements in survival following the Norwood procedure,
early mortality remains as high as 20% to 30%.4 It is possible that use of the hybrid procedure in patients with high-risk single ventricle will reduce overall stage I palliation-related morbidity and mortality. Meanwhile, the hybrid procedure may also be utilized in neonatal candidates in whom it is unclear whether durable and robust biventricular circulation can be achieved safely and reliably, thus allowing for interval observation of further cardiac ‘‘differentiation’’ prior to ultimate decision making regarding a definitive repair strategy is undertaken. For example, in patients with complex left ventricular outflow tract (LVOT) obstruction, a hybrid strategy to initial neonatal palliation may allow for interval growth of left heart structures without
1
The Heart Institute, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, USA Corresponding Author: Bryan H. Goldstein, Cincinnati Children’s Hospital Medical Center, MLC 2003, 3333 Burnet Avenue, Cincinnati, OH 45229, USA. Email: [email protected]
Downloaded from pch.sagepub.com at NORTHERN ARIZONA UNIVERSITY on May 28, 2015
604
World Journal for Pediatric and Congenital Heart Surgery 5(4)
Abbreviations and Acronyms CHD CPB HLHS LVOT RV-PA VSD
congenital heart disease cardiopulmonary bypass hypoplastic left heart syndrome left ventricular outflow tract right ventricle to pulmonary artery ventricular septal defect
necessitating a decision regarding long-term repair strategy at the time of initial palliation. Thus, this type of patient could progress without the perioperative morbidity associated with early ‘‘forced’’ two-ventricle repair or, alternatively, without necessitating the use of a conduit to provide RV-PA continuity inherent to a Norwood/Rastelli style repair. Herein, the outcome following the performance of a hybrid stage I procedure in an extremely preterm and low-birth weight infant with posterior malaligned ventricular septal defect (VSD), complex LVOT, and arch obstruction is reported.
Case Report A 28-week gestational age 1.1 kg infant male was postnatally diagnosed with moderate posterior malalignment VSD, severe LVOT obstruction with hypoplastic aortic annulus and bicommisural valve, and hypoplastic transverse aortic arch with discrete coarctation. The aortic valve annulus measured 3.2 mm (Z score of 3.8) while the ascending aorta measured 4.9 mm, the transverse arch measured 2.4 mm (Z score 2.1) and the aortic isthmus measured 1 mm (Z score 3.2) as assessed by transthoracic echocardiography (Figures 1 and 2). The mitral valve annulus was normal, and the left ventricle was apex forming. There was a small patent foramen ovale (PFO) present. Surfactant was administered to the patient because of rapidly increasing oxygen deficiency resulting from prematurity. Routine newborn screening revealed a diagnosis of severe congenital hypothyroidism; thyroid replacement therapy was initiated. After extensive discussion between the neonatal, cardiology, cardiac intensive care, and cardiac surgical teams, the decision was made to proceed with a hybrid stage I palliation due to a number of patient factors including extreme low-birth weight, extreme prematurity as well as complexity of the necessary repair. Most in the group felt that this patient would ultimately require a Norwood/Rastelli style operation, given the nature of the LVOT obstruction. On day of life 10, a median sternotomy was performed. After dissecting out the PAs bilaterally, a 3.5-mm GORE-TEX shunt (W.L. Gore & Associates, Flagstaff, Arizona) was transected, longitudinally incised into two 2-mm wide strips, and each marked (but not cut) centrally, 2 mm in from each edge, to establish a mark-to-mark distance of 7 mm in length. These bands were placed circumferentially around the branch PAs, overlapped at the marks to establish a circumference of 7 mm (or a PA diameter of just over 2 mm), and sewn together using 6-0 Prolene. A pursestring suture was then placed in the proximal main PA, immediately distal to the sinutubular junction, and a 6F sheath was
Figure 1. Two-dimensional echo image in parasternal long-axis plane, obtained upon initial presentation, demonstrating crowded left ventricle outflow tract with presence of substantial subvalvar tissue. The aortic valve annulus was reported to measure 3.2 mm (Z score 3.8).
advanced into the main PA and secured in place. Heparin was administered. A directional catheter and 0.014-in coronary pressure guidewire were introduced and utilized to measure the distal PA pressure bilaterally. Initial bilateral mean PA pressure was 14 mm Hg without substantial pulsatility (pulse pressure < 1 mm Hg) identified. Biplane main PA angiography was performed to evaluate the banded branch PAs and ductal anatomy. Adjustments were then made to loosen the bilateral PA bands, given the lack of pulsatility seen by pressure tracing, the tight angiographic appearance of the bands, and the expected long duration of banded branch PAs in this very preterm 1.1 kg neonate. Following band adjustment, the bilateral mean PA pressure measured 25 to 28 mm Hg with a pulse pressure of 7 to 8 mm Hg, which we felt to be satisfactory. Repeat angiography demonstrated somewhat looser appearing PA bands, each slightly proximal to PA branching, with qualitatively equivalent right- and left-sided pulmonary venous return on levophase. In our practice, we rely upon the constellation of angiographic, branch PA pressure, and saturation data to achieve adequate PA band tightness and appropriate balance of pulmonary and systemic circulations. Following completion of the PA band manipulation, focus shifted to endovascular stenting of the ductus arterious. A 0.018-in floppy-tipped stiffshaft guidewire was advanced across the ductus into the descending aorta. Two 6 20 mm eV3 Prote´ge´ self-expanding Nitinol stents (ev3 Endovascular, Plymouth, Minnesota) were sequentially deployed (telescoped) in the ductus arteriosus to ensure adequate coverage across the entirety of the ductal arch. Lower extremity saturations were in the mid-high 80’s while upper extremity saturations were in the low 90’s with excellent hemodynamics. Due to the small patient size, the decision was made to leave the chest open at that time. Delayed sternal closure took place uneventfully on postoperative day 2. The atrial septum was left uninstrumented. Postoperatively, the patient was managed by the neonatal and cardiac intensive care services. Although extubated within a few weeks postoperatively, the patient developed respiratory
Downloaded from pch.sagepub.com at NORTHERN ARIZONA UNIVERSITY on May 28, 2015
Karani et al
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Figure 2. Two-dimensional echo image with and without color Doppler, obtained upon initial presentation, demonstrating the presence of posteriorly deviated conal septum (posterior malalignment VSD) with associated left to right shunt. The VSD was reported to measure 4 mm. VSD indicates ventricular septal defect.
distress requiring reintubation and mechanical ventilation at 2 months of life. Cardiac catheterization at that time demonstrated excellent hemodynamics (branch PA pressure means of 8 and 12 mm Hg, mean right atrial pressure of 4 mm Hg, and RV end-diastolic pressure of 6 mm Hg) without ductal arch obstruction. Although left atrial pressure was not directly obtained, the atrial septum was left uninstrumented given the paucity of evidence for left atrial or pulmonary venous hypertension in the setting of normal distal PA pressure. Necrotizing enterocolitis developed and was treated medically with intravenous antibiotics and parenteral nutrition. Ultimately, the patient was discharged to home at 4.5 months of age and 3.9 kg with no ventilatory or oxygen requirements, receiving oral medications and a combination of oral and gavage feeding. Echocardiography at discharge demonstrated excellent RV systolic function, no significant atrioventricular valve regurgitation, an unobstructed ductal arch, unobstructed ascending aorta with exclusive antegrade flow, no gradient across the crowded LVOT, and banded PAs with systolic gradients of 60 to 70 mm Hg. After an uneventful outpatient course, at approximately 8 months of age and 6.9 kg, the patient underwent an elective complete repair. Imaging at that time demonstrated substantial subaortic obstruction but an aortic valve annulus that now measured 7.3 mm (Z score 1.8; Figure 3). Therefore, the biventricular repair included aortic arch reconstruction, PFO suture closure, VSD CorMatrix patch (CorMatrix, Roswell, Georgia) closure, subaortic stenosis resection, and PA band removal with bilateral PA patch reconstruction. The LVOT was managed by resecting a large shelf of subaortic muscle; the valve was dilated with a Hagar dilator. The aorta was reconstructed
Figure 3. Left ventriculogram in left anterior oblique and cranial angulation, obtained shortly before complete surgical repair, demonstrating severe long-segment subvalvar aortic obstruction. The posterior malalignment ventricular septal defect is also visualized with contrast seen entering the right ventricle.
by resecting the PDA and ductal stent entirely, followed by homograft patch augmentation from the distal ascending aorta all the way to the proximal descending aorta. The perioperative
Downloaded from pch.sagepub.com at NORTHERN ARIZONA UNIVERSITY on May 28, 2015
606
World Journal for Pediatric and Congenital Heart Surgery 5(4)
course was uncomplicated, and the patient was discharged home on the eighth postoperative day. At outpatient followup at 16 months of age, echo demonstrated a normally functioning aortic valve with trivial LVOT obstruction (peak instantaneous pressure gradient of 15 mm Hg), normal left and right ventricular function, and no residual intracardiac shunting.
Discussion To date, the dominant discussion surrounding the use of the hybrid stage I procedure relates to its role as an alternative to the Norwood operation, in patients with HLHS and related variants. Although some centers have chosen to employ the hybrid strategy as a Norwood alternative in patients with standard risk, most centers have instead opted to use the hybrid approach for high-risk Norwood candidates. In the present case presentation, we detail successful use of the hybrid stage I procedure as an initial palliative strategy in a patient with both substantial risk factors (extreme prematurity and extreme low birth weight at 1.1 kg) and not typical HLHS anatomy (severe LVOT obstruction with malaligned VSD and arch hypoplasia/coarctation). Moreover, the hybrid stage I strategy was employed as a successful bridge for an extremely high-risk Norwood candidate—or primary biventricular repair candidate—to undergo ultimately successful and uncomplicated biventricular repair. Although some have favored a single modality approach to the treatment of all HLHS and variants, individual circumstances (anatomic, physiologic, center, or even surgeon specific) frequently demand a more tailored approach.5 In our center, the treatment of HLHS utilizes the hybrid stage I approach for patients with intact or highly restrictive atrial septum, large left ventricular to coronary sinusoids, prematurity (< 32 weeks gestation), and patients with end-organ dsyfunction that does not recover in 10 days following presentation in shock. Those patients with genetic abnormalities and/or substantial extracardiac anomalies are also considered. Use of the hybrid stage I procedure as a bridge to a decision, either in patients with complex cardiac morphology such that it is unclear whether a durable and robust biventricular circulation can be achieved safely and reliably or as in the current case with complex LVOT obstruction with multiple risk factors present, is a more recent adaptation. In this particular case, the degree of prematurity, small birth weight, and presence of congenital hypothyroidism all combined to favor a less invasive approach to initial palliation or repair. Moreover, this strategy allowed for interval observation of aortic annular growth, thereby delaying the ultimate decision and allowing for a primary repair that might have not been considered feasible in the neonatal period. Performance of the procedure was not technically different from routine hybrid stage I procedures in older and larger neonates. Equipment was not altered for the case. Achieving optimal PA band diameter to generate an acutely balanced circulation and still allow for a greater degree of postoperative growth, in the setting of anatomically small branch PAs, was
the most technically challenging aspect of the procedure. Bilateral distal branch PA pressures, systemic blood pressure, differential extremity saturations, and angiographic appearance of the banded branch PAs were simultaneously integrated to allow an informed decision to be made.6 Early postoperative hemodynamics were very stable in this patient, despite the extreme prematurity and low birth weight. Differences in postoperative hemodynamics between Norwood and hybrid palliated stage I patients have been detailed elsewhere.7 Use of the hybrid stage I procedure in this case was chosen to maximize both short- and long-term outcomes. A key aspect that drove this decision was the avoidance of CPB and circulatory arrest in this 28-week preterm infant. Cardiopulmonary bypass exposure during the neonatal period, when the immature brain carries substantial risk of neurological injury, is associated with poorer long-term neurodevelopmental outcomes. Preterm infants specifically demonstrate reduced neurodevelopmental outcomes compared to other congenital heart disease (CHD) populations.8 Long-term neurodevelopmental outcomes following the hybrid stage I procedure have not yet been well defined, although limited early follow-up data have not identified a difference between hybrid and Norwood cohorts.9 Rigorous long-term comparative neurodevelopmental follow-up studies will be essential to understanding the role of hybrid stage I palliation in patients with highand standard-risk HLHS as well as in other CHD populations where the hybrid approach may offer potential benefit.
Conclusion In this case of an infant with postnatal diagnosis of posterior malaligned VSD, LVOT obstruction, and arch hypoplasia with coarctation, in addition to extreme prematurity and extreme low birth weight, a hybrid stage I strategy to initial palliation was employed, thereby acting as a bridge to a decision. The infant successfully transitioned to outpatient care followed by a complete two-ventricle repair at eight months of age. No clinically evident neurologic insults occurred during management. 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. Norwood WI, Lang P, Casteneda AR, Campbell DN. Experience with operations for hypoplastic left heart syndrome. J Thorac Cardiovasc Surg. 1981;82(4): 511-519. 2. Sano S, Ishino K, Kawada M, et al. Right ventricle–pulmonary artery shunt in first-stage palliation of hypoplastic left heart syndrome. J Thorac Cardiovasc Surg. 2003;126(2): 504-510. 3. Gibbs JL, Wren C, Watterson KG, Hunter S, Leslie Hamilton JR. Stenting of the arterial duct combined with banding of the
Downloaded from pch.sagepub.com at NORTHERN ARIZONA UNIVERSITY on May 28, 2015
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