Blalock-Taussig Shunt versus Ductal Stenting as Palliation for Duct-Dependent Pulmonary Circulation.

Objectives: There is limited data published from outside North America and Europe comparing the outcomes of a modified Blalock-Taussig shunt (MBTS) and ductal stenting as the first palliative procedure for infants with duct-dependent pulmonary circulation. This study reports the National Heart Center's, in Muscat, Oman, experience in comparing the outcomes of these 2 interventions. Methods: This retrospective study included all infants with duct-dependent pulmonary circulation who received either a MBTS or ductal stenting from 2016-2019. The primary outcomes were death or re-interventions. Secondary outcomes included death, subsequent re-interventions, survival to subsequent surgical intervention, survival to hospital discharge, post-procedural mechanical ventilation and duration of intensive care unit stay. Results: A total of 71 patients were included in the study, 33 (46%) of whom received ductal stenting. The prevalence of the primary outcome (death or re-intervention) in the patent ductus arteriosus (PDA) stent group was 54.5% versus 31.6% in the MBTS group but this was not statistically significant (P = 0.06). There was no difference between the 2 groups in terms of time to next surgical intervention (P = 0.233). The PDA stent group had shorter post-procedural, mechanical ventilation and intensive care unit stay durations (P <0.05). Syndromic patients were at higher risk of mortality compared to non-syndromic patients. Conclusion: MBTS and ductal stenting are both acceptable modalities as a palliative intervention for infants with duct-dependant pulmonary circulation. Syndromic patients are at higher risk of mortality. This can be considered an important factor for patient selection.

Extubation Failure in Infants with Modified Blalock-Taussig Shunt: The Incidence, Predictors, and Outcomes.

OBJECTIVES: Infants with congenital heart diseases often require mechanical ventilation and a prolonged intensive care unit (ICU) stay due to complex cardiopulmonary complications. The primary objective of the study was to determine the incidence and predictors of tracheal extubation failure in infants undergoing modified Blalock-Taussig shunt (MBTS). The secondary objective was to evaluate if extubation failure was associated with increased mortality and longer ICU and hospital stays. DESIGN: Single-center, retrospective, cohort study. SETTING: Tertiary center pediatric cardiac ICU. PARTICIPANTS: Infants who underwent MBTS between January 2010 and December 2019. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The demographic data and details related to the preoperative, intraoperative, and pretracheal extubation clinical conditions in the ICU were compared between the 2 study arms. Statistically significant predictors were analyzed using multivariate analysis. The p value was based on the Student's -t test for continuous variables and the chi-square test for categorical variables. A total of 146 infants were recruited for the study. Extubation failure occurred in 27 infants (18.5%), resulting in longer ICU and hospital stays. Extubation failure was deemed to be positively associated with preoperative mechanical ventilation duration, the need for escalation of the inotropic score, diaphragmatic paralysis, and systolic blood pressure ≤50th percentile at the time of extubation. CONCLUSIONS: The incidence rate of extubation failure after placement of MBTS was 18.5%. Preoperative mechanical ventilation, diaphragmatic paralysis, the need for escalation of the inotropic score, and systolic blood pressure ≤50th percentile could be considered predictors of extubation failure in these infants.

Comparación de resultados inmediatos y a mediano plazo de la anastomosis de Blalock-Taussig versus la colocación de stent en tracto de salida de ventrículo derecho en neonatos sintomáticos con tetralogía de Fallot / Comparison of immediate and mid-term outcomes of Blalock-Taussig shunt versus right ventricular outflow tract stenting in symptomatic neonates with tetralogy of Fallot

RESUMEN Introducción: El manejo inicial de neonatos con tetralogía de Fallot (TF), con síntomas asociados a una anatomía desfavorable y un flujo vascular pulmonar significativamente reducido es controversial, y un desafío clínico. Objetivo: Describir la evolución clínica y comparar el crecimiento de ramas pulmonares en neonatos con TF sintomáticos ingresados al Departamento de Cardiología del Hospital de Niños de Córdoba, desde marzo de 2011 hasta marzo de 2021, que recibieron anastomosis de Blalock-Taussig modificada (aBTm) versus colocación de stent en tracto de salida de ventrículo derecho (sTSVD). Material y métodos: Estudio retrospectivo, observacional. Se identificaron 113 pacientes con TF; 20 de ellos (18%) fueron neonatos sintomáticos y requirieron paliación inicial. Las variables categóricas se expresan como porcentaje; las continuas como mediana y rango intercuartilo (RIC). Un valor de p <0,05 se consideró significativo. Resultados: De los 20 pacientes incluidos en el estudio, 11 (55%) constituyen el grupo aBTm y 9 (45%) el grupo sTSVD. En el grupo aBTm la rama pulmonar derecha (RPD) pre paliación tenía un score Z -3 (RIC 4,20), que aumentó a -1,6 (RIC 1,56) (p = 0,11) post intervención; y la rama pulmonar izquierda (RPI) un score Z -2,5 (RIC 4,8) que se incrementó a -1,80 (RIC 2,36) (p = 0,44). En el grupo sTSVD la RPD pre paliación tuvo un score Z -3,45 (RIC 3,83) que aumentó a - 2,5 (RIC 3,58) (p = 0,021) y la RPI un score Z -4,10 (RIC 2,51) que se incrementó a -2,00 (RIC 3,75) (p = 0,011). La saturación de O2 (SO2) pre intervención fue 75% (RIC 6), y aumentó a 87% (RIC 9) en el grupo aBTm (p = 0,005); e inicialmente fue 75% (RIC 16) y aumentó a 91% (RIC 13) en el grupo sTSVD (p = 0,008). La mediana de estadía hospitalaria post procedimiento fue 10 días (RIC 11) en el grupo aBTm, y 6 (RIC 2) en el grupo sTSVD (p= 0,095). Conclusiones: En neonatos con TF sintomáticos, ambas estrategias paliativas mejoran la condición clínica. En los que recibieron sTSVD, se objetivó un crecimiento mayor de las ramas pulmonares. Mayor número de casos y seguimiento más largo serán necesarios para confirmar estos hallazgos.

ABSTRACT Background: The initial management of neonate patients with tetralogy of Fallot (TOF) associated with an unfavorable anatomy and significantly reduced pulmonary vascular flow is controversial and continues to be a clinical challenge. Objective: The aim of this study was to describe the clinical evolution and to compare pulmonary artery branch development in symptomatic neonatal TOF patients who received a modified Blalock Taussig shunt (mBT) versus right ventricular outflow tract stent placement (RVOTs) at the Department of Cardiology, Hospital de Niños de Córdoba, between March 2011 and March 2021. Methods: A retrospective, observational study identified 113 patients with TOF, 20 of which (18%) were symptomatic neonates requqiring initial palliative intervention. Categorical variables are expressed as percentage and continuous variables as median and interquartile range (IQR). A p value <0.05 was considered significant. Results: Among the 20 patients included in the study, 11 (55%) formed the mBT group and 9 (45%) the RVOTs group. In the mBT group, pre-palliative procedure right pulmonary artery (RPA) Z score was -3 (IQR 4.20) and increased to -1.6 (IQR 1.56) (p = 0.11) and left pulmonary artery (LPA) Z score of -2.5 (IQR 4.8) increased to -1.80 (IQR 2.36) (p = 0.44). In the RVOTs group, RPA Z score prior to palliative intervention was -3.45 (IQR 3.83) and increased to -2.5 (IQR 3.58) (p = 0.021) and LPA Z score of -4.10 (IQR 2.51) to -2.00 (IQR 3.75) (p = 0.011). Pre-intervention peripheral O2 saturation of 75% (IQR 6) increased to 87% (IQR 9) in the mBT group (p= 0.005) and from initially 75% (IQR 16) to 91% (IQR 13) in the RVOTs group (p= 0.008). Mean hospital stay after the procedure was 10 days (IQR 11) in the mBT group and 6 days (IQR 2) in the RVOTs group (p= 0.095). Conclusions: In symptomatic neonates with TOF, both palliative strategies improved the clinical condition. In patients who received RVOTs, there was greater development of pulmonary artery branches. A larger number of cases and longer-term follow-up will be necessary to confirm these findings.

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.

Intervenção Paliativa Endovascular no Lactente com Tetralogia de Fallot: Uma Série de Casos / Palliative Endovascular Intervention in Infants with Tetralogy of Fallot: A Case Series

Resumo Fundamento Tendo em vista os casos de lactentes sintomáticos com Tetralogia de Fallot (TF), baixo peso ao nascimento e anatomia complexa, o implante de stent na via de saída do ventrículo direito (VSVD) tem sido indicado alternativamente à cirurgia de Blalock-Taussig (BT). Objetivo Avaliar o implante endovascular de stent na VSVD como abordagem primária no lactente com TF e não candidato à cirurgia de BT, bem como relatar seus resultados a médio prazo e até a retirada do stent na cirurgia corretiva. Métodos Entre outubro de 2015 e abril de 2018, uma série de seis lactentes portadores de TF receberam stents para desobstrução da VSVD. Os parâmetros hemodinâmicos foram comparados em períodos pré e pós-implante. Resultados As medianas de idade e peso no momento do procedimento foram de 146,5 dias e 4,9 kg, respectivamente. O gradiente sistólico máximo diminuiu de 63,5 mmHg para 50,5 mmHg, enquanto o diâmetro dos ramos pulmonares direito e esquerdo aumentou de 3,5 mm para 4,9 mm e 4,3 mm, respectivamente. O índice de Nakata aumentou de 96,5 mm para 108,3 mm; assim como o peso, de 4,9 kg para 5,5 kg. A saturação de oxigênio aumentou de 83,5% para 93%. Houve um caso de migração do stent e dois óbitos, um deles devido à embolização do stent e o outro não teve relação com o procedimento. Conclusões O implante de stent na VSVD como procedimento paliativo na TF se mostra uma alternativa promissora para o tratamento de lactentes com má anatomia e baixo peso ao nascimento.

Abstract Background Endovascular stent placement in the right ventricular outflow tract (RVOT) has been an alternative to Blalock-Taussig (BT) surgery in the treatment of Tetralogy of Fallot (TOF) in symptomatic infants with low birth weight and complex anatomy. Objective To evaluate endovascular stent placement in the RVOT as a primary treatment for infants with TOF who are not candidates for BT surgery, and evaluate medium-term outcomes until the stent is removed during corrective surgery. Methods Six infants with TOF were treated with RVOT stenting from October 2015 to April 2018. Hemodynamic parameters were compared between the pre- and post-stenting periods. Results At the time of stenting, participants had a median age and weight of 146.5 days and 4.9 kg, respectively. Peak systolic gradient decreased from 63.5 mm Hg to 50.5 mm Hg, while the diameter of the left and right pulmonary arteries increased from 3.5 mm to 4.9 mm and 4.3 mm, respectively. The Nakata index increased from 96.5 mm to 108.3 mm; weight increased from 4.9 kg to 5.5 kg; and oxygen saturation, from 83.5% to 93%. There was one case of stent migration and two deaths, one caused by stent embolization and the other unrelated to study procedures. Conclusions RVOT stenting is a promising alternative for the palliative treatment of TOF in infants with low birth weight and complex anatomy.

Outcomes of Infants Undergoing Modified Blalock-Taussig Shunt Procedures in Oman: A retrospective study.

OBJECTIVES: A modified Blalock-Taussig (mBT) shunt procedure is a common palliative surgery used to treat infants and children with cyanotic congenital heart disease (CCHD). This study aimed to report the outcomes of infants and children undergoing mBT shunt procedures in Oman. In addition, risk factors associated with early mortality, inter-stage mortality and reintervention were assessed. METHODS: This retrospective cohort study was conducted from January 2016 to December 2018 at the National Heart Centre, Muscat, Oman. All paediatric patients with CCHD undergoing mBT shunt procedures as a primary palliative procedure during this period were included. Data were retrieved from electronic hospital records. Kaplan-Meier survival curves were used to describe overall survival. RESULTS: A total of 50 infants and children were included in this study. The in-hospital mortality and interstage mortality rates were 10% and 6.7%, respectively. Preoperative mechanical ventilation (odds ratio [OR] = 3.00, 95% confidence interval [CI]: 1.98-4.76; P = 0.007) and cardiopulmonary bypass (OR = 4.09, 95% CI: 2.44-6.85; P = 0.002) were significant risk factors for early mortality. In-hospital and interval surgical reintervention rates were 12% and 13.3%, respectively. Following the primary shunt procedure, the median time to second-stage surgery was 15.5 months (range: 5.0-34.0 months). CONCLUSION: The findings of this study support those reported in international research regarding the risks associated with mBT shunt surgeries. In particular, preoperative mechanical ventilation and cardiopulmonary bypass were significant risk factors for early mortality.

On-Table Verification of Aortopulmonary Shunt Patency Through Ipsilateral Pulmonary Venous Blood Flow Assessment by Transesophageal Echocardiography.

Intraoperative transesophageal echocardiography is a well-established modality for the evaluation of the adequacy of the surgical repair of complex congenital heart lesions. This case report highlights the important role played by real-time transesophageal echocardiography during the evaluation of the patency of a left modified Blalock-Taussig shunt in a child with pulmonary atresia, nonconfluent pulmonary arteries, and borderline hemodynamic/ventilator parameters. Changes observed in the pulmonary venous blood flow pattern provided reassurance to the surgical team about the patency of the shunt and thereby avoided its reconstruction.

Duct Stenting Versus Modified Blalock-Taussig Shunt in Neonates With Duct-Dependent Pulmonary Blood Flow: Associations With Clinical Outcomes in a Multicenter National Study.

BACKGROUND: Infants born with cardiac abnormalities causing dependence on the arterial duct for pulmonary blood flow are often palliated with a shunt usually between the subclavian artery and either pulmonary artery. A so-called modified Blalock-Taussig shunt allows progress through early life to an age and weight at which repair or further more stable palliation can be safely achieved. Modified Blalock-Taussig shunts continue to present concern for postprocedural instability and early mortality such that other alternatives continue to be explored. Duct stenting (DS) is emerging as one such alternative with potential for greater early stability and improved survival. METHODS: The purpose of this study was to compare postprocedural outcomes and survival to next-stage palliative or reparative surgery between patients undergoing a modified Blalock-Taussig shunt or a DS in infants with duct-dependent pulmonary blood flow. All patients undergoing cardiac surgery and congenital interventions in the United Kingdom are prospectively recruited to an externally validated national outcome audit. From this audit, participating UK centers identified infants <30 days of age undergoing either a Blalock-Taussig shunt or a DS for cardiac conditions with duct-dependent pulmonary blood flow between January 2012 and December 31, 2015. One hundred seventy-one patients underwent a modified Blalock-Taussig shunt, and in 83 patients, DS was attempted. Primary and secondary outcomes of survival and need for extracorporeal support were analyzed with multivariable logistic regression. Longer-term mortality before repair and reintervention were analyzed with Cox proportional hazards regression. All multivariable analyses accommodated a propensity score to balance patient characteristics between the groups. RESULTS: There was an early (to discharge) survival advantage for infants before next-stage surgery in the DS group (odds ratio, 4.24; 95% confidence interval, 1.37-13.14; P=0.012). There was also a difference in the need for postprocedural extracorporeal support in favor of the DS group (odds ratio, 0.22; 95% confidence interval, 0.05-1.05; P=0.058). Longer-term survival outcomes showed a reduced risk of death before repair in the DS group (hazard ratio, 0.25; 95% confidence interval, 0.07-0.85; P=0.026) but a slightly increased risk of reintervention (hazard ratio, 1.50; 95% confidence interval, 0.85-2.64; P=0.165). CONCLUSIONS: DS is emerging as a preferred alternative to a surgical shunt for neonatal palliation with evidence for greater postprocedural stability and improved patient survival to destination surgical treatment.

Comparison Between Patent Ductus Arteriosus Stent and Modified Blalock-Taussig Shunt as Palliation for Infants With Ductal-Dependent Pulmonary Blood Flow: Insights From the Congenital Catheterization Research Collaborative.

BACKGROUND: Infants with ductal-dependent pulmonary blood flow may undergo palliation with either a patent ductus arteriosus (PDA) stent or a modified Blalock-Taussig (BT) shunt. A balanced multicenter comparison of these 2 approaches is lacking. METHODS: Infants with ductal-dependent pulmonary blood flow palliated with either a PDA stent or a BT shunt from January 2008 to November 2015 were reviewed from the 4 member centers of the Congenital Catheterization Research Collaborative. Outcomes were compared by use of propensity score adjustment to account for baseline differences between groups. RESULTS: One hundred six patients with a PDA stent and 251 patients with a BT shunt were included. The groups differed in underlying anatomy (expected 2-ventricle circulation in 60% of PDA stents versus 45% of BT shunts; P=0.001) and presence of antegrade pulmonary blood flow (61% of PDA stents versus 38% of BT shunts; P<0.001). After propensity score adjustment, there was no difference in the hazard of the primary composite outcome of death or unplanned reintervention to treat cyanosis (hazard ratio, 0.8; 95% confidence interval [CI], 0.52-1.23; P=0.31). Other reinterventions were more common in the PDA stent group (hazard ratio, 29.8; 95% CI, 9.8-91.1; P<0.001). However, the PDA stent group had a lower adjusted intensive care unit length of stay (5.3 days [95% CI, 4.2-6.7] versus 9.19 days [95% CI, 7.9-10.6]; P<0.001), a lower risk of diuretic use at discharge (odds ratio, 0.4; 95% CI, 0.25-0.64; P<0.001) and procedural complications (odds ratio, 0.4; 95% CI, 0.2-0.77; P=0.006), and larger (152 mm2/m2 [95% CI, 132-176] versus 125 mm2/m2 [95% CI, 113-138]; P=0.029) and more symmetrical (symmetry index, 0.84 [95% CI, 0.8-0.89] versus 0.77 [95% CI, 0.75-0.8]; P=0.008] pulmonary arteries at the time of subsequent surgical repair or last follow-up. CONCLUSIONS: In this multicenter comparison of palliative PDA stent and BT shunt for infants with ductal-dependent pulmonary blood flow adjusted for differences in patient factors, there was no difference in the primary end point, death or unplanned reintervention to treat cyanosis. However, other markers of morbidity and pulmonary artery size favored the PDA stent group, supporting PDA stent as a reasonable alternative to BT shunt in select patients.

Postoperative B-type natriuretic peptide monitoring for the assessment of the magnitude of shunting through Blalock-Taussig anastomoses.

BACKGROUND: The Modified Blalock-Taussig shunt (MBTS) is the most common palliative operation performed in patients with complex cardiac defects. Postoperative morbidity and mortality rates are high, mainly due to shunt thrombosis and over-shunting. Over-shunting may be difficult to identify postoperatively based on conventional criteria. Since plasma B-type natriuretic peptide (BNP) concentrations correlate with the magnitude of shunting in various left-to-right shunt cardiac defects, we investigated its ability to identify postoperative MBTS over-shunting. METHODS AND RESULTS: This retrospective, observational study included 42 consecutive patients (median age 9.50days, IQR: 6.00-58.25) undergoing MBTS for obstruction of the pulmonary blood flow at a tertiary referral pediatric cardiac center. The BNP threshold concentrations which accurately predicted outcome and MBTS over-shunting were derived using the ROC methodology. 443 BNP concentrations were analysed. The presence of atrio-ventricular valve regurgitation was the most important component of overall variance (72.75%). In 34 patients without regurgitation, BNP concentrations were predictive of a duration of mechanical ventilation >8days and of intensive care stay >11days, with ROC areas of 0.655 [0.597-0.719], 0.650 [0.589-0.711], a negative predictive value for the >1035pgmL-1 threshold of 0.93 and 0.96 respectively. SaO2 was less accurate for the prediction of both outcomes. In patients in whom the pulmonary flow was entirely MBTS-supplied, a BNP concentrations >1052pgmL-1 was predictive of a pulmonary-to-systemic ratio>2. CONCLUSION: In MBTS patients without atrio-ventricular valve regurgitation, maintaining BNP below 1000pgmL-1 may represent a therapeutic target to avoid over-shunting.

Decision-Making for Surgery in the Management of Patients with Univentricular Heart.

A series of technical refinements over the past 30 years, in combination with advances in perioperative management, have resulted in dramatic improvements in the survival of patients with univentricular heart. While the goal of single-ventricle palliation remains unchanged - normalization of the pressure and volume loads on the systemic ventricle, the strategies to achieve that goal have become more diverse. Optimal palliation relies on a thorough understanding of the changing physiology over the first years of life and the risks and consequences of each palliative strategy. This review describes how to optimize surgical decision-making in univentricular patients based on a current understanding of anatomy, physiology, and surgical palliation.