Modified Blalock-Taussig Shunt Research Articles

Change in Pulmonary Arteries after Modified Blalock-Taussig Shunt Procedure: Analysis Based on Computed Tomography.

Although the modified Blalock-Taussig shunt remains the mainstay method of palliation for augmenting pulmonary blood flow in various congenital heart diseases, the shunt must be carefully designed to achieve the best outcomes. This study investigated the effect of shunt configuration on pulmonary artery growth and growth discrepancy. Twenty patients with successful modified Blalock-Taussig shunt takedown were analyzed. Pulmonary artery and shunt characteristics were obtained using computed tomography scans. Differences in the baseline and follow-up diameter ratios and growth in the ipsilateral and contralateral arteries were calculated. The angle between the shunt and pulmonary artery, as well as the distance from the main pulmonary artery bifurcation, were measured. Correlations between pulmonary arteries and shunt configurations were analyzed. The median interval time between shunt placement and takedown was 154.5 days (interquartile range, 113.25-276.25 days). Follow-up values of the ipsilateral-to-contralateral pulmonary artery diameter ratio showed no significant correlation with the shunt angle (ρ=0.429, p=0.126) or distance (ρ=0.110, p=0.645). The shunt angle and distance from the main pulmonary bifurcation showed no significant correlation (ρ=-0.373, p=0.189). Pulmonary artery growth was negatively correlated with shunt angle (ipsilateral, ρ=-0.565 and p=0.035; contralateral, ρ=-0.578 and p=0.030), but not with distance (ipsilateral, ρ=-0.065 and p=0.786; contralateral, ρ=-0.130 and p=0.586). Shunt configuration had no significant effect on growth imbalance. The angle and distance of the shunt showed no significant correlation with each other. A more vertical shunt was associated with significant pulmonary artery growth. We suggest a more vertical graft design for improved pulmonary artery growth.

Technical Details of a Novel Surgical Procedure for Construction of the Modified Blalock–Taussig Shunt (UKC’s Modification): A Video Presentation

We describe herein the surgical technique on a 2.5-years-old male child weighing 10 kilograms diagnosed with a functionally univentricular heart, disproportionately small right subclavian artery, and hypoplastic pulmonary arteries (Mc Goon’s ratio of less than 1.0).5 We interposed a short segment of polytetrafluroethylene graft between the right brachiocephalic artery and the intrapericardial portion of the right pulmonary artery closest to the bifurcation of the pulmonary trunk on the right side.

Longitudinal analysis of systemic ventricular function and atrioventricular valve function after the Norwood procedure.

To evaluate longitudinal systemic ventricular function and atrioventricular valve regurgitation in patients after the neonatal Norwood procedure. Serial postoperative echocardiographic images before Fontan completion were assessed in neonates who underwent the Norwood procedure between 2001 and 2020. Ventricular function and atrioventricular valve regurgitation were compared between patients with modified Blalock-Taussig shunt and right ventricle to pulmonary artery conduit. A total of 335 patients were identified including 273 hypoplastic left heart syndrome and 62 of its variants. Median age at Norwood was 8 (7-12) days. Modified Blalock-Taussig shunt was performed in 171 patients and the right ventricle to pulmonary artery conduit in 164 patients. Longitudinal ventricular function and atrioventricular valve regurgitation were evaluated using a total of 4352 echocardiograms. After the Norwood procedure, ventricular function was initially worse (1-30 days) but thereafter better (30 days to stage II) in the right ventricle to pulmonary artery conduit group (P < 0.001). After stage II, the ventricular function was inferior in the right ventricle to the pulmonary artery conduit group (P < 0.001). Atrioventricular valve regurgitation between the Norwood procedure and stage II was more frequent in the modified Blalock-Taussig shunt group (P < 0.001). After stage II, there was no significant difference in atrioventricular valve regurgitation between the groups (P = 0.171). The effect of shunt type on haemodynamics after the Norwood procedure seems to vary according to the stage of palliation. After the Norwood, the modified Blalock-Taussig shunt is associated with poorer ventricular function and worse atrioventricular valve regurgitation compared to right ventricle to pulmonary artery conduit. Whereas, after stage II, modified Blalock-Taussig shunt is associated with better ventricular function and comparable atrioventricular valve regurgitation, compared to the right ventricle to pulmonary artery conduit.

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

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. 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. 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. 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.

Pulmonary Annulus Growth Pattern in Patients with Tetralogy of Fallot Prior to Surgical Repair.

The size of the pulmonary valve annulus often determines the feasibility of pulmonary valve preservation at the time of intracardiac repair of Tetralogy of Fallot. Currently, there is limited available data regarding the growth pattern and the determining factors that contribute towards pulmonary valve annulus growth. This retrospective study included patients who underwent surgical repair of Tetralogy of Fallot with or without prior palliation. These patients had an echocardiogram at the time of initial diagnosis and a second echocardiogram prior to intracardiac repair. The sizes of the pulmonary annulus, the right and left pulmonary arteries with z-scores were recorded. Patients with improvement in the pulmonary annulus z-scores between the 2 echocardiographic examinations were allocated in Group I (n = 46) and Group II (n = 68) were those with no improvement. A total of 114 patients were included in the study. The right and left pulmonary arteries size and z scores improved significantly between the 2 echocardiograms. Although the median size of the pulmonary annulus increased between the 2 echocardiograms (6 and 7.9 mm; P<0.001), there was no significant change in the z-score (-2.2, -2.34; P = 0.185). Multivariate logistic regression analysis showed that gender, blood group, presence of collaterals, and palliation with Blalock-Taussig shunt had no impact on the improvement in pulmonary annulus z-score. In Tetralogy of Fallot, the pulmonary valve annulus z-score may not change significantly prior to the intracardiac repair. Although in certain subgroups there may be an improvement, there was no specific factor that could be identified and had an influence on this improvement.

Assessment of the pulmonary arterial growth and results of two-stage repair in infants with severe form of tetralogy of Fallot

Aim: assess of the pulmonary artery growth and the outcomes of complete repair after palliative treatment in infants with critical form of Tetralogy of Fallot.Methods. This was prospective randomized two-center study (2019 to 2022). Its included infants with Tetralogy of Fallot who underwent palliation with either stenting of the right ventricular outflow tract (stent group, n=21) or modified Blalock-Taussig shunt (shunt group, n=21).Results. In the stent group Nakata index increase from median 104.2 to 208.6 mm2/m2, while in the shunt group, it increased from 107.3 to 169.4 mm2/m2 (p&lt;0,01). Mixed model analysis showed that in stent group the right pulmonary artery growth rate was 2.05*10-2 z scores/day, which was 3.01 times higher than in the shunt group. In stent group the left pulmonary artery growth rate was 2.3*10-2 z scores/day, which was 1.47 times higher than in the shunt group. In the stent group, there was one noncardiac-related mortality during the intermediate period. Transannular patch repair of the right ventricular outflow tract was performed in 12 patients (60%) in the stent group and in 15 patients (71.4%) in the shunt group (p=0.52) during complete repair. At 8 cases (40%) in the stent group and 6 cases (28.6%) in the shunt group, pulmonary artery replacement was performed. Time to surgical repair was shorter in the stent group (p=0.046), while the aortic cross clamp time (p&lt;0,01) and cardiopulmonary bypass time (p&lt;0,01) were significantly shorter in the shunt group.Conclusions. Right ventricular outflow tract stenting provides hemodynamic stabilization and uniform growth of the pulmonary artery compared to modified Blalock-Taussig shunt.

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.

Application of Foley balloon catheter in palliative surgery for pulmonary atresia with an intact ventricular septem, with additional cases of pulmonary atresia with ventricular septal defect and tetralogy of Fallot

BackgroundPulmonary atresia and tetralogy of Fallot can require palliative surgery in the neonatal period due to severe hypoxia; however, limitations of established techniques include high failure rate and need for cardiopulmonary bypass. Herein, right ventricular outflow tract reconstruction on a beating heart using a Foley balloon catheter is described.MethodsA retrospective review of patients who underwent right ventricular outflow tract reconstruction on a beating heart using a Foley balloon catheter at our institution between September 2018 and March 2022 was completed. During the procedure, a Foley balloon catheter was used to occlude the blood from the right ventricular inflow tract.ResultsEight patients with pulmonary atresia and intact ventricular septum underwent an off-pump right ventricular outflow tract reconstruction. One patient with pulmonary atresia and ventricular septal defect, and two patients with tetralogy of Fallot underwent an on-pump right ventricular outflow tract reconstruction on a beating heart. The procedures were successful in all patients. Patent ductus arteriosus ligation without modified Blalock-Taussig shunt placement was performed in three patients with pulmonary atresia with intact ventricular septum and two patients with tetralogy of Fallot, ductus arteriosus was left open in four patients with pulmonary atresia with intact ventricular septum. All patients remained clinically well without serious complications.ConclusionsRight ventricular outflow tract reconstruction on a beating heart using a Foley balloon catheter for pulmonary atresia and tetralogy of Fallot is a feasible alternative to catheter-based interventions or traditional surgical treatment, especially in patients with muscular infundibular stenosis or hypoplastic pulmonary annulus. Further studies with more cases are needed to verify feasibility and superiority of this approach.

Impact of calorie intake and weight gain after Norwood procedure on the outcome of stage II palliation.

This study aimed to assess the impact of caloric intake and weight-for-age-Z-score after the Norwood procedure on the outcome of bidirectional cavopulmonary shunt. A total of 153 neonates who underwent the Norwood procedure between 2012 and 2020 were surveyed. Postoperative daily caloric intake and weight-for-age-Z-score up to five months were calculated, and their impact on outcome after bidirectional cavopulmonary shunt was analysed. Median age and weight at the Norwood procedure were 9 days and 3.2 kg, respectively. Modified Blalock-Taussig shunt was used in 95 patients and right ventricle to pulmonary artery conduit in 58. Postoperatively, total caloric intake gradually increased, whereas weight-for-age-Z-score constantly decreased. Early and inter-stage mortality before stage II correlated with low caloric intake. Older age (p = 0.023) at Norwood, lower weight (p < 0.001) at Norwood, and longer intubation (p = 0.004) were correlated with low weight-for-age-Z-score (< -3.0) at 2 months of age. Patients with weight-for-age-Z-score < -3.0 at 2 months of age had lower survival after stage II compared to those with weight-for-age-Z-score of -3.0 or more (85.3 versus 92.9% at 3 years after stage II, p = 0.017). There was no difference between inter-stage weight gain and survival after bidirectional cavopulmonary shunt between the shunt types. Weight-for-age-Z-score decreased continuously throughout the first 5 months after the Norwood procedure. Age and weight at Norwood and intubation time were associated with weight gain. Inter-stage low weight gain (Z-score < -3) was a risk for survival after stage II.

Predicting Factors for Mortality in Patients After the Modified Blalock-Taussig Shunt Procedure in Developing Countries: A Retrospective Study.

Blalock-Taussig (BT) is a palliative procedure that preserves blood circulation to the lungs and alleviates cyanosis in patients with congenital heart diseases and reduced pulmonary blood flow. BT shunt remains a routinely performed procedure in developing countries before definitive surgery. However, evidence on predictor factors of mortality after this procedure is still scarce in Indonesia. This study evaluated the predictive factors of mortality after the BT shunt procedure. This retrospective study evaluated the medical record data of all postoperative BT shunt patients at Dr. Cipto Mangunkusumo Hospital, Jakarta, Indonesia, from 2016 to 2020. We performed univariate and multivariate analyses to identify the predictors of in-hospital mortality. The total subjects in this study were 197 children, 107 (54.3%) boys and 90 (45.7%) girls. The median values for age and body weight at the time of surgery were 20 months (11 days - 32 years) and 7.9 (2.7-42) kg. The most prevalent diagnosis was the Tetralogy of Fallot, found in 80 (40.6%) patients. In-hospital postoperative mortality was 20.8% (41 patients). Based on multivariate analysis, predictors associated with mortality were weight <4.25 kg (OR 20.9; 95% CI 7.4-59.0; p < 0.0001) and emergency procedures (OR 3.5; 95% CI 1.3-9.5; p = 0.016). The mortality rate after BT shunt at PJT Rumah Sakit Cipto Mangunkusumo was 20.8%. Based on multivariate analysis, weight <4.25 kg and emergency procedures are two predictors of mortality in BT shunt.

New insights learned from the pulmonary to systemic blood flow ratio to predict the outcome in patients with hypoplastic left heart syndrome in the pre-Glenn stage: a single-center study.

To the best of our knowledge, no study has been made until now to determine whether the ratio between pulmonary and systemic blood flow (Qp/Qs) in the pre-stage II (PS2) or pre-Glenn stage can predict the outcome in patients with hypoplastic left heart syndrome (HLHS) who underwent Norwood (NW) palliation. From January 2016 to August 2022, 80 cardiac catheterizations in 69 patients with HLHS in NW palliation stage with modified Blalock-Taussig shunt (MBTS) were retrospectively recruited. The Qp/Qs was measured under stable conditions using the Fick formula. None of the patients were intubated. Patients were divided into two groups: Group 1 included patients who underwent planned cardiac catheterization (n = 56), and Group 2 had unplanned examination (n = 13), in which the indication for cardiac catheterization was desaturation in 11 patients and pulmonary over-circulation in two. The composite primary outcome was defined as accomplishing the planned operations (Glenn and Fontan) with freedom from death and reoperation, referring to palliative therapy or heart transplantation. The secondary outcome was freedom from transcatheter intervention in MBTS or pulmonary arteries. The median follow-up was 48 months (range 6-72 months). The median value of Qp/Qs in Group 1 was 1.75 (range 1.5-2.2). In Group 2, the 11 patients with desaturation, the median value of Qp/Qs was 1.25 (range 0.9-1.45). The two patients with suspected pulmonary overcalculation showed Qp/Qs of 2.3 and 2.5, respectively; a reduction of the shunt size was required. Approximately 96.4% of patients in Group 1 achieved the primary outcome compared with only 30.7% in Group 2. The need for reintervention was 1.8% in Group 1 compared with 61.3% in Group 2. There is a significant relationship between Qp/Qs and the impaired outcome (death, palliative therapy, or heart transplantation) with a p-value of 0.001, a relative risk factor of 3.1, and a 95% confidence interval of 1.4-7.1. No significant relationship between the Qp/Qs and the size of MBTS (p-value of 0.073) was noted. The Qp/Qs in PS2 can predict outcomes in patients with HLHS in Norwood stage with MBTS. The Qp/Qs between 1.5 and 2.2 with a median of 1.75 seems to be optimal in the patients in PS2. Qp/Qs of <1.5 is associated with pulmonary stenosis, shunt stenosis, and pulmonary hypertension.

Graph theory applications in congenital heart disease

Graph theory can be used to address problems with complex network structures. Congenital heart diseases (CHDs) involve complex abnormal connections between chambers, vessels, and organs. We proposed a new method to represent CHDs based on graph theory, wherein vertices were defined as the spaces through which blood flows and edges were defined by the blood flow between the spaces and direction of the blood flow. The CHDs of tetralogy of Fallot (TOF) and transposition of the great arteries (TGA) were selected as examples for constructing directed graphs and binary adjacency matrices. Patients with totally repaired TOF, surgically corrected d-TGA, and Fontan circulation undergoing four-dimensional (4D) flow magnetic resonance imaging (MRI) were included as examples for constructing the weighted adjacency matrices. The directed graphs and binary adjacency matrices of the normal heart, extreme TOF undergoing a right modified Blalock–Taussig shunt, and d-TGA with a ventricular septal defect were constructed. The weighted adjacency matrix of totally repaired TOF was constructed using the peak velocities obtained from 4D flow MRI. The developed method is promising for representing CHDs and may be helpful in developing artificial intelligence and conducting future research on CHD.

Evaluation of Portal, Splenic, and Hepatic Vein Flows in Children Undergoing Congenital Heart Surgery

Little is known about changes in portal, splenic, and hepatic vein flow patterns in children undergoing congenital heart surgery. This study aimed to determine the characteristics of portal, splenic, and hepatic vein flow patterns using ultrasonography in children undergoing cardiac surgery. Single-center, prospective observational study. Tertiary children's hospital, operating room. Children undergoing cardiac surgery. The authors obtained ultrasound data from the heart, inferior vena cava, portal, splenic, and hepatic veins before and after surgeries. In the biventricular group, which included children with atrial and ventricular septal defects and pulmonary stenosis (n=246), the portal pulsatility index decreased from 38.7% to 25.6% (p < 0.001) after surgery. The preoperative portal pulsatility index was significantly higher in patients with pulmonary hypertension (43.3% v 27.4%; p < 0.001). In the single-ventricle group (n=77), maximum portal vein flow velocities of Fontan patients were significantly lower (13.5 cm/s) compared with that of patients with modified Blalock-Taussig shunt (19.7 cm/s; p=0.035) or bidirectional cavopulmonary shunt (23.1 cm/s; p < 0.001). The cardiac index was inversely correlated with the portal pulsatility index in the bidirectional cavopulmonary shunt and Fontan circulation. (β=-5.693, r2=0.473; p=0.001) The portal pulsatility index was correlated with splenic venous pulsatility and hepatic venous atrial reverse flow velocity in biventricular and single-ventricle groups. The characteristics of venous Doppler patterns in the portal, splenic, and hepatic veins differed according to congenital heart disease. Further studies are required to determine the association between splanchnic venous Doppler findings and clinical outcomes in this population.

Palliative Procedures for Congenital Heart Disease: Imaging Findings and Complications

Palliative procedures are performed for congenital heart diseases that are not amenable for definitive surgical procedures or as a component of hybrid procedures along with transcatheter interventions. Multimodality imaging plays an important role in the follow-up of these palliative procedures, mainly for the timely detection of complications and for planning any subsequent palliative or definitive procedure. Echocardiography is the first-line imaging modality, with CT and MRI used as complementary techniques in indeterminate cases. MRI provides anatomic, functional, flow, and tissue characterization information. CT is performed for the evaluation of vascular anatomy and when MRI cannot be performed due to contraindications, challenges, or artifacts. The modified Blalock-Taussig shunt procedure is the most common systemic-pulmonary artery (PA) shunt procedure, with thrombus being the most serious complication. Other complications of systemic-PA shunts include shunt stenosis, infection, pulmonary overcirculation, and cardiac failure. The Glenn shunt procedure is the second stage of palliation in single ventricle physiology, with thrombus, stenosis, superior vena cava syndrome, and infection being the common complications. The Fontan shunt procedure is the third stage of palliation in single ventricle physiology. Complications can be cardiovascular (heart failure, valve regurgitation, thromboembolism, shunt stenosis, arteriovenous malformation), venolymphatic (collaterals, protein-losing enteropathy, plastic bronchitis), or hepatic (congestion, cirrhosis, portal hypertension). PA banding is used to decrease pulmonary flow or to train the systemic ventricle. Complications include stenosis, thrombus, erosion, pseudoaneurysm, and subaortic obstruction. Atrial septostomy and atrial switch procedures are performed for increasing intracardiac mixing. Complications of atrial septostomy can be mechanical, traumatic, embolic, or electrical. Complications of the atrial switch procedure include baffle stenosis, baffle leak, and systemic ventricle failure. The authors review the role of multimodality imaging in the evaluation of these palliative procedures. © RSNA, 2023 See the invited commentary by Bardo and Popescu in this issue. Quiz questions for this article are available through the Online Learning Center.

Fetal pulmonary valvuloplasty for pulmonary atresia with intact ventricular septum: a single-center clinical experience.

Fetal pulmonary valvuloplasty for pulmonary atresia with intact ventricular septum: a single-center clinical experience.

A Single-Centre Retrospective Review ofModified Blalock-Taussig Shunts: A22-YearExperience.

This single-centre retrospective study explores demographics and outcomes of patients who underwent a modified Blalock-Taussig shunt (MBTS) over a 22-year period. The predominant surgical approach in this study is a lateral thoracotomy, in contrast to a midline sternotomy. Risks and outcomes of this approach are compared with national and international literature. Demographic, anatomical, clinical, surgical and outcome data of all patients who underwent a MBTS between 2000 and 2022 were collected and analysed, excluding Norwood procedures, which are not performed at this institution. Short- and long-term morbidity and mortality is described. Over the 22-year study period, 185 MBTS were performed in 162 patients, at a median age of 16 days (interquartile range [IQR] 5-59 days) and weight of 3.47 kg (IQR 3-4.25 kg, minimum weight 2 kg). Of these, 79% of patients had a biventricular circulation. Cardiac diagnoses included both univentricular and biventricular anatomy; tetralogy of Fallot (TOF) (36%), transposition of the great arteries/ventricular septal defect/pulmonary stenosis (TGA/VSD/PS) (11%), pulmonary atresia with intact ventricular septum (PA/IVS) (23%), pulmonary atresia with ventricular septal defect (PA/VSD) (14%), other (16%). The most common size of MBTS was 4 mm (71%); 93% were performed via a lateral thoracotomy. There were 47 cases of major operative morbidity, which did not differ significantly with cardiac diagnosis. Overall all-cause mortality was 13.5%. Early operative mortality was 4.3%. Mortality varied with cardiac diagnosis, 6% with TOF and 19% with PA/IVS. There was no era effect on mortality rates, however a lower frequency of major morbidity (23% vs 7%, p=0.03) was observed in the most recent third of the study period. Risk factors for shunt reintervention or mortality included weight <2.5 kg (HR=2.79 [1.37, 5.65], p=0.005), and pre- (HR=3.31 [1.86, 5.9], p<0.001) or postoperative lactic acidosis (HR=1.37 [1.25,1.5], p<0.001). These rates are comparable to those in the literature, with the predominant approach a midline sternotomy. Hobbes etal. from Royal Children's Hospital in Melbourne, Australia reported an overall and operative mortality rate of 12.8% and 5.2%, respectively, while Sasikumar etal. from The Hospital for Sick Children in Toronto, Canada reported an overall and operative mortality of 16% and 10%, respectively, for MBTS procedures over the same time period, however including smaller weight infants. Petrucci etal. described outcomes from the multi-institutional Society of Thoracic Surgeons Congenital Heart Surgery database reporting an overall mortality in MBTS of 7.2% in 1,273 patients with both single and double ventricle anatomy. Mortality rates and risk factors for adverse outcomes are comparable to those previously reported for both univentricular and biventricular groups. These results highlight that outcomes of MBTS performed via lateral thoracotomy are comparable to those by midline sternotomy as reported in the literature. Operating via the lateral approach may be advantageous as it avoids the complications of a midline sternotomy.

Interventional Management of Acute Thrombosis of the Modified Blalock-taussig Shunt in a Case of Tricuspid Atresia

Abstract Introduction: Acute thrombosis of the modified Blalock-Taussig shunt (mBTS) in patients with univentricular physiology is a life-threatening event. Case presentation: We present a case of acute mBTS thrombosis complicating a hemodynamic evaluation before a bidirectional Glenn procedure for tricuspid atresia. After failed balloon angioplasty and catheter-directed selective thrombolysis, the patient was successfully managed by stent implantation into the thrombosed shunt. To the best of our knowledge, this was the first case of acute mBTS thrombosis treated by catheter intervention in Romania. Conclusions: Even a routine invasive hemodynamic evaluation might be complicated by a life-threatening condition. Stent implantation in the setting of acute mBTS thrombosis could be lifesaving.

Right ventricular outflow tract stenting promotes pulmonary artery development in tetralogy of fallot.

Right ventricular outflow tract (RVOT) stenting seems to be suggested as a promising treatment option and an alternative to modified Blalock-Taussig shunt (mBTS) in the initial palliation of patients with Fallot-type lesions in recent years. This study sought to assess the effect of RVOT stenting on the growth of the pulmonary artery (PA) in patients with Tetralogy of Fallot (TOF). Retrospective review analyzing 5 patients with Fallot-type congenital heart disease with small pulmonary arteries who underwent palliative with RVOT stenting and 9 patients underwent modified Blalock-Taussig shunt within 9 years period. Differential left PA (LPA) and right PA (RPA) growth was measured by Cardiovascular Computed Tomography Angiography (CTA). RVOT stenting improved arterial oxygen saturation from median of 60% (interquartile range [IQR]: 37% to 79%) to 95% (87.5% to 97.5%) (p = 0.028). The LPA diameter Z-score improved from -2.843 (-3.51-2.037) to -0.78 (-2.3305-0.19) (p = 0.03), the RPA diameter Z-score improved from median -2.843 (-3.51-2.037) to -0.477 (-1.1145-0.459) (p = 0.002), the Mc Goon ratio increased from median 1 (0.8-1.105) to 1.32 (1.25-1.98) (p = 0.017). There were no procedural complications and all 5 patients have undergone final repair in the RVOT stent group. In the mBTS group, the LPA diameter Z-score improved from -1.494 (-2.242-0.6135) to -0.396 (-1.488-1.228) (p = 0.15), the RPA diameter Z-score improved from median -1.328 (-2.036-0.838) to 0.088 (-0.486-1.223) (p = 0.007), and there were 5 patients occur different complications and 4 patients was not attained the standards of final surgical repair. RVOT stenting, compared with mBTS, seems to better promote pulmonary artery growth, improve arterial oxygen saturations, and have less procedure complications in patients with TOF who being absolute contraindicated for primary repair due to high risks.

Comparison between the modified Blalock-Taussig shunt and right ventricular outflow tract stent in the palliative treatment for tetralogy of Fallot.

For patients with tetralogy of Fallot (TOF) who are not suitable candidates for primary corrective surgery or have a high surgical risk, transcatheter right ventricular outflow tract (RVOT) stent implantation is considered a safe and effective palliative intervention. This study aims to investigate the therapeutic outcomes of RVOT stent implantation in neonates and infants with TOF in comparison with the modified Blalock-Taussig shunt (mBTS) and to compare the impact of the 2 palliative interventions on arterial oxygen saturation and pulmonary artery development in pediatric patients. Clinical data of 32 patients with TOF admitted to the Second Xiangya Hospital of Central South University from March 2011 to March 2021 were retrospectively collected. The patients were divided into an mBTS group (undergoing mBTS, n=15) and a stent implantation group (undergoing RVOT stenting, n=17) according to the surgical procedures. The 2 groups were assessed and compared in the surgical-related arterial oxygen saturation, postoperative complication rate, mortality rate, and re-intervention rate. The development of the patients' main pulmonary artery, right pulmonary artery, and left pulmonary artery was assessed by z-scores according to echocardiographic results. The children in the stent implantation group were younger and less weighed compared with the mBTS group (both P<0.05). Compared with the preoperative period, children in the stent implantation group had significantly higher arterial oxygen saturation [(75±17)% vs (96±3)%, P=0.026]; z-scores of pulmonary trunk [(-2.82±1.27) points vs (0.86±0.77) points, P=0.014], right pulmonary artery [(-1.88±0.59) points vs (-0.28±0.71) points, P=0.011], and left pulmonary artery [(-2.34±0.36) points vs (-1.67±0.36) points, P=0.036] were significantly increased. However, there were no significant differences in arterial oxygen saturation and pulmonary artery z-scores between pre- and post-mBTS procedures (all P>0.05). RVOT stent would have good surgical outcomes used in TOF patients with low weight and severe comorbidities. It also leads to an higher postoperative oxygen saturation and better promotion of pulmonary artery growth with RVOT stent compared to mBTS.

Influence of the bronchus on the vascular growth of major aortopulmonary collateral arteries.

Patients with major aortopulmonary collateral arteries (MAPCAs) often require additional surgical or catheter intervention after unifocalization (UF) due to stenosis and poor growth. We hypothesized that the UF design influences vascular growth; assessment was based on the passing route related to the bronchus. We enrolled 5 patients with pulmonary atresia (PA), ventricular septal defect and MAPCA who underwent UF and subsequent definitive repair at our institute from 2008 to 2020. Angiography and computed tomography scans were routinely performed before surgical intervention to clarify pulmonary circulation and the relationships between MAPCAs and the bronchus, which revealed peculiar MAPCAs directed to the pulmonary hilum passing behind the bronchus (defined as retro-bronchial MAPCAs; rbMAPCAs). Vascular growth of rbMAPCAs, non-rbMAPCAs and the native pulmonary artery were assessed using the angiograms before and after repair. The angiogram before UF [age 42 (24-76) days, body weight 3.2 (2.7-4.2) kg] showed that the diameter of the original unilateral PA, rbMAPCA and non-rbMAPCA was 19.95 ± 6.65, 20.72 ± 5.36 and 20.29 ± 7.42 mm/m2, respectively (P = 0.917). UF was completed in a single-stage with the placement of modified Blalock-Taussig shunt through median sternotomy at the age of 1.6 (1.0-2.5) months. Angiograms performed 3.0 (1.0-10.0) years after UF completion demonstrated a smaller rbMAPCA diameter at peri-bronchial region (3.84 ± 2.84 mm/m2) compared to the native unilateral PAs (16.11 ± 5.46 mm/m2, P < 0.0001) and non-rbMAPCA (10.13 ± 4.44 mm/m2, P = 0.0103). RbMAPCAs tend to be stenosed at the point where they cross the bronchus and emerge in the middle mediastinum after in situ UF.