A Single-Centre Retrospective Review of Modified Blalock-Taussig Shunts: A 22-Year Experience.

INTRODUCTION: 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. MATERIALS AND METHODS: 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. RESULTS: 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. CONCLUSION: 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.

Comparison between the modified Blalock-Taussig shunt and right ventricular outflow tract stent in the palliative treatment for tetralogy of Fallot. / 改良Blalock-Taussigåˆ†æµæœ¯ä¸Žå³å¿ƒå®¤æµå‡ºé“æ”¯æž¶æ¤å ¥æœ¯å§‘æ¯æ€§æ²»ç–—æ³•æ´›å››è”ç—‡çš„æ¯”è¾ƒ.

OBJECTIVES: 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. METHODS: 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. 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). CONCLUSIONS: 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.

Outcomes of duct stenting and modified Blalock-Taussig shunt in cyanotic congenital heart disease with duct-dependent pulmonary circulation.

BACKGROUND: Transcatheter ductus arteriosus stenting (DS) is emerging as an alternative method to modified Blalock-Taussig shunt (MBTS) in providing pulmonary blood flow in cyanotic congenital heart disease (CCHD) with duct-dependent pulmonary circulation. OBJECTIVE: To evaluate post-procedural outcomes and survival between patients undergoing DS and MBTS. METHODS: All infants ≤ 60 days of age having CCHD with diminished pulmonary blood flow who underwent palliative procedure either with MBTS or DS at King Chulalongkorn Memorial Hospital during January 1st, 2013 and December 31th, 2017 were retrospectively reviewed. RESULTS: 98 patients were included; 34 patients underwent a transcatheter DS and 64 patients underwent MBTS. There was no significant difference in post-procedural outcomes and overall mortality rate between two groups (17.6% in MBTS group and 6.1% in DS group, p = 0.09). Single ventricle morphology was the major risk factor associated with increased mortality compared with biventricular morphology (aHR 3.9, 95% CI 1.49-10.2, p = 0.01). There was similar number of early and pre-repair additional interventions focusing on MBTS/DS patency between two groups. The MBTS group had a greater number of early interventions on PA branch stenosis related to baseline diagnosis. Risk factors associated with additional intervention were pre-existing pulmonary branch stenosis (aHR 2.54, 95% CI 1.3-4.97, p = 0.006) and body weight less than 2.5 kg (aHR 3.33, 95% CI 1.57-7.08, p = 0.003). Having pulmonic valve perforation or balloon pulmonary valvuloplasty to promote antegrade pulmonary blood flow could result in a lower number of additional interventions required before definitive repair. CONCLUSION: Duct stenting is a feasible and safe alternative to MBTS in cyanotic infants with duct-dependent pulmonary circulation. However, mortality rate was significantly higher in patients with single ventricle that required careful follow-up after procedure.

Patent ductus arteriosus stenting versus modified Blalock-Taussig shunt for palliation of duct-dependent pulmonary blood flow lesions.

BACKGROUND: Patent ductus arteriosus (PDA) stenting is an alternative to modified Blalock-Taussig shunt (MBTS) as first-stage palliation of duct-dependent lesions. The superiority of one approach over the other is still controversial. Our objective was to compare PDA  stent versusMBTS for palliation in regard to safety, efficacy, and efficiency. METHODS: From 2010 to 2021, 134 patients had first-stage palliation with either PDA stent (n = 83) or MBTS (n = 51). Twenty-seven patients failed the primary treatment and were converted to the other group. The study endpoints were hospital outcomes, interstage reintervention, and concomitant procedures at the second-stage palliation. RESULTS: Patients with PDA stent were significantly younger. The prevalence of antegrade pulmonary blood flow (PBF) was higher in patients who had MBTS and graft thrombosis was higher in the PDA stent. Hospital stay was significantly longer in patients who had MBTS. Predictors of prolonged mechanical ventilation were low-weight, MBTS, and conversion. Intensive care unit stay significantly increased with conversion, low-weight, and antegrade PBF. The interstage intervention was required more frequently in PDA-stent group. Predictors of reintervention were conversion and pulmonary atresia with the intact interventricular septum. Pulmonary artery plasty was required more frequently during the second-stage palliation in PDA-stent group. CONCLUSION: PDA stent is an alternative to MBTS for first-stage palliation. It is associated with shorter hospital stays and avoidance of surgery at the expense of a high rate of stent thrombosis and interstage reintervention. Conversion increased the risk of the procedure. More studies are needed to determine factors that affect PDA-stent outcomes and patient selection criteria.

Outcomes After Stage I Norwood Palliation in a Recently Established Program Can Achieve Results Similar to Longer Established Services.

BACKGROUND: Infants with hypoplastic left heart syndrome (HLHS) or similar single ventricle cardiac lesions require a three-stage surgical approach, the first step being the Stage I Norwood procedure. The Queensland Children's Hospital (QCH) in Australia is a tertiary hospital providing the only cardiac surgical service to children in Queensland and northern New South Wales. OBJECTIVE: To review the centre's outcomes of Norwood procedures performed in the last 6 years. MATERIALS AND METHODS: We retrospectively evaluated all infants undergoing the stage I Norwood procedure between January 2015 and August 2021. Mortality, intensive care length of stay, events of cardiac arrest following surgery and duration of mechanical ventilation were calculated and analysed for subgroups depending on type of pulmonary shunt type (right-ventricle-to-pulmonary-artery shunt [RVPAS] vs the modified Blalock-Taussig shunt [MBTS]). RESULTS: Forty-nine (49) patients were included. Overall survival to stage two operation (Glenn) was 90%. Both shunts were used evenly with the RVPA conduit preferred for HLHS and the MBTS largely chosen for hypoplastic left heart variants. In univariable analysis there was no difference in cardiac arrest or mortality rate for the patient with a RVPAS compared to the patient with a MBTS. CONCLUSION: We show that a recently established Norwood program can achieve results that are comparable to those reported by longer established centres, and the international literature.

Seroma formation after modified Blalock-Taussig shunt which caused shock due to pulmonary vein compression.

Seroma formation is a relatively rare complication seen after a modified Blalock-Taussig shunt. Herein, we report a rare case of seroma formation on the posterior aspect of the left atrium without it touching the graft, and presenting with shock, due to pulmonary vein compression.

High acetylsalicylic acid dosing in infants after modified Blalock-Taussig shunt.

OBJECTIVE: Shunt-related adverse events are frequent in infants after modified Blalock-Taussig despite use of acetylsalicylic acid prophylaxis. A higher incidence of acetylsalicylic acid-resistance and sub-therapeutic acetylsalicylic acid levels has been reported in infants. We evaluated whether using high-dose acetylsalicylic acid can decrease shunt-related adverse events in infants after modified Blalock-Taussig. METHODS: In this single-centre retrospective cohort study, we included infants ⩽1-year-old who underwent modified Blalock-Taussig placement and received acetylsalicylic acid in the ICU. We defined acetylsalicylic acid treatment groups as standard dose (⩽7 mg/kg/day) and high dose (⩾8 mg/kg/day) based on the initiating dose. RESULTS: There were 34 infants in each group. Both groups were similar in age, gender, cardiac defect type, ICU length of stay, and time interval to second stage or definitive repair. Shunt interventions (18 versus 32%, p=0.16), shunt thrombosis (14 versus 17%, p=0.74), and mortality (9 versus 12%, p=0.65) were not significantly different between groups. On multiple logistic regression analysis, single-ventricle morphology (odds ratio 5.2, 95% confidence interval of 1.2-23, p=0.03) and post-operative red blood cells transfusion ⩾24 hours [odds ratio 15, confidence interval of (3-71), p<0.01] were associated with shunt-related adverse events. High-dose acetylsalicylic acid treatment [odds ratio 2.6, confidence interval of (0.7-10), p=0.16] was not associated with decrease in these events. CONCLUSIONS: High-dose acetylsalicylic acid may not be sufficient in reducing shunt-related adverse events in infants after modified Blalock-Taussig. Post-operative red blood cells transfusion may be a modifiable risk factor for these events. A randomised trial is needed to determine appropriate acetylsalicylic acid dosing in infants with modified Blalock-Taussig.

Potential Role of Transfontanelle Ultrasound for Infants Undergoing Modified Blalock-Taussig Shunt.

OBJECTIVE: Transfontanelle ultrasound is a noninvasive method for assessing cerebral blood flow in neonates and infants. The authors applied this technique as a point-of-care tool, before and after modified Blalock-Taussig shunt procedure, to evaluate cerebral perfusion. DESIGN: Retrospective, observational study. SETTING: Tertiary care children's hospital. PARTICIPANTS: Ten infants undergoing modified Blalock-Taussig shunt procedure. OBSERVATION: Transfontanelle ultrasound examinations with modified resistive index were analyzed before and after the modified Blalock-Taussig shunt procedure. MEASUREMENTS AND MAIN RESULTS: Two infants died and 2 patients required a revision procedure due to shunt thrombosis. Baseline-modified resistive index and regional cerebral oxygenation were comparable between the right and left hemisphere. However, after the procedure, the modified resistive index decreased at both sides of the internal carotid arteries compared with baseline values (p value right side = 0.012, left side = 0.036) and was greater at the ipsilateral internal carotid arteries with the shunt (p = 0.012, mean difference = 0.07, 95% confidence interval [CI] 0.02-0.12). Four infants with the large patent ductus arteriosus presented diastolic reverse flows at both internal carotid arteries at baseline. However, the diastolic reverse flow disappeared after the procedure. An infant who developed diastolic reverse flow after the procedure, died. CONCLUSIONS: Transfontanelle ultrasound is a feasible tool for assessing the pattern of shunt flow and cerebral perfusion before and after the modified Blalock-Taussig shunt procedure. The transfontanelle ultrasound examinations may have potential role in assessing "over-shunting," but it needs more studies.

Evaluation of cerebral oxygenation and perfusion with conversion from an arterial-to-systemic shunt circulation to the bidirectional Glenn circulation in patients with univentricular cardiac abnormalities.

OBJECTIVE: Superior vena cava pressure after the bidirectional Glenn operation usually is higher than that associated with the preceding shunt-dependent circulation. The aim of the present study was to determine whether the acute elevation in central venous pressure was associated with changes in cerebral oxygenation and perfusion. DESIGN: Single-center prospective, observational cohort study. SETTING: Academic children's hospital. PARTICIPANTS: Infants with single-ventricle lesions and surgically placed systemic-to-pulmonary artery shunts undergoing the bidirectional Glenn operation. INTERVENTIONS: Near-infrared spectroscopy and transcranial Doppler sonography were used to measure regional cerebral oxygen saturation and cerebral blood flow velocity. MEASUREMENTS AND MAIN RESULTS: Mean differences in regional cerebral oxygen saturation and cerebral blood flow velocity before anesthetic induction and shortly before hospital discharge were compared using the F-test in repeated measures analysis of variance. In the 24 infants studied, mean cerebral oxygen saturation increased from 49%±2% to 57%±2% (p = 0.007), mean cerebral blood flow velocity decreased from 57±4 cm/s to 47±4 cm/s (p = 0.026), and peak systolic cerebral blood flow velocity decreased from 111±6 cm/s to 99±6 cm/s (p = 0.046) after the bidirectional Glenn operation. Mean central venous pressure was 8±2 mmHg postinduction of anesthesia and 14±4 mmHg on the first postoperative day and was not associated with a change in cerebral perfusion pressure (p = 0.35). CONCLUSIONS: The bidirectional Glenn operation in infants with a shunt-dependent circulation is associated with an improvement in cerebral oxygenation, and the lower cerebral blood flow velocity is likely a response of intact cerebral autoregulation.

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

Background: 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. Methods: 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. Results: 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). Conclusion: 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.

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

Objectives: 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. Methods: 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. Results: 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. Conclusion: 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.

Impact of pulmonary artery coarctation on pulmonary artery growth and definitive repair following modified Blalock-Taussig shunt.

OBJECTIVE: Pulmonary artery coarctation may pose a risk for pulmonary stenosis and subsequent failure to achieve definitive repair. We sought to assess the impact of pulmonary artery coarctation on pulmonary artery growth. METHODS: A retrospective chart review was performed in 130 patients, including 37 single ventricles with a modified Blalock-Taussig shunt as first palliation. Pulmonary artery coarctation was defined as discrete stenosis of the pulmonary artery, with a diameter of less than 3 mm and with the ductus arteriosus connected. Preoperative echocardiography showed pulmonary artery coarctation in 29 patients (22%). Concomitant pulmonary artery plasty was performed in 14 patients with discrete stenosis having a diameter of less than 2 mm. RESULTS: Pre-modified Blalock-Taussig shunt left pulmonary artery z-scores were lower in patients with pulmonary artery coarctation than in those without (-4.0 [-5.8, -2.1] vs -1.7 [-2.6, -0.8], P < .001), and this remained the same even after modified Blalock-Taussig shunt (-2.5 [-5.1, -0.5] vs -0.5 [-2.4, 0.8], P = .010). Concomitant pulmonary artery plasty did not result in catch-up growth of the left pulmonary artery (post-modified Blalock-Taussig shunt left pulmonary artery z-score in patients with pulmonary artery plasty: -3.0 (-6.5, -2.0) versus those without: -1.8 (-3.3, -0.3), P = .279). Definitive repair/Fontan completion was achieved in 111 patients (85%), and this was not affected by the presence of pulmonary artery coarctation. CONCLUSIONS: Pulmonary artery coarctation affected disproportionate pulmonary artery growth throughout the staged repair, but did not result in failure of definitive repair/Fontan completion. Pulmonary artery plasty during the neonatal period did not contribute to catch-up growth of the left pulmonary artery; therefore, surgical indications and timing should be carefully considered.

The Effects of the Mechanical Properties of Vascular Grafts and an Anisotropic Hyperelastic Aortic Model on Local Hemodynamics during Modified Blalock-Taussig Shunt Operation, Assessed Using FSI Simulation.

Cardiovascular surgery requires the use of state-of-the-art artificial materials. For example, microporous polytetrafluoroethylene grafts manufactured by Gore-Tex® are used for the treatment of cyanotic heart defects (i.e., modified Blalock-Taussig shunt). Significant mortality during this palliative operation has led surgeons to adopt mathematical models to eliminate complications by performing fluid-solid interaction (FSI) simulations. To proceed with FSI modeling, it is necessary to know either the mechanical properties of the aorta and graft or the rheological properties of blood. The properties of the aorta and blood can be found in the literature, but there are no data about the mechanical properties of Gore-Tex® grafts. Experimental studies were carried out on the mechanical properties vascular grafts adopted for modified pediatric Blalock-Taussig shunts. Parameters of two models (the five-parameter Mooney-Rivlin model and the three-parameter Yeoh model) were determined by uniaxial experimental curve fitting. The obtained data were used for patient-specific FSI modeling of local blood flow in the "aorta-modified Blalock-Taussig shunt-pulmonary artery" system in three different shunt locations: central, right, and left. The anisotropic model of the aortic material showed higher stress values at the peak moment of systole, which may be a key factor determining the strength characteristics of the aorta and pulmonary artery. Additionally, this mechanical parameter is important when installing a central shunt, since it is in the area of the central anastomosis that an increase in stress on the aortic wall is observed. According to computations, the anisotropic model shows smaller values for the displacements of both the aorta and the shunt, which in turn may affect the success of preoperative predictions. Thus, it can be concluded that the anisotropic properties of the aorta play an important role in preoperative modeling.

Acquired von Willebrand syndrome is common in infants with systemic-to-pulmonary shunts: Retrospective case-series.

Background: Although acquired von Willebrand syndrome (aVWS) has been described in congenital heart disease before, anatomical features leading to aVWS with characteristic reduction or loss of high molecular weight von Willebrand multimers (HMWM) are not well known. This study assesses the prevalence and effects of aVWS in infants with systemic-to-pulmonary shunts (SPS). Methods: This retrospective single-center study analyzes diagnostic data of infants with complex congenital heart defects requiring palliation with SPS. During the study period between 12/15-01/17 fifteen consecutive patients were eligible for analysis. Results of von Willebrand factor antigen (VWF:Ag), collagen binding activity (VWF:CB) and von Willebrand factor multimer analysis were included. Results: In all 15 patients with SPS an aVWS could be found. Blood samples were collected between 5 and 257 days after shunt implantation (median 64 days). None of the patients demonstrated increased bleeding in everyday life. However, 6 out of 15 patients (40%) showed postoperative bleeding complications after SPS implantation. Following shunt excision multimeric pattern normalized in 8 of 10 (80%) patients studied. Conclusions: This study shows that in patients undergoing SPS implantation aVWS might emerge. Pathogenesis can be explained by shear stress resulting from turbulent flow within the shunt. Knowledge of aVWS existence is important for the consideration of replacement therapy with von Willebrand factor containing products and antifibrinolytic treatment in bleeding situations. Implementation of methods for rapid aVWS detection is required to achieve differentiated hemostatic therapy and reduce the risk of complications caused by empiric replacement therapy.

Influence of Shunt Type on Survival and Right Heart Function after the Norwood Procedure for Aortic Atresia.

The study objective was to compare the results after Norwood procedure between modified Blalock-Taussig shunt (MBTS) and right ventricle-to-pulmonary artery conduit (RVPAC) according to Sano in patients with hypoplastic left heart syndrome (HLHS) and aortic atresia (AA). A total of 146 neonates with HLHS and AA who underwent the Norwood procedure at our institution between 2001 and 2020 were divided into 2 groups according to shunt type (MBTS or RVPAC). Survival after the Norwood procedure was compared between the groups. Longitudinal right ventricular and tricuspid valve function in each group were evaluated using cubic splines method. RVPAC was performed in 103 patients and MBTS in 43 according to surgeon preference. There were no differences in the 30-day mortality rates (16.5% vs 16.3%, P  = 0.973). Survival at 0.5, 1 and 3 years was 79.6%, 74.6%, and 68.9% in RVPAC and 66.8%, 64.3%, and 58.5% in MBTS (P  =  0.293). Among 23 patients undergoing tricuspid valve procedure, different mechanisms of tricuspid regurgitation were observed between the groups. Longitudinal analysis revealed greater prevalence of late right ventricular dysfunction in RVPAC patients. In 77 patients who completed Fontan procedure, the postoperative N-terminal pro B-type natriuretic peptide value was significantly higher in RVPAC vs MBTS (554 vs 276 ng/L, P  =  0.007). No survival advantage of RVPAC over MBTS was observed in neonates with HLHS and AA undergoing the Norwood procedure. Longitudinal analysis demonstrated a greater prevalence of right ventricular dysfunction and higher N-terminal pro B-type natriuretic peptide values during late follow-up in patients with RVPAC.

Shunt resistance is associated with clinically important outcomes after the Norwood operation.

Background: In single-ventricle physiology, focus on pulmonary vascular resistance neglects the resistance in the conduit supplying the pulmonary inflow. Methods: Conduit length and diameter, which can approximate conduit resistance, are available in the public dataset of Single Ventricle Reconstruction (SVR) trial. Conduit resistance was then calculated for SVR trial participants and the relationship with clinically important variables (death or transplant at 1 year, pulmonary artery size at second-stage palliation, pulmonary-to-systemic blood flow ratio, and supplemental oxygen requirement) was explored. To validate this calculated resistance, calculated resistance was compared with catheterization measurements at a single institution (not included in the SVR trial). Results: In the institutional dataset, calculated and measured resistances had an intraclass correlation of 0.78 for modified Blalock-Taussig shunts (MBTS). Within the SVR trial, transplant-free survivors had a lower MBTS resistance (median, 8.3 Woods Units [WU]. interquartile range [IQR], 6.5-11.1 WU) than patients who died or required transplantation (median, 13.0 WU; IQR, 9.4-16.6 WU, P = .0001). When we controlled for left pulmonary artery diameter after the Norwood procedure in the SVR trial, for each unit increase in MBTS resistance, the left pulmonary artery diameter at stage II decreased (-0.006 ± 0.002 cm, P = .005). When we controlled for pulmonary vascular resistance, greater MBTS resistance was associated with a decrease in log pulmonary-to-systemic blood flow ratio (-0.04 ± 0.015, P = .0048) in the SVR trial. Patients in the SVR trial requiring supplemental oxygen on admission for stage II palliation had greater MBTS resistance (median. 11.1 WU; IQR, 6.6-16.6 WU) than patients not requiring oxygen (median 8.3, WU; IQR, 6.5-11.1 WU, P = .015). Conclusions: Conduit resistance is associated with important clinical outcomes after Norwood; however, further studies are required to guide conduit resistance optimization.

Effects of Patent Ductus Arteriosus on the Hemodynamics of Modified Blalock-Taussig Shunt Based on Patient-Specific Simulation.

The question of preserving the patent ductus arteriosus (PDA) during the modified Blalock-Taussig shunt (MBTS) procedure remains controversial. The goal of this study was to investigate the effects of the PDA on the flow features of the MBTS to help with preoperative surgery design and postoperative prediction. In this study, a patient with pulmonary atresia and PDA was included. A patient-specific three-dimensional model was reconstructed, and virtual surgeries of shunt insertion and ductus ligation were performed using computer-aided design. Computational fluid dynamics was utilized to analyze the hemodynamic parameters of varied models based on the patient-specific anatomy and physiological data. The preservation of the PDA competitively reduced the shunt flow but increased total pulmonary perfusion. The shunt flow and ductal flow collided, causing significant and complicated turbulence in the pulmonary artery where low wall shear stress, high oscillatory shear index, and high relative residence time were distributed. The highest energy loss was found when the PDA was preserved. The preservation of PDA is not recommended during MBTS procedures because it negatively influences hemodynamics. This may lead to pulmonary overperfusion, inadequate systemic perfusion, and a heavier cardiac burden, thus increasing the risk of heart failure. Also, it seems to bring no benefit in terms of reducing the risk for thrombosis.

Intraoperative fluorescence with indocyanine green in congenital cardiac surgery: Potential applications of a novel technology.

BACKGROUND: Achieving successful repair of congenital heart defects requires attention to detail. Careful evaluation of anastomotic site patency, reimplanted coronary arteries, location of epicardial coronaries, and myocardial perfusion may be necessary to ensure safe conduct of the operation and achieve excellent outcomes. METHODS: Intraoperative fluorescence angiography (IOFA) was performed using indocyanine green in patients undergoing the following procedures: coronary artery reimplantation, coronary artery unroofing, evaluation of intraoperative coronary anatomy, reoperation requiring ventriculotomy, coarctation/interrupted aortic arch repair, systemic-to-pulmonary artery shunt, Norwood procedure, thoracic duct localization, and vascular rings. RESULTS: The technique was feasible in all patients. No mortality or adverse events related to the dye were encountered. Adequate intraoperative imaging was obtained in 15 patients (20 images), which correlated well with postoperative studies. The imaging quality was superior for assessing shunt patency, myocardial perfusion, and anastomotic patency and determining the location of epicardial coronary arteries but was less so for assessing branch pulmonary arteries. CONCLUSIONS: IOFA is a useful and safe technique that can provide a quick on-table assessment of a variety of congenital surgical procedures. This may help answer questions that can minimize postoperative interventions and help ensure a smooth perioperative course and excellent outcomes.

Subclavian artery pseudoaneurysm long after the division of modified Blalock-Taussig shunt.

A massive but asymptomatic left subclavian artery pseudoaneurysm was diagnosed in a 30-year-old female patient with transposition of the great arteries, ventricular septal defect, and pulmonary atresia. After undergoing bilateral modified Blalock-Taussig shunts at the age of 4 months and 3 years, respectively, she underwent the Rastelli operation and division of both shunts at the age of 6 years of age. The pseudoaneurysm was not discovered at the follow-up investigation at age 14. During the time period from age 18 to 30 years, she was lost to follow-up, she was confirmed to be free from infectious disease, traumatic accident, or vasculitis. Pregnancy-induced hypertension was not associated during her pregnancy. Graft replacement of the left subclavian artery and redo right ventricular outflow tract reconstruction were successfully performed under deep hypothermic circulatory arrest at the age of 33 years.

Pulmonary artery growth after Modified Blalock-Taussig shunt: A single center experience.

OBJECTIVE: This study evaluates growth of pulmonary artery (PA) between different age groups after Modified Blalock-Taussig shunt (MBTS) based on a single center experience. METHODS: We retrospective analyzed outcomes of 90 patients undergoing MBTS in our institute from January 1, 2010 to May 1, 2018. Patients were divided into three groups: Group 1, ≦2 months, Group 2, >2 months, ≦24 wmonths, Group 3, >24 months. The outcome included PA growth, overall survival rates and postoperative complications. RESULTS: 23 patients were involved in Group 1, while 49 in Group 2 and 18 in Group 3. The diameter of the PA, McGoon ratio, Nakata index and the oxygen saturation increased significantly after MBTS. Compared to pre-MBTS, there was no statistically significant increase of McGoon ratio in Group 3 after performing MBTS, but it witnessed less secondary cardiac surgery rate compared with Group 2 (11.11% vs. 48.98%, P = 0.005). Cumulative survival rates of three groups were 60.53%, 85.70%, 94.40% at 1 year; 60.53%, 78.30%, 87.75% at 3 years and 60.53%, 78.30%, 87.75% at 5 years. Multivariable analysis showed diastolic blood pressure <30 mmHg [OR 14.14 (1.92-104.32), P = 0.009], cardiopulmonary bypass use [OR 16.79 (2.05-137.67), P = 0.009] and single ventricle anomaly [OR 8.80 (1.18-65.54), P = 0.034] were predictors of perioperative mortality. CONCLUSION: MBTS in our institute is a conventional and effective procedure for growth of PA especially for patients younger than 24 months. Patients with biventricular anomaly, no cardiopulmonary bypass use in surgery and relatively high postoperative diastolic blood pressure will likely offer a good prognosis.