Sternotomy approach for the modified Blalock-Taussig shunt

Role of BT shunt in tetralogy of Fallot

INTRODUCTION

Modified Blalock-Taussig shunt (BT shunt) is a palliative operation used for cyanotic heart diseases with decreased pulmonary blood supply. The definitive management of tetralogy of Fallot (TOF) is total corrective surgery, but these patients can be palliated with BT shunt. In the modern world, the BT shunt is getting out of favour in patients with TOF. In this article, we will share our 5-year experience at our institute, which also shows a decreasing trend.

PATIENTS AND METHODS

It is a retrospective study. Files of all the patients admitted in our department from January 2019 to December 2023 were reviewed. Age, weight, hospital stay, inotropic support duration, mechanical ventilation duration, and outcomes were studied.

RESULTS

From January 2019 to December 2023, 173 patients underwent BT shunt for TOF. The mean age was 31 months, and the mean weight was 9.3 kg. The overall mortality for BT shunt was 15% after BT shunt. Hypercyanotic spell not controlled by medical management was the most common indication for BT shunt in our setup. Most of the patients with hypercyanotic spells were also candidates for total correction but due to the emergency, BT shunt was performed.

CONCLUSION

The role of BT shunt in patients with TOF is decreasing due to PDA/RVOT stenting, it is likely that the BT shunt in TOF will become a thing of the past in the future even in developing countries like ours.

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

Background

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.

Methods

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.

Results

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).

Conclusion

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.

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.

Borrowing from Adult Cardiac Surgeons-Bringing Congenital Heart Surgery Up to Speed in the Minimally Invasive Era

The majority of congenital and adult cardiac surgery is performed through a median sternotomy. For surgeons, this incision provides excellent exposure; however, for patients, a median sternotomy confers a poorer cosmetic outcome and the possibility of postoperative respiratory dysfunction, chronic pain, and deep sternal wound infections. Despite the advances in adult cardiac surgery, the use of minimally invasive techniques in pediatric patients is largely limited to small case series and less complex repairs. In this article, we review the risks, benefits, and limitations of the minimally invasive congenital cardiac approaches being performed today. The interest in these approaches continues to grow as more data supporting reduced morbidity, decreased length of stay, and faster recovery are published. In the future, as the technology and surgical familiarity improve, these alternative approaches will become more common, and may someday become the standard of care.

Interventions on patent ductus arteriosus and its impact on congenital heart disease

The ductus arteriosus (DA) connects the pulmonary artery to the aorta to bypass the pulmonary circulation in utero. It normally closes within 24-72 hours after birth due to increased pulmonary resistance from an increase in oxygen partial pressure with the baby's first breath. Medical treatment can help close the DA in certain situations where closure is delayed. However, in duct-dependent cardiac defects, the presence of the DA is crucial for survival and as such medical and surgical techniques have evolved to prevent closure. This review aims to outline the two main management options for keeping a ductus arteriosus patent. This includes stenting the PDA and shunting via a modified Blalock-Taussig shunt. Whilst both techniques exist, multicentre trials have found equal mortality end points but significantly reduced morbidity with stenting than shunting. This is also reflected by shorter recovery times, reduced requirement for extracorporeal membrane oxygenation (ECMO), and improved quality of life, although stent longevity remains a limiting factor.

Pulmonary atresia with ventricular septal defect and tetralogy of Fallot: transannular path augmentation versus systemic to pulmonary artery shunt for first-stage palliation

BACKGROUND

Pulmonary atresia with ventricular septal defect and severe tetralogy of Fallot require a palliative procedure for pulmonary artery rehabilitation. For first-stage palliation, two main surgical options are still debated: right ventricle to pulmonary artery connection and modified Blalock-Taussig shunt. We compared the clinical outcomes of the two procedures.

METHODS

From 1995 to 2018, 88 patients needed palliation (pulmonary atresia with ventricular septal defect n = 47; tetralogy of Fallot n = 41). Among these patients, 70 modified Blalock-Taussig shunt and 18 transannular path augmentation were performed before 6 months of age. Using a 1:1 propensity score match analysis, 20 patients were included in the analysis. The primary outcome was in-hospital mortality and pulmonary artery growth.

RESULTS

After matching, the pre-operative Nakata was smaller in transannular path augmentation 54 ± 24 mm2/m2 than modified Blalock-Taussig shunt 109 ± 31 mm2/m2 (p < 0.001). The age and weight were similar (p = 0.31 and p = 0.9, respectively). There was no difference in in-hospital mortality (p = 0.3). The Nakata index before biventricular repair and delta Nakata were smaller in modified Blalock-Taussig shunt group (206 ± 80 mm2/m2, 75 ± 103 mm2/m2) than transannular path augmentation (365 ± 170 mm2/m2, 214 ± 165 mm2/m2; p = 0.03; p < 0.001). Median time to biventricular repair was similar (p = 0.46). The rate of interstage reintervention was similar (p = 0.63).

CONCLUSIONS

The transannular path augmentation is better for the rehabilitation of the native pulmonary artery. Despite a smaller pulmonary artery, right ventricle to pulmonary artery connection is equivalent to modified Blalock-Taussig shunt for rate of biventricular repair and time to biventricular repair.

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.

What are the non-cardiac prognostic factors affecting mortality in neonates with aortopulmonary shunt

Background/aim: Systemic to pulmonary shunts (SPS) have proven to be highly effective for the palliation of neonates with cyanotic congenital heart disease. Mortality after SPS surgery in neonates has multifactorial basis. We aimed to investigate the clinical results of the SPS in relation to the underlying cardiac disease and to identify the risk factors contributing to an adverse outcome.Material and method: All neonates who underwent first shunt insertion for cyanotic congenital heart disease during the study period from 1 January 2014 to 31 December 2017 were included. A retrospective review of patient records was done. Patients were grouped into two different categories: survived with or without any reintervention and death before or after any reintervention till discharge.Result: During the study period, 47 patients underwent SPS shunt placement. Patients who survived with or without any reintervention were in Group 1 and patients who died before or after any reintervention till discharge were in Group 2. Preoperative epinephrine requirement and mechanical ventilation and postoperative erythrocyte transfusion need were statistically significant.Conclusion: Although primary cardiac pathology is the most important prognostic factor, some other preoperative and postoperative factors like preoperative epinephrine requirement, and postoperative erythrocyte transfusion might also affect the prognosis. As there are very few centers in the region that specialize in pediatric cardiac surgery, a multicenter approach will be helpful in reaching reliable conclusions.

Blalock-Taussig Shunt Size: Should it be Based on Body Weight or Target Branch Pulmonary Artery Size?

The study aimed to revisit the in-hospital predictors of shunt thrombosis (ST) in the foreground of the pulmonary artery size in patients who received modified Blalock-Taussig shunt (mBTS) as the first-stage palliation. Data from 80 patients who received mBTS as their initial palliative procedure between February 2012 and January 2017 was retrospectively collected. The median age and weight of the patients at the time of their mBTS procedure was 4 days (IQR 2-22 days) and 3.2 kg (IQR 2.8-3.7 kg), respectively. Of the 80 patients in the study, 11 (13.8%) developed ST. The diameter and corresponding z scores of the pulmonary arteries were significantly lower in patients with ST. The median shunt size/shunted pulmonary artery size (S/PA) ratio was considerably higher in patients with ST. In logistic regression analysis, pulmonary artery hypoplasia (PAH) [odds ratio (OR) = 13.7 (0.06-0.21), p < 0.001], S/PA ratio ≥ 0.9 [OR = 8.1 (0.03-0.53), p = 0.03], prematurity [OR = 9.5 (0.05-0.33), p = 0.003], and shunt size/weight (S/W) ratio ≥ 1.3 [OR = 6.4 (0.04-0.67), p = 0.012] were found to have a significant impact on ST. The best combination of sensitivity and specificity of the S/W (0.73 and 0.75) and the S/PA ratio (0.73 and 0.80) were achieved at the cut-off value of 1.3 and 0.9, respectively. The Youden index of S/PA was 0.52. While the area under the curve (AUC) of the S/W ratio was 0.686 ± 0.12 (p = 0.049), the AUC of the S/PA ratio was 0.791 ± 0.08 (p = 0.002). In conclusion, instead of weight, considering the size of the target pulmonary artery and thereby, the S/PA ratio would be more instructive in determining shunt size. There were a high number of patients in our study who showed PAH having received a shunt size based on their body weight. By contrast, our results showed that the S/PA ratio of ≥ 0.9 would be a good predictor of in-hospital ST.

Effects of protocol-based management on the post-operative outcome after systemic to pulmonary shunt

Objectives

Systemic to pulmonary shunt (commonly known as Modified Blalock-Taussig shunt) is a palliative procedure in cyanotic heart diseases to overcome inadequate blood flow to the lungs. Based on the most recent risk stratification score, the mortality and morbidity of this procedure is still high especially in neonates and over-shunting patients. We developed and implemented protocol-based management in March 2013 to better standardize the management of these patients. The aim of this study is to evaluate the effects of applying this protocol-based management in our center.

Methods

We conducted a retrospective cohort study through chart review analysis.We included all children who underwent MBTS from January 2000 till December 2015. We compared the early postoperative outcome of patients operated after the protocol-based management implementation (March 2013 till December 2015) (protocol group) with patients operated before implementing the MBTS protocoled management (control group).

Results

197 patients underwent MBTS from January 2000 till December 2015. Of the 197 patients, 25 patients were in the protocol group and 172 patients were in the control group. There was a significant improvement in the postoperative course and less morbidity after protocoled management implementation as reflected in ventilation time, reintubation rate, inotropic support duration, intensive care unit ICU stay and significantly lower postoperative complications in the protocol group. Mortality of the control group versus protocol group (19.3% VS 8%) with Standardized Mortality Ratio (SMR) dropped from 2.27 before protocoled management to 0.94 after protocoled management (protocol group).

Conclusion

The study suggests that protocoled management of patients with MBTS can improve the postoperative course and early outcome.

Risk Factors for Failure of Systemic-to-Pulmonary Artery Shunts in Biventricular Circulation

Systemic-to-pulmonary artery shunt placement is an established palliative procedure for congenital heart disease, but it is associated with high morbidity and mortality. Data of all patients with biventricular circulation who underwent systemic-to-pulmonary artery shunt implantation between 2000 and 2016 were reviewed. Endpoints of the study were shunt failure and shunt-related mortality. Shunt failure was defined as any shunt dysfunction requiring intervention or reoperation. Shunt-related mortality was defined as death due to shunt dysfunction. A total of 217 shunts (central shunt, n = 131, Blalock-Taussig shunt, n = 86) were implanted in 178 patients. The median age of the patients was 98 days [1 day to 1.2 years]. Corrective surgery was performed at a median time of 0.6 years [3 months to 7 years] after shunt placement. Shunt failure was diagnosed in 21 patients (9.6%) at a median time of 14.6 days [0 days to 2 years]. Causes of shunt failure were stenosis (n = 11; 5%) and thrombosis (n = 10; 4.6%). The rate of freedom from shunt failure was 89.9 ± 2.6% at 1 year, the rate of shunt-related mortality was 3% (n = 5), and the rate of freedom from shunt-related mortality at 1 year was 97.5 ± 1%. Platelet transfusion was required in 43 patients (20%), all for postoperative thrombocytopenia. Perioperative platelet transfusion (p = 0.03) and shunt size of 3 mm (p = 0.03) were identified as risk factors for shunt failure. Shunt size of 3 mm was also identified as a risk factor for shunt-related mortality. The ideal shunt size in patients with biventricular circulation requiring a systemic-to-pulmonary artery shunt is 3.5 mm or larger. Platelet transfusion increases the risk of shunt failure and should be avoided. Type of shunt and diagnosis have no influence on morbidity or mortality after shunt placement.

Major Adverse Events Following Over-Shunting Are Associated With Worse Outcomes Than Major Adverse Events After a Blocked Systemic-to-Pulmonary Artery Shunt Procedure

OBJECTIVES

Causes of major adverse event after systemic-to-pulmonary shunt procedure are usually shunt occlusion or over-shunting. Outcomes categorized on the basis of these causes will be helpful both for quality improvement and prognostication.

DESIGN

Retrospective cohort analysis of children who underwent a systemic-to-pulmonary shunt after excluding those who had it for Norwood or Damus-Kaye-Stansel procedure.

SETTING

The Royal Children's Hospital, Melbourne, VIC, Australia.

PATIENTS

From 2008 to 2015, 201 children who had a systemic-to-pulmonary shunt were included.

INTERVENTIONS

Major adverse event is defined as one or more of cardiac arrest, chest reopening, or requirement for extracorporeal membrane oxygenation. Study outcome is a "composite poor outcome," defined as one or more of acute kidney injury, necrotizing enterocolitis, brain injury, or in-hospital mortality.

MEASUREMENTS AND MAIN RESULTS

Median (interquartile range) age was 12 days (6-38 d) and median (interquartile range) time to major adverse event was 5.5 hours (2-17 hr) after admission. Overall, 36 (18%) experienced a major adverse event, and reasons were over-shunting (n = 17), blocked shunt (n = 13), or other (n = 6). Fifteen (88%) in over-shunting group suffered a cardiac arrest compared with two (15%) in the blocked shunt group (p < 0.001). The composite poor outcome was seen in 15 (88%) in over-shunting group, four (31%) in the blocked shunt group, and 56 (34%) in those who did not experience a major adverse event (p < 0.001). By multivariable analysis, predictors for composite poor outcome were major adverse event due to over-shunting (no major adverse event-reference; over-shunting odds ratio, 18.60; 95% CI, 3.87-89.4 and shunt-block odds ratio, 1.57; 95% CI, 0.46-5.35), single ventricle physiology (odds ratio, 4.70; 95% CI, 2.34-9.45), and gestation (odds ratio, 0.84/wk increase; 95% CI, 0.74-0.96).

CONCLUSIONS

Infants who suffer major adverse event due to over-shunting experience considerably poorer outcomes than those who experience events due to shunt block. A mainly hypoxic event with maintenance of systemic perfusion (as often seen in a blocked shunt) is less likely to result in poorer outcomes than those after a hypoxic-ischemic event (commonly seen in over-shunting).

Outcomes of Blalock-Taussig shunts in current era: A single center experience

OBJECTIVES

Mortality associated with the modified Blalock-Taussig shunt (MBTS) remains high despite advanced perioperative management. This study was formulated to provide data on (1) current indications, (2) outcomes, and (3) factors affecting mortality and morbidity.

DESIGN

A retrospective single center chart review identified 95 children (excluding hypoplastic left heart lesions) requiring a MBTS. Mortality and major morbidity were analyzed using the Kaplan Meier method and risk factor analysis using Cox's proportional hazard regression.

RESULTS

Median age was 8 (0-126) days, weight 3.1(1.7-5.4) kg. Seventy-three percent were neonates, 58% duct dependent and 73% had single ventricle physiology. Ninety-seven percent had a sternotomy approach for shunt placement with 70% receiving a 3.5 mm graft. Mean graft index (shunt cross sectional area [mm² ]/BSA [m² ]) was 44.39 ± 8.04 and shunt size (mm) to body weight (kg) ratio 1.1 ± 0.2. Hospital mortality was 12%, with an interval mortality of 6%. Shunt thrombosis/stenosis occurred in 23% and pulmonary over circulation in 30%, while shunt reoperation was required in 12% and catheter intervention in 8% of the cohort. At 1-year, survival was 82.0% (95% CI [72.7%, 88.4%]), and survival free of major morbidity 61.4% (95% CI [50.7%, 70.5%]). Duct dependency predisposed to mortality (P = .01, HR 6.74 [1.54, 29.53]) and composite outcome (mortality and major morbidity) (P = .04, HR 2.15, CI [1.036, 4.466]) and higher graft index to mortality (P = .005, HR 1.07 [1.02, 1.12]).

CONCLUSIONS

The commonest indication for a MBTS in the current era was single ventricle palliation. Morbidity and mortality was considerable, partly explained by the higher at risk population. Alternative methods to maintain pulmonary blood flow in place of a MBTS requires further investigation.

Risk Factors for Thrombosis, Overshunting and Death in Infants after Modified Blalock-Taussig Shunt

BACKGROUND

The Modified Blalock-Taussig shunt procedure can provide increased flow of blood to the lungs for babies born with certain congenital heart defects. We evaluated 44 subjects under 2 years of age who had a Modified Blalock-Taussig shunt (MBTS) procedure performed from 2009-2013, to investigate risk factors for thrombosis, overshunting and death.

METHODS

The study subjects included in our investigation were severely cyanotic newborns with pulmonary stenosis or atresia and duct dependent circulation, and infants having Tetralogy of Fallot with small pulmonary arteries who underwent a MBTS procedure in our facility from 2009-2013. We duly noted patient preoperative characteristics such as hemoglobin, hematocrit, mean platelet volume, prothrombin time and partial thromboplastin time. Our study investigated the risk factors for post-operative overcirculation, thrombosis and death.

RESULTS

The age and weight of patients in our study at the time of procedure ranged from 1 day to 20 months old (median 12 days), and 2.4 kg to 12 kg (mean 4.6 kg), respectively. A total of 8 patients died following surgery, and. 4 (9.1%) had shunt thrombosis, of which one died during shunt revision. Partial thromboplastin time was 28.7 seconds in patients with thrombosis, and 35 in all other patients (p = 0.04). Overcirculation was detected in 5 patients; shunt size/body weight was 1.25 in patients who had overcirculation, and 1.06 in all other patients.

CONCLUSIONS

It is important to assess risk factors associated with the MBTS operation. The results of our study suggest that a preoperative low aPTT value may be an indicator for thrombosis in infants who have undergone MBTS surgery.

Disease-specific outcome analysis of palliation with the modified Blalock-Taussig shunt

BACKGROUND

Albeit being a simple surgical procedure, adverse outcomes with the modified Blalock-Taussig shunt (MBTS) are commonly reported in generalizing terms, independent of the underlying heart disorder.

METHODS

From August 1995 to December 2013, a total of 150 children underwent an MBTS for tetralogy of Fallot (TOF; n = 44, 29%), pulmonary atresia with ventricular septal defect (PA/VSD; n = 28, 19%), pulmonary atresia with intact ventricular septum (PA/IVS; n = 17, 11%), transposition of the great arteries with ventricular septal defect (TGA/VSD) with pulmonary stenosis (PS; n = 12, 8%), Ebstein malformation (n = 2, 1%), and complex univentricular anomalies (n = 47, 31%). Outcome analysis focused on operative mortality and survival until shunt takedown, adjusted to the underlying disease.

RESULTS

In-hospital mortality was 8.7% (n = 13), and interstage mortality was 5.1% (n = 7), resulting in 86.1% survival to the next surgery. Hospital mortality was 14% in PA/VSD, 13% in univentricular heart, and 18% in PA/IVS, while no mortality was observed in TOF, TGA/VSD/PS, and Ebstein disease. A shunt-related complication was observed in 18% (n = 27) of the children, including acute thrombosis (n = 7, 5%), shunt stenosis (n = 3, 2%), overshunting (n = 7, 5%), and pulmonary artery stenosis (n = 10, 7%). Multivariate analysis of shunt-dependent time survival identified a shunt complication occurring in a univentricular circulation (hazard ratio [HR] 4.10, 95% confidence interval [CI] = 1.05-17.43, P = .01) and increased shunt size-to-weight ratio (HR 2.72, 95% CI = 0.80-9.18, P = .04) as risk factors. Shunt thrombosis was also a negative outcome predictor in PA/VSD, when requiring associated unifocalization (P = .05).

CONCLUSION

This study shows that the outcome of palliation with the MBTS is importantly affected by the occurrence of a shunt-related complication, whose circulatory effect is even more dismal in single ventricle hearts. Since an increased shunt size-to-weight ratio additionally compromises the shunt-dependent survival, it emphasizes that the choice of the shunt with regard to size as well as surgical approach remains critical.

Numerical simulation and hemodynamic analysis of the modified Blalock-Taussig shunt

The modified Blalock-Taussig (mB-T) shunt is an effective palliative surgical method in the treatment of cyanotic congenital heart diseases. It increases the pulmonary blood flow through an implanted shunt between systemic and pulmonary arteries. The surgical technique improved over the years. However, it is still a challenge to control appropriate distribution of blood flow through this shunt after this kind of procedure till now. Here, we report on the method of computational fluid dynamics (CFD) for the hemodynamic studies of a patient-specific case after the mB-T shunt. The analysis system that we validated previously in the studies of the Norwood procedure was applied to predict the hemodynamic characteristics in the mB-T hunt area. The real-time velocities derived from Echocardiography measurements and the blood pressure wave reflections from peripheral vessels were utilized as boundary conditions to physiologically capture the blood flow information in the simulation. The local pressure, blood flow distribution and wall shear stress were calculated. The results suggest pressure decreases greatly through the shunt and around 40% of blood flow is distributed from the systemic circulation to pulmonary arteries in one cardiac cycle. These indict computational hemodynamics may be applied in future studies of establishing quantitative standards to evaluate the outcomes of the mB-T shunt and to optimize the implantation of the mB-T shunt in virtual surgeries.

MEDICAL IMAGE-BASED HEMODYNAMIC ANALYSIS FOR MODIFIED BLALOCK–TAUSSIG SHUNT

Modified Blalock–Taussig (mB–T) shunt is an effective palliative surgical method in the treatment of cyanotic congenital heart diseases. Although the surgical technique has improved over the years, it is still a challenge to control appropriate blood flow through the conduit. The formation of thrombosis in the conduit after the mB–T shunt may lead to severe desaturation or reoperation in some cases. Here, we applied the method of computational fluid dynamics (CFD) to study a patient-specific case based on medical images after the mB–T shunt. The real-time velocities derived from echocardiography and the pulsatile pressure waves measured during the operation were utilized as boundary conditions to physiologically capture the blood flow information in simulation. The calculated results were coincident with clinical measurements. Local pressure, blood flow distribution, streamlines, wall shear stress (WSS) and centrifugal force in the bended conduit were investigated. The results indicate that pressure decreases greatly through the conduit. The combined action of pulsatile pressure and WSS may lead to the damage of blood cells. The computational hemodynamics can be applied in future studies of establishing quantitative standards to evaluate surgical outcomes of the mB–T shunt.

Strictly-posterior thoracotomy: a minimal-access approach for construction of the modified Blalock-Taussig shunt in West African children

Introduction

In resource-poor settings, the modified Blalock-Taussig shunt (MBTS) is often performed for symptomatic relief of Fallot's tetralogy. From September 2011, we adopted the strictly posterior thoracotomy (SPOT), a minimal-access technique for the MBTS and report the cosmetic advantages in this communication.

Methods

We retrospectively analyzed the records of consecutive patients in whom the SPOT approach was used to construct the MBTS. Study end-points were early mortality, improvement in peripheral oxygenation, morbidity, and the cosmetic appeal.

Results

Between September 2011 and January 2013, 15 males and 8 females, median age 4 years (1.3 - 17 years) and weight 13 kg (11 - 54 kg) underwent the MBTS through the SPOT approach. The polytetrafluoroethylene grafts used ranged from sizes 4 - 6mm (median 5mm). The median preoperative SpO2 was 74% (55% - 78%), increasing to a postoperative median value of 84% (80% - 92%). Shunts were right-sided in 22 patients and left-sided in one. There were no shunt failures. Hospital stay ranged from 7 - 10 days. There was one early death (4.3%), and two postoperative complications (re-exploration for bleeding and readmission for drainage of pleural effusion). The surgical scars had excellent cosmetic appeal: they ranged from 5-10 cm in length; all were entirely posterior and imperceptible to the patient.

Conclusion

The SPOT approach represents a safe and cosmetically superior alternative to the standard posterolateral thoracotomy, the scar being imperceptible to the patient. The excellent cosmetic appeal and preservation of body image makes this approach particularly attractive in children and young adults.

Is sternotomy superior to thoracotomy for modified Blalock-Taussig shunt?

A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was: is sternotomy approach superior to a thoracotomy approach for a modified Blalock-Taussig shunt procedure? More than 58 papers were found using the search as described below, of which 11 papers represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. Three of seven papers compared the sternotomy and thoracotomy approaches. The operative approach was a significant predictor of shunt failure. The criterion used to define early shunt failure was either the complete occlusion during hospitalization or the need to return to the operating room for a second shunt. The studies that compared the thoracotomy and sternotomy approaches observed increased shunt failure rates in the thoracotomy group. The sternotomy approach was associated with advantages like less pulmonary artery distortion, ease of technical performance, cosmetic advantage of a single sternotomy incision, ease of ligation of patent ductus, less phrenic nerve injury, less collateral formation in chest wall adhesions and less thoracotomy induced scoliosis. However, other papers studied either the sternotomy approach only or the thoracotomy approach and drew conclusions regarding risk factors for operative morbidity and mortality. We conclude that the sternotomy approach is beneficial to neonates and infants undergoing modified Blalock-Taussig shunt when compared with the conventional thoracotomy approach.

Outcomes of systemic to pulmonary artery shunts in patients weighing less than 3 kg: analysis of shunt type, size, and surgical approach

OBJECTIVE

To evaluate outcomes of systemic to pulmonary artery shunts (SPS) in patients weighing less than 3 kg with regard to shunt type, shunt size, and surgical approach.

METHODS

Patients weighing less than 3 kg who underwent modified Blalock-Taussig or central shunts with polytetrafluoroethylene grafts at our institution from January 1, 2000, to May 31, 2011, were reviewed. Patients who had undergone other major concomitant procedures were excluded from the analysis. Primary outcomes included mortality (discharge mortality and mortality before next planned palliative procedure or definitive repair), cardiac arrest and/or extracorporeal membrane oxygenation (ECMO), and shunt reintervention.

RESULTS

In this cohort of 80 patients, discharge survival was 96% (77/80). Postoperative cardiac arrest or ECMO occurred in 6/80 (7.5%), and shunt reintervention was required in 14/80 (17%). On univariate analysis, shunt reintervention was more common in patients with 3-mm shunts (11/30, 37%) compared with 3.5-mm (2/36, 6%) or 4-mm shunts (1/14, 7%) (P < .003). There were no statistically significant associations between shunt type, shunt size, or surgical approach and cardiac arrest/ECMO or mortality. Multiple logistic regression demonstrated that a shunt size of 3 mm (P = .019) and extracardiac anomaly (P = .047) were associated with shunt reintervention, whereas no variable was associated with cardiac arrest/ECMO or mortality.

CONCLUSIONS

In this high-risk group of neonates weighing less than 3 kg at the time of SPS, survival to discharge and the next planned surgical procedure was high. Outcomes were good with the 3.5- and 4-mm shunts; however, shunt reintervention was common with 3-mm shunts.

Optimal Initial Palliation for Patients With Functionally Univentricular Hearts

This review will outline the optimal, initial palliation for children who are born with a functionally univentricular heart. Optimizing the initial palliation is of critical importance in this patient population to prevent potential problems such as systemic outflow and pulmonary vein obstruction that may complicate further surgical intervention. The palliative techniques that are discussed include pulmonary artery banding, modified Blalock-Taussig shunt, Damus-Kaye-Stansel procedure, modified Norwood, hybrid, and early bidirectional Glenn. Our recommendations for optimal palliation for children with a univentricular heart are based on our experience with nearly 200 patients who had either a lateral tunnel or extracardiac Fontan procedure and 130 patients who had Fontan conversion with arrhythmia surgery.

A novel provisional aortopulmonary shunt may help avoid neonatal cardiopulmonary bypass: report of two cases

A novel temporary aortopulmonary shunt, constructed between the aorta and main pulmonary artery with flexible cannulas, was used to facilitate right ventricular outflow tract reconstruction in one neonate and creation of a central aortopulmonary shunt in a second neonate. Although cardiopulmonary bypass is readily available in Turkey, the strategy described in the case report may prove especially useful in developing nations with limited access to cardiopulmonary bypass (CPB).

A comparison of Blalock-Taussig shunts with and without closure of the ductus arteriosus in neonates with pulmonary atresia

BACKGROUND

The question of whether to close the patent ductus arteriosus when performing primary modified Blalock-Taussig (MBT) shunt surgery in neonates is still not clearly answered. The aim of this report was to compare the results of closure versus nonclosure of the patent ductus arteriosus during MBT shunt surgery in neonates with pulmonary atresia.

METHODS

This retrospective study included neonates with pulmonary atresia who underwent primary MBT shunt surgery through a sternotomy approach at our institution between January 1997 and October 2010. Mortality, resuscitation events, and the need for reintervention within the first 48 postoperative hours were studied as primary outcomes.

RESULTS

Sixty-two neonates (mean age 6.9±5.5 days) underwent a MBT procedure. The arterial duct was closed surgically in 31 patients, and left open in 31 patients. Compared with patients in whom the PDA was left open, patients with a surgically closed arterial duct had a higher incidence of resuscitation events (29.0% versus 0%, p=0.0012), reinterventions (35.5% versus 3.2%, p=0.0013), and higher early hospital mortality (9.7% versus 0%, p=0.038). Time to extubation and length of hospital stay did not differ between the two groups (p=0.16 and p=0.73, respectively). A trend toward a higher maximum vasoactive-inotropic score in the group with a closed duct was observed (median 13.5 versus 10, p=0.10).

CONCLUSIONS

In newborns with pulmonary atresia, ductal closure during MBT shunt procedure is associated with increased incidence of resuscitation events, need for reintervention, and increased mortality during the early postoperative period.

Sternotomy Approach for Modified Blalock-Taussig Shunt: Is it a Safe Option?

Central aorta-pulmonary artery shunts have fallen into disfavor because of shunt thrombosis and congestive heart failure, and a modified Blalock-Taussig shunt via thoracotomy can lead to pulmonary artery hypoplasia and distortion. We reviewed the outcomes of a modified Blalock-Taussig shunt by a sternotomy approach in 20 infants from July 2007 to October 2009. Their mean age was 5.79 months, and median weight was 5.4 kg. A 4-mm graft was placed in 11 patients, a 5-mm graft in 8, and a 3.5-mm graft in 1. There was no incidence of sepsis, seroma, or phrenic nerve palsy. There was one hospital death. The mean hospital stay was 10.4 ± 4.3 days (range, 8–15 days). The mean oxygen saturation at discharge was 89% (range, 81%–93%). The sternotomy approach is technically easier to perform, cosmetically preferable, and probably hemodynamically superior. Correction of branch pulmonary stenosis is easily incorporated into this procedure. The theoretical disadvantage of this method is a potential technical difficulty with sternal reentry for subsequent procedures.

Outcome in infants less than 3 kilograms for placement of saphenous venous homografts as systemic-to-pulmonary arterial shunts

BACKGROUND

Establishing stable and adequate flow of blood to the lungs using a systemic-to-pulmonary arterial shunt in infants with low birth weight may involve significant morbidity and mortality. We reviewed our experience with this procedure in patients weighing less than 3 kilograms.

METHODS

Between June, 2002, and June, 2007, we placed systemic-to-pulmonary arterial shunts in 32 infants weighing less than 3 kilograms, the range being 1.8 to 2.86 kg, with a median of 2.5 kg. The median age at placement of the shunt was 8 days, with a range from 2 to 70 days. In 17 patients (53%), the anatomic defects had produced a functionally univentricular heart, while 15 (47%) had defects which permitted staging to biventricular repair. Patients staged to univentricular palliation were much more likely to have a circulation dependent on the arterial duct as compared with those staged to biventricular palliation (p < 0.001). The latter patients tended to have smaller pulmonary arteries, significantly the left pulmonary artery, which has a median diameter of 3.6 versus 2.0 mm, p = 0.01. In all patients a saphenous venous homograft was used as the conduit, its size ranging in diameter from 2.5 to 4 mm, with a median of 3.0 mm.

RESULTS

The overall hospital mortality rate for the entire cohort was 6.25%, with 2 patients dying. There was no significant difference between the two groups with regard to length of stay in intensive care or hospital. Follow-up has ranged from 3 months to 4.7 years, with a mean of 2.1 years). Of those with functionally univentricular hearts, 3 have subsequently died, along with 1 patient having a biventricular circulation (p = 0.3). All deaths occurred before takedown of the shunt. A trend toward longer survival was noted in those with biventricular as compared to functionally univentricular circulations (p = 0.06).

CONCLUSION

Systemic-to-pulmonary arterial shunts can be constructed safely in infants with biventricular physiology born with low weight. Those having functionally univentricular circulations carry an increased rate of mortality for the period of shunting. Using the saphenous venous homograft permits use of smaller grafts, which does not significantly increase the risk for thrombosis or survival when compared to previous studies using polytetrafluoroethylene grafts.

Ductus-associated proximal pulmonary artery stenosis in patients with right heart obstruction

Proximal pulmonary artery stenosis is a common acquired lesion in infants treated for congenital heart disease. We hypothesized that a large number of stenoses develop at the site of ductal insertion in patients with right ventricular outflow tract obstruction (RVOTO) and that these patients are at risk for developing hypoplasia of the ipsilateral pulmonary artery. The surgical and cardiac catheterization databases at our institution during the years 1988-2000 were searched for all patients under 1 year of age carrying a diagnosis of pulmonary atresia with intact ventricular septum (PA), tetralogy of Fallot (TOF) or pulmonary stenosis (PS), yielding 700 patients (62 PA, 373 TOF, 265 PS). The cardiac catheterization database was also searched for all patients with any diagnosis under 1 year of age found at catheterization to have proximal pulmonary artery stenosis. Proximal pulmonary artery stenosis associated with the ductal insertion site was diagnosed at catheterization in 33 infants (18 with PA, 5 with TOF, 6 with PS, 4 other diagnoses). This represents 29% of patients with PA, 1% with TOF and 2% with PS. Among patients with RVOTO and ductal insertion site-associated stenosis, there was a high prevalence (59%) of associated distal pulmonary arterial hypoplasia, defined as diameter of the stenosed vessel at first distal branch < or = 80% the diameter of the contralateral vessel. Symptomatology failed to identify this lesion; therefore, a high index of suspicion is necessary if proximal pulmonary artery stenosis is to be detected early in these patients.

Radiofrequency perforation in the treatment of acquired left pulmonary artery atresia following repair of tetralogy of Fallot

Acquired pulmonary artery discontinuity can complicate operative repair of certain congenital heart defects. We describe successful recanalization of acquired left pulmonary artery atresia using radiofrequency energy in a 14-month-old child who had previously undergone repair of tetralogy of Fallot with pulmonary atresia.

Reducing the trauma of congenital heart surgery

While describing the circulatory system in De Moto Cordis, in 1628, William Harvey developed precepts for investigation, which could be modified slightly to guide the adoption of new technology and technique in the twenty-first century. Harvey might suggest (1) careful and accurate observation and description of a new technique, (2) a tentative explanation of how the technique improves on existing techniques, (3) a controlled testing of the hypothesis, and (4) conclusions based on the results of the experiments. Also, he might admonish surgery today, with its massively enhanced capabilities for information management, to rigorously test the validity of these conclusions with quantitative reasoning. In the future, precise measurement of the "trauma" of surgery, or even an individual surgeon, may be possible, and the long-term impact of a chest wall incision on a patient's self-esteem may be predictable. Absent such objective measures, justifications for "minimally invasive" deviations from conventional technique in surgery for CHD lack substance. Morbidity, mortality, and physiological endpoints will continue to form the foundation for therapeutic plans; however, the potential for emerging technology to reduce the trauma of these plans remains tantalizing.

Systemic pulmonary shunts in neonates: early clinical outcome and choice of surgical approach

BACKGROUND

Systemic pulmonary shunt remains a major strategy for the palliation of cyanotic lesions in neonates despite the associated morbidity and mortality.

METHODS

Between March 1993 and December 1998, 79 systemic pulmonary shunts were performed in 75 neonates with cyanosis and severely reduced pulmonary blood flow. The mean age was 11.5 days and the mean weight, 3 kg. All neonates were dependent on duct flow and prostaglandin E1 infusion for adequate oxygenation.

RESULTS

The systemic pulmonary shunt was performed through a right thoracotomy in 36 patients, left thoracotomy in 6, and median sternotomy in 33 patients. The 30-day mortality was 3 patients (4%). Univariate and logistic regression analyses revealed a weight less than 2 kg (p = 0.039) and preoperative mechanical ventilation (p = 0.008), to be predictors of early mortality, whereas pulmonary hypoplasia (p = 0.55), diagnostic group (p = 0.79), shunt size (p = 0.2), and surgical approach (p = 0.5) were not. There were seven episodes of shunt-related complications that required early intervention.

CONCLUSIONS

Systemic pulmonary shunt remains an effective palliative measure in cyanotic neonates despite specific complications. Both low weight and preoperative ventilation represent significant risk factors for early mortality.

Pulmonary artery stenosis after systemic-to-pulmonary shunt operations

OBJECTIVE

Systemic-to-pulmonary shunt operations are still required for palliation of certain congenital heart defects. The aim of this study was to analyze the incidence and etiology of the development of pulmonary artery stenosis after these procedures.

METHODS AND RESULTS

Pre- and post-operative angiograms of 59 patients who underwent 54 peripheral and 12 central shunt operations were analyzed retrospectively. Patients without prior cardiovascular interventions (group I, n = 47) were differentiated from patients with prior interventions (group II, n = 12). In group I, all peripheral shunts were inserted contralaterally to the ductus arteriosus. Follow-up for all patients was 1.8 years (4 days-7.8 years). Pulmonary artery stenosis was diagnosed in 12/59 patients (20.3%, group I 12/47; group II 0) after a time interval of 4 days up to 5.3 years and only after Blalock-Taussig shunts (one classical, 11 modified) (12/40 = 30%). The stenoses were located ipsilaterally to the shunt in 7/12 and contralaterally in 5/12. Statistical analysis did not show any impact of age, weight, sex, shunt type or size, pulmonary artery diameters, Nakata and McGoon indices and prior interventions on the development of pulmonary artery stenosis. However, a patent ductus arteriosus and administration of Prostaglandin E1 had a significant impact on the development of pulmonary artery stenosis on the side of the ductus arteriosus.

CONCLUSION

Pulmonary artery stenosis is not a rare event after systemic-to-pulmonary shunt operations. A patent ductus arteriosus with or without administration of Prostaglandin E1 is related to pulmonary artery stenosis on the side of the ductus arteriosus. Pulmonary artery stenosis on the side of a peripheral shunt may be caused by inappropriate surgical technique, increased intimal proliferation, or pulmonary artery kinking. Treatment depends on severity of cyanosis and on further surgical plans.