Risk factors for acute shunt blockage in children after modified Blalock-Taussig shunt operations

Outcomes and Predictors of Failure of Systemic-to-Pulmonary Shunts: Experience of a Single Institution Over 14 Years

BackgroundSystemic artery-to-pulmonary artery (SA-PA) shunts provide effective palliation for complex congenital heart disease (CHD) but carry a risk for morbidity and mortality. We aimed to comprehensively analyze our experience with SA-PA shunts.MethodsOur institutional Society of Thoracic Surgeons (STS) database was queried to identify patients who underwent SA-PA shunts from 2009 to 2022, excluding those who underwent the Norwood procedure, right ventricle-PA shunt, or fenestrated patch. Definitions from the STS Congenital Heart Surgery Database Specifications were used. Shunt failure included dysfunction secondary to thrombosis, obstruction, stenosis, or outgrowth requiring intervention.ResultsA total of 287 patients met inclusion criteria. Shunts were placed at a median of 15.0 days (interquartile range 7.0-39.5). A thoracotomy approach was used in 178 out of 287 patients (62.0%), and cardiopulmonary bypass was employed in only 46 of 287 cases (16.0%). Survival to the next stage was 89.5% (246/275), with in-hospital mortality of 6.3% (18/287) and interstage mortality of 4.2% (12/287). Shunt failure occurred in 54/287 (18.8%), and 77/287 (26.8%) required reintervention for shunt-related complications. On multivariable analysis, poorer shunt failure-free survival was associated with any syndrome, left-sided arch vessel shunt origin, concurrent complex repairs, competitive flow from a patent ductus arteriosus, and delayed antiplatelet initiation. The thoracotomy approach was protective. Risk factors for worse survival to the next stage included shunt thrombosis and perioperative platelet transfusion.ConclusionsWhile complications remain common, our contemporary results demonstrate that SA-PA shunts remain a reliable palliation for CHD with insufficient pulmonary blood flow. Risk reduction may involve careful management of competitive pulmonary blood flow and prompt initiation of antiplatelet therapy.

Exploratory Use of Glycoprotein IIb/IIIa Inhibition in Prevention of Blalock-Taussig Shunt Thrombosis

OBJECTIVES

Morbidity and mortality related to modified Blalock-Taussig shunt (mBTTS) thrombosis remain a significant risk. Platelet inhibition following mBTTS may reduce this risk. However, oral antiplatelet agents have variable absorption following surgery. We determine risk factors for mBTTS thrombosis and hypothesize that IV glycoprotein IIb/IIIa inhibitor (tirofiban) as a bridge to oral aspirin reduces the rate of shunt thrombosis in the immediate postoperative period. End points within the 14-day follow-up period include mBTTS thrombosis, overall thrombosis, bleeding, length of stay, and mortality.

DESIGN

Retrospective, Institutional Review Board-approved cohort study.

SETTING

Single-center cardiac ICU.

PATIENTS

Patients under the age of 18 who had an mBTTS placed within the study period of January 2008 to December 2018 were included.

INTERVENTIONS

Patients were divided into two groups: standard of care (SOC) anticoagulation alone and SOC with tirofiban as a bridge to oral aspirin.

MEASUREMENTS AND MAIN RESULTS

Freedom from mBTTS thrombosis was estimated using the Kaplan-Meier method. A multivariable predictive model using the four most significant risk factors was developed using logistic regression. A total of 272 patients were included: 36 subjects in the SOC/tirofiban group and 236 in the SOC group. Shunt thrombosis occurred in 26 (11%) SOC group with zero in SOC/tirofiban group ( p = 0.03). The median time to thrombosis was 0 days (range, 0-12 d). The area under the curve for the predictive model (anticoagulation group, history of coagulopathy, intraoperative shunt clipping, and shunt size/weight ratio) is 0.790 ( p < 0.001). Prevalence of bleeding and mortality was not significantly different between the groups.

CONCLUSIONS

Highest risk for shunt thrombosis following mBTTS occurs within the first few days after surgical procedure. Tirofiban is a safe addition to SOC and may be an effective strategy to prevent early mBTTS thrombosis.

Current evidence for pharmacologic therapy following stage 1 palliation for single ventricle congenital heart disease

INTRODUCTION

Infants with single ventricle congenital heart disease are vulnerable to complications between stage 1 and stage 2 of palliation. Pharmaceutical treatment during this period is varied and often dependent on institutional practices as there is little evidence supporting a particular treatment path.

AREAS COVERED

This review focuses on medical management of patients following stage I palliation. We performed a scoping review of the current literature regarding angiotensin converting enzyme inhibitors and digoxin treatment in the interstage period. In addition, we discuss other medication classes frequently used in these patients.

EXPERT OPINION

Due to significant heterogeneity of anatomy, rarity of disease, and other confounding factors, there is limited evidence to support most commonly used medications within the interstage period. Digoxin is associated with improved mortality within the interstage period and should be considered; however, no large randomized controlled trial exists supporting its use. Prevention of thrombotic complication with aspirin is also associated with improved outcomes and should be considered unless a contraindication exists. The addition of other prescriptions in this patient population should be considered only after an evaluation of the risks and benefits of each medication, recognizing the burden and risk of polypharmacy in this fragile patient population.

Impact of Medical Interventions and Comorbidities on Norwood Admission for Patients with Hypoplastic Left Heart Syndrome

The purpose of these analyses was to determine how specific comorbidities and medical interventions impact risk of inpatient mortality in those with hypoplastic left heart syndrome undergoing Norwood procedure. The secondary aims were to determine the impact of these on billed charges, postoperative length of stay, and risk of cardiac arrest. Admissions from 2004 to 2015 in the Pediatric Health Information System database with hypoplastic left heart syndrome and Norwood procedure were identified. Admission characteristics, patient interventions, and the presence of comorbidities were captured. A total of 5,138 admissions were identified meeting inclusion criteria. Of these 829 (16.1%) experienced inpatient mortality, and 352 (6.7%) experienced cardiac arrest. The frequency of inpatient mortality did not significantly change over the course of the study era. The frequency of cardiac arrest significantly decreased from 7.4% in 2004 to 4.3% in 2015 (p = 0.04). The frequency of pharmacologic therapies, particularly vasoactive use, decreased as the study period progressed. Regression analyses demonstrated a significant association between cardiac arrest and inpatient mortality with arrhythmias, acute kidney injury, and pulmonary hypertension. Similarly, regression analyses demonstrated a significant association between increase in billed charges and length of stay with year of surgery, presence of heart failure, syndromes, and acute kidney injury. For patients with hypoplastic left heart syndrome undergoing the Norwood procedure, the frequency of pharmacologic therapies and cardiac arrest has decreased over time. There are significant associations between acute kidney injury, arrythmias, and pulmonary hypertension with cardiac arrest and mortality.

Predictors of Neurological Outcome Following Infant Cardiac Surgery Without Deep Hypothermic Circulatory Arrest

The aim of this study is to describe the clinical characteristics, perioperative course and neuroimaging abnormalities of infants with congenital heart disease (CHD) undergoing heart surgery without deep hypothermic circulatory arrest (DHCA) and identify variables associated with neurological outcome. Infants with CHD undergoing open-heart surgery without DHCA between 2009 and 2017 were identified from a cardiac surgery database. Full-term infants < 10 weeks of age at the time of surgery who had both a pre- and postoperative brain magnetic resonance imaging exam (MRI) were included. Clinical characteristics and perioperative variables were collected from the electronic medical record. Brain Injury Scores (BIS) were assigned to pre- and postoperative brain MRIs. Variables were examined for association with neurological outcome at 12 months of age or greater. Forty-two infants were enrolled in the study, of whom 69% (n = 29) had a neurological assessment ≥ to 12 months of age. Adverse neurological outcome was associated with longer intensive care unit (ICU) stay (P = 0.003), lengthier mechanical ventilation (P = 0.031), modified Blalock-Taussig (MBT) shunt procedure (P = 0.005) and postoperative seizures (P = 0.005). Total BIS scores did not predict outcome but postoperative infarction and/or intraparenchymal hemorrhage (IPH) was associated with worse outcome by multivariable analysis (P = 0.018). Infants with CHD undergoing open-heart surgery without DHCA are at increased risk of worse neurological outcome when their ICU stay is prolonged, mechanical ventilation is extended, MBT shunt is performed or when postoperative seizures are present. Cerebral infarctions and IPH on postoperative MRI are also associated with worse outcome.

Anterograde blood flow associated with modified Blalock-Taussig shunt does not modify pulmonary artery growth compared with modified Blalock-Taussig shunt alone

BACKGROUND

The main difference between extreme tetralogy of Fallot (TOF) and pulmonary atresia with ventricle septal defect (PA/VSD) is anterograde pulmonary blood flow (APBF). It is speculated that the association of modified Blalock-Taussig shunt (mBTS) with APBF favours shunt thrombosis, but promotes better pulmonary artery growth.

AIM

To compare pulmonary artery growth after mBTS between TOF and PA/VSD.

METHODS

From 1995 to 2018, 77 mBTS procedures were performed in infants (aged<1 year): 45 for TOF; 32 for PA/VSD. Using a 1/1 propensity score-matched analysis, 38 patients were included (19 per group). Delta Nakata was defined as the difference in the Nakata index before biventricular repair and before mBTS.

RESULTS

After matching, the preoperative Nakata index was similar in the two groups (TOF 101±34 vs. PA/VSD 106±35 mm²/m²; P=0.75). Age and weight were similar (TOF 24±20 days, 3.3±0.6kg vs. PA/VSD 24±33 days, 3.3±0.9kg; P=0.84 and P=0.77, respectively). There was no difference in rates of in-hospital mortality (TOF 0% vs. PA/VSD 10%; P=0.13) or mBTS thrombosis (TOF 15% vs. PA/VSD 10%; P=0.63). The left and right pulmonary artery diameters at time of biventricular repair were similar (TOF 7.5±2.2 and 6.7±2.1 vs. PA/VSD 8±2.7 and 7.1±2.5mm; P=0.43 and P=0.78, respectively), as were delta Nakata (TOF 112±102 vs. PA/VSD 107±66 mm²/m²; P=0.89), median age for biventricular repair (P=0.83) and reintervention rates (TOF 10% vs. PA/VSD 15%; P=0.67).

CONCLUSIONS

We found no difference in pulmonary artery growth between APBF with mBTS versus mBTS alone. Thus, we could not show an increase in mBTS thrombosis with APBF.

Predictors of death after receiving a modified Blalock-Taussig shunt in cyanotic heart children: A competing risk analysis

Objective

To determine risk factors affecting time-to-death ≤90 and >90 days in children who underwent a modified Blalock-Taussig shunt (MBTS).

Methods

Data from a retrospective cohort study were obtained from children aged 0–3 years who experienced MBTS between 2005 and 2016. Time-to-death (prior to Glenn/repair), time-to-alive up until December 2017 without repair, and time-to-progression to Glenn/repair following MBTS were presented using competing risks survival analysis. Demographic, surgical and anesthesia-related factors were recorded. Time-to-death ≤90 days and >90 days was analyzed using multivariate time-dependent Cox regression models to identify independent predictors and presented by adjusted hazard ratios (HR) and 95% confidence intervals (CI).

Results

Of 380 children, 119 died, 122 survived and 139 progressed to Glenn/repair. Time-to-death probability (95% CI) within 90 days was 0.18 (0.14–0.22). Predictors of time-to-death ≤90 days (n = 63) were low weight (<3 kg) (HR 7.6, 95% CI:2.8–20.4), preoperative ventilator support (HR 2.7, 95% CI:1.3–5.6), postoperative shunt thrombosis (HR 5.0, 95% CI:2.4–10.4), bleeding (HR 4.5, 95% CI:2.1–9.4) and renal failure (HR 4.1, 95% CI:1.5–10.9). Predictors of time-to-death >90 days (n = 56) were children diagnosed with pulmonary atresia with ventricular septal defect and single ventricle (compared to tetralogy of fallot) (HR 3.2, 95% CI:1.2–7.7 and HR 3.1, 95% CI:1.3–7.6, respectively), shunt size/weight ratio >1.1 vs <0.65 (HR 6.8, 95% CI:1.4–32.6) and longer duration of mechanical ventilator (HR 1.002, 95% CI:1.001–1.004). Shunt size/weight ratio ≥1.0 (vs <1.0) and ≥0.65 (vs <0.65) were predictors for overall time-to-death in neonates and toddlers, respectively (HR 13.1, 95% CI:2.8–61.4 and HR 7.8, 95% CI:1.7–34.8, respectively).

Conclusions

Perioperative factors were associated with time-to-death ≤90 days, whereas particular cardiac defect, larger shunt size/weight ratio, and longer mechanical ventilation were associated with time-to-death >90 days after receiving MBTS. Larger shunt size/weight ratio should be reevaluated within 90 days to minimize the risk of shunt over flow.

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.

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&lt;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.

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).

Effect of modified Blalock-Taussig shunt anastomosis angle and pulmonary artery diameter on pulmonary flow

OBJECTIVE

This study aimed to identify the best graft-to-pulmonary artery (PA) anastomosis angle measuring pulmonary blood flow, wall shear stress (WSS), and shunt flow.

METHODS

A tetralogy of Fallot with pulmonary atresia computer model was used to study three different modified Blalock-Taussig shunt (mBTS) anastomosis angle configurations with three different PA diameter configurations. Velocity and WSS were analyzed, and the flow rates at the right PA (RPA) and left PA (LPA) were calculated.

RESULTS

A 4-mm and 8-mm diameter of RPA and LPA, respectively with vertical shunt angle produces the highest total flow. In the RPA larger diameter than the LPA configutations, the left-leaning shunt produces the lowest total PA flow whereas in the LPA larger diameter than the RPA configuratios, the right-leaning shunt produces the lowest total PA flow. Therefore, the shunt anastomosis should not be leaned through the narrow side of PA to reach best flow. As the flow inside the shunt increased, WSS also increased due to enhanced velocity gradients.

CONCLUSION

The anastomosis angle between the conduit and PA affects the flow to PA. Vertical anastomosis configurations increase the total PA flow; thus, these configurations are preferable than the leaned configurations.

Stem Cell Therapy for Congenital Heart Disease: A Systematic Review

BACKGROUND

Congenital heart disease (CHD) constitutes the most prevalent and heterogeneous group of congenital anomalies. Although surgery remains the gold standard treatment modality, stem cell therapy has been gaining ground as a complimentary or alternative treatment option in certain types of CHD. The aim of this study was to present the existing published evidence and ongoing research efforts on the implementation of stem cell-based therapeutic strategies in CHD.

METHODS

A systematic review was conducted by searching Medline, ClinicalTrials.gov, and the Cochrane library, along with reference lists of the included studies through April 23, 2017.

RESULTS

Nineteen studies were included in this review (8 preclinical, 6 clinical, and 5 ongoing trials). Various routes of cardiac stem cell delivery have been reported, including intracoronary, intramyocardial, intravenous, and epicardial. Depending on their origin and level of differentiation at which they are harvested, stem cells may exhibit different properties. Preclinical studies have mostly focused on modeling right ventricle dysfunction or failure and pulmonary artery hypertension by using pressure or volume overload in vitro or in vivo. Only a limited number of clinical trials on patients with CHD exist, and these primarily focus on hypoplastic left heart syndrome. Cell-based tissue engineering has recently been introduced, and research currently is focusing on developing cell-seeded grafts and patches that could potentially grow in parallel with whole body growth once implanted in the heart.

CONCLUSIONS

It seems that stem cell delivery to the diseased heart as an adjunct to surgical palliation may provide some benefits over surgery alone in terms of cardiac function, somatic growth, and quality of life. Despite encouraging preliminary results, stem cell therapies for patients with CHD should only be considered in the setting of well-designed clinical trials. More wet laboratory research experience is needed, and translation of promising findings to large clinical studies is warranted to clearly define the efficacy and safety profile of this alternative and potentially groundbreaking therapeutic approach.

Incidence and Management of Thrombotic and Thromboembolic Complications Following the Norwood Procedure: A Systematic Review

Background:

The stage 1 Norwood procedure and its variants represent the first step of palliation for hypoplastic left heart syndrome. Although appropriate postoperative thromboprophylaxis is integral, significant variance remains across institutional practices. The purpose of this systematic review is to estimate the incidence of thrombosis and thromboembolism following the Norwood or modified Blalock-Taussig shunt procedure and examine current thromboprophylaxis regimens.

Methods:

Ovid MEDLINE and Embase were searched from January 2000 to June 2016 for primary studies explicitly reporting incidence of thrombosis, thromboembolism (strokes and pulmonary embolisms), or shunt occlusion in neonates, infants, and children undergoing the Norwood procedure or any variant. All-cause mortality was a secondary outcome of interest.

Results:

Of 887 identified articles, 15 cohort studies were deemed eligible, the majority including modified Blalock-Taussig shunt patients. Reported incidence of thrombosis ranged from 0% to 40%; thromboembolic events were rarely reported. Overall mortality ranged from 4.5% to 31.3% across studies. Although most studies involved the long-term acetylsalicylic acid use, thromboprophylaxis strategies varied across studies. Due to substantial variability in event rates, no correlation was identified with thrombotic complications.

Discussion:

Clinical practice guidelines recommend that patients receive intraoperative unfractionated heparin therapy and either aspirin or no antithrombotic therapy postoperatively. Our findings suggest a substantial risk of thrombosis and thromboembolism and demonstrate substantial variation in thromboprophylaxis practices.

Conclusion:

Although postoperative thromboprophylaxis seems optimal, it remains controversial whether the long-term aspirin use is most effective. Our findings highlight the lack of a gold-standard thromboprophylaxis strategy and emphasize the need for more consistency.

Role of thrombophilia factors in acute systemic-pulmonary shunt obstruction

BACKGROUND

Systemic-pulmonary shunts are widely used in initial palliation in cyanotic congenital heart disease. The incidence and the relationship between acute shunt obstruction and thrombophilia are not precisely defined. The aim of this study was to determine the frequency of shunt obstruction in the early postoperative period, and to define the frequency and presence of thrombophilia factors in patients treated for acute shunt thrombosis.

METHODS

Between October 2010 and October 2012, 77 patients who had systemic-pulmonary shunt operation were included in this prospective study. Patients who developed shunt obstruction were examined in terms of inherited and acquired thrombophilia factors.

RESULTS

Median patient age was 61 days and median weight was 4.3 kg. Thirty-three patients were neonates. Diameter of the Gore-Tex grafts used for the shunt ranged from 3 mm to 5 mm. Acute shunt occlusion rate was 10% (8/77), and all of these occurred in the first 24 h. Thrombophilia was found in three of eight patients who underwent intervention (surgical and/or transcatheter) due to shunt thrombosis (presence of anti-phospholipid antibodies, n = 1; protein C deficiency, n = 1; and factor V Leiden mutation, n = 1) and only one patient died.

CONCLUSIONS

Acute shunt obstruction developed in 10% of patients who underwent systemic-pulmonary shunt, and emergency surgery or transcatheter intervention can be life saving in this context. Acute shunt obstruction can occur due to mechanical and hemodynamic problems, but clinicians should also consider and evaluate thrombophilia factors.

Early versus delayed umbilical cord clamping in infants with congenital heart disease: a pilot, randomized, controlled trial

OBJECTIVE

Delayed umbilical cord clamping (DCC) at birth may provide a better neonatal health status than early umbilical cord clamping (ECC). However, the safety and feasibility of DCC in infants with congenital heart disease (CHD) have not been tested. This was a pilot, randomized, controlled trial to establish the safety and feasibility of DCC in neonates with CHD.

STUDY DESIGN

Pregnant women admitted >37 weeks gestational age with prenatal diagnosis of critical CHD were enrolled and randomized to ECC or DCC. For ECC, the umbilical cord was clamped <10 s after birth; for DCC, the cord was clamped ~120 s after delivery.

RESULTS

Thirty infants were randomized at birth. No differences between the DCC and ECC groups were observed in gestational age at birth or time of surgery. No differences were observed across all safety measures, although a trend for higher peak serum bilirubin levels (9.2±2.2 vs 7.3±3.2 mg dl(-1), P=0.08) in the DCC group than in the ECC group was noted. Although similar at later time points, hematocrits were higher in the DCC than in the ECC infants during the first 72 h of life. The proportion of infants not receiving blood transfusions throughout hospitalization was higher in the DCC than in the ECC infants (43 vs 7%, log-rank test P=0.02).

CONCLUSION

DCC in infants with critical CHD appears both safe and feasible, with fewer infants exposed to red blood cell transfusions than with ECC. A more comprehensive appraisal of this practice is warranted.

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.

Heterotaxy syndrome infants are at risk for early shunt failure after Ladd procedure

BACKGROUND

Cardiac-specific risks and complications after a Ladd procedure in patients with heterotaxy syndrome (HS) and intestinal rotational anomalies (IRA) are unknown. We sought to (1) describe rates of hospital mortality and early systemic-to-pulmonary (S-P) artery shunt failure after the Ladd procedure in patients with HS and (2) explore risk factors associated with early shunt failure in patients with HS with single ventricle (SV).

METHODS

This retrospective study included all Ladd procedures performed from January 1999 to December 2012 in patients with HS at a single center. Risk factors investigated for early S-P artery shunt failure included birth weight, gestational age, sex, age at and timing of Ladd procedure relative to cardiac operations, and shunt type.

RESULTS

Ladd procedure was performed on 54 infants with HS and congenital heart disease. Hospital mortality for the entire cohort was 5.6% (3 of 54 patients). Early shunt failure occurred in 19% (4 of 21) of HS infants with SV. Mean preoperative blood urea nitrogen (BUN) levels were higher in HS infants with early shunt failure (20 versus 12.5 mg/dL; p = 0.054).

CONCLUSIONS

Patients with SV and HS with S-P artery shunts are at risk for early shunt failure after a Ladd procedure. A higher mean preoperative BUN level is noted in patients with HS and early shunt failure. Careful risk-benefit analysis is indicated before recommending routine elective Ladd procedures in patients with HS.

Initial use of endothelial progenitor cells capturing stents in paediatric congenital heart disease

INTRODUCTION

Stenosis, mediated by neointimal hyperplasia and thrombosis, is a major limiting factor in successful stent implantation. The introduction of a stent, coated in its endoluminal surface by antihuman CD34 antibodies with endothelial progenitor cell-capturing properties, opens the possibility of promoting a rapid and normal functioning coverage by endothelium and thus avoids both an excessive cell proliferation within stent and the need for long-term dual antiplatelet therapy. These stents, developed for adult coronary artery disease, have not yet been implanted in children or in those with congenital heart disease.

OBJECTIVE AND METHODS

In this paper, we describe the implantation of Genous® stents in three children with cyanotic congenital heart disease and obstructed systemic-to-pulmonary shunts. We describe the use of this stent and address its potential feasibility in paediatric congenital heart disease.

RESULTS

To maintain the patency of two modified Blalock-Taussig shunts and one ductus arteriosus, four Genous® stents were implanted in three infants with cyanotic heart disease. All procedures were immediately successful, with resolution of stenosis and improvement in transcutaneous oxygen saturation from 66% ± 3.6% to 92% ± 2.6%. In the follow-up, one stent had no occlusion; however, the remaining two had partial occlusion after 5 and 5.5 months, which were successfully managed with balloon dilatation preceding elective definitive surgical correction.

CONCLUSION

In our preliminary experience, we demonstrated that Genous® stent implantation was feasible in infants with complex congenital heart disease. Additional studies with larger samples and longer follow-up are required to confirm the potential benefits of this technology in this clinical setting.

Systemic-pulmonary artery shunts in infants: modified Blalock-Taussig and central shunt procedures

Access is gained through a midline sternotomy, the thymus partially excised and the superior part of the pericardium is opened. The innominate vein is retracted and the innominate artery is mobilized up to the bifurcation. The aorta is retracted to the left, the superior vena cavae to the right and the right atrial appendage inferiorly. The adventitia around the right pulmonary artery (PA) is dissected, taking care to incise the bulky pericardial reflection between the superior vena cavae and the trachea. Heparin is administrated. An occlusive clamp is applied to the right PA to test for haemodynamic tolerance prior to proceeding with the interposition of a suitable size artificial vascular prosthesis, based on the weight of the patient, between the innominate artery, or proximal subclavian artery and the right PA. Alternatively, if a sufficient main PA is present and adequate flow from a patent ductus arteriosus an end-to-side interposition shunt may be constructed between the ascending aorta and the main PA, provided the patient is stable with the test occlusion of the main PA. The management of the patent arterial ductus depends on whether or not there is forward flow through the PA.

[Outcomes of home monitoring after palliative cardiac surgery in infants with congenital heart disease]

PURPOSE

Common conditions, such as dehydration or respiratory infection can aggravate hypoxia and are associated with interstage mortality in infants who have undergone palliative surgery for congenital heart diseases. This study was done to evaluate the efficacy of a home monitoring program (HMP) in decreasing infant mortality.

METHODS

Since its inception in May 2010, all infants who have undergone palliative surgery have been enrolled in HMP. This study was a prospective observational study and infant outcomes during HMP were compared with those of previous comparison groups. Parents were trained to measure oxygen saturation, body weight and feeding volume and to contact the hospital through the hotline for emergency situations. Telephone counseling was conducted by clinical nurse specialists every week post discharge.

RESULTS

Forty-one infants were enrolled in HMP. Nine hundred telephone counseling sessions were conducted. Seventy-three infants required telephone triage with the most common conditions being gastrointestinal (50.7%) and respiratory symptoms (32.9%). With HMP intervention, interstage mortality decreased from 18.6% (8/43) to 9.8% (4/41) (χ²=1.15, p=.283).

CONCLUSION

Results indicate that active measures and treatments using the HMP decrease mortality rates, however further investigation is required to identify various factors that contribute to hemodynamic complications during the interstage period.

Stenting of the right ventricular outflow tract in the high-risk infant with cyanotic teratology of Fallot

Neonatal tetralogy of Fallot (TOF) repair carries an increased risk of low birthweight or premature infants. Studies are investigating stents in the right ventricular outflow tract (RVOT) as an alternative to aortopulmonary shunts. The authors review their institutional experience with RVOT stenting in the high-risk infant with TOF. Data on sequential patients who received RVOT stents were reviewed, with collection of their surgical, echocardiographic, and catheterization data. Size-matched control subjects were identified and outcomes compared. Six infants went to the catheterization lab for RVOT stenting from 2008 to 2010. Five of these patients had placement of an RVOT stent after balloon dilation. The median saturations were 71% on 48% fraction of inspired oxygen (FiO2), with improvement to 94% (p < 0.001) on 39% FiO2 24 h after stent placement. As shown by echocardiography, the diameter of the median right pulmonary artery (RPA) was 2.6 mm (z-score, -3.3), and the diameter of the left pulmonary artery (LPA) was 2.0 mm (z-score, -4.5). Repeat echocardiography before surgery showed a statistically significant increase in RPA and LPA size as well as a modified McGoon ratio (p < 0.05). Four of the five patients subsequently underwent TOF repair. No stent fractures occurred. One patient had repair 10 days after stent placement secondary to stent malposition and tricuspid valve injury. The authors' experience with stents in the RVOT of TOF patients has yielded good results, with significant improvement in oxygen saturations. Patients had successful elective surgical repair and stent removal without longer cardiopulmonary bypass times or recognizable complications compared with shunted patients.

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.

COMPUTATIONAL FLUID DYNAMICS OF TWO PATIENT-SPECIFIC SYSTEMIC TO PULMONARY SHUNTS

Tetralogy of Fallot is the most common cyanotic congenital heart defect. For severe cases, inserting a systemic to pulmonary shunt, which distributes part of systemic artery blood into the pulmonary artery, is the preferable palliative surgery. Based on the computed tomography images and three-dimensional geometry technologies, two patient-specific anatomical options of systemic to pulmonary shunts including the aorta to pulmonary shunt (APS) and innominate artery to pulmonary shunt (IPS) have been simulated for computational fluid dynamics. The objective of this study was to predict the hemodynamics within the shunts and confirm, through patient-specific simulations, the shunt with the optimal performance. Results indicated that both options created high velocity gradients and pressure gradients at the proximal end of the shunts. Obvious flow recirculation appeared at the inner region near the proximal end of the shunts. Part of the reverse flow from the descending aorta, left subclavian artery, left carotid artery and innominate artery was driven into the shunts during the diastolic period. The IPS provided better balanced and more adequate blood flow distributions between the systemic and pulmonary circulations. The APS provided slightly excessive pulmonary blood flow which can ultimately result in cardiac failure and pulmonary hypertension.

Antithrombotic therapy in neonates and children: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines

BACKGROUND

Neonates and children differ from adults in physiology, pharmacologic responses to drugs, epidemiology, and long-term consequences of thrombosis. This guideline addresses optimal strategies for the management of thrombosis in neonates and children.

METHODS

The methods of this guideline follow those described in the Methodology for the Development of Antithrombotic Therapy and Prevention of Thrombosis Guidelines: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines.

RESULTS

We suggest that where possible, pediatric hematologists with experience in thromboembolism manage pediatric patients with thromboembolism (Grade 2C). When this is not possible, we suggest a combination of a neonatologist/pediatrician and adult hematologist supported by consultation with an experienced pediatric hematologist (Grade 2C). We suggest that therapeutic unfractionated heparin in children is titrated to achieve a target anti-Xa range of 0.35 to 0.7 units/mL or an activated partial thromboplastin time range that correlates to this anti-Xa range or to a protamine titration range of 0.2 to 0.4 units/mL (Grade 2C). For neonates and children receiving either daily or bid therapeutic low-molecular-weight heparin, we suggest that the drug be monitored to a target range of 0.5 to 1.0 units/mL in a sample taken 4 to 6 h after subcutaneous injection or, alternatively, 0.5 to 0.8 units/mL in a sample taken 2 to 6 h after subcutaneous injection (Grade 2C).

CONCLUSIONS

The evidence supporting most recommendations for antithrombotic therapy in neonates and children remains weak. Studies addressing appropriate drug target ranges and monitoring requirements are urgently required in addition to site- and clinical situation-specific thrombosis management strategies.

Unilateral pulmonary artery banding to promote contralateral pulmonary artery growth

A full-term baby with double-outlet right ventricle and total anomalous pulmonary venous connection (TAPVC) complicated with left main pulmonary artery (PA) stenosis, presented with heart failure caused by increased pulmonary blood flow. Based on significant discrepancies in size and development between the left and right PAs, we performed right PA banding concomitant with TAPVC repair to promote left PA growth and restrict overall PA flow. PA-graphy performed 3 months after surgery showed marked increase in the left PA size with appropriately low pressure, which enabled us to successfully complete Glenn anastomosis. Under appropriate patient selection, unilateral PA banding for patients with unbalanced peripheral PA size could serve as an effective and less invasive strategy to simultaneously promote PA growth and control PA flow.