Early and Long-Term Clinical Outcomes of Ductal Stenting Versus Surgical Aortopulmonary Shunt Among Young Infants with Duct-Dependent Pulmonary Circulation

Surgical aortopulmonary shunting (SAPS) and ductal stenting (DS) are the main palliations in infants with cyanotic congenital heart diseases (CHD). We aimed to study the safety and efficacy of DS and to compare it with SAPS as a palliative procedure in infants with CHD and duct-dependent pulmonary circulation. Retrospective institutional clinical data review of consecutive infants aged < 3 months who underwent DS or SAPS over 5 years. The primary outcome was procedural success which was defined as event-free survival (mortality, need for re-intervention, procedural failure) at 30 days post-procedure. The secondary outcome was defined by a composite of death, major adverse cardiovascular events, or need for re-intervention at 6 months and on long-term follow-up. We included 102 infants (DS, n = 53 and SAPS, n = 49). The median age at DS and SAPS was 4 days (IQR 2.0-8.5) and 8 days (IQR 4.0-39.0), respectively. The median weight at intervention was 3.0 kg (IQR 3.0-3.0) and 3.0 kg (IQR 2.5-3.0) in the two respective arms. Tetralogy of Fallot with pulmonary atresia was the most common indication for DS and SAPS. The 30-day mortality was significantly higher in SAPS group as compared with DS group (p < 0.05). However, 30-day major adverse cardiac events (MACE) rates were similar in both groups (p = 0.29). DS was associated with shorter duration of mechanical ventilation, duration of stay in the intensive care and hospital stay than with SAPS. At 6 months, there was no significant difference in terms of mortality or event-free survival. Long-term MACE-free survival was also comparable (p = 0.13). DS is an effective and safer alternative to SAPS in infants with duct-dependent pulmonary circulation, offering reduced procedure-related mortality and morbidity than SAPS. Careful study of ductal anatomy is crucial to procedural success. However, long-term outcomes are similar in both procedures.

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

OBJECTIVES

To evaluate longitudinal systemic ventricular function and atrioventricular valve regurgitation in patients after the neonatal Norwood procedure.

METHODS

Serial postoperative echocardiographic images before Fontan completion were assessed in neonates who underwent the Norwood procedure between 2001 and 2020. Ventricular function and atrioventricular valve regurgitation were compared between patients with modified Blalock-Taussig shunt and right ventricle to pulmonary artery conduit.

RESULTS

A total of 335 patients were identified including 273 hypoplastic left heart syndrome and 62 of its variants. Median age at Norwood was 8 (7-12) days. Modified Blalock-Taussig shunt was performed in 171 patients and the right ventricle to pulmonary artery conduit in 164 patients. Longitudinal ventricular function and atrioventricular valve regurgitation were evaluated using a total of 4352 echocardiograms. After the Norwood procedure, ventricular function was initially worse (1-30 days) but thereafter better (30 days to stage II) in the right ventricle to pulmonary artery conduit group (P < 0.001). After stage II, the ventricular function was inferior in the right ventricle to the pulmonary artery conduit group (P < 0.001). Atrioventricular valve regurgitation between the Norwood procedure and stage II was more frequent in the modified Blalock-Taussig shunt group (P < 0.001). After stage II, there was no significant difference in atrioventricular valve regurgitation between the groups (P = 0.171).

CONCLUSIONS

The effect of shunt type on haemodynamics after the Norwood procedure seems to vary according to the stage of palliation. After the Norwood, the modified Blalock-Taussig shunt is associated with poorer ventricular function and worse atrioventricular valve regurgitation compared to right ventricle to pulmonary artery conduit. Whereas, after stage II, modified Blalock-Taussig shunt is associated with better ventricular function and comparable atrioventricular valve regurgitation, compared to the right ventricle to pulmonary artery conduit.

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

OBJECTIVES

For patients with tetralogy of Fallot (TOF) who are not suitable candidates for primary corrective surgery or have a high surgical risk, transcatheter right ventricular outflow tract (RVOT) stent implantation is considered a safe and effective palliative intervention. This study aims to investigate the therapeutic outcomes of RVOT stent implantation in neonates and infants with TOF in comparison with the modified Blalock-Taussig shunt (mBTS) and to compare the impact of the 2 palliative interventions on arterial oxygen saturation and pulmonary artery development in pediatric patients.

METHODS

Clinical data of 32 patients with TOF admitted to the Second Xiangya Hospital of Central South University from March 2011 to March 2021 were retrospectively collected. The patients were divided into an mBTS group (undergoing mBTS, n=15) and a stent implantation group (undergoing RVOT stenting, n=17) according to the surgical procedures. The 2 groups were assessed and compared in the surgical-related arterial oxygen saturation, postoperative complication rate, mortality rate, and re-intervention rate. The development of the patients' main pulmonary artery, right pulmonary artery, and left pulmonary artery was assessed by z-scores according to echocardiographic results.

RESULTS

The children in the stent implantation group were younger and less weighed compared with the mBTS group (both P<0.05). Compared with the preoperative period, children in the stent implantation group had significantly higher arterial oxygen saturation [(75±17)% vs (96±3)%, P=0.026]; z-scores of pulmonary trunk [(-2.82±1.27) points vs (0.86±0.77) points, P=0.014], right pulmonary artery [(-1.88±0.59) points vs (-0.28±0.71) points, P=0.011], and left pulmonary artery [(-2.34±0.36) points vs (-1.67±0.36) points, P=0.036] were significantly increased. However, there were no significant differences in arterial oxygen saturation and pulmonary artery z-scores between pre- and post-mBTS procedures (all P>0.05).

CONCLUSIONS

RVOT stent would have good surgical outcomes used in TOF patients with low weight and severe comorbidities. It also leads to an higher postoperative oxygen saturation and better promotion of pulmonary artery growth with RVOT stent compared to mBTS.

Trends in Ductus Arteriosus Stent Versus Blalock-Taussig-Thomas Shunt Use and Comparison of Cost, Length of Stay, and Short-Term Outcomes in Neonates With Ductal-Dependent Pulmonary Blood Flow: An Observational Study Using the Pediatric Health Information Systems Database

BACKGROUND

The modified Blalock-Taussig-Thomas shunt is the gold standard palliation for securing pulmonary blood flow in infants with ductal-dependent pulmonary blood flow. Recently, the ductus arteriosus stent (DAS) has become a viable alternative.

METHODS AND RESULTS

This was a retrospective multicenter study of neonates ≤30 days undergoing DAS or Blalock-Taussig-Thomas shunt placement between January 1, 2017 and December 31, 2020 at hospitals reporting to the Pediatric Health Information Systems database. We performed generalized linear mixed-effects modeling to evaluate trends in intervention and intercenter variation, propensity score adjustment and inverse probability weighting with linear mixed-effects modeling to analyze length of stay and cost of hospitalization, and generalized linear mixed modeling to analyze differences in 30-day outcomes. There were 1874 subjects (58% male, 61% White) from 45 centers (29% DAS). Odds of DAS increased with time (odds ratio [OR] 1.23, annually, P<0.01 [95% CI, 1.10-1.38]) with significant intercenter variation (median OR, 3.81 [95% CI, 2.74-5.91]). DAS was associated with shorter hospital length of stay (ratio of geometric means, 0.76 [95% CI, 0.63-0.91]), shorter intensive care unit length of stay (ratio of geometric means, 0.77 [95% CI, 0.61-0.97]), and less expensive hospitalization (ratio of geometric means, 0.70 [95% CI, 0.56-0.87]). Intervention was not significantly associated with odds of 30-day transplant-free survival (OR,1.18 [95% CI, 0.70-1.99]) or freedom from catheter reintervention (OR, 1.02 [95% CI, 0.65-1.58]), but DAS was associated with 30-day freedom from composite adverse outcome (OR, 1.51 [95% CI, 1.11-2.05]).

CONCLUSIONS

Use of DAS is increasing, but there is variability across centers. Though odds of transplant-free survival and reintervention were not significantly different after DAS, and DAS was associated with shorter length of stay and lower in-hospital costs.

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

Objectives

There is limited data published from outside North America and Europe comparing the outcomes of a modified Blalock-Taussig shunt (MBTS) and ductal stenting as the first palliative procedure for infants with duct-dependent pulmonary circulation. This study reports the National Heart Center's, in Muscat, Oman, experience in comparing the outcomes of these 2 interventions.

Methods

This retrospective study included all infants with duct-dependent pulmonary circulation who received either a MBTS or ductal stenting from 2016-2019. The primary outcomes were death or re-interventions. Secondary outcomes included death, subsequent re-interventions, survival to subsequent surgical intervention, survival to hospital discharge, post-procedural mechanical ventilation and duration of intensive care unit stay.

Results

A total of 71 patients were included in the study, 33 (46%) of whom received ductal stenting. The prevalence of the primary outcome (death or re-intervention) in the patent ductus arteriosus (PDA) stent group was 54.5% versus 31.6% in the MBTS group but this was not statistically significant (P = 0.06). There was no difference between the 2 groups in terms of time to next surgical intervention (P = 0.233). The PDA stent group had shorter post-procedural, mechanical ventilation and intensive care unit stay durations (P <0.05). Syndromic patients were at higher risk of mortality compared to non-syndromic patients.

Conclusion

MBTS and ductal stenting are both acceptable modalities as a palliative intervention for infants with duct-dependant pulmonary circulation. Syndromic patients are at higher risk of mortality. This can be considered an important factor for patient selection.

Chronic inflammatory pulmonary artery lesion causing right pulmonary artery stenosis 15 years post Blalock-Taussig shunt ligation

Discrete central endovascular pulmonary arterial lesions raise clinical concern for malignancy such as primary pulmonary artery sarcoma. We present a case of a female in her late teens who had an obstructive mid right pulmonary artery lesion found on follow-up imaging 15 years after Tetralogy of Fallot repair. The lesion was in the vicinity of a previously ligated Blalock-Taussig shunt and causing right PA stenosis with delayed perfusion to the right lung, and a flow-related distal left PA aneurysm. The lesion was excised and confirmed histologically to be inflammatory in nature. Intraoperative microbiology demonstrated growth of the Kytococcus species, and she was managed with 6 weeks of intravenous antibiotics, with a full recovery.

Haemodynamic and clinical variables after surgical systemic to pulmonary artery shunt placement versus arterial ductal stenting

BACKGROUND

Transcatheter stenting of the arterial duct is an alternative to surgical systemic to pulmonary artery shunt in neonates with parallel circulation. The current study compares haemodynamic and laboratory values in these patients for the first 48 hours after either intervention.

METHODS

Neonates with ductal dependent pulmonary blood flow who underwent surgical shunt placement or catheter-based arterial ductal stent placement between January 2013 and January 2022 were identified. Haemodynamic variables included heart rate, blood pressure, near infrared spectroscopy, central venous pressure, vasoactive inotropic score, and arterial saturation. Laboratory variables collected included blood urea nitrogen, serum creatinine, and serum lactate. Variables were collected at baseline, upon post-procedural admission, 6 hours after admission, 12 hours after admission, and 48 hours after admission. Secondary outcomes included post-procedural mechanical ventilation duration, post-procedural hospital length of stay, need for reintervention, need for extracorporeal membrane oxygenation, cardiac arrest, and inpatient mortality.

RESULTS

Of the 52 patients included, 38 (73%) underwent shunt placement while 14 (27%) underwent a stent placement. Heart rates, renal oxygen extraction ratio, and cerebral oxygen extraction ratio were significantly lower in the stent group (p = <0.01, 0.01, and < 0.01, respectively).Haemoglobin and vasoactive inotropic scores were significantly lower in the stent group (p = <0.01, <0.01, respectively). The stent group had increased risk for cardiac arrest (p = 0.04).

CONCLUSION

Patients who undergo arterial ductal stent placement have lower heart rates, haemoglobin, renal oxygen extraction ratio, cerebral oxygen extraction ratio, and vasoactive inotropic score in the first 48 hours post-procedure compared to patients with shunt placement.

Catheter Intervention for Flow Regulatory Clips on Palliative Shunts and Conduits in Patients with Congenital Heart Disease

Catheter intervention (CI) for a Blalock-Taussig shunt (BTS) or a ventricle-to-pulmonary artery conduit (VPC) is often required after a palliative surgery for congenital heart disease. Flow regulatory clips help improve interstage mortality; their use necessitates CIs to prevent cyanosis. To study the CI outcomes in patients who underwent palliative surgery with either BTSs or VPCs with flow regulatory clips. This single-center retrospective study evaluated demographic characteristics and interventional outcomes of 49 consecutive pediatric patients who required CI for BTS (BTS group) or VPC (VPC group) between January 2008 and September 2018. Overall, 34 and 18 procedures were performed in the BTS and VPC groups, respectively. Moreover, 19/32 (59.3%) and 12/17 (70.1%) patients from the BTS and VPC groups had flow regulatory clips, respectively. All clips were unclipped successfully; one patient in each group underwent staged unclipping. A higher proportion of "clipped patients" underwent CI due to desaturation [clipped vs. non-clipped: BTS, 10/20 (50.0%) vs. 3/14 (21.4%), p = 0.092; VPC, 9/13 (69.2%) vs. 1/5 (20.0%), p = 0.060]. Most clipped patients successfully progressed to the next stage [BTS, 19/20 (95.0%); VPC, 12/13 (92.3%)]. Severe adverse events (SAEs) were more frequent in the VPC group than in the BTS group [3/13 (23.1%) vs. 0/20 (0%), p = 0.024]. Two patients developed an atrioventricular block (requiring an atropine infusion), while one died due to pulmonary overcirculation. While the indication of CI was cyanosis for a higher proportion of clipped patients, all clips were unclipped successfully. The incidence of CI-related SAEs was higher in the VPC group than in the BTS group.

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.

Relation of Norwood Shunt Type and Frequency of Arrhythmias at 6 Years (from the Single Ventricle Reconstruction Trial)

The Norwood procedure with a right ventricular to pulmonary artery shunt (RVPAS) decreases early mortality, but requires a ventriculotomy, possibly increasing risk of ventricular arrhythmias (VAs) compared with the modified Blalock-Taussig shunt (MBTS). The effect of shunt and Fontan type on arrhythmias by 6 years of age in the SVRII (Single Ventricle Reconstruction Extension Study) was assessed. SVRII data collected on 324 patients pre-/post-Fontan and annually at 2 to 6 years included antiarrhythmic medications, electrocardiography (ECG) at Fontan, and Holter/ECG at 6 years. ECGs and Holters were reviewed for morphology, intervals, atrioventricular conduction, and arrhythmias. Isolated VA were seen on 6-year Holter in >50% of both cohorts (MBTS 54% vs RVPAS 60%), whereas nonsustained ventricular tachycardia was rare and observed in RVPAS only (2.7%). First-degree atrioventricular block was more common in RVPAS than MBTS (21% vs 8%, p = 0.01), whereas right bundle branch block, QRS duration, and QTc were similar. Antiarrhythmic medication usage was common in both groups, but most agents also supported ventricular function (e.g., digoxin, carvedilol). Of the 7 patients with death or transplant between 2 and 6 years, none had documented VAs, but compared with transplant-free survivors, they had somewhat longer QRS (106 vs 93 ms, p = 0.05). Atrial tachyarrhythmias varied little between MBTS and RVPAS but did vary by Fontan type (lateral tunnel 41% vs extracardiac conduit 29%). VAs did not vary by Fontan type. In conclusion, at 6-year follow-up, benign VAs were common in the SVRII population. However, despite the potential for increased VAs and sudden death in the RVPAS cohort, these data do not support significant differences or increased risk at 6 years. The findings highlight the need for ongoing surveillance for arrhythmias in the SVR population.

In-hospital Morbidity and Mortality Following Modified Blalock-Taussig-Thomas Shunts

BACKGROUND

The modified Blalock-Taussig-Thomas shunt (mBTTs) is a critically important palliation for patients with insufficient pulmonary blood flow associated with congenital heart disease. Following creation of a mBTTs, patients experience high rates of early postoperative morbidity and mortality.

METHODS

This is a single-institution retrospective cohort study. A query of the Society of Thoracic Surgeons database identified relevant patients whose health records were manually queried for echocardiography and operative reports. Patients with ductal-dependent systemic circulation were excluded. Primary outcomes were early serious adverse events and in-hospital mortality. Secondary outcomes were time to primary outcomes and postoperative lengths of stay. We investigated the correlation of demographics, presence of competitive pulmonary blood flow, and surgical and anatomic factors on outcomes.

RESULTS

After exclusions, our cohort resulted in 155 patients. 33 (21.3%) patients experienced an early serious adverse event, ten (6.5%) early shunt malfunction, and 11 (7.1%) in-hospital mortality. Smaller shunt size, smaller shunted pulmonary artery size, surgical approach, and site of proximal shunt anastomosis were independently associated with morbidity and mortality.

CONCLUSIONS

Anatomical elements imparting increased resistance along the mBTTs predispose to increased morbidity and mortality, particularly in the early postoperative period. Despite the significant heterogeneity of patients receiving such shunts, similar risk profiles are observed regardless of lesion or presence of competitive flow. Surgical approach via thoracotomy with shunt anastomosis to the subclavian artery, where feasible, results in the subclavian artery as the point of natural resistance allowing for placement of larger shunts, yielding lower morbidity and mortality.

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

OBJECTIVE

Pulmonary artery coarctation may pose a risk for pulmonary stenosis and subsequent failure to achieve definitive repair. We sought to assess the impact of pulmonary artery coarctation on pulmonary artery growth.

METHODS

A retrospective chart review was performed in 130 patients, including 37 single ventricles with a modified Blalock-Taussig shunt as first palliation. Pulmonary artery coarctation was defined as discrete stenosis of the pulmonary artery, with a diameter of less than 3 mm and with the ductus arteriosus connected. Preoperative echocardiography showed pulmonary artery coarctation in 29 patients (22%). Concomitant pulmonary artery plasty was performed in 14 patients with discrete stenosis having a diameter of less than 2 mm.

RESULTS

Pre-modified Blalock-Taussig shunt left pulmonary artery z-scores were lower in patients with pulmonary artery coarctation than in those without (-4.0 [-5.8, -2.1] vs -1.7 [-2.6, -0.8], P < .001), and this remained the same even after modified Blalock-Taussig shunt (-2.5 [-5.1, -0.5] vs -0.5 [-2.4, 0.8], P = .010). Concomitant pulmonary artery plasty did not result in catch-up growth of the left pulmonary artery (post-modified Blalock-Taussig shunt left pulmonary artery z-score in patients with pulmonary artery plasty: -3.0 (-6.5, -2.0) versus those without: -1.8 (-3.3, -0.3), P = .279). Definitive repair/Fontan completion was achieved in 111 patients (85%), and this was not affected by the presence of pulmonary artery coarctation.

CONCLUSIONS

Pulmonary artery coarctation affected disproportionate pulmonary artery growth throughout the staged repair, but did not result in failure of definitive repair/Fontan completion. Pulmonary artery plasty during the neonatal period did not contribute to catch-up growth of the left pulmonary artery; therefore, surgical indications and timing should be carefully considered.

Arterial duct stent versus surgical shunt for patients with duct-dependent pulmonary circulation: a meta-analysis

BACKGROUND

Both systemic-pulmonary shunt and arterial duct stent could be the palliation of duct-dependent pulmonary circulation. We aimed to compare the safety and efficacy of the two approaches.

METHODS

The PubMed, EMBASE, and Cochrane Library databases were searched through December 2019 for studies comparing stent implantation and surgical shunt in duct-dependent pulmonary circulation. The baseline characteristics included ventricle physiology and cardiac anomaly. The main outcomes were hospital stay and total mortality. Additional outcomes included procedural complications, intensive care unit (ICU) stay, pulmonary artery growth at follow-up, and other indexes. A random- or fixed-effects model was used to summarize the estimates of the mean difference (MD)/risk ratio (RR) with 95% confidence intervals (CIs).

RESULTS

In total, 757 patients with duct-dependent pulmonary circulation from six studies were included. Pooled estimates of hospital stay (MD, - 4.83; 95% CI - 7.92 to - 1.74; p < 0.05), total mortality (RR 0.44; 95% CI 0.28-0.70; p < 0.05), complications (RR 0.49; 95% CI 0.30-0.81; p < 0.05) and ICU stay (MD, - 4.00; 95% CI - 5.96 to - 2.04; p < 0.05) favored the stent group. Significant differences were found in the proportions of patients with a single ventricle (RR 0.82; 95% CI 0.68-0.98; p < 0.05) or a double ventricle (RR 1.23; 95% CI 1.07-1.41; p < 0.05) between the stent and shunt groups. Additionally, pulmonary artery growth showed no significant differences between the two groups.

CONCLUSION

Arterial duct stent appears to have not inferior outcomes of procedural complications, mortality, hospital and ICU stay, and pulmonary artery growth in selected patients compared with a surgical shunt.

TRIAL REGISTRATION

CRD42019147672.

Extracorporeal cardiopulmonary resuscitation with low pump flow for blocked modified Blalock-Taussig shunt followed by spontaneous recanalization

A 2-week-old male newborn with a double inlet left ventricle developed a cardiac arrest following modified Blalock-Taussig anastomosis in pediatric intensive care unit. Probable causes of the arrest were hemodynamic instability and thrombosed shunt, which was later recanalized on extracorporeal membrane oxygenation therapy, which was successfully used with a pump flow lower than recommended in these patients-without the shunt clip, but without any complications.

Red Blood Cell Transfusion After Stage I Palliation Is Associated With Worse Clinical Outcomes

Background Packed red blood cell transfusion may improve oxygen content in single-ventricle neonates, but its effect on clinical outcomes after Stage 1 palliation is unknown. Methods and Results Retrospective multicenter analysis of packed red blood cell transfusion exposures in neonates after Stage 1 palliation, excluding those with intraoperative mortality or need for extracorporeal membrane oxygenation. Transfusion practice variability was assessed, and multivariable regression used to identify transfusion risk factors. After propensity score adjustment for severity of illness, clinical outcomes were compared between transfused and nontransfused subjects. Of 396 subjects, 323 (82%) received 930 postoperative red blood cell transfusions. Packed red blood cell volume (median 9-42 mL/kg [P<0.0001]), donor exposures (1-2 [P<0.0001]), transfusion number (1-3 [P<0.0001]), and pretransfusion hemoglobin (12.1-13 g/dL, P=0.0049) varied between sites. Cyanosis (P=0.02), chest tube output (P=0.0003), and delayed sternal closure (P=0.0033) increased transfusion risk. Transfusion was associated with prolonged mechanical ventilation (6 [interquartile range 4, 12] versus 3 [1, 5] days, P=0.02) and intensive care unit stay (19 [12, 33] versus 9 [6, 19] days, P=0.016). When stratified by number of transfusions (0, 1, or >1), duration of mechanical ventilation (3 [1, 5] versus 4 [3, 6] versus 9 [5, 16] days [P<0.0001]) and intensive care unit stay (9 [6, 19] versus 13 [8, 25] versus 21 [13, 38] days [P<0.0001]) increased for those transfused more than once. Most subjects who died were transfused, though the association with mortality was not significant. Conclusions Packed red blood cell transfusion after Stage 1 palliation is common, and transfusion practice is variable. Transfusion is a significant predictor of longer intensive care unit stay and mechanical ventilation. Further studies to define evidence-based transfusion thresholds are warranted.

Heart failure in single right ventricle congenital heart disease: physiological and molecular considerations

Because of remarkable surgical and medical advances over the past several decades, there are growing numbers of infants and children living with single ventricle congenital heart disease (SV), where there is only one functional cardiac pumping chamber. Nevertheless, cardiac dysfunction (and ultimately heart failure) is a common complication in the SV population, and pharmacological heart failure therapies have largely been ineffective in mitigating the need for heart transplantation. Given that there are several inherent risk factors for ventricular dysfunction in the setting of SV in addition to probable differences in molecular adaptations to heart failure between children and adults, it is perhaps not surprising that extrapolated adult heart failure medications have had limited benefit in children with SV heart failure. Further investigations into the molecular mechanisms involved in pediatric SV heart failure may assist with risk stratification as well as development of targeted, efficacious therapies specific to this patient population. In this review, we present a brief overview of SV anatomy and physiology, with a focus on patients with a single morphological right ventricle requiring staged surgical palliation. Additionally, we discuss outcomes in the current era, risk factors associated with the progression to heart failure, present state of knowledge regarding molecular alterations in end-stage SV heart failure, and current therapeutic interventions. Potential avenues for improving SV outcomes, including identification of biomarkers of heart failure progression, implications of personalized medicine and stem cell-derived therapies, and applications of novel models of SV disease, are proposed as future directions.

Differences in Cost of Care by Palliation Strategy for Infants With Ductal-Dependent Pulmonary Blood Flow

BACKGROUND

In infants with ductal-dependent pulmonary blood flow, initial palliation with patent ductus arteriosus (PDA) stent or modified Blalock-Taussig (BT) shunt have comparable mortality but discrepant length of stay, procedural complication rates and reintervention burdens, which may influence cost. The relative economic impact of these palliation strategies is unknown.

METHODS AND RESULTS

Retrospective study of infants with ductal-dependent pulmonary blood flow palliated with PDA stent (n=104) or BT shunt (n=251) from 2008 to 2015 at 4 centers of the Congenital Catheterization Research Collaborative. Inflation-adjusted inpatient hospital costs were calculated for first year of life using Pediatric Health Information System data. Costs derived from outpatient catheterizations not in Pediatric Health Information System were imputed. Costs were compared using propensity score-adjusted multivariable models, to account for baseline differences between groups. After propensity score adjustment, first year of life costs were significantly lower in PDA stent ($215 825 [190 644-244 333]) than BT shunt ($249 855 [230 693-270 609]) patients ( P=0.05). After addition of imputed costs, first year of life costs were not significantly different between PDA stent ($226 403 [200 274-255 941]) and BT shunt ($252 072 [232 955-272 759]) groups ( P=0.15). Patient characteristics associated with higher costs included: younger gestational age, genetic syndrome, noncardiac diagnoses, procedural complications, extracorporeal membrane oxygenation, duration of ventilation, intensive care unit and hospital length of stay and reintervention ( P≤0.02 for all).

CONCLUSIONS

In this first multicenter comparative cost study of PDA stent or BT shunt as palliation for infants with ductal-dependent pulmonary blood flow, adjusted for baseline differences, PDA stent was associated with lower to equivalent costs over the first year of life. Combined with previous evidence suggesting clinical noninferiority, these findings suggest that PDA stent provides competitive health care value.

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

BACKGROUND

The Modified Blalock-Taussig shunt (MBTS) is the most common palliative operation performed in patients with complex cardiac defects. Postoperative morbidity and mortality rates are high, mainly due to shunt thrombosis and over-shunting. Over-shunting may be difficult to identify postoperatively based on conventional criteria. Since plasma B-type natriuretic peptide (BNP) concentrations correlate with the magnitude of shunting in various left-to-right shunt cardiac defects, we investigated its ability to identify postoperative MBTS over-shunting.

METHODS AND RESULTS

This retrospective, observational study included 42 consecutive patients (median age 9.50days, IQR: 6.00-58.25) undergoing MBTS for obstruction of the pulmonary blood flow at a tertiary referral pediatric cardiac center. The BNP threshold concentrations which accurately predicted outcome and MBTS over-shunting were derived using the ROC methodology. 443 BNP concentrations were analysed. The presence of atrio-ventricular valve regurgitation was the most important component of overall variance (72.75%). In 34 patients without regurgitation, BNP concentrations were predictive of a duration of mechanical ventilation >8days and of intensive care stay >11days, with ROC areas of 0.655 [0.597-0.719], 0.650 [0.589-0.711], a negative predictive value for the >1035pgmL^-1 threshold of 0.93 and 0.96 respectively. SaO₂ was less accurate for the prediction of both outcomes. In patients in whom the pulmonary flow was entirely MBTS-supplied, a BNP concentrations >1052pgmL^-1 was predictive of a pulmonary-to-systemic ratio>2.

CONCLUSION

In MBTS patients without atrio-ventricular valve regurgitation, maintaining BNP below 1000pgmL^-1 may represent a therapeutic target to avoid over-shunting.

Is a hybrid strategy a lower-risk alternative to stage 1 Norwood operation?

BACKGROUND

For neonates with critical left ventricular outflow tract obstruction (LVOTO), hybrid procedures are an alternative to the Norwood stage 1 procedure. Despite perceived advantages, however, outcomes are not well defined. Therefore, we compared outcomes after stage 1 hybrid and Norwood procedures.

METHODS

In a critical LVOTO inception cohort (2005-2014; 20 institutions), a total of 564 neonates underwent stage 1 palliation with the Norwood operation with a modified Blalock-Taussig shunt (NW-BT; n = 232; 41%), Norwood operation with a right ventricle-to-pulmonary artery conduit (NW-RVPA; n = 222; 39%), or a hybrid procedure (n = 110; 20%). Post-stage 1 outcomes were analyzed via competing-risks and parametric hazard analyses and compared among all 564 patients and between patients who underwent propensity-matched hybrid and those who underwent NW-BT/NW-RVPA.

RESULTS

By 6 years after the stage 1 operation, 50% ± 3%, 7% ± 2%, and 4% ± 1% of patients transitioned to Fontan, transplantation, and biventricular repair, respectively, whereas 7% ± 2% were alive without transition and 32% ± 2% died. Risk factors for death without transition included procedure type, smaller ascending aorta, aortic valve atresia, and lower birth weight. Risk-adjusted 4-year survival was better after NW-RVPA than after NW-BT or hybrid (76% vs 60% vs 61%; P < .001). Furthermore, for neonates with lower birth weight (<∼2 kg), an interaction between birth weight and hybrid resulted in a trend toward better survival after hybrid compared with NW-BT or NW-RVPA. For propensity-matched neonates between hybrid and NW-BT (88 pairs), 4-year survival was similar (62% vs 57%; P = .58). For propensity-matched neonates between hybrid and NW-RVPA (81 pairs), 4-year survival was better after NW-RVPA (59% vs 75%; P = .008).

CONCLUSIONS

For neonates with critical LVOTO undergoing single-ventricle palliation, NW-RVPA was associated with the best overall survival. Hybrid strategies are not a lower-risk alternative to Norwood operations overall; however, the impact of lower birth weight on survival may be mitigated after hybrid procedures compared with Norwood operations.

Catheter-based interventions for modified Blalock-Taussig shunt obstruction: a 20-year experience

Thrombotic occlusion of a modified Blalock-Taussig (BT) shunt is rare, leading to life-threatening hypoxemia. Rescue percutaneous interventions may allow recanalization of the systemic-to-pulmonary shunt but data on large patients' scales are lacking. We aimed to describe safety and effectiveness of catheter-based interventions to restore modified BT shunt patency. All patients who attempted transcatheter intervention for thrombotic occlusion of a modified BT shunt at our Institution from 1994 to 2014 were reviewed. Characteristics, management, and outcomes of the 28 identified patients were analyzed. Thirty-three procedures were performed at a median age of 0.6 years old (range 0.03-32.1 years) and a median weight of 5.8 kg (range 2.2-82 kg). Percutaneous intervention consisted in 33 balloon angioplasty (100 %) and 14 stent implantations (42.4 %). Thrombolytic agents were also used in 6.1 % cases. No peri-procedural death occurred but complications were observed in five patients (15.2 %), including one catheter-induced transient complete atrioventricular block, one cardiac tamponade, and one massive thrombo-embolic stroke. Early procedural success was obtained in 28 patients (84.8 %) and remained long-lasting in 26 patients (78.8 %). A young age and a low body-weight at the time of the procedure were significantly associated with procedural failure (p = 0.0364 and p = 0.0247, respectively). Although technically challenging and carrying potential major complications, transcatheter intervention can be considered as an efficient rescue strategy to restore patency in case of thrombotic obstruction of a modified BT shunt.

Post Blalock-Taussig shunt mediastinal mass - a single shadow with two different destinies

The modified Blalock-Taussig shunt is a synthetic shunt between the subclavian and pulmonary artery, used in the treatment of congenital cyanotic heart diseases with pulmonary hypoperfusion. Delayed complications include progressive failure of the shunt, serous fluid leak, and pseudoaneurysm formation. We report two different and rare mediastinal vascular complications following modified BT shunt surgery in this case report. The first one is a seroma, due to serous fluid leakage through the shunt graft, which is a relatively benign complication. The second one is a pseudoaneurysm, arising from the shunt, a frequently fatal complication. Generally, X-ray chest is used for screening in these patients. CT angiography plays a vital role in the diagnosis of both these conditions. Management in pseudoaneurysm should be aggressive, as timely intervention may be life saving, while in seroma the management is most often conservative occasionally requiring surgical intervention.

Interventions after Norwood procedure: comparison of Sano and modified Blalock-Taussig shunt

Improved results have evolved from the modified Norwood procedure (NP). This study compares the incidence of interventions after NP with the Sano (n = 37) and modified Blalock-Taussig (BT n = 70) shunt. Incidence, location, interval of interventions, and weight were retrospectively analysed for 107 neonates undergoing NP during the period from October 2002 to December 2009. Forty-six (43.0 %) patients underwent interventions, mostly for dilatation of the aortic arch ([DAA] n = 26 [24.3 %]; Sano n = 10, BT n = 16, p = 0.6), dilatation of the shunt ([DS] n = 15 [14.0 %]; Sano n = 11, BT n = 4; p = 0.002), or closure of aortopulmonary collaterals ([APC] n = 15 [14.0 %]; Sano n = 3, BT n = 12; p = 0.08). Mean interval after NP and body weight at DAA, DS, and APC were 72.4 ± 18.9, 108.5 ± 15.8, and 110.7 ± 17.8 days and 4.5 ± 1.3, 4.9 ± 1.9, 5.3 ± 1.2 kg, respectively. The interventions were not associated with mortality but with a greater rate of complications (9 of 46 [21.4 %]) compared with the rate after diagnostic catheterization (0 of 45, p = 0.03). Complications included closure of the femoral or subclavian artery (n = 5), cerebral embolic or bleeding events (n = 4), cardiopulmonary resuscitation (n = 3), and temporary heart block (n = 2). Actuarial survival was similar from the postoperative month 8 onward at 78.6 ± 4.9 % (95 % confidence interval [CI] 67.0-86.5 %) for Sano and 78.4 ± 6.8 % (95 % CI 61.4-88.6 %) for BT (p = 0.95). Interventions after NP were common irrespective of shunt type. However, a significantly greater rate of shunt interventions was noted in the Sano group. In particular, interventions addressing the aortic arch and the shunt were related with a significant rate of complications.

The Norwood procedure: in favor of the RV-PA conduit

Evolution of the Norwood procedure has culminated in there currently being three treatment strategies available for initial management: the 'classical' Norwood (utilizing a Blalock-Taussig shunt), the Norwood with right-ventricle to pulmonary artery (RV-PA) conduit, and the 'hybrid' Norwood procedure utilizing bilateral pulmonary artery banding and ductal stenting. Each variant has its potential advantages and disadvantages, and this paper looks to examine the evidence in favor of each strategy, with emphasis on the supportive data for the RV-PA conduit. The 'classical' procedure has the benefit of the greatest accumulated surgical experience and avoids any incision into the ventricle. However, the diastolic run-off of the Blalock-Taussig shunt can cause hemodynamic instability and unpredictable coronary steal phenomenon. The RV-PA conduit has the advantage of maintaining diastolic pressure with a more stable postoperative course, but at the cost of a ventriculotomy that may have detrimental long-term sequelae. The 'hybrid' procedure has the advantage of avoiding cardiopulmonary bypass, but does not always secure coronary blood flow and has a high inter-stage morbidity and reintervention rate. The evidence shows that each technique may have its place in future management, and that treatment algorithms could emerge that direct the choice of procedure for specific patient groups.

Variation in perioperative care across centers for infants undergoing the Norwood procedure

OBJECTIVES

In the Single Ventricle Reconstruction trial, infants undergoing the Norwood procedure were randomly allocated to undergo a right ventricle-to-pulmonary artery shunt or a modified Blalock-Taussig shunt. Apart from shunt type, subjects received the local standard of care. We evaluated variation in perioperative care during the Norwood hospitalization across 14 trial sites.

METHODS

Data on preoperative, operative, and postoperative variables for 546 enrolled subjects who underwent the Norwood procedure were collected prospectively on standardized case report forms, and variation across the centers was described.

RESULTS

Gestational age, birth weight, and proportion with hypoplastic left heart syndrome were similar across sites. In contrast, all recorded variables related to preoperative care varied across centers, including fetal diagnosis (range, 55%-85%), preoperative intubation (range, 29%-91%), and enteral feeding. Perioperative and operative factors were also variable across sites, including median total support time (range, 74-189 minutes) and other perfusion variables, arch reconstruction technique, intraoperative medication use, and use of modified ultrafiltration (range, 48%-100%). Additional variation across centers was seen in variables related to postoperative care, including proportion with an open sternum (range, 35%-100%), median intensive care unit stay (range, 9-44 days), type of feeding at discharge, and enrollment in a home monitoring program (range, 1%-100%; 5 sites did not have a program). Overall, in-hospital death or transplant occurred in 18% (range across sites, 7%-39%).

CONCLUSIONS

Perioperative care during the Norwood hospitalization varies across centers. Further analysis evaluating the underlying causes and relationship of this variation to outcome is needed to inform future studies and quality improvement efforts.

Multidetector-row computed tomography visualized peripheral pulmonary artery patency in a patient with occluded modified Blalock-Taussig shunt

Multidetector-row computed tomography visualized peripheral pulmonary artery patency in a 19-year-old female with a single ventricle and an occluded Blalock-Taussig shunt whereas conventional invasive angiography did not.

Late emergency arterial duct stenting in a patient with tetralogy of Fallot and occluded Blalock-Taussig shunt

Over the last decade or so, stent implantation to the arterial duct has achieved acceptance as an alternative to aortopulmonary shunt procedure. We present the case of a patient with tetralogy of Fallot with diminished pulmonary flow and complete proximal occlusion of a right-sided Blalock-Taussig shunt. Surgical repair was not possible because of relative contraindications, and the interventional shunt recanalisation attempt was unsuccessful. The coronary stent was implanted into arterial duct. This resulted in oxygen saturation increase with normal contrast flow to the left pulmonary artery and right pulmonary artery (prior to the procedure we suspected non-confluent pulmonary artery). This brief report evaluates the feasibility of this new therapeutical option in such special patients with duct-dependent pulmonary blood flow.