Evaluation of tissue-engineered human acellular vessels as a Blalock-Taussig-Thomas shunt in a juvenile primate model.

Objectives: Palliative treatment of cyanotic congenital heart disease (CCHD) uses systemic-to-pulmonary conduits, often a modified Blalock-Taussig-Thomas shunt (mBTTs). Expanded polytetrafluoroethylene (ePTFE) mBTTs have associated risks for thrombosis and infection. The Human Acellular Vessel (HAV) (Humacyte, Inc) is a decellularized tissue-engineered blood vessel currently in clinical trials in adults for vascular trauma, peripheral artery disease, and end-stage renal disease requiring hemodialysis. In addition to restoring blood flow, the engineered HAV demonstrates the capacity for host cellular remodeling into native-like vasculature. Here we report preclinical evaluation of a small-diameter (3.5 mm) HAV as a mBTTs in a non-human primate model. Methods: We implanted 3.5 mm HAVs as right subclavian artery to pulmonary artery mBTTs in non-immunosuppressed juvenile rhesus macaques (n = 5). HAV patency, structure, and blood flow were assessed by postoperative imaging from 1 week to 6 months. Histology of HAVs and surrounding tissues was performed. Results: Surgical procedures were well tolerated, with satisfactory anastomoses, showing feasibility of using the 3.5 mm HAV as a mBTTs. All macaques had some immunological reactivity to the human extracellular matrix, as expected in this xenogeneic model. HAV mBTTs remained patent for up to 6 months in animals, exhibiting mild immunoreactivity. Two macaques displaying more severe immunoreactivity to the human HAV material developed midgraft dilatation without bleeding or rupture. HAV repopulation by host cells expressing smooth muscle and endothelial markers was observed in all animals. Conclusions: These findings may support use of 3.5 mm HAVs as mBTTs in CCHD and potentially other pediatric vascular indications.

Outcomes After Hybrid Palliation for Infants With Critical Left Heart Obstruction.

BACKGROUND: Hybrid palliation (bilateral pulmonary artery banding with or without ductal stenting) is an initial management strategy for infants with critical left heart obstruction and serves as palliation until subsequent operations are pursued. OBJECTIVES: This study sought to determine patient characteristics and factors associated with subsequent outcomes for infants who underwent hybrid palliation. METHODS: From 2005 to 2019, 214 of 1,236 prospectively enrolled infants within the Congenital Heart Surgeons' Society's critical left heart obstruction cohort underwent hybrid palliation across 24 institutions. Multivariable hazard modeling with competing risk methodology was performed to determine risk and factors associated with outcomes of biventricular repair, Fontan procedure, transplantation, or death. RESULTS: Preoperative comorbidities (eg, prematurity, low birth weight, genetic syndrome) were identified in 70% of infants (150 of 214). Median follow-up was 7 years, ranging up to 17 years. Overall 12-year survival was 55%. At 5 years after hybrid palliation, 9% had biventricular repair, 36% had Fontan procedure, 12% had transplantation, 35% died without surgical endpoints, and 8% were alive without an endpoint. Factors associated with transplantation were absence of ductal stent, older age, absent interatrial communication, smaller aortic root size, larger tricuspid valve area z-score, and larger left ventricular volume. Factors associated with death were low birth weight, concomitant genetic syndrome, cardiopulmonary bypass use during hybrid palliation, moderate to severe tricuspid valve regurgitation, and smaller ascending aortic size. CONCLUSIONS: Mortality remains high after hybrid palliation for infants with critical left heart obstruction. Nonetheless, hybrid palliation may facilitate biventricular repair for some infants and for others may serve as stabilization for intended functional univentricular palliation or primary transplantation.

A ROTEM-guided algorithm aimed to reduce blood product utilization during neonatal and infant cardiac surgery.

BACKGROUND: Neonates and infants undergoing cardiac surgery tend to receive high volumes of blood products. The use of rotational thromboelastometry (ROTEM®) has been shown to reduce the administration of blood products in adults after cardiac surgery. We sought to develop a targeted administration of blood products based on ROTEM® to reduce blood product utilization during and after neonatal and infant cardiac surgery. METHODS: We conducted a retrospective review of data from a single center for neonates and infants undergoing congenital cardiac surgery using cardiopulmonary bypass (CPB) from September 2018-April 2019 (control group). Then, using a ROTEM® algorithm, we collected data prospectively between April-November 2021 (ROTEM group). Data collected included age, weight, gender, procedure, STAT score, CPB time, aortic cross-clamp time, volume, and type of blood products administered in the operating room and cardiothoracic intensive care unit (CTICU). In addition, ROTEM® data, coagulation profile in CTICU, chest tube output at 6 and 24 hours, use of factors concentrate, and thromboembolic complications were recorded. RESULTS: The final cohort of patients included 28 patients in the control group and 40 patients in the ROTEM group. The cohort included neonates and infants undergoing the following procedures: arterial switch, aortic arch augmentation, Norwood procedure, and comprehensive stage II procedure. There were no differences in the demographics or procedure complexity between the two groups. Patients in the ROTEM® group received fewer platelets (36 ± 12 vs. 49 ± 27 mL/kg, p 0.028) and cryoprecipitate (8 ± 3 vs. 15 ± 10 mL/kg, p 0.001) intraoperatively when compared to the control group. CONCLUSION: The utilization of ROTEM® may have contributed to a significant reduction in some blood product administration during cardiac surgery for infants and neonates. ROTEM® data may play a role in reducing blood product administration in neonatal and infant cardiac surgery.

Patch Materials for Pulmonary Artery Arterioplasty and Right Ventricular Outflow Tract Augmentation: A Review.

Patch augmentation of the right ventricular outflow tract (RVOT) and pulmonary artery (PA) arterioplasty are relatively common procedures in the surgical treatment of patients with congenital heart disease. To date, several patch materials have been applied with no agreed upon clinical standard. Each patch type has unique performance characteristics, cost, and availability. There are limited data describing the various advantages and disadvantages of different patch materials. We performed a review of studies describing the clinical performance of various RVOT and PA patch materials and found a limited but growing body of literature. Short-term clinical performance has been reported for a multitude of patch types, but comparisons are limited by inconsistent study design and scarce histologic data. Standard clinical criteria for assessment of patch efficacy and criteria for intervention need to be applied across patch types. The field is progressing with improvements in outcomes due to newer patch technologies focused on reducing antigenicity and promoting neotissue formation which may have the ability to grow, remodel, and repair.

Proactive risk mitigation for cardiac arrest prevention in high-risk patients with congenital heart disease.

Objective: The prevalence of postoperative cardiac arrest (CA) increases with cardiothoracic surgical case complexity and is associated with a 40% to 50% mortality. Despite having a low overall surgical mortality rate at our center, our postoperative CA rates were higher than expected, with an observed-to-expected ratio of 2.6. Utilizing quality improvement methodology, we evaluated the influence of proactive risk mitigation on postprocedure CA in a high-risk cohort of pediatric cardiac patients. Methods: This single-center study utilized the Institute for Healthcare Improvement model. We created and implemented our Proactive Mitigation to Decrease Serious Adverse Events program in July 2020, prospectively enrolling preidentified high-risk patients. Enrolled patients underwent scheduled multidisciplinary reviews via virtual platform at 2 periprocedural time points with discussion of patient-specific risks and the subsequent development of proactive risk mitigation plans. Primary outcome measures were derived from the Pediatric Cardiac Critical Care Consortium national registry and included rate of postprocedure CA within 7 days and an institution-specific observed-to-expected ratio for postoperative CA. Results: Our baseline median number of high-risk cases between postprocedure CAs was 3. Following project initiation, median high-risk cases between events increased to 7. Our observed-to-expected ratio for postoperative CA decreased from 2.56 during the 12 months before Proactive Mitigation to Decrease Serious Adverse Events program implementation to 1.01 during the 12 months after Proactive Mitigation to Decrease Serious Adverse Events program implementation, and hospital length of stay decreased by ∼10 days. Conclusions: Implementation of periprocedure-related proactive risk mitigation strategies in high-risk pediatric cardiac patients led to improvement in postprocedure CA with a 133% increase in high-risk cases between events.

Preemptive stenting of the left pulmonary artery during comprehensive stage 2 procedure does not influence Fontan candidacy.

Objective: Pulmonary artery reconstruction during comprehensive stage 2 (CS2) procedure can be challenging. Since 2017, we have employed preemptive left pulmonary artery (LPA) stenting. We hypothesized that LPA stenting promotes adequate growth and without compromising Fontan candidacy. Herewith, we report our midterm results. Methods: From 2002 to 2020, 159 patients underwent CS2. Patients were divided as follows: no stent (n = 122; Group 1) and perioperative LPA stent (n = 37; Group 2). Group 2 was subdivided according to unplanned stent (n = 17; Group 2a) or preemptive stent (n = 20; Group 2b). Relevant perioperative data was reviewed. Nonparametric statistics were utilized. Results: Median age and weight at surgery and hospital length of stay after CS2 did not differ between groups. Median cardiopulmonary bypass and crossclamp times were significantly greater in Group 1 (265 vs 243 minutes [P = .021] and 46 vs 26 minutes [P = .008]). In-hospital mortality was similar between Groups 1 and 2 (9.0% vs 18.9%, respectively [P = .1348]). Group 2b demonstrated a superior survival compared to Group 2a (P = .0335) but not Group 1 (P > .9999). Preemptive stenting significantly increased median hilar LPA diameter at CS2 exit angiogram compared with no stenting (P < .0001). Groups 2a and 2b significantly increased the pre-Fontan diameter of the hilar LPA when compared with Group 1 (6.1 and 6.8 vs 5.7 mm, respectively [P < .0001]). A further 120 patients underwent Fontan operation (75%). Median follow-up for Groups 1 and 2 were 7.4 and 3.0 years, respectively. Conclusions: Perioperative LPA stenting during CS2 does not adversely affect pulmonary growth. Preemptive stenting seems advantageous for LPA growth in preparation for Fontan completion.

Norwood operation versus comprehensive stage II after bilateral pulmonary artery banding palliation for infants with critical left heart obstruction.

OBJECTIVE: To determine patient characteristics and outcomes after Norwood versus comprehensive stage II (COMPSII) for infants with critical left heart obstruction who had prior hybrid palliation (bilateral pulmonary artery banding ± ductal stent). METHODS: From 23 Congenital Heart Surgeons' Society institutions (2005-2020), 138 infants underwent hybrid palliation followed by either Norwood (n = 73, 53%) or COMPSII (n = 65). Baseline characteristics were compared between Norwood and COMPSII groups. Parametric hazard model with competing risk methodology was used to determine risk and factors associated with outcomes of Fontan, transplantation, or death. RESULTS: Infants who underwent Norwood versus COMPSII had a higher prevalence of prematurity (26% vs 14%, P = .08), lower birth weight (median 2.8 vs 3.2 kg, P < .01) and less frequent ductal stenting (37% vs 99%; P < .01). Norwood was performed at a median age of 44 days and median weight of 3.5 kg, versus COMPSII at 162 days and 6.0 kg (both P < .01). Median follow-up was 6.5 years. At 5 years after Norwood and COMPSII, respectively; 50% versus 68% had Fontan (P = .16), 3% versus 5% had transplantation (P = .70), 40% versus 15% died (P = .10), and 7% versus 11% are alive without transition, respectively. For factors associated with either mortality or Fontan, only preoperative mechanical ventilation occurred more frequently in the Norwood group. CONCLUSIONS: Higher prevalence of prematurity, lower birth weight, and other patient-related characteristics in the Norwood versus COMPSII groups may influence differences in outcomes that were not statistically significant for this limited risk-adjusted cohort. The clinical decision regarding Norwood versus COMPSII after initial hybrid palliation remains challenging.

Surgical outcomes of infective endocarditis in pediatrics: Moving the needle to a contemporary, multidisciplinary approach.

BACKGROUND: Infective endocarditis (IE) is an uncommon disease in children that, when present, is accompanied by significant morbidity and mortality. The presence of congenital heart disease often complicates management. The aim of the present study is to describe the characteristics and outcomes of children undergoing surgery for IE. METHODS: A retrospective chart review from 2004 to 2020 was conducted to identify consecutive patients younger than age 20 years with IE undergoing surgery. RESULTS: A total of 94 patients with IE were identified, of whom 47 underwent surgery at a median age of 16.7 years. Thirty-one patients (65.95%) had congenital heart disease. Vegetation and embolic phenomena occurred in 41 and 29 patients (87.23% and 61.7%), respectively, with the brain as most common location (57.1%). Native valve involvement had a greater tendency to embolize (P < .001). Staphylococcus spp was the most common organism (49%). The mitral valve was the most affected (31.9%). Seven (14.9%) patients had multivalvar involvement and valve replacement was the most common procedure performed (37 patients; 78.7%). There were 3 operative deaths (6.4%). Median length of hospital stay was 21 days. Risk factors for prolonged hospital stay were time to surgery in days (P < .001) and native valvar involvement (P = .05). Five patients (10.6%) had postoperative recurrent IE. Survival at 1 and 5 years was 93.6% and 89.4%, respectively. CONCLUSIONS: Children with IE can undergo surgery with acceptable results. The morbidity, but not mortality, is driven by embolic complications. Staphylococcus spp and native valve involvement are significant risk factors. VIDEO ABSTRACT.

Impact of Maternal-Fetal Environment on Outcomes Following the Hybrid Procedure in the Single Ventricle Population.

Treatment of infants with hypoplastic left heart syndrome (HLHS) remains challenging, and those affected remain with significant risks for mortality and morbidity throughout their lifetimes. The maternal-fetal environment (MFE) has been shown to affect outcomes for infants with HLHS after the Norwood procedure. The hybrid procedure, comprised of both catheterization and surgical components, is a less invasive option for initial intervention compared to the Norwood procedure. It is unknown how the MFE impacts outcomes following the hybrid procedure. This is a single-center, retrospective study of infants born with HLHS who underwent hybrid palliation from January 2009 to August 2021. Predictor variables analyzed included fetal, maternal, and postnatal factors. The primary outcome was mortality prior to Stage II palliation. We studied a 144-subject cohort. There was a statistically significant difference in mortality prior to stage II palliation in infants with prematurity, small for gestational age, and aortic atresia subtype (p < 0.001, p = 0.009, and p = 0.008, respectively). There was no difference in mortality associated with maternal diabetes, hypertension, obesity, smoking or illicit drug use, or advanced maternal age. State and national area deprivation index scores were associated with increased risk of mortality in the entire cohort, such that infants born in areas with higher deprivation had a higher incidence of mortality. Several markers of an impaired MFE, including prematurity, small for gestational age, and higher deprivation index scores, are associated with mortality following hybrid palliation. Individual maternal comorbidities were not associated with higher mortality. The MFE may be a target for prenatal counseling and future interventions to improve pregnancy and neonatal outcomes in this population.

Tricuspid Valve and Right Ventricular Function Throughout the Hybrid Palliation Strategy for Hypoplastic Left Heart Syndrome and Variants.

BACKGROUND: Tricuspid valve (TV) and right ventricular (RV) function are major determinants of morbidity and mortality in patients with hypoplastic left heart syndrome (HLHS). We sought to retrospectively evaluate these parameters throughout the hybrid palliation strategy. METHODS: From 2002 to 2018, 203 patients with HLHS and variants presented for hybrid stage I (HS1). Echocardiographic evaluation of tricuspid regurgitation (TR) and RV function was assessed at multiple time points. Clinical outcomes including tricuspid valvuloplasty, transplantation, and death were reviewed. RESULTS: The most prevalent HLHS subtype was aortic atresia/mitral atresia. The presence of significant TR and/or RV dysfunction was 14.78% and 9.36%, respectively, at the time of initial HS1. There were 185 survivors following HS1 (91.13%, n = 185/203), while 147 patients underwent comprehensive stage II or bidirectional Glenn shunt (72.41%, n = 147/203). Tricuspid valvuloplasty was undertaken in nine patients (4.86%, n = 9/185). Ultimately, 100 patients underwent the Fontan procedure. The odds of development of significant TR and/or RV dysfunction were not statistically different throughout the stages of palliation (TR: odds ratio [OR] = 0.14-0.25, P = .5260; RV dysfunction: OR = 0.02-0.13, P = .3992). However, the risk of death and/or transplant was 2.5- to 3.8-fold when either were present alone or in combination (TR: OR = 2.58, P = .0356; RV dysfunction: OR = 3.84, P = .0262). Transplant-free survival at 15 years was 44.8%. CONCLUSION: Following hybrid palliation for HLHS, the majority of survivors have normal RV and TV functions. Tricuspid valvuloplasty was required in few patients. Once significant TR and/or RV dysfunction ensues, there is a two- to three-fold risk of death and/or transplant.

Right aortic arch with situs solitus.

PATIENTS: We reviewed all patients evaluated at our center with situs solitus, levocardia, and a right aortic arch that were born between January 2000 and January 2018. RESULTS: From our databases, we identified 204 patients. We excluded patients with a double aortic arch from analysis. Of the 204 patients, 103 (50%) were male. Of the 204 patients, 95 (47%) had an isolated right aortic arch. Of the 95 with an isolated right aortic arch, 4 (4%) had chromosome 22q11.2 deletion syndrome, and 89 (94%) had a vascular ring. Of the 204 patients, 109 (53%) had a surgical intracardiac malformation. Of the 109, with an associated surgical intracardiac malformation, 38 (35%) had chromosome 22q11.2 deletion syndrome, and 28 (26%) had a vascular ring. Overall, of the 204 patients, 200 (98%) had a vascular ring, an associated intracardiac malformation, or both. Prenatal detection was 85% (40/47) for the subset of patients born in Southern Nevada between January 2015 and January 2018. CONCLUSION: this review, to best of our knowledge, reports one of largest series of right aortic arches in the literature. Data from our cohort demonstrates that a right aortic arch in situs solitus is almost always associated with pathology. Further, our center's right aortic arch prenatal detection rate exceeds previous reports.

A composite noninvasive index correlates with liver fibrosis scores in post-Fontan patients: Preliminary findings.

OBJECTIVE: We hypothesized that clinic-based, hepatic-ultrasound, elastography measurements, either alone or in combination with other noninvasive variables, might correlate with liver-biopsy fibrosis scores in patients post-Fontan. METHODS: Between March 2012 and February 2017, we identified patients post-Fontan that underwent elective cardiac catheterization and simultaneous transvenous hepatic biopsy. From this group, we selected patients that met inclusion criteria for liver-ultrasound, shear-wave elastography. Utilizing the results of elastography, laboratory testing, and time post-Fontan, we constructed a composite Fontan hepatic index as a sum of elastography measurements in kilopascals, model for end-stage liver disease excluding INR scores, and the square root of the number of years post-Fontan. Further, we analyzed correlations between Fontan hepatic index values and fibrosis scores from hepatic biopsy. RESULTS: We identified a total of 79 post-Fontan patients that underwent cardiac catheterization and liver biopsy. Of the 79 patients, 53 met inclusion criteria, and 32 consented to undergo hepatic-ultrasound elastography. Of the 32 that underwent elastography, data from 30 patients was used for analysis. We found no statistically significant differences in demographics, laboratory values, or cardiac catheterization data between the 30 included patients and the 21 that did not participate. Utilizing data from the 30 included patients, we found a strong, highly statistically significant correlation between the Fontan hepatic index values and total fibrosis scores (R = 0.8, P < .00001). However, the cohort size prevented reliable discriminating cut-off values for the range of total fibrosis scores. CONCLUSIONS: In a small cohort of patients post-Fontan, preliminary findings suggest that the composite Fontan hepatic index might be a clinically useful, noninvasive method of serially monitoring for hepatic fibrosis. Further studies, with large patient cohorts, are necessary to validate our findings and develop clinically useful discriminatory cutoff values.

Right aortic arch with situs solitus frequently heralds a vascular ring.

OBJECTIVE: We hypothesized that a right aortic arch in situs solitus, with or without an associated cardiovascular malformation, is often associated with a vascular ring. METHODS: From those born in Southern Nevada between March 2012 and March 2017, we identified 50 (3.6 per 10,000 live births) with a right aortic arch and situs solitus. From the 50 patients, 6 did not meet inclusion criteria for further analysis. RESULTS: Of the 44 remaining, 33 (75%) had a vascular ring. Of the 33 with a vascular ring, 26 (79%) occurred with an isolated right aortic arch, and 7 (21%) had an associated cardiovascular malformation. Of the total 44 patients with a right aortic arch in situs solitus, 34 (79%) were diagnosed prenatally. CONCLUSIONS: In conclusion, we found a right aortic arch in situs solitus was often associated with a vascular ring. Further, to the best of our knowledge, no previous general population study has demonstrated an equal or higher right aortic arch, prenatal detection rate of 79%.

Vascular Ring Diagnosis and Management: Notable Trends Over 25 Years.

BACKGROUND: Vascular rings (VRs) are recognized as uncommon but not rare cardiovascular malformations. METHODS: We analyzed data from all patients born in Southern Nevada, who underwent diagnosis and management of VR from 1990 to 2015, RESULTS: From 1990 to 2015, a total of 92 patients were diagnosed prenatally and postnatally. Of the 92 patients, 73 (79%) had right aortic arch and aberrant left subclavian artery (RAA-ALS) with a left ductus arteriosus or ligamentum, 17 (19%) had a double aortic arch (DAA), and 2 (2%) had a pulmonary artery sling. Of the 92 patients, 75 had an isolated VR and 17 VR had significant additional congenital heart disease (CHD). Of the 75 patients with an isolated VR, 52 underwent surgical repair, and the most common surgical diagnosis was DAA in 6 (66%) of 9 for the period 1990 to 2005 versus less common in 9 (21%) of 43 during the period 2006 to 2015, P < .05. The isolated VR repair age significantly negatively correlated with increasing time from 1990 to 2015, R = -0.7 (P < .0001). Of the 75 isolated VR, 23 remain asymptomatic. The 17 VR with CHD were treated during infant palliation or intracardiac repair. Of the total 92 VR, 60 were born after a 2004 community introduction of the three-vessel fetal echocardiography view, from then the prenatal-detection rate has significantly increased-2004 to 2006, 0 (0%) of 9; 2007 to 2009, 1 (9%) of 11; 2010 to 2012, 11 (55%) of 20; and 2013 to 1015, 14 (70%) of 20 (P < .0001). CONCLUSION: Over 25 years in Southern Nevada, VR prenatal diagnosis has increased, isolated VR age at surgery has decreased, and the percentage of those with RAA-ALS has increased.