Molecular Pathways and Animal Models of Tetralogy of Fallot and Double Outlet Right Ventricle.

Tetralogy of Fallot and double-outlet right ventricle are outflow tract (OFT) alignment defects situated on a continuous disease spectrum. A myriad of upstream causes can impact on ventriculoarterial alignment that can be summarized as defects in either i) OFT elongation during looping morphogenesis or ii) OFT remodeling during cardiac septation. Embryological processes underlying these two developmental steps include deployment of second heart field cardiac progenitor cells, establishment and transmission of embryonic left/right information driving OFT rotation and OFT cushion and valve morphogenesis. The formation and remodeling of pulmonary trunk infundibular myocardium is a critical component of both steps. Defects in myocardial, endocardial, or neural crest cell lineages can result in alignment defects, reflecting the complex intercellular signaling events that coordinate arterial pole development. Importantly, however, OFT alignment is mechanistically distinct from neural crest-driven OFT septation, although neural crest cells impact indirectly on alignment through their role in modulating signaling during SHF development. As yet poorly understood nongenetic causes of alignment defects that impact the above processes include hemodynamic changes, maternal exposure to environmental teratogens, and stochastic events. The heterogeneity of causes converging on alignment defects characterizes the OFT as a hotspot of congenital heart defects.

Fetal double outlet right ventricle without heterotaxy syndrome: Diagnostic spectrum, associated extracardiac pathology and clinical outcomes.

OBJECTIVES: To document the clinical spectrum and outcomes of fetal double outlet right ventricle (DORV) without heterotaxy in a recent diagnostic era. METHODS: Prenatal cases of DORV consecutively diagnosed from 2007 to 2018 were retrospectively identified. Clinical records, including details regarding genetic testing and pre and postnatal imaging were reviewed. RESULTS: DORV was diagnosed in 99 fetuses without heterotaxy. The most common anatomic subtype was subaortic ventricular septal defect (VSD) and normally related great arteries with (n = 45, 45%) or without (n = 13, 13%) pulmonary stenosis. The remainder had a subpulmonic VSD with transposed great arteries (n = 15, 15%), atrioventricular valve atresia (n = 24, 24%), or remote VSD (n = 2, 2%). A genetic diagnosis was found in 32 (34%) of 93 tested. Major extracardiac anomalies were found in 40 (40%), including 17/24 (71%) with and 22/69 (32%) without an abnormal karyotype, with VACTERL association in 9. Genetic and/or extracardiac pathology was identified in 37/58 (64%) with a subaortic VSD, 5/15 (33%) with a subpulmonic VSD, 9/24 (38%) of those with AV valve atresia and 2/2 (100%) with a remote VSD. A genetic abnormality was a significant predictor of fetal demise (9/37 vs 1/62 p < 0.01) or pregnancy termination (12/35 vs 9/64 p = 0.03). CONCLUSIONS: Fetal DORV is associated with a high rate of genetic abnormalities and extracardiac pathology. The presence of genetic abnormalities impacts prenatal outcomes and parental decision-making.

Arterial switch operation for Taussig-Bing anomaly with aortic arch obstruction.

INTRODUCTION: The short-term survival rate after single-stage correction of Taussig-Bing anomaly with aortic arch obstruction remains favorable. However, some cases are encountered occasionally in which single-stage correction was not performed during the neonatal period. Accordingly, we evaluated the midterm outcomes of different surgical strategies. METHODS: Seven patients who underwent an arterial switch operation and intraventricular rerouting as definitive surgery between 2007 and 2017 were investigated. Of these 7 patients, 3 had undergone previous pulmonary artery banding and aortic arch reconstruction. RESULTS: The median body weight at definitive surgery was 3.3 kg (range 2.9-8.3 kg). At definitive surgery, the arrest time for single-stage correction (162.3 ± 21.7 min) was significantly shorter than that of staged repair (206.3 ± 5.1 min, p = 0.020). There was no hospital or late death. One patient in both strategy groups underwent aortic reintervention 54 months and 7.1 months after the definitive operation. Neoaortic valve (perinatal pulmonary valve) diameter decreased significantly from the perinatal valve diameter following definitive surgery (median +4.94z and +2.12z, respectively, p = 0.016) but there was no significant difference in the neopulmonary valve (perinatal aortic valve) diameter. Both single-stage correction and staged repair patients showed a similar trend. At the last follow-up, no patient had greater than mild neoaortic or neopulmonary valve regurgitation. CONCLUSION: The surgical outcomes of both single-stage correction and staged correction for Taussig-Bing anomaly with aortic arch obstruction are excellent. Both strategies produce similar changes in the diameter and regurgitation grade of the neoaortic and neopulmonary valves.

Diagnostic performance of fetal intelligent navigation echocardiography (FINE) in fetuses with double-outlet right ventricle (DORV).

The main objective of this study was to investigate the diagnostic performance of FINE in generating and displaying 3 specific abnormal fetal echocardiography views such as left ventricular outflow tract (LVOT) view, right ventricular outflow tract (RVOT) view, and 3-vessels and trachea (3VT) view in fetuses with double-outlet right ventricle (DORV). In this prospective study, thirty fetuses diagnosed with DORV by fetal echocardiography in the second and third trimesters were enrolled. One or more STIC volume data-sets were collected from the 4-chamber view as initial view for each fetus, one optimal volume per fetus was selected for on-line analysis using FINE, and the diagnosis plane image was optimized using the Virtual Intelligent Sonographer Assistance (VIS-assistance).The visualization rates of 3 specific abnormal fetal echocardiography views of DORV and key diagnostic elements were calculated. One or more STIC volumes (n = 30 total) were obtained in 25 patients. A single STIC volume per patient was analyzed using the FINE method. FINE was able to successfully generate and display 3 specific abnormal fetal echocardiography views. The display rates of the 3 specific abnormal fetal echocardiography views (3VT, LVOT, RVOT) were 84.0%, 76.0% and 84.0%, respectively. By applying intelligent navigation technology to STIC volume data-sets, the FINE method can successfully generate three specific abnormal cardiac fetal echocardiography diagnostic views in fetuses with DORV, the FINE method can be used for screening and remote consultation of fetal DORV.

Effect of Stiffened and Dilated Ascending Aorta on Aerobic Exercise Capacity in Repaired Patients With Complex Congenital Heart Disease.

Several studies have reported aortic dilation and increased stiffness of the ascending aorta in patients after repair of congenital heart disease (CHD), which may be a predominant cardiovascular risk. However, the clinical significance has not been described in detail. In this retrospective study, 175 repaired patients with complex CHD achieving biventricular circulation and age-matched 39 control subjects were reviewed (median age: 14.9 and 15.7 years, respectively). We measured the diameters of the ascending aorta and descending aorta from catheterization angiograms to yield Z-scores and stiffness indexes (ß) using diameter fluctuations corresponding to pulsatile pressures. Clinical profile, peak oxygen uptake during the cardiopulmonary exercise test, and incidence of unscheduled hospitalization during follow-up was also reviewed. Compared with controls, patients with complex CHD, except for those with aortic coarctation, exhibited significant dilation and increased stiffness of the aortic root and ascending aorta, but not of the descending aorta. In this CHD population (n = 147, including 112 conotruncal anomalies), exercise capacities correlated independently with the diameter Z-score and stiffness index of the ascending aorta along with the history of repetitive thoracotomies, reduced forced vital capacity, and right ventricular hypertension. During a follow-up period (median 15.6 years), either dilation (Z-score >3.5) or increased stiffness (ß >6.0) of the ascending aorta stratified morbidity, but no synergistic impact was detected. In conclusion, in repaired patients with complex CHD, a stiffened and dilated ascending aorta was frequently found, exerting significant adverse impacts on diminished exercise capacity and morbidity.

Personalized Perioperative Multi-scale, Multi-physics Heart Simulation of Double Outlet Right Ventricle.

For treatment of complex congenital heart disease, computer simulation using a three-dimensional heart model may help to improve outcomes by enabling detailed preoperative evaluations. However, no highly integrated model that accurately reproduces a patient's pathophysiology, which is required for this simulation has been reported. We modelled a case of complex congenital heart disease, double outlet right ventricle with ventricular septal defect and atrial septal defect. From preoperative computed tomography images, finite element meshes of the heart and torso were created, and cell model of cardiac electrophysiology and sarcomere dynamics was implemented. The parameter values of the heart model were adjusted to reproduce the patient's electrocardiogram and haemodynamics recorded preoperatively. Two options of in silico surgery were performed using this heart model, and the resulting changes in performance were examined. Preoperative and postoperative simulations showed good agreement with clinical records including haemodynamics and measured oxyhaemoglobin saturations. The use of a detailed sarcomere model also enabled comparison of energetic efficiency between the two surgical options. A novel in silico model of congenital heart disease that integrates molecular models of cardiac function successfully reproduces the observed pathophysiology. The simulation of postoperative state by in silico surgeries can help guide clinical decision-making.

Percutaneous edge-to-edge repair for common atrioventricular valve regurgitation in a patient with heterotaxy syndrome, single ventricle physiology, and unbalanced atrioventricular septal defect.

Congenital heart disease patients, specifically with unbalanced atrioventricular septal defects and common atrioventricular valves requiring single ventricle palliation, have substantial morbidity and mortality. Atrioventricular valve regurgitation (AVVR) is associated with poor outcomes in single ventricle patients, and many of them require surgical treatment of AVVR in their lifetimes. We describe a unique case of transcatheter edge-to-edge valve repair using the MitraClip system (Abbott, Chicago, IL) in a single ventricle patient with severe common AVVR.

Biventricular repair of double-outlet right ventricle with noncommitted ventricular septal defect using intraventricular conduit.

OBJECTIVE: Biventricular repair of double-outlet right ventricle with noncommitted ventricular septal defect is preferred, but previously developed surgical procedures are complicated and associated with high mortality and morbidity. We developed a technique using an intraventricular conduit to connect the ventricular septal defect and the aorta in this anomaly in patients aged more than 2 years. METHODS: Thirty-one patients (age 2-23 years; median, 5.4) with double-outlet right ventricle with noncommitted ventricular septal defect underwent biventricular repair with intraventricular conduit. A 16-mm or 19-mm polytetrafluoroethylene (Gore-Tex; WL Gore & Associates, Flagstaff, Ariz) vascular prosthesis was used to construct the intraventricular conduit rerouting the ventricular septal defect to the aorta, with enlargement of the ventricular septal defect and resecting the hypertrophic muscular bands in the bilateral conus when necessary. Follow-up was made in all patients with a median duration of 93 months (range, 8-140 months). RESULTS: One patient died during hospitalization and 1 patient died at 8 months after operation, making the mortality 6.5%. The peak pressure gradient across the left ventricular outflow tract was less than 30 mm Hg in all patients but 1 (3.3%). In the last patient, it increased from 16 mm Hg early after operation to 50 mm Hg at 7 years follow-up. The peak pressure gradient across the right ventricular outflow tract ranged from 6 to 30 mm Hg in all patients. One patient had moderate mitral regurgitation with New York Heart Association class II. One patient had preoperative severe pulmonary arterial hypertension (mean pressure, 50 mm Hg) and was treated with bosentan. Other patients were in New York Heart Association class I. CONCLUSIONS: Biventricular repair with intraventricular conduit is a relatively simple and safe procedure for patients aged more than 2 years with double-outlet right ventricle with noncommitted ventricular septal defect, with excellent early and midterm outcomes.

Fetuses with single ventricle congenital heart disease manifest impairment of regional brain growth.

OBJECTIVE: Anomalous neurological development associated with congenital heart disease (CHD) has been reported as early as third trimester of fetal development. While several studies have characterized variations in CHD neurodevelopmental outcomes in early childhood, these reports are often confounded by postnatal factors such as surgical outcome. Recent studies have focused on the comparing neurological variations between fetuses with CHD and normal controls. In this work, we present a comparison of in utero variations in brain development between fetuses with different types of CHD, by analyzing them under categories of single ventricle versus biventricular cardiac anatomy. METHODS: Using recent advances in fetal magnetic resonance imaging (MRI), we quantify the volumetric trajectories of various brain tissues (such as cortical plate, developing white matter, cerebrospinal fluid [CSF], and cerebellum). RESULTS: Our study is the first to differentiate between intraventricular and extra-axial CSF thereby allowing us to better identify variations in brain composition of the fetuses. CONCLUSIONS: Overall, our findings show that while total brain volume is similar between fetuses with single and biventricular anatomy, they exhibit statistically significant disparity in brain composition.

Edwards Sapien XT® pulmonic valve compression after resuscitation and successful redilatation.

Despite the increasing use of percutaenous valves, little is known about valve performance after external chest compression. We report a case of a compressed pulmonary Edwards Sapien® XT valve after resuscitation. With the patient on ECMO, successful redilatation was performed with unimpaired postprocedural valve function. We aim to increase the awareness for valve distortion after external chest compression with increasing numbers of transcatheter valvulations. We suggest that immediate re-evaluation of the implanted device via biplane fluoroscopy is mandatory after resuscitation in such cases.

Echocardiographic Classification and Surgical Approaches to Double-Outlet Right Ventricle for Great Arteries Arising Almost Exclusively from the Right Ventricle.

Selecting an appropriate surgical approach for double-outlet right ventricle (DORV), a complex congenital cardiac malformation with many anatomic variations, is difficult. Therefore, we determined the feasibility of using an echocardiographic classification system, which describes the anatomic variations in more precise terms than the current system does, to determine whether it could help direct surgical plans. Our system includes 8 DORV subtypes, categorized according to 3 factors: the relative positions of the great arteries (normal or abnormal), the relationship between the great arteries and the ventricular septal defect (committed or noncommitted), and the presence or absence of right ventricular outflow tract obstruction (RVOTO). Surgical approaches in 407 patients were based on their DORV subtype, as determined by echocardiography. We found that the optimal surgical management of patients classified as normal/committed/no RVOTO, normal/committed/RVOTO, and abnormal/committed/no RVOTO was, respectively, like that for patients with large ventricular septal defects, tetralogy of Fallot, and transposition of the great arteries without RVOTO. Patients with abnormal/committed/RVOTO anatomy and those with abnormal/noncommitted/RVOTO anatomy underwent intraventricular repair and double-root translocation. For patients with other types of DORV, choosing the appropriate surgical approach and biventricular repair techniques was more complex. We think that our classification system accurately groups DORV patients and enables surgeons to select the best approach for each patient's cardiac anatomy.

Xq26.1-26.3 duplication including MOSPD1 and GPC3 identified in boy with short stature and double outlet right ventricle.

Xq25q26 duplication syndrome has been reported in individuals with clinical features such as short stature, intellectual disability, syndromic facial appearance, small hands and feet, and genital abnormalities. The symptoms are related to critical chromosome regions including Xq26.1-26.3. In this particular syndrome, no patient with congenital heart disease was previously reported. Here, we report a 6-year-old boy with typical symptoms of Xq25q26 duplication syndrome and double outlet right ventricle (DORV) with pulmonary atresia (PA). He had the common duplicated region of Xq25q26 duplication syndrome extending to the distal region including the MOSPD1 locus. MOSPD1 regulates transforming growth factor beta (TGFß) 2,3 and may be responsible for cardiac development including DORV. In the patient's lymphocytes, mRNA expression of TGFß2 was lower than control, and might cause DORV as it does in TGFß2-deficient mice. Therefore, MOSPD1 is a possible candidate gene for DORV, probably in combination with GPC3. Further studies of the combined functions of MOSPD1 and GPC3 are needed, and identification of additional patients with MOSPD1 and GPC3 duplication should be pursued.

Double-outlet right ventricle revisited.

OBJECTIVES: Double-outlet right ventricle is a form of ventriculoarterial connection. The definition formulated by the International Society for Nomenclature of Paediatric and Congenital Heart Disease is based on hearts with both arterial trunks supported in their greater part by a morphologically right ventricle. Bilateral infundibula and ventricular septal defects are highly debated criteria. This study examines the anatomic controversies surrounding double-outlet right ventricle. We show that hearts with double-outlet right ventricle can have atrioventricular-to-arterial valvular continuity. We emphasize the difference between the interventricular communication and the zone of deficient ventricular septation. METHODS: The hearts examined were from the University of Florida in Gainesville; Johns Hopkins All Children's Hospital, St Petersburg, Fla; and Lurie Children's Hospital, Chicago, Ill. Each specimen had at least 75% of both arterial roots supported by the morphologically right ventricle, with a total of 100 hearts examined. The morphologic method was used to assess anatomic features, including arterial-atrioventricular valvular continuity, subarterial infundibular musculature, and the location of the hole between the ventricles. RESULTS: Most hearts had fibrous continuity between one of the arterial valves and an atrioventricular valve, with bilateral infundibula in 23%, and intact ventricular septum in 5%. CONCLUSIONS: Bilateral infundibula are not a defining feature of double-outlet right ventricle, representing only 23% of the specimens in our sample. The interventricular communication can have a posteroinferior muscular rim or extend to become perimembranous (58%). Double-outlet right ventricle can exist with an intact ventricular septum.

Impedance to retrograde and forward flow in chronic mitral regurgitation and the physiology of a double outlet ventricle.

OBJECTIVE: Mitral regurgitation (MR) is generally characterised as exhibiting a 'low impedance leak into the left atrium'. This notion is widely accepted without measured impedance data. The aim of this study was to define the impedance to retrograde and forward blood flow and to examine hydraulic (pressure-volume) and mechanical (stress-shortening) function in chronic severe MR. METHODS: A mathematical model of a double outlet ventricle was developed and the ratio of retrograde to forward impedance was plotted over a wide range of regurgitant fraction (RF). The model predicts that an impedance ratio >1 indicates that the impedance to retrograde flow exceeds that of forward flow. Left ventricular (LV) systolic pressure/flow rate was used as an index of impedance (mm Hg/mL/s). Data from 10 patients with severe MR were used to assess the clinical applicability of the model. All patients had degenerative valve disease with partial flail leaflet, an RF >50% and an ejection fraction (EF) >0.60. There were seven males and three females, aged 59±10. LV volumes as well as retrograde and forward flow rates were determined with echocardiographic and Doppler techniques. RESULTS: The model indicates that the impedance ratio is >1 when the RF ranges from zero to 57%. Clinical data: end-diastolic volume=184±47 mL; EF=0.63±3%; RF=53±4%. Values for retrograde and forward impedance were 0.77±0.17 and 0.63±0.12 (p=0.003); the impedance ratio was 1.22±0.19. Total impedance to LV emptying was low (0.35±0.06). The ratio of systolic wall stress to EF (580±81 g/cm2) was normal. Data are mean±SD. CONCLUSIONS: The model, supported by clinical data, indicates that the impedance to retrograde flow exceeds the impedance to forward flow in chronic severe MR. These findings refute the notion of a low impedance leak into the left atrium. The double outlet of an enlarged ventricle provides a mechanism for low total impedance to ejection in the presence of a normal stress-shortening relation.