Bridging Leaflets Research Articles

Atrioventricular septal defect: An extended approach to prenatal sonographic imaging of the atrioventricular valves

AbstractAn atrioventricular septal defect (AVSD) is diagnosed with prenatal sonography using the 4‐chamber view (4CV) of the fetal heart. Prenatal 2D sonographic imaging of normal and AVSD short axis (SAX) atrioventricular (AV) valve views have not been well described. The aim is to describe the 2D sonographic 4‐chamber and SAX view of the AV valves when an AVSD is present compared to normal AV valves. The 4CV AVSD heart demonstrates no offset of AV valves due to the abnormal valve structure. Complete and intermediate AVSD has a septum primum defect and inlet ventricular septal defect (VSD). The partial AVSDs have either a septum primum defect or just an inlet VSD with an intact primum septum. The SAX view of AVSD demonstrates the common AV junction and the bridging leaflets. In ventricular diastole valves have a “figure 8” and “dumbbell” shape in partial and complete AVSD, respectively. These appearances are not seen in the normal heart in SAX as both tricuspid and mitral valve are separate valves. The SAX view can be obtained by locating a sagittal aortic arch view and then scanning slightly towards the left side of the fetus, near the base of the heart and the AV valves. An in‐depth interrogation of the abnormal fetal heart is obtained without specialised 4D capable ultrasound machines providing information to assist in counselling during the pregnancy and for postnatal surgical planning. Future research to assess the feasibility of incorporating the SAX view into routine practice and by general sonographers is suggested.

Abstract 12837: A Novel Index to Predict Post-Operative Left Atrioventricular Valve Morbidity in Atrioventricular Septal Defects

Introduction: Morbidity of the left atrioventricular valve (LAVV) remains the leading indication for reoperation on atrioventricular septal defects (AVSDs). While qualitative 2D and quantitative 3D risk factors have been identified, no quantitative 2D measurement yet exists to predict poor postoperative outcomes. The aim of this study was to evaluate objective measurements of the LAVV and subvalvar apparatus in relation to postoperative outcomes. Methods: A retrospective review was performed on 2D echocardiograms of patients undergoing surgical repair of an AVSD from January 1, 2014 to December 31, 2021. Demographic and perioperative data were collected from the electronic medical record. The hingepoint-to-hingepoint length of the superior, mural and inferior bridging leaflets in early diastole, as well as LAVV chordal length at end-diastole were measured and indexed to body surface area. A poor outcome was defined by significant LAVV regurgitation (moderate or greater), LAVV stenosis (5mmHg or greater), need for second cardiopulmonary bypass run, postoperative ECMO, reoperation, or death. LAVV measurements were compared to composite outcome by Wilcoxon rank sum test. Results: Of 120 patients with adequate perioperative imaging, 47 (39.2%) had a poor outcome. Indexed LAVV chordal length was significantly different between those who experienced a poor outcome and those who did not, with shorter chordal length predictive of a poor outcome. Interestingly, mural leaflet size was not associated with a poor outcome. Conclusions: Indexed LAVV chordal length is a novel measurement shown to predict a poor postoperative outcome in AVSD. Additional analysis is necessary to assess whether short chords are more predictive of LAVV regurgitation or stenosis, and to determine a numeric cut-off of indexed chordal length for predicting poor outcome.

Repair of Common Atrioventricular Valve in Univentricular Circulation Using Adjustable Annular Bridging Technique

The main reason for common atrioventricular valve regurgitation is the enlargement of the valve annulus contralaterally to the aorta and pulmonary artery. Edge-to-edge repair can be used to address the regurgitation; however, there might be potential disadvantage that a fixed bridging leaflet could have a restrictive motion, leading to recurrence of atrioventricular valve regurgitation. To avoid this issue and address the anteroposterior dilatation of the annulus, we have developed an adjustable annular bridging technique. The main reason for common atrioventricular valve regurgitation is the enlargement of the valve annulus contralaterally to the aorta and pulmonary artery. Edge-to-edge repair can be used to address the regurgitation; however, there might be potential disadvantage that a fixed bridging leaflet could have a restrictive motion, leading to recurrence of atrioventricular valve regurgitation. To avoid this issue and address the anteroposterior dilatation of the annulus, we have developed an adjustable annular bridging technique. Commentary: The Adjustable Bridge – Definitely a Useful Technique; HoweverOperative Techniques in Thoracic and Cardiovascular SurgeryVol. 27Issue 3PreviewI am grateful to the authors and commend them for sharing their technique of adjustable annular bridge for patients with single-ventricle (SV) hearts and atrioventricular valve regurgitation (AVVR).1 They have provided clear technical detail and excellent illustrations and video. No one questions the significance of AVVR in these patients, its significant impact on prognosis, and the difficulty in achieving durable, excellent valve competence. Likewise, we acknowledge the numerous technical repair tools at our disposal and that frequently we use most, if not all, of them in any given case (side to side, cleft or scallop closure, various degrees of annuloplasty, etc.). Full-Text PDF Commentary: Atrioventricular Valve Repair in Univentricular Hearts: No Longer a Bridge Too Far?Operative Techniques in Thoracic and Cardiovascular SurgeryVol. 27Issue 3PreviewIt is increasingly apparent that atrioventricular valve (AVV) failure is a major cause of mortality in patients with a Fontan circulation.1 Furthermore, patients with a common AVV are at the highest risk of AVV failure among those with a Fontan circulation.1-4 Atrioventricular valve repair is notoriously difficult in the setting of a common AVV, and failed repair is associated with very high mortality.3 One of the major contributing factors to AVV failure in these patients is the attenuated fibrous skeleton of the heart, which increases the risk of annular dilatation. Full-Text PDF

Long-Term Outcome Up To 40 Years after Single Patch Repair of Complete Atrioventricular Septal Defect in Infancy or Childhood.

Objectives Patients with repaired complete atrioventricular septal defect (CAVSD) represent an increasing portion of grown-ups with congenital heart disease. For repair of CAVSD, the single-patch technique has been employed first. This technique requires division of the bridging leaflets, thus, among other issues, long-term function of the atrioventricular valves is of particular concern. Methods Between 1978 and 2001, 100 consecutive patients with isolated CAVSD underwent single-patch repair in our institution. Hospital mortality was 11%. Primary endpoints were clinical status, atrioventricular valve function, and freedom from reoperation in long term. Follow-up was obtained contacting the patient and/or caregiver, and the referring cardiologist. Results Eighty-three patients were eligible for long-term follow-up (21.0 ± 8.7, mean ± standard deviation [21.5; 2.1–40.0, median; min–max] years after surgical repair). Actual long-term mortality was 3.4%. Quality of life (QoL; self- or caregiver-reported in patients with Down syndrome) was excellent or good in 81%, mild congestive heart failure was present in 16%, moderate in 3.6% as estimated by New York Heart Association classification. Echocardiography revealed normal systolic left ventricular function in all cases. Regurgitation of the right atrioventricular valve was mild in 48%, mild–moderate in 3.6%, and moderate in 1.2%. The left atrioventricular valve was mildly stenotic in 15% and mild to moderately stenotic in 2%; regurgitation was mild in 54%, mild to moderate in 13%, and moderate in 15% of patients. Freedom from left atrioventricular-valve-related reoperation was 95.3, 92.7, and 89.3% after 5, 10, and 30 years, respectively. Permanent pacemaker therapy, as an immediate result of CAVSD repair ( n = 7) or as a result of late-onset sick sinus syndrome ( n = 5), required up to six reoperations in single patients. Freedom from pacemaker-related reoperation was 91.4, 84.4, and 51.5% after 5, 10, and 30 years, respectively. Conclusion Up to 40 years after single-patch repair of CAVSD, clinical status and functional results are promising, particularly, in terms of atrioventricular valve function. Permanent pacemaker therapy results in a life-long need for surgical reinterventions.

Ellis-Van-Creveld Syndrome and Congenital Cardiac Anomaly: Common Atrium with Atrioventricular Canal Septal Defect

Background: Children presenting with physical features of chondro-ectodermal dysplasia (Ellis-Van Creveld syndrome) such as skeletal and joint abnormalities often have concomitant congenital cardiac anomalies. Presence of cardiorespiratory symptoms in children with Ellis-Van Craved syndrome warrants a thorough cardiologic evaluation to recognize and treat underlying congenital heart anomaly. Aim: A child with physical stigmata of Ellis-Van-Creveld syndrome is evaluated to detect an associated congenital cardiac anomaly and accomplish successful repair of the underlying cardiac lesion to reduce the cardiac related morbidity and improve the patient survival. Case Presentation: Ten years old boy with chondroectodermal dysplasia (dental anomalies, genu valgum and other skeletal abnormalities) presented with dyspnea and cyanosis. Cardiac evaluation by 2D echo revealed an atrioventricular (AV) canal septal defect with AV valve regurgitation and a common atrium. Angiocardiography showed a goose neck deformity of the left ventricular outflow tract. The Qp/Qs was 3.4: 1, with systemic arterial oxygen desaturation (SaO2 of 0.7) and O2 saturation in the common atrium was 0.7. The pulmonary venous connections to the common atrium were anomalous. Atriotomy on cardiopulmonary bypass and on a cardioplegic arrest discerned a partial AV canal septal defect with a common bridging leaflet, clefts in septal leaflets of tricuspid and mitral vlalves, an incompletely closed interventricular communication, and a common atrium with highly anomalous pulmonary venous insertions well anterior (8 cm) to vena caval orifices. Intracardiac repair was performed with two patches of Goertex to partition the common atrium into the pulmonary and systemic venous chambers after repair of the partial AV canal septal defect. Patient required only a temporary afterload reduction with enalapril; otherwise patient had an uneventful postoperative course. At a 2-year follow-up, the child was well without AV valve regurgitation and had normal biventricular function. Conclusion: A child with Ellis-Van-Creveld syndrome with skeletal abnormalities and dental anomalies had manifested with cardio-respiratory symptoms. Preoperative cardiac and intraoperative evaluation showed a common atrium with severely anomalous pulmonary venous connection and partial AV canal septal defect. Successful biventricular repair was accomplished by repairing the partial AV canal septal defect and partitioning the common atrium into left and right atrium by a complex atrial routing technique with two patches of Gore-Tex. On a follow-up at 2 years, the patient had adequate biventricular function without AV valve regurgitation. 114264

Echocardiographic assessment of atrioventricular canal defects

AV canal defects (AVCD) are caused by maldevelopment of the endocardial cushions and typically include a primum atrial septal defect (ASD), an inlet ventricular septal defect (VSD), and a common atrioventricular valve. The variations in deformities provide the basis for the many terms used in the anatomical classifications: partial, transitional, intermediate, and complete common AVCD (balanced or unbalanced). The balanced complete common AVCDs are classified as Rastelli A, B, C depending on the anomaly of the anterior bridging leaflet division and attachments. Unbalanced complete AVCDs occur when the common AV valve leads primarily into the RV or LV. Echocardiographic apical, subcostal, and parasternal views are the best views to image AV canal defects. These views can help determine the type of repair required for the various AV canal defects.

Ventriculoatrial malalignment in atrioventricular septal defect resulting in uniatrial biventricular connection: surgical options

BackgroundUniatrial biventricular connection (UBC) is a rare cardiovascular anomaly characterized by absence of one atrioventricular connection and drainage of the other atrium via a solitary atrioventricular valve into both ventricles. The absent atrioventricular connection may affect either the left or right atrium. Because of the absence of one atrioventricular connection hearts with UBC have been classified among functionally univentricular hearts requiring palliative treatment according to the Fontan principle.Aims/objectiveWe report two further patients with UBC. In one of these patients careful echocardiographic examination of the atrioventricular junction in early infancy revealed the possibility of biventricular repair based on the favorable anatomy of the atrioventricular valve and balanced ventricles in the presence of an inlet ventricular septal defect (VSD).Case presentationsBoth patients presented in the neonatal period for evaluation of complex congenital heart disease. The anatomy of the atrioventricular valves in our patients was indistinguishable from atrioventricular septal defects exhibiting the morphology of a common valve with superior and inferior bridging leaflets. The common atrioventricular valve was connected exclusively to the right atrium draining into both ventricles while the left atrium drained into the right atrium via a secundum atrial septal defect. In one of our patients biventricular repair with good longterm-result was performed by reseptation of the atria, patch repair of the VSD and septation of the atrioventricular valve. The second patient underwent univentricular palliation according to the Fontan principle.Discussion/conclusionThe echocardiographic findings in our patients suggest that at least some patients with UBC represent a variant of atrioventricular septal defects associated with extreme ventriculoatrial malalignment resulting in fusion of the deviated primary atrial septum with the lateral aspect of the atrioventricular junction. This offers the option of septation of the common atrioventricular valve and biventricular repair in patients with adequate size of both ventricles. Exact echocardiographic analysis of the morphology of the atrioventricular valve is essential to distinguish these patients with a morphologically common atrioventricular valve in early infancy from other variants of absent atrioventricular connection and to select those who are suitable for biventricular repair.

A New Method for Atrioventricular Valve Repair in Atrioventricular Septal Defect

The left atrioventricular valve in atrioventricular septal defect is conventionally repaired by suturing the "cleft." This can be complicated with stretching or dehiscence of the sutured zone by naturally diverging cordal traction and stenosis by restricting leaflet mobility. This complication prompted us to develop a different approach, especially for adults and adolescents, who might have undergone surgical repair previously. The technique consists of not closing or reopening the cleft, constructing neocordae connecting the cordless edge of each bridging leaflet to the opposite papillary muscle-that is, the papillary muscle to which it has no natural connection ("crossing neocordae")-and inserting an annuloplasty ring.

Surgical repair of atrioventricular septal defects: incidence and mode of failure of the left atrioventricular valve.

Our goal was to investigate the outcome of the left atrioventricular valve (LAVV) after repair of atrioventricular septal defects (AVSDs) by analysing the mechanisms of LAVV failure. A retrospective investigation of 202 children with AVSD, operated on between 1992 and 2016, was performed. Analysis focused on freedom from reoperation for LAVV dysfunction, with specific attention to the modes of failure. The population consisted of 129 (64%) patients with complete AVSD (cAVSD) and 73 (36%) patients with partial AVSD (pAVSD), corrected at a median age of 3.9 (interquartile range 3.4) months and 29.0 (interquartile range 90.4) months, respectively. Within a median follow-up period of 5.9 (interquartile range 12.6) years, 27 (13.4%) patients required reoperation for LAVV failure, respectively, in 17 (13.2%) patients with cAVSD and 10 (13.9%) patients with pAVSD. Freedom from reoperation for LAVV at 10 years was 87 ± 4% for cAVSD and 87 ± 5% for pAVSD (P = 0.789). The failure mode was predominantly technical in cAVSD (71% vs 20% in pAVSD), whereas residual anatomical anomalies entailed more frequently LAVV regurgitation (LAVVR) in pAVSD (80% vs 29% in cAVSD) (P = 0.018). Cleft suture dehiscence (n = 8) and incomplete cleft closure (n = 6) were considered technical failures, whereas remnant distortions of the subvalvular apparatus (n = 9), small asymmetric bridging leaflet (n = 2), double orifice (n = 1) and additional cleft (n = 1) were considered anatomical lesions. The incidence of repair at the 1st reoperation was 92.6%. Eight patients needed a 2nd and 2 patients a 3rd repeat LAVV operation. Five patients finally ended with a mechanical prosthesis. In the long term, patients with AVSD are still subject to LAVV failure. Despite systematic cleft closure, patients with cAVSD develop LAVV failure mainly because of a recurrent/residual deficit at the cleft, amenable to technical improvement. Patients with pAVSD need increased attention for additional anatomical features of the LAVV at the time of primary repair.

Augmentation of Bridging Leaflets in Repair of Atrioventricular Canal Defects

Left atrioventricular (AV) valve regurgitation is the most common complication after a atrioventricular canal defect (AVCD) repair. Despite what appears to be a less complex repair, patients with partial and transitional AV canal have higher reoperation rates for left AV valve regurgitation and left ventricular outflow tract (LVOT) obstruction. Retraction of bridging leaflets with secondary attachments to the septal crest commonly produces increased tension and flattening of the medial left AV valve leaflet and LVOT obstruction after cleft closure. We describe a novel technique of detachment and patch augmentation of bridging leaflets to avoid these complications.

Staged Left Ventricular Recruitment and Biventricular Conversion for Patients With Borderline Left Heart

A borderline left heart may be present in patients with hypoplastic left heart syndrome or an unbalanced atrioventricular canal defect. Traditionally, such patients have been managed either by high-risk biventricular repair in infancy or during the neonatal period, or by definitive single-ventricle palliation. In this article, we present an approach for staged left ventricular recruitment that promotes gradual rehabilitation of left heart structures and allows delay in the commitment to either a single-ventricle pathway or a biventricular pathway. The rationale, techniques, and early results are described.

Clarifying the morphology of the ostium primum defect.

The 'ostium primum' defect is still frequently considered to be the consequence of deficient atrial septation, although the key feature is a common atrioventricular junction. The bridging leaflets of the common atrioventricular valve, which are joined to each other, are depressed distal to the atrioventricular junction, and fused to the crest of the muscular ventricular septum, which is bowed in the concave direction towards the ventricular apex. As a result, shunting across the defect occurs between the atrial chambers. These observations suggest that the basic deficiency in the 'ostium primum' defect is best understood as a product of defective atrioventricular septation, rather than an atrial septal defect. We have now encountered four examples of 'ostium primum' defects in mouse embryos that support this view. These were identified from a large number of mouse embryo hearts collected from a normal, outbred mouse colony and analysed by episcopic microscopy as part of an ongoing study of normal mouse cardiac development. The abnormal hearts were identified from embryos collected at embryonic days 15.5, 16.5 and 18.5 (two cases). We have analysed the features of the abnormal hearts, and compared the findings with those obtained in the large number of normally developed embryos. Our data show that the key feature of normal atrioventricular septation is the ventral growth through the right pulmonary ridge of a protrusion from the dorsal pharyngeal mesenchyme, confirming previous findings. This protrusion, known as the vestibular spine, or the dorsal mesenchymal protrusion, reinforces the closure of the primary atrial foramen, and muscularises along with the mesenchymal cap of the primary atrial septum to form the ventro-caudal buttress of the oval foramen, identified by some as the 'canal septum'. Detailed analysis of the four abnormal hearts suggests that in each case there has been failure of growth of the vestibular spine, with the result that the common atrioventricular junction found earlier during normal development now persists during cardiac development. Failure of separation of the common junction also accounts for the trifoliate arrangement of the left atrioventricular valve in the abnormal hearts. Analysis of the episcopic datasets also permits recognition of the location of the atrioventricular conduction axis. Comparison of the location of this tract in the normal and abnormal hearts shows that there is no separate formation of a ventricular component of the 'canal septum' as part of normal development. We conclude that it is abnormal formation of the primary atrial septum that is the cause of so-called 'secundum' atrial septal defects, whereas it is the failure to produce a second contribution to atrial septation (via growth of the vestibular spine) that results in the 'ostium primum' defect.

A Novel Technique for Repair of Complete Atrioventricular Canal Defect: The Central Patch Technique.

Two-patch, single-patch, and modified single-patch repairs are accepted techniques for repair of complete atrioventricular (AV) canal defects. We propose a novel, alternative technique: the central patch technique. For the central patch technique, the superior and inferior bridging leaflets are attached with simple sutures to the right and left of their coaptation point. Both bridging leaflets are incised along a line above the ventricular crest, similar to a traditional single-patch technique. An oval pericardial patch is sewn to the central defect created in the AV valve tissue. Interrupted, horizontal mattress sutures are placed along the ventricular crest, through the midline of the central patch and through the edge of the atrial septal defect (ASD) patch. Tying the sutures simultaneously closes the ventricular septal defect (VSD) and secures the ASD patch to the ventricular crest. Repair of the left AV valve and ASD closure are performed in the routine fashion. Five patients underwent the central patch technique repair of complete AV canal defect. Weight was 4.8 to 6.3 kg; age was four to eight months. Cardiopulmonary bypass and myocardial times averaged 137 minutes and 109 minutes, respectively. No patient had more than mild left AV valve regurgitation or trivial residual VSD at completion of repair. No patient developed left ventricular outflow tract obstruction. The central patch technique is applicable to all forms of complete AV canal defect. Subjectively, it offers technical advantages compared to standard techniques and may result in a shorter learning curve for junior congenital heart surgeons. Results are preliminary but are consistent with standard techniques.

Preliminary results of direct closure of an atrioventricular septal defect: revisiting the original technique

Background: This study aims to assess the preliminary results of direct closure of atrioventricular septal defect (AVSD). Methods: Thirteen patients (complete type n=7, partial type n=6) who underwent AVSDs correction with direct closure technique in our department between September 2009 and June 2011 were included. Two patients with concomitant pulmonary stenosis were managed in a single session. For direct suture closure of ventricular septal defect (VSD), multiple interrupted Teflon pledgets sutures were placed on the right side of the interventricular septal crest and then they were passed through the bridging leaflets of the common valve. For direct closure of primum atrial septal defect (ASD) in patients with complete type VSD closure sutures were used by passing through the remnant of interatrial septum and tied off. Results: The median age of the patients was 13 months. The median age (7.5 months) and weight (4.3 kg) of the patients with complete type was lower. The mean VSD size was 30.4±10 mm/m2. The mean cardiopulmonary bypass and ischemic cross clamp times were 51.3±11.2 min and 34.7±10.9 min, respectively. There was no in-hospital mortality. All patients were discharged with sinus rhythm and less than (2+) atrioventricular valve regurgitation. All the patients were followed. The mean follow-up was 12.1±4.1 months. Repeated echocardiograms did not revealed any progressive atrioventricular valve dysfunction or left ventricular outflow tract gradient. Conclusion: Direct closure technique for repair of atrioventricular septal defect is rapid and simple surgery for the management of this complex pathology. This easily reproducible technique could also encourage and facilliate earlier repair of this pathology, preventing potential technical challenges.

Repair of Atrioventricular Septal Defect Associated With Tetralogy of Fallot or Double-Outlet Right Ventricle: 30 Years of Experience

The surgical outcomes of atrioventricular septal defect (AVSD) associated with tetralogy of Fallot (TOF) or double-outlet right ventricle (DORV) have improved in recent times. However, high mortality and reoperation rates are still reported. This study reviews our surgical experience in patients with complete AVSD and TOF or DORV. Between 1980 and 2010, 48 consecutive patients with AVSD associated with TOF (n = 26) or DORV (n = 22) underwent complete repair; of which, 19 had staged repair. A transatrial-transpulmonary approach with the 2-patch technique was the preferred surgical technique. Data were obtained from inpatient and outpatient medical files. The mortality rates were 8.3% (4 of 48) for in-hospital death and 13.6% (6 of 44) for late death. Mean follow-up was 8.0 ± 8.7 years (median 10.8 years; range from 2 months to 30 years). Actuarial survival was 76% at 5 years and 71% at 20 years. No deaths occurred after 2001. Reoperations were required in 16 of 48 patients (33%). The overall freedom from reoperation was 55% at 5 and 20 years. Down syndrome was protective for reoperation (p = 0.022). Complete AVSD associated with TOF or DORV can be repaired with good survival. Detachment of the superior bridging leaflet provided excellent exposure. However, reoperation rate remains high.

Real-Time 3-Dimensional Transesophageal Echocardiography of the Atrioventricular Septal Defect

Being able to view the morphological details of the heart malformation in any patient with the diagnosis of atrioventricular septal defect (AVSD) is invaluable in surgical planning, especially in the current era of modified 1-patch versus 2-patch techniques. Real-time 3-dimensional transesophageal echocardiography (RT 3D TEE) is a recently developed technique that allows real-time high-quality images akin to viewing the heart specimen. We present the principal pathomorphological features of AVSD as visualized by RT 3D TEE. The hallmark of AVSD is a common atrioventricular junction guarded by a common atrioventricular valve.1 In the normal heart, when seen from atrial perspective, the aortic valve is wedged between the mitral and tricuspid valve. In AVSD, because of the common AV junction, the aortic valve is in an “unwedged” position (Figure 1). The valve consists of 5 leaflets: the superior and inferior bridging leaflets, each of which overrides the ventricular septum, a left mural leaflet, a right anterior, and a right inferior leaflet (Figure 2). Whether the bridging leaflets are joined together distinguishes the complete form from the partial form. In partial AVSD (also termed “ostium primum ASD”), a tongue of leaflet tissue connects the bridging leaflets and the undersides of these leaflets …

Early Surgical Correction of Atrioventricular Valvular Regurgitation in Single-Ventricle Patients

The purpose of this study is to evaluate the effectiveness of early surgical correction for atrioventricular valve regurgitation (AVVR) in single-ventricle patients. The medical records of 39 single-ventricle patients who underwent atrioventricular surgery more than once between 1996 and 2008 were reviewed. The mean preoperative grade of AVVR was 2.6 ± 0.7. Four patients underwent valvular operations at first palliative surgery, 3 patients before bidirectional cavopulmonary connection, 13 at bidirectional cavopulmonary connection, 6 in the interstage between bidirectional cavopulmonary connection and Fontan, 10 at Fontan, and 3 after Fontan procedure. Surgical techniques for valve were edge-to-edge sutures for bridging leaflets, leaflet cleft repair, partial or complete annuloplasty with strip, or artificial valve implantation. Although there was no statistical significance, the patients who underwent early operation (AVVR grade less than 2) showed a tendency toward better atrioventricular valvular function during the postoperative follow-up (57.1 months, range: 2 ∼ 129 months). None of the patients whose preoperative AVVR grade less than 2 showed an AVVR more than 2 at the final echocardiography. There were 4 deaths overall due to sepsis, Fontan failure, and sudden cardiac arrest. Final echocardiographic findings showed a mean AVVR of 1.6 ± 0.8 and acceptable cardiac function. All living patients were in a good New York Heart Association functional class (1.07 ± 0.2). Even though we could not find statistically significant evidence of benefit for early correction of AVVR in single-ventricle patients, the patients undergoing early valvular operation for regurgitation showed a tendency toward better atrioventricular valvular function at midterm.

No-Patch Technique for Complete Atrioventricular Canal Repair

Although no-patch repair was the first surgical treatment for complete atrioventricular canal, patch repairs are currently more widely used. We assessed the safety of forgoing a patch during the correction of complete atrioventricular canal in 8 consecutive patients. The complete atrioventricular canal was repaired using sutures placed on the right of the ventricular septal defect crest, passed through the bridging leaflet, and to the facing part of the ostium primum defect. There were no early deaths; all patients were in sinus rhythm without left ventricular outflow tract obstruction. This no-patch technique produces results comparable with the modified single-patch repair, while reducing ischemic time.

Morphology and Morphogenesis of Atrioventricular Septal Defect With Common Atrioventricular Junction

For many years, the lesions now often described as atrioventricular septal defects were considered to represent atrioventricular canal malformations or endocardial cushion defects. It was also long recognized that patients with the so-called ostium primum defect should be included in this category. The phenotypic feature of these hearts is the presence of a common atrioventricular junction, as opposed to separate right and left atrioventricular junctions. The presence of the common atrioventricular junction underscores the associated phenotypic features, such as the presence of a trifoliate left atrioventricular valve, which has no resemblance to a cleft mitral valve; unwedging of the subaortic outflow tract; and disproportion between the inlet and outlet dimensions of the left ventricle. These features are comparable in patients having the so-called partial, intermediate, and complete variants of the malformation. Anatomical differentiation depends on the morphology of the leaflets of the common atrioventricular valve that bridge the ventricular septum. If these bridging leaflets are fused one to the other, then there are dual orifices, rather than a common orifice, within the common atrioventricular junction. The relationships of the bridging leaflets to the septal structures determine the potential for shunting across the atrioventricular septal defect, which can occur at atrial and ventricular levels or exclusively at either atrial or ventricular level. Rarely, the atrioventricular septal defect may close spontaneously. Recent evidence from studies of cardiac development shows that rather than being an endocardial cushion defect, the malformation results from failure of ingrowth into the developing heart from the dorsal mesenchymal tissues.

Anatomy of Common Atrioventricular Junction With Complex Associated Lesions

The essence of the lesion increasingly described as atrioventricular septal defect is the presence of a common atrioventricular junction. In most instances, the common junction is itself shared in more or less equal fashion between the cardiac chambers, producing the so-called balanced arrangement, which can be considered the default option. Complexity can be produced at various levels within this standard lesion. The most complex malformations are seen in the setting of visceral heterotaxy. Greatest complexity is seen with right isomerism. This always includes totally anomalous pulmonary venous connection, even when the pulmonary veins return to the heart. Still further complexity is often added by the presence of pulmonary stenosis or atresia. Imbalance can involve either the atrial or ventricular chambers. Imbalance at atrial level produces one form of double outlet atrium, but typically with balanced ventricles. Ventricular imbalance represents spectrums extending either to double inlet left or right ventricle through a common atrioventricular valve. Complexity at the level of the ventriculoarterial junctions is seen in the form of abnormal ventriculoarterial connections, notably tetralogy of Fallot or double outlet right ventricle. In these settings, the superior bridging leaflet is free-floating. Hypoplasia of the left atrioventricular valve is part of right ventricular dominance and is often associated with the so-called parachute malformation. Dual orifice is also a problem. In both these lesions, the zone of apposition between the bridging leaflets is the effective inlet to the left ventricle.