Atrioventricular septal defects with severe left ventricular hypoplasia

Risk analysis for patients with a functionally univentricular heart after systemic-to-pulmonary shunt placement

OBJECTIVES

To investigate risk factors for mortality after systemic-to-pulmonary (SP) shunt procedures in patients with a functionally univentricular heart using the Japan Cardiovascular Surgery Database registry.

METHODS

Clinical data from 75 domestic institutions were collected. Overall, 812 patients with a functionally univentricular heart who underwent initial SP shunt palliation were eligible for analysis. Patients with pulmonary atresia with an intact ventricular septum and patients with a SP shunt as part of the Norwood procedure were excluded. Risk factors for 30- and 90-day mortalities were analysed using a logistic regression model.

RESULTS

Median age and body weight at SP shunt placement were 41 days and 3.6 kg, respectively. Modified Blalock-Taussig shunt, central shunt and other types of SP shunts were applied in 689 (84.9%), 94 (11.8%) and 30 (3.7%) patients, respectively. Cardiopulmonary bypass was utilized in 410 patients (51%) for 128 min (median, 19-561). There were 411 isolated SP shunt procedures. Median hospital stay was 27 days, and 742 (91.4%) patients were discharged. The 30- and 90-day mortality rates were 3.4% and 6.0%, respectively. Placement of a central shunt was identified as a risk factor for 30-day mortality, while lower body weight, preoperative ventilator support, right atrial isomerism and coexistence of major aortopulmonary collateral arteries and an unbalanced atrioventricular septal defect were identified as risk factors for 90-day mortality.

CONCLUSIONS

SP shunt carries a high mortality rate in patients with a functionally univentricular heart when it is performed in smaller patients with complex cardiac anomalies.

Challenges in the Surgical Treatment of Atrioventricular Septal Defect in Children With and Without Down Syndrome in Romania-A Developing Country

Background: Atrioventricular septal defect (AVSD) is a cardiac malformation that accounts for up to 5% of total congenital heart disease, occurring with high frequency in people with Down Syndrome (DS). We aimed to establish the surgical challenges and outcome of medical care in different types of AVSD in children with DS compared to those without DS (WDS). Methods: The study included 62 children (31 with DS) with AVSD, evaluated over a 5 year period. Results: Complete AVSD was observed in 49 (79%) children (27 with DS). Six children had partial AVSD (all WDS) and seven had intermediate types of AVSD (4 with DS). Eight children had unbalanced complete AVSD (1 DS). Median age at diagnosis and age at surgical intervention in complete AVSD was not significantly different in children with DS compared to those WDS (7.5 months vs. 8.6). Median age at surgical intervention for partial and transitional AVSDs was 10.5 months for DS and 17.8 months in those without DS. A large number of patients were not operated: 13/31 with DS and 8/31 WDS. Conclusion: The complete form of AVSD was more frequent in DS group, having worse prognosis, while unbalanced AVSD was observed predominantly in the group without DS. Children with DS required special attention due to increased risk of pulmonary hypertension. Late diagnosis was an important risk factor for poor prognosis, in the setting of suboptimal access to cardiac surgery for patients in Romania. Although post-surgery mortality was low, infant mortality before surgery remains high. Increased awareness is needed in order to provide early diagnosis of AVSD and enable optimal surgical treatment.

Surgical palliation of univentricular heart disease in children with Down's syndrome: A systematic review

Objectives

No standard protocol is available for the management of children with Down's syndrome (DS) and a functional single ventricle. This review attempts to determine the outcomes of the single ventricular surgical palliation pathway in high-risk children with DS.

Methods

Several databases were searched using the following MeSH terms: ‘Congenital heart disease’, ‘Atrioventricular septal defect’, ‘Balanced AVSD’, ‘Unbalanced AVSD’, ‘Down's syndrome’, ‘Univentricular repair’, ‘bidirectional Glenn procedure’, and ‘Fontan procedure’. A structured algorithm was used for the selection of studies for an in-depth analysis.

Results

There was no universal agreement on the best surgical approach for unbalanced atrioventricular septal defect in DS. The majority of paediatric cardiac surgeons did not recommend the complete Fontan procedure; conversely, the use of a Glenn shunt (superior cavopulmonary connection) was preferred.

Conclusions

Careful assessment of the suitability for Fontan surgery, including the absence of elevated pulmonary vascular resistance, pulmonary arterial anatomy, and function of the dominant ventricle, is mandatory. A staged surgical procedure ending with complete Fontan repair provides acceptable medium-term results.

Right-Dominant Unbalanced Atrioventricular Septal Defect: Echocardiography in Surgical Decision Making

BACKGROUND

Management of right-dominant atrioventricular septal defect (AVSD) remains a challenge given the spectrum of ventricular hypoplasia. The purpose of this study was to assess whether reported echocardiographic indices and additional measurements were associated with operative strategy in right-dominant AVSD.

METHODS

A blinded observer retrospectively reviewed preoperative echocardiograms of patients who underwent surgery for right-dominant AVSD (January 2000 to July 2013). Ventricular dimensions, atrioventricular valve index (AVVI; left valve area/right valve area), and right ventricular (RV)/left ventricular (RV/LV) inflow angle were measured. A second observer measured a subset of studies to assess agreement. Pearson correlation analysis was performed to examine the relationship between ventricular septal defect size (indexed to body surface area) and RV/LV inflow angle in systole. A separate validation cohort was identified using the same methodology (August 2013 to July 2016).

RESULTS

Of 46 patients with right-dominant AVSD (median age, 1 day; range, 0-11 months), overall survival was 76% at 7 years. Twenty-eight patients (61%) underwent single-ventricle palliation and had smaller LV dimensions and volumes, AVVIs (P = .005), and RV/LV inflow angles in systole (P = .007) compared with those who underwent biventricular operations. Three patients undergoing biventricular operations underwent transplantation or died and had lower indexed LV end-diastolic volumes compared with the remaining patients (P = .005). Interobserver agreement for the measured echocardiographic indices was good (intraclass correlation coefficient = 0.70-0.95). Ventricular septal defect size and RV/LV inflow angle in systole had a strong negative correlation (r = -0.7, P < .001). In the validation cohort (n = 12), RV/LV inflow angle in systole ≤ 114° yielded sensitivity of 100% and AVVI ≤ 0.70 yielded sensitivity of 88% for single-ventricle palliation.

CONCLUSIONS

Mortality remains high among patients with right-dominant AVSD. RV/LV inflow angle in systole and AVVI are reproducible measurements that may be used in conjunction with several echocardiographic parameters to support suitability for a biventricular operation in right-dominant AVSD.

The angulation of the septal structures impacts ventricular imbalance in atrioventricular septal defects with a common atrioventricular junction

OBJECTIVE

Multiplanar re-formatting of full-volume three-dimensional echocardiography data sets offers new insights into the morphology of atrioventricular septal defects. We hypothesised that distortion of the alignment between the atrial and ventricular septums results in imbalanced venous return to the ventricles, with consequent proportional ventricular hypoplasia.

METHODS

A single observer evaluated 31 patients, with a mean age of 52.09 months, standard deviation of 55, and with a range from 2 to 264 months, with atrioventricular septal defects, of whom 17 were boys. Ventricular imbalance, observed in nine patients, was determined by two-dimensional assessment, and confirmed at surgical inspection in selected cases when a univentricular strategy was undertaken. Offline analysis using multiplanar re-formatting was performed. A line was drawn though the length of the ventricular septum and a second line along the plane of the atrial septum, taking the angle between these two lines as the atrioventricular septal angle. We compared the angle between 22 patients with adequately sized ventricles, and those with ventricular imbalance undergoing univentricular repair.

RESULTS

In the 22 patients undergoing biventricular repair, the septal angle was 0 in 14 patients; the other eight patients having angles ranging from 1 to 36, with a mean angle of 7.4°, and standard deviation of 11.1°.The mean angle in the nine patients with ventricle imbalance was 28.6°, with a standard deviation of 3.04°, and with a range from 26 to 35°. Of those undergoing univentricular repair, two patients died, with angles of 26 and 30°, respectively.

CONCLUSIONS

The atrioventricular septal angle derived via multiplanar formatting gives important information regarding the degree of ventricular hypoplasia and imbalance. When this angle is above 25°, patients are likely to have ventricular imbalance requiring univentricular repair.

Unbalanced atrioventricular septal defect: definition and decision making

Unbalanced atrioventricular septal defect is an uncommon lesion with widely varying anatomic manifestations. When unbalance is severe, diagnosis and treatment is straightforward, directed toward single-ventricle palliation. Milder forms, however, pose a challenge to current diagnostic and therapeutic approaches. The transition from anatomies that are capable of sustaining biventricular physiology to those that cannot is obscure, resulting in uneven application of surgical strategy and excess mortality. Imprecise assessments of ventricular competence have dominated clinical decision making in this regard. Malalignment of the atrioventricular junction and its attendant derangement of inflow physiology is a critical factor in determining the feasibility of biventricular repair in the setting of unbalanced atrioventricular septal defect. The atrioventricular valve index accurately identifies unbalanced atrioventricular septal defect and also brings into focus a zone of transition from anatomies that can support a biventricular end state and those that cannot.

Echocardiographic features defining right dominant unbalanced atrioventricular septal defect: a multi-institutional Congenital Heart Surgeons' Society study

BACKGROUND

Definition and management of right dominant unbalanced atrioventricular septal defect (AVSD) remains challenging because unbalance entails a spectrum of left heart hypoplasia. Previous work has highlighted atrioventricular valve (AVV) index as a reasonable defining echocardiographic measure. We sought to assess which additional echocardiographic features might provide further characterization.

METHODS AND RESULTS

From a multi-institutional cohort of complete AVSD, 52 preoperative echocardiograms of patients with presumed right dominant unbalanced AVSD (based on AVV index) and 60 randomly selected preoperative echocardiograms from patients with presumed balanced AVSD were reviewed. Cluster analysis of echocardiographic variables was used to group patients with similar features. Discriminant function analysis was used to explore which variables differentiated these groups. Three groups were identified from the cluster analysis. Echocardiographic variables that differentiated these groups were right ventricle:left ventricle inflow angle, LV width/LV length, left AVV color diameter at smallest inflow, left AVV color diameter at annulus, right AVV overriding left atrium, and LV width. Based on procedures and outcomes, 1 group likely represented balanced patients, whereas 2 groups with similar outcomes likely represented unbalanced patients. The dominant differentiating echocardiographic variable between the 3 cluster groups was the right ventricle:LV inflow angle (partial R²=0.86), defined as the angle between the base of the right ventricle and LV free wall, using the crest of the ventricular septum as apex of the angle.

CONCLUSIONS

The angle of right ventricle/LV inflow and other surrogates of inflow may be important defining echocardiographic measures of right dominant unbalanced AVSD, although confirmation is needed.

Unbalanced atrioventricular septal defect: defining the limits of biventricular repair

Unbalanced atrioventricular septal defect (uAVSD) is a challenging lesion with suboptimal outcomes in the current era. Severe forms of uAVSD mandate univentricular repair with well-documented outcomes. Determining the feasibility of biventricular repair (BVR) in patients with moderate forms of uAVSD is difficult. Ventricular hypoplasia has traditionally formed the cornerstone of defining uAVSD. However, malalignment of the atrioventricular junction and related derangements of the anatomy and physiology of the atrioventricular inflow play a central role in establishing and sustaining a biventricular end state. Atrioventricular valve index, left ventricular inflow index, and right ventricle/left ventricle inflow angle are important recently described measures of inflow physiology. Additional patient anatomic and physiologic factors that impact BVR feasibility undoubtedly exist. A recently launched Congenital Heart Surgeons Society prospective inception cohort study will address these and other issues that impair our ability to predict BVR feasibility in uAVSD.

Echocardiographic definition and surgical decision-making in unbalanced atrioventricular septal defect: a Congenital Heart Surgeons' Society multiinstitutional study

BACKGROUND

Although identification of unbalanced atrioventricular septal defect (AVSD) is obvious when extreme, exact criteria to define the limits of unbalanced are not available. We sought to validate an atrioventricular valve index (AVVI) (left atrioventricular valve area/total atrioventricular valve area, centimeters squared) as a discriminator of balanced and unbalanced forms of complete AVSD and to characterize the association of AVVI with surgical strategies and outcomes.

METHODS AND RESULTS

Diagnostic echocardiograms and hospital records of 356 infants with complete AVSD at 4 Congenital Heart Surgeons' Society (CHSS) institutions (2000-2006) were reviewed and AVVI measured (n=315). Patients were classified as unbalanced if AVVI≤0.4 (right dominant) or ≥0.6 (left dominant). Surgical strategy and outcomes were examined across the range of AVVI. Competing risks analysis until the time of commitment to a surgical strategy examined 4 end states: biventricular repair (BVR), univentricular repair (UVR), pulmonary artery banding (PAB), and death before surgery. A prediction nomogram for surgical strategy based on AVVI was developed. The majority of patients had balanced AVSD (0.4<AVVI<0.6) and underwent BVR. Patients with AVVI<0.19 uniformly underwent UVR. Heterogeneous repair strategies were found when 0.19≤AVVI≤0.39 (UVR and BVR), with a disproportionate number of deaths in this range. AVVI≥0.6 (left dominant) was less common. The proportion of subjects predicted for the end states at 12 months after diagnosis are: BVR, 86%; UVR, 7%; PAB, 1%; death without surgery, 1%; alive without surgery, 5%.

CONCLUSIONS

AVVI effectively characterizes the transition between balanced and unbalanced AVSD with important correlation to anatomic substrate and selected surgical strategy.

Outcomes for patients with unbalanced atrioventricular septal defects

Infants with an unbalanced atrioventricular septal defect (AVSD) frequently present with comorbidities that may have an impact on their medical course and outcome. This study aimed to assess outcomes and explore possible prognostic indicators for patients undergoing surgical palliation for an unbalanced AVSD. The medical records of all infants presenting to the authors' institution with an unbalanced AVSD over a 5-year period were retrospectively reviewed for assessment of outcomes and comorbidities. The study group consisted of 44 patients with an overall survival rate of 51% for the entire follow-up period. The majority of these patients (88%) underwent single-ventricle palliation, with an 83% rate of survival to initial hospital discharge and an overall long-term survival rate of 50%. The midterm outcome was significantly worse than that for a cohort of hypoplastic left heart syndrome patients undergoing single-ventricle palliation during the same period (P = 0.03). In addition, 30% of the patients required either repair or replacement of their systemic atrioventricular valve at initial palliation or during subsequent follow-up evaluation. Of the patients with an unbalanced AVSD, 75% had associated congenital anomalies. In conclusion, infants with an unbalanced AVSD are a high-risk population with diminished midterm survival compared with palliated patients who have more classic forms of hypoplastic heart syndromes. This may be due to the higher incidence of both severe atrioventricular valve regurgitation and important associated congenital anomalies.

Surgical management of unbalanced atrioventricular canal defect

Approximately 10% of endocardial cushion defects exhibit unbalance at the atrioventricular inlet. When the atrioventricular valve sits more over one ventricle than the other, the contralateral ventricle is typically hypoplastic. Surgical intervention for unbalanced atrioventricular canal has a much higher morbidity and mortality than for the balanced form of the defect. With unbalanced atrioventricular canal to the right, no universal criteria are in place to choose single versus biventricular repair. In many cases, risk factors have been extrapolated from other lesions with left ventricular hypoplasia. Even if biventricular repair is successful, the reoperation rate is high for this lesion. Little data exist in the literature regarding left unbalanced atrioventricular canal. In general, right ventricular hypoplasia is better tolerated than left ventricular hypoplasia, and biventricular repair is usually possible. If cyanosis or high systemic venous pressure results, the one and one half ventricle repair (biventricular repair with bidirectional Glenn anastomosis) is an option. This article reviews the present understanding of unbalanced atrioventricular canal and discusses diagnostic and surgical strategies for this complex lesion.

The small left ventricle: How small is too small for biventricular repair?

Left ventricular hypoplasia is associated with a variety of congenital heart defects, including critical aortic stenosis, unbalanced atrioventricular canal, and total anomalous pulmonary venous connection, and is almost uniformly fatal without surgical or catheter-directed intervention. Accurately determining whether the left ventricle can adequately support the systemic circulation can be challenging and may be approached in a variety of ways, depending on the cardiac defect. The decision is more difficult in the present era of pediatric cardiology and cardiothoracic surgery because other options, such as the Norwood procedure and cardiac transplantation, are available to infants with left ventricular hypoplasia with improving survival. This report is a review of the present understanding of left ventricular hypoplasia and gives suggestions about how to stratify these complex patients to single versus two-ventricle repair. Copyright 1999 by W.B. Saunders Company

Atrioventricular canal defect and hypoplastic left heart syndrome as discordant congenital heart defects in twins

We report on a twin pair presenting with atrioventricular canal defect (AVCD) with right ventricular dominance in one twin, and classic hypoplastic left heart syndrome (HLHS) in the other. According to the developmental-mechanistic approach, AVCDs belong to the group of extracellular matrix abnormalities, whereas classic HLHS is included among flow lesions. Twin pairs with congenital heart defect (CHD) generally have concordant defects by mechanistic group. The occurrence of AVCD and classic HLHS in twins or siblings has never been reported. Interestingly, hypoplasia of the left ventricle is the anatomic characteristic which unifies the discordant CHDs observed in our twins. The occurrence of CHD in both members of the twin pair implies a strong influence of genetic factors. At present, the genetic basis determining the different cardiac phenotypes observed in our twins is unknown. The report of these peculiar associations may be useful to stimulate further studies and shed light on the etiology of CHDs.

Morphometric analysis of unbalanced common atrioventricular canal using two-dimensional echocardiography

OBJECTIVES

This study was designed to define morphometric echocardiographic variables of unbalanced common atrioventricular canal (CAVC) that could aid in appropriate referral for surgical repair.

BACKGROUND

Unbalanced CAVC has a high surgical mortality rate. This may be secondary to inappropriate referral of some patients for two-ventricle repair (closure of septal defects) instead of single-ventricle repair (Norwood palliation and Fontan operation).

METHODS

The echocardiograms of 103 patients with CAVC were retrospectively reviewed. In the subcostal left anterior oblique view, the area of the atrioventricular (AV) valve aportioned over each ventricle was measured, and an AV valve index (AVVI) was calculated as left/right valve area. The ventricular cavity ratio between the two ventricles was estimated as left ventricular length times width divided by right ventricular length times width. These variables were correlated with surgical referral and outcome.

RESULTS

Patients previously categorized as having balanced CAVC all had AVVI > 0.67 (n = 77). Of the patients with unbalanced CAVC (n = 26), 11 had ductal-dependent circulation and underwent Norwood palliation (AVVI 0.21 +/- 0.13, mean +/- SD), and 15 had two-ventricle repair (AVVI 0.51 +/- 0.12, p < 0.0001). Of these 15 patients, 9 have survived, with no difference in mean AVVI between survivors and nonsurvivors (0.52 +/- 0.11 versus 0.49 +/- 0.13, p = 0.72). For all 103 patients, AVVI correlated with ventricular cavity ratio. However, of the unbalanced CAVC group who underwent two-ventricle repair, three nonsurvivors had a discrepancy between AVVI and ventricular cavity ratio (low AVVI but normal ventricular size). A large ventricular septal defect was present in all six nonsurvivors but in only four of nine survivors (p < 0.05).

CONCLUSIONS

Echocardiographic morphometry is useful in defining unbalance in CAVC. If AVVI is < 0.67 in the presence of a large ventricular septal defect, a single-ventricle approach to repair should be considered.

Partial atrioventricular canal with congestive heart failure in the first year of life: surgical options

BACKGROUND

An important subgroup of patients with partial atrioventricular canal require an operation in the first year of life because of refractory congestive heart failure.

METHODS

From June 1982 to April 1995, of 128 patients with partial atrioventricular canal, 35 patients (27%) underwent surgical treatment at less than 1 year of life. Associated cardiac anomalies were present in 22 patients. Only 7 patients (20%) had Down's syndrome. Five patients with left ventricular hypoplasia underwent aortic coarctectomy (3 patients) or Norwood operation (2 patients). The other 30 patients underwent anatomic repair in 24 cases and aortic coarctectomy in 6. The surgical results of patients submitted for anatomic repair were retrospectively correlated with the echocardiographic mitral valve diameter.

RESULTS

There were 7 deaths (29%) after anatomic repair, 2 (22%) after aortic coarctectomy, and 2 (100%) after Norwood operation. Infants with a mitral valve diameter less than 2.5 x 10-2 m/m2 died at repair. In a mean follow-up of 73.5 months there were five secondary mitral valve plasties and three repairs after aortic coarctectomy.

CONCLUSIONS

Among patients with partial atrioventricular canal, there is an important subgroup with clinical signs of heart failure in the first year of life. Left-sided obstructive lesions and complex mitral valve anomalies seem to play a fundamental role in the clinical evolution and prognosis of these patients. The echocardiographic mitral valve diameter may be useful for determining the correct surgical indication.