Outcomes of left atrial isomerism over a 28-year period at a single institution

Surgical Outcome of Heterotaxy Syndrome in a Single Institution

Heterotaxy syndrome encompasses a wide range of anatomical variants including poor pulmonary vascular development. Surgical outcome remains poor in this difficult subgroup. Between April 1996 and November 2004, 27 patients with visceral heterotaxy were enrolled in this study. The median age at presentation was 25 days. There were 11 patients with asplenia and 16 with polysplenia. There were 5 deaths (4 in patients with asplenia, 1 in a patient with polysplenia). All patients with asplenia were scheduled for single-ventricle repair, and 5 completed a modified Fontan procedure. Of the 16 patients with polysplenia, 8 completed 2-ventricle repair and 6 had a modified Fontan. In polysplenia, actuarial survival was 93.8% at 4 months, and remained constant thereafter. In asplenia, survival was 81.8% at 1 month, and 53.0% at 1 year. A significant correlation was found between nonconfluent pulmonary arteries and mortality. The medium-term result in polysplenia was satisfactory, but not in asplenia. Nonconfluent pulmonary arteries carry a high risk of mortality, and a strategy to create pulmonary vascular confluence and satisfactory pulmonary blood flow is mandatory.

Heterotaxy Syndrome: Proceedings From the 10th International PCICS Meeting

A session dedicated to heterotaxy syndrome was included in the program of the Tenth International Conference of the Pediatric Cardiac Intensive Care Society in Miami, Florida in December 2014. An invited panel of experts reviewed the anatomic considerations, surgical considerations, noncardiac issues, and long-term outcomes in this challenging group of patients. The presentations, summarized in this article, reflect the current approach to this complex multiorgan syndrome and highlight future areas of clinical interest and research.

CHD associated with syndromic diagnoses: peri-operative risk factors and early outcomes

CHD is frequently associated with a genetic syndrome. These syndromes often present specific cardiovascular and non-cardiovascular co-morbidities that confer significant peri-operative risks affecting multiple organ systems. Although surgical outcomes have improved over time, these co-morbidities continue to contribute substantially to poor peri-operative mortality and morbidity outcomes. Peri-operative morbidity may have long-standing ramifications on neurodevelopment and overall health. Recognising the cardiovascular and non-cardiovascular risks associated with specific syndromic diagnoses will facilitate expectant management, early detection of clinical problems, and improved outcomes--for example, the development of syndrome-based protocols for peri-operative evaluation and prophylactic actions may improve outcomes for the more frequently encountered syndromes such as 22q11 deletion syndrome.

Functionally Univentricular Heart With Right Atrial Isomerism and Mixed Total Anomalous Pulmonary Venous Drainage

Patients with right atrial isomerism and total anomalous pulmonary venous connection (TAPVC) in a functionally univentricular heart are a challenging subset with a high mortality rate. We present the case of a patient with univentricular heart who had right atrial isomerism and associated mixed TAPVC (supracardiac, cardiac, and infracardiac). The anatomy was delineated precisely, and the patient underwent first-stage univentricular palliation consisting of TAPVC repair and bilateral bidirectional superior cavopulmonary anastomosis.

Cardiac and Non-Cardiac Abnormalities in Heterotaxy Syndrome

Thoraco-abdominal viscera have unique morphological asymmetry, unlike the body's external organs. Heterotaxy syndrome is a disorder in which there is a loss of normal left to right asymmetry of thoraco-abdominal viscera and their naturally proscribed spatial relationship. It has multiple anatomical alterations, culminating into physiological and hemodynamic consequences. It is divided into two groups on the basis of morphology of the two atrial appendages. These subgroups are - 1) Isomerism of right atrial appendage (asplenia syndrome); 2) Isomerism of left atrial appendage (polysplenia syndrome); Patients from group I, usually have severe cardiac malformations and present early. They may have duct dependent lesions and eventually may undergo Fontan surgery. However, extracardiac anomalies are more common in group II. All the patients must be evaluated in detail to rule out anomalies like gut-malrotation. Patients must be provided with special care for their susceptibility to infection due to absence of spleen or presence of splenic malfunction. Majority of these patients may have genetic link and may present in families. Hence, genetic evaluation is necessary before assuming long term outcome.

Biventricular repair in heterotaxy patients

BACKGROUND

Heterotaxy patients' hearts may or may not be suitable for biventricular repair depending on anatomy. Even in the subset that are amenable to surgical septation, cardiac anatomy may present multiple difficulties in achieving a satisfactory repair. However, it is also well known that heterotaxy patients are not ideal candidates for univentricular repair.

METHODS

From 2007 until 2012, a total of 20 patients (11 male) with heterotaxy syndrome underwent biventricular repair (left atrial isomerism: 10 and right atrial isomerism: 10) in our center. Their median age at surgery was 40 (range: 3-108) months. Ten patients had dextrocardia. Eleven patients presented with bilateral superior vena cava, three with inferior vena cava (IVC) draining into left atrium, and six with IVC interruption with azygos or hemiazygos continuation. Anomalous pulmonary venous drainage was present in eight patients. One had a common atrium. Atrioventricular septal defect (AVSD) occurred in nine (complete AVSD in seven) patients. Eight patients had double outlet right ventricle (DORV), one had d-transposition of great arteries (d-TGA), and two had congenitally corrected transposition of the great arteries (CC-TGA). Prior palliative procedures included pulmonary artery banding in three patients and left modified Blalock-Taussig shunt in one patient. Complex intra-atrial baffle constructions were required in all patients to direct pulmonary and systemic venous inflow to the appropriate ventricle. Complete AVSDs were corrected using two-patch technique. Intraventricular tunnel repair was done for DORV. Combined atrial and arterial switch was required to rectify abnormal connections in a child with congenitally corrected transposition with normal pulmonary valve, while a Rastelli + Senning was needed in two children with CC-TGA with pulmonary atresia (n = 1) and double outlet of the right ventricle (n = 1).

RESULTS

Major early postoperative complications included intestinal gangrene in four patients for which they underwent bowel resection. Two of these patients could not be salvaged. One patient required coiling of aortopulmonary collateral for early postoperative pulmonary hemorrhage. Two patients needed a tracheostomy for prolonged mechanical ventilatory support. Five patients had a pacemaker implanted for complete heart block. There were no instances of atrial baffle stenosis. Median follow-up was 27 (range: 2-46) months. There was one late death secondary to pneumonia.

CONCLUSIONS

Satisfactory survival outcomes can be achieved in heterotaxy patients who undergo hemodynamically acceptable biventricular repair. Borderline ventricular hypoplasia and trivial atrioventricular valve regurgitation should not be considered as discouraging factors in anatomically suitable heterotaxy patients as it is possible to adopt a two-stage repair in such patients to achieve biventricular repair at a later stage. Anticipating a higher incidence of conduction problems and gut malrotation preemptively can help reduce the morbidity.

Racial disparities in heterotaxy syndrome

BACKGROUND

Heterotaxy syndrome (HTX) is a constellation of defects including abnormal organ lateralization and often including congenital heart defects. HTX has widely divergent population-based estimates of prevalence, racial and ethnic predominance, and mortality in current literature.

METHODS

The objective of this study was to use a population-based registry to investigate potential racial and ethnic disparities in HTX. Using the Texas Birth Defects Registry, we described clinical features and mortality of HTX among infants delivered from 1999 to 2006. We calculated birth prevalence and crude prevalence (cPR) ratios for infant sex, maternal diabetes, and sociodemographic factors.

RESULTS

A total of 353 HTX cases were identified from 2,993,604 births (prevalence ratio = 1.18 per 10,000 live births. HTX prevalence was approximately 70% higher among infants of Hispanic and non-Hispanic black mothers and 28% higher among female infants (cPR = 1.28; 95% confidence interval,1.04-1.59). There was a twofold higher female preponderance for infants of mothers who were non-Hispanic white or black. Mothers with diabetes were three times more likely to have a child with HTX compared with nondiabetics (cPR = 3.13; 95% confidence interval, 2.12-4.45). Among nondiabetics, HTX cases were 86% more likely to have a Hispanic mother and 72% a non-Hispanic black mother. First-year mortality for live born children with HTX was 30.9%.

CONCLUSION

This study represents one of the largest population-based studies of HTX to date, with a novel finding of higher rates of HTX among Hispanic infants of mostly Mexican origin, as well as among female infants of only non-Hispanic white and black mothers. These findings warrant further investigation.

An unusual occurrence: a case of venous thromboembolism in pregnancy associated with heterotaxy syndrome

BACKGROUND

Heterotaxy is a relatively uncommon congenital anomaly that is usually diagnosed incidentally on imaging studies in adults. We present an unusual case of venous thromboembolism in a 26 year old pregnant female with Heterotaxy syndrome.

CASE PRESENTATION

A 26 year-old pregnant female at 13 weeks gestation suffered cardiac arrest with successful cardiac resuscitation and return of spontaneous circulation. The cardiac arrest was secondary to massive pulmonary embolism requiring thrombolytic therapy and stabilization of hemodynamics. She had extensive evaluation to determine the etiology for the pulmonary embolism and was noted to have an anatomic variation consistent with heterotaxy syndrome on imaging studies. After thrombolysis the patient was treated with UFH and then switched to enoxaparin without complication until 25 weeks of gestation when she experienced worsening abdominal pain with associated headaches, lightheadedness and elevated blood pressures needing elective induction of labor. The infant died shortly after delivery. The anticoagulation was continued for additional 3 months and she was subsequently placed on low dose aspirin to prevent recurrent venous thromboembolic episodes. She is currently stable on low dose aspirin and is into her third year after the venous thromboembolism without any recurrence.

CONCLUSION

To our knowledge, this is the first reported case of venous thromboembolism in pregnancy associated with heterotaxy syndrome. A discussion on pathophysiology of venous thromboembolism in pregnancy and heterotaxy syndrome has been undertaken along with treatment approach in such situations.

Non-cardiac issues in patients with heterotaxy syndrome

Management of complex congenital heart disease in patients with Heterotaxy syndrome (HS) has steadily improved. However, there is an insufficient appreciation of various non-cardiac issues that might impact the overall status of these patients. This article briefly reviews the implications of gastrointestinal, immunologic, genitourinary, respiratory, and central nervous system involvement in HS patients with a view to aid in their comprehensive clinical management.

Perinatal and infant outcomes of prenatal diagnosis of heterotaxy syndrome (asplenia and polysplenia)

Patients with heterotaxy syndrome (HS) have a range of anomalies and outcomes. There are limited data on perinatal outcomes after prenatal diagnosis. To determine the factors influencing perinatal and infant outcomes, we analyzed prenatal and postnatal variables in fetuses with HS from 1995 to 2011. Of 154 fetuses with HS, 61 (40%) had asplenia syndrome (ASP) and 93 (60%) had polysplenia syndrome (PSP). In the ASP group, 22 (36%) patients were elected for termination of pregnancy, 4 (10%) had fetal death, and 35 of 39 (90%) continued pregnancies were live born. In the PSP group, 12 (13%) patients were elected for termination of pregnancy, 5 (6%) had fetal death (4 with bradyarrhythmia), and 76 of 81 (94%) continued pregnancies were live born. Bradyarrhythmia was the only predictor of fetal death. In the live-born ASP group, 43% (15 of 35) died, 7 because of pulmonary vein stenosis, 4 postoperatively, and 4 because of noncardiac causes. In the live-born PSP group, 13% (10 of 76) died, 5 postoperatively, 2 from bradyarrhythmia, 1 from a cardiac event, and 2 from noncardiac causes. Pulmonary vein stenosis and noncardiac anomalies were independent risk factors for postnatal death. Only 8% of ASP patients achieved biventricular circulation, compared with 65% of PSP patients. In the live-born cohort, the 5-year survival rate was 53% for ASP and 86% for PSP. In conclusion, most PSP patients are currently alive with biventricular circulation in contrast with few ASP patients. Bradyarrhythmia was the only predictor of fetal death. Pulmonary vein stenosis and noncardiac anomalies were predictors of postnatal death.

Defects in laterality with emphasis on heterotaxy syndromes with asplenia and polysplenia: an autopsy case series at a single institution

Heterotaxy is a rare disease with high morbidity and mortality. Controversy exists over how to classify these syndromes with most cases stratified into asplenia/polysplenia syndromes or right/left isomerism. In an effort to review comprehensively specific pheonotypes associated with heterotaxy syndromes, we reviewed published cases series, adopted a classification scheme based on spleen status, and evaluated autopsy cases retrospectively with abnormal laterality at our institution. We categorized 116 cases as situs inversus totalis, polysplenia, asplenia, and single right-sided spleen. Cardiovascular abnormalities occurred in 87.1% of polysplenia, 90.5% of asplenia, and all cases of single right-sided spleen. For polysplenia, 48.9% had bilateral bilobed lungs, 87% had right-sided stomach, 58.1% had midline symmetric liver, and 60.4% had malrotated intestines. For asplenia, 51.9% had bilateral trilobed lungs, 86.7% had right-sided stomach, 45.8% had symmetric liver, and 65.5% had malrotated intestines. Atrioventricular septal defects occurred in 91.2% of asplenia compared to 56.8% of polysplenia cases. Eight percent had pulmonary/aortic stenosis or atresia. Double outlet right ventricle was more common in polysplenia (32.6%) compared to asplenia (21.4%). Total anomalous systemic venous return was described in 55.6% of polysplenia and total anomalous pulmonary venous connections in 81% of asplenia cases. Greater than half of the cases had no heterotaxy diagnosis. Although, we found similar heterotaxy-associated characteristics, the frequencies differed from previous studies. We found great variation in how heterotaxy-associated defects were described, diagnosed, and reported. Although there are known associated characteristics with the polysplenia/asplenia syndromes, correct identification requires a standardized approach for diagnosis and reporting.

Heterotaxy syndrome and malrotation: does isomerism influence risk and decision to treat

PURPOSE

Controversy remains regarding the management of the asymptomatic heterotaxy syndrome (HS) patient with suspected intestinal rotational abnormalities. We evaluated the outcomes for our HS population to identify frequency of malrotation and identify characteristics of children who might benefit from expectant management.

METHODS

After IRB approval, a retrospective review of all patients treated for HS at a large tertiary care children's hospital between January 2008 and June 2012 was performed. For the purpose of this paper, malrotation was defined as an operative note that described the presence of Ladd's bands and a narrow mesentery.

RESULTS

Thirty-eight patients with HS were identified, including 18 who underwent abdominal exploration. Left atrial isomerisation (LAI) was identified in 13 individuals, and right atrial isomerisation (RAI) was noted in 25. The rate of surgical intervention did not vary between the 2 groups (54%). Malrotation was found in 8 patients: one with LAI and 7 with RAI. This difference in incidence was statistically significant (p=0.04).

CONCLUSION

These data suggest that the direction of atrial isomerisation influences the likelihood of true malrotation, where RAI patients are more likely to be malrotated. Given the inherent risk of surgery on this medically fragile patient population, surgeons should consider expectant management for asymptomatic LAI patients.

Management and outcomes of heterotaxy syndrome associated with pulmonary atresia or pulmonary stenosis

BACKGROUND

Historic outcomes of patients with heterotaxy and pulmonary atresia or pulmonary stenosis (PA/PS) have been poor and in the current era are incompletely described. We reviewed our management of these patients and associated risk factors for death.

METHODS

We retrospectively reviewed the records of all patients with heterotaxy and PA/PS treated in our institution from January 1, 2002, to August 31, 2012. Death data were also confirmed with the Social Security Death Index. The log-rank test was done to assess six risk factors for death.

RESULTS

We identified 42 patients with heterotaxy and PA/PS. Median age at the first operation was 6.5 days, and median follow-up was 3.5 years. Death data were complete for all patients. Overall mortality was 19% (8 of 42). The 30-day, 1-year, and 5-year mortality estimation was 4.76%, 12.3%, and 19.1% respectively, as determined by the Kaplan-Meier method. The log-rank test showed total anomalous pulmonary venous return (TAPVR) (p<0.05) and obstructed TAPVR requiring an operation at less than 30 days (p=0.001) were significant risk factors for death.

CONCLUSIONS

In the current era, surgical treatment of heterotaxy and PA/PS can result in good outcomes. Associated TAPVR and obstructed TAPVR requiring neonatal correction were noted to be risk factors for death.

Ladd's procedure in functional single ventricle and heterotaxy syndrome: does timing affect outcome?

BACKGROUND

Infants with univentricular hearts often require intervention, such as a systemic to pulmonary shunt, as part of a staged surgical palliation. This physiology is inherently unstable, and interim mortality ranges from 4% to 15%. Heterotaxy syndrome confers a high incidence of intestinal rotation and fixation abnormalities. Controversy persists as to the need for elective Ladd's procedure. The purpose of this study is to review our experience in children with heterotaxy syndrome and functionally univentricular hearts who underwent Ladd's procedure.

METHODS

A retrospective chart review (2005 to 2010) from our institutional database identified patients with heterotaxy syndrome who underwent a Ladd's procedure.

RESULTS

Nine patients (3 boys and 6 girls) underwent Ladd's procedure. Patient demographics were as follows: median gestational age, 38 weeks (range, 37 to 39); median birth weight, 2.7 kg (range, 2 to 3.4 kg); and median age at Ladd's procedure, 180 days (range, 7 to 1,080). Four patients (44%) exhibited feeding intolerance with documented intestinal rotation and fixation abnormalities. Two of these patients underwent Ladd's procedure before cardiac surgery, 1 of whom had subsequent pulmonary artery banding, had recurrent necrotizing enterocolitis, and died. Two children had Ladd's procedure after initial cardiac palliation; both had shunt thrombosis during abdominal surgery, with a mortality of 50%. Five patients who were asymptomatic underwent Ladd's procedure after second-stage palliation. Mortality in this group was 0%.

CONCLUSIONS

Ladd's procedure in single ventricle heterotaxy patients who are tolerating enteral feeding should be performed after physiologic palliation to a more balanced circulation, ideally after cavopulmonary connection. Symptomatic neonates pose management challenges. Timing of abdominal surgery should be carefully considered, given the significant risk of mortality in these patients.

The phenotypic spectrum of ZIC3 mutations includes isolated d-transposition of the great arteries and double outlet right ventricle

Disease causing mutations for heterotaxy syndrome were first identified in the X-linked laterality gene, ZIC3. Mutations typically result in males with situs ambiguus and complex congenital heart disease; however affected females and one male with isolated d-transposition of the great arteries (d-TGA) have been reported. We hypothesized that a subset of patients with heart defects common to heterotaxy but without laterality defects would have ZIC3 mutations. We also sought to estimate the prevalence of ZIC3 mutations in sporadic heterotaxy. Patients with TGA (n = 169), double outlet right ventricle (DORV; n = 89), common atrioventricular canal (CAVC; n = 41), and heterotaxy (n = 54) underwent sequencing of ZIC3 exons. We tested 90 patients with tetralogy of Fallot (TOF) to correlate genotype with phenotype. Three potentially disease-related missense mutations were detected: c.49G > T (Gly17Cys) in a female with isolated DORV, c.98C > T (Ala33Val) in a male with isolated d-TGA, and c.841C > T (His281Tyr) in a female with sporadic heterotaxy. We also identified a novel insertion (CPFP333ins) in a family with heterotaxy. All were absent in 200 control patients and the 1000 Genomes Project (n = 629). No significant mutations were found in patients with TOF. Functional studies demonstrated reduced transcriptional activity of the ZIC3 His281Tyr mutant protein. ZIC3 mutations were rarely identified in isolated DORV and d-TGA suggesting that a subset of DORV and d-TGA may fall within the spectrum of laterality defects. ZIC3 mutations were found in 3.7% of patients with sporadic heterotaxy; therefore testing should be considered in patients with heterotaxy.

Evaluation of cardiac manifestations in pediatric liver transplant candidates

Knowledge concerning the involvement of the cardiovascular system in children awaiting liver transplant is limited. Therefore, no guidelines have been established on evaluating this group of patients for cardiac disease. This review examines the diverse cardiovascular manifestations of liver disease in children. We also discuss the available testing and its applicability in screening for cardiac disease in this vulnerable population.

Outcome of left atrial isomerism at a single institution

Left atrial isomerism includes a complex spectrum of cardiac and extracardiac anomalies. The records of all patients with left isomerism born during the period of 1973-2010 and treated at the Children's Hospital, Helsinki were reviewed. The short- and long-term outcomes were studied. The review included 38 patients (50% females). The overall survival with left atrial isomerism was 63% during a median follow-up time of 16 years (range, 4-30 years). Extracardiac anomalies were noted in 14 (37%) of 38 cases. Cardiac defects included dextrocardia in 26%, partially or totally anomalous pulmonary venous return in 29%, common atrium in 50%, atrioventriculoseptal defect in 73%, single ventricle in 40%, ventriculoseptal defect without atrioventricular defect in 11%, transposition in 21%, double outlet of the right ventricle in 26%, pulmonary stenosis or atresia in 61%, and left ventricular outflow obstruction in 24% of the cases. Cardiac arrhythmias were presented in 71% and pacemaker treatment in 29% of the cases. Of the 38 patients, 33 had cardiac surgery. Simple palliative methods were used in 11 cases, single-ventricle palliation in 12 cases, and operation with a biventricular track in 10 cases. In the groups that had surgery, 3 of 11 patients, 3 of 12 patients, and 3 of 10 patients died, respectively. In this review, 14 deaths occurred, associated with extracardiac anomalies in five cases and with cardiac arrhythmia in four cases. Five postoperative deaths occurred. At this writing, all three patients who had heart transplantation are alive. Complicated heart defects associated with severe arrhythmias and extracardiac anomalies contribute to a high mortality rate with left isomerism. Cardiac transplantation was considered a good option for selected patients.

Atrioventricular valve repair for patient with heterotaxy syndrome and a functional single ventricle

Heterotaxy syndrome is a mortality risk factor for patients with complex heart disease. These patients often have common atrioventricular valve (CAVV) morphology and significant atrioventricular valve regurgitation - yet another mortality risk factor in congenital heart disease. Thus, patients with both heterotaxy syndrome and atrioventricular valve regurgitation are at highest risk of mortality. A large number of patients with heterotaxy syndrome have CAVV and a functional single ventricle. These patients are more difficult to operate than patients with biventricular morphology because in the former, the CAVV is often less adapted to systemic afterload than the mitral valve. Herein, we present the results of atrioventricular valve repair surgeries performed at the Okayama University Hospital on patients with heterotaxy syndrome, atrial isomerism, and a functional single ventricle. In addition, we review the current literature in this typically challenging patient population. In-depth understanding of reasonable management strategies and resolution of technical issues will help guide surgeons during this procedure.

Improving outcomes of the surgical management of right atrial isomerism

BACKGROUND

Patients with right atrial isomerism (RAI) have several cardiac malformations historically resulting in significant morbidity and mortality. We sought to assess whether current surgical strategies have improved the outcomes of patients with RAI.

METHODS

A retrospective review of our database from 1997 to 2010 identified 60 consecutive patients with RAI who underwent initial palliation at Mt. Fuji Shizuoka Children's Hospital. All of the patients had a functional single ventricle. Of the 60 patients, 33 patients (51.7%) had obstructed total anomalous pulmonary venous drainage (TAPVD), 23 patients (40.3%) had significant (more than moderate) atrioventricular valvular regurgitation (AVVR), 7 patients (12.3%) had hiatus hernia, and 4 patients (6.7%) had major aortopulmonary collateral arteries. Pulmonary outflow atresia was present in 39 of the patients (65%), and 46 patients had systemic-to-pulmonary artery shunts. Of the 33 patients with TAPVD, 18 underwent repair of the condition at initial palliation, 9 others at the time of a Glenn operation, 2 more through a Fontan operation, and 4 at the interstage between palliative surgeries. Eight of the 23 patients with significant AVVR underwent atrioventricular valve repair at initial palliation, 8 others at the time of Glenn operation, 4 others at the time of Fontan operation, and 3 during the interstage between operations. An initial neonatal surgical procedure was performed in 30 patients (50%). The mean follow-up period for patients in the study was 53.1 months.

RESULTS

Operative mortality after initial palliation was 15.4% (4 of 26 patients) before 2003 and 17.6% (6 of 34 patients) after 2004 (p=NS). Five-year survival was 53.8% before 2003 and 81.7% after 2004 (p=0.035, log-rank test). A multivariate analysis identified persistent AVVR of more than moderate degree (p=0.04) as a factor associated with late mortality.

CONCLUSIONS

The outcomes of surgery for RAI are improving. Neonatal palliative surgery for RAI carries a high operative risk of early mortality, and persistent significant AVVR remains a risk factor for late mortality.

The incidence and characteristics of supraventricular tachycardia in left atrial isomerism: a high incidence of atrial fibrillation in young patients

BACKGROUND

In left atrial isomerism (LAI), both atria show left atrial morphology. Although bradyarrhythmias are frequent and highly complex in LAI patients, previous studies have reported a low incidence of supraventricular tachycardia (SVT).

METHODS

To evaluate the incidence and characteristics of SVT in LAI, we retrospectively evaluated the clinical characteristics of SVTs in 83 patients with LAI (age at last follow-up, 15.3±10.5 years).

RESULTS

There were 27 SVTs in 19 patients (23%), including nine episodes of atrial fibrillation (AF) and eight non-reentrant SVTs. Sixteen of the 19 patients with SVT had histories of atriotomy, but the three patients with AF or non-reentrant tachycardia had no history of atriotomy. The rates of freedom from SVT were 66% and 59% at ages of 20 and 30 years, respectively; the corresponding rates for freedom from AF were 89% and 74%. In multivariate analysis, the predictors of SVT were age (OR, 1.14; 95% CI, 1.06-1.26; p=0.003) and sinus node dysfunction (SND) (OR, 3.88; 95% CI, 1.57-13.34; p=0.01).

CONCLUSIONS

In patients with LAI, SVTs are common, and AF and non-reentrant SVTs are the major type of SVTs. The incidence of AF was high in young patients with LAI. The lack of anatomical barriers in the atria that allow the formation of macro-reentrant circuits may account for the higher incidence of AF and non-reentrant SVT than macro-reentrant tachycardia. Moreover, the increasing prevalence of SND with age should contribute to a higher incidence of SVT.

The cardiac malpositions

Dextrocardia was known in the 17th century and was 1 of the first congenital malformations of the heart to be recognized. Fifty years elapsed before Matthew Baillie published his account of complete transposition in a human of the thoracic and abdominal viscera to the opposite side from what is natural. In 1858, Thomas Peacock stated that "the heart may be congenitally misplaced in various ways, occupying either an unusual position within the thorax, or being situated external to that cavity." In 1915, Maude Abbott described ectopia cordis, and Richard Paltauf's remarkable illustrations distinguished the various types of dextrocardia. In 1928, the first useful classification of the cardiac malpositions was proposed, and in 1966, Elliott et al's radiologic classification set the stage for clinical recognition. The first section of this review deals with the 3 basic cardiac malpositions in the presence of bilateral asymmetry. The second section deals with cardiac malpositions in the presence of bilateral left-sidedness or right-sidedness. Previous publications on cardiac malpositions are replete with an arcane vocabulary that confounds rather than clarifies. Even if the terms themselves are understood, inherent complexity weighs against clarity. This review was designed as a guided tour of an unfamiliar subject.

Increased postoperative and respiratory complications in patients with congenital heart disease associated with heterotaxy

OBJECTIVE

Patients with heterotaxy and complex congenital heart disease underwent cardiac surgery with high mortality and morbidity. Recent studies have revealed an association among heterotaxy, congenital heart disease, and primary ciliary dyskinesia. We undertook a retrospective review of patients undergoing cardiac surgery at Children's National Medical Center between 2004 and 2008 to explore the hypothesis that there is increased mortality and respiratory complications in heterotaxy patients.

METHODS

Retrospective review was performed on postsurgical outcomes of 87 patients with heterotaxy and congenital heart disease exhibiting the full spectrum of situs abnormalities associated with heterotaxy. As controls patients, 634 cardiac surgical patients with congenital heart disease, but without laterality defects, were selected, and surgical complexities were similar with a median Risk Adjustment in Congenital Heart Surgery-1 score of 3.0 for both groups.

RESULTS

We found the mean length of postoperative hospital stay (17 vs 11 days) and mechanical ventilation (11 vs 4 days) were significantly increased in the heterotaxy patients. Also elevated were rates of tracheostomies (6.9% vs 1.6%; odds ratio, 4.6), extracorporeal membrane oxygenation support (12.6% vs 4.9%: odds ratio, 2.8), prolonged ventilatory courses (23% vs 12.3%; odds ratio, 2.1) and postsurgical deaths (16.1% vs 4.7%; odds ratio, 3.9).

CONCLUSIONS

Our findings show heterotaxy patients had more postsurgical events with increased postsurgical mortality and risk for respiratory complications as compared to control patients with similar Risk Adjustment in Congenital Heart Surgery-1 surgical complexity scores. We speculate that increased respiratory complications maybe due to ciliary dysfunction. Further studies are needed to explore the basis for the increased surgical risks for heterotaxy patients undergoing cardiac surgery.

Left atrial isomerism: biventricular repair

OBJECTIVE

Biventricular repair of hearts with left atrial isomerism often necessitates complex atrial and ventricular baffle procedures. We analysed our experience with an accent on baffle techniques.

METHODS

From 1997 until 2008, 12 patients (four male) with left atrial isomerism received biventricular repair. Their median age at surgery was 9 (range: 1-24) months. Four patients had dextrocardia. Nine patients presented with left superior vena cava, three with absent right superior vena cava, five with unroofed coronary sinus and nine others with inferior vena cava interruption with (hemi)azygos continuation. Anomalous pulmonary venous drainage was present in three patients. Eight had a monoatrium. Atrioventricular septal defect (AVSD) occurred in six (complete AVSD in two), One patient with complete AVSD had right pulmonary agenesia with long segment tracheal stenosis. Multiple VSDs presented in one whereas three patients had double-outlet right ventricle (DORV) (one with borderline LV hypoplasia). Two had previous pulmonary artery banding. Complex intra-atrial baffle constructions were performed in seven patients. Complete AVSDs were corrected using two patches and all other AVSDs had one patch repair. Multiple VSDs were closed directly. DORV patients had intraventricular tunnel repair.

RESULTS

No early mortality occurred. Median follow-up was 54 (range: 2-134) months. One patient with complete AVSD and pulmonary agenesia died late after tracheal repair. Four patients needed five re-operations (closure of residual ASD (one), relief of left (two) or right (two) ventricular outflow obstruction, pulmonary artery branch plasty (one)). There was no atrial baffle stenosis. Four received a pacemaker. All survivors are in NYHA class I.

CONCLUSIONS

Survival and functional status of left isomerism patients after biventricular repair is good. Complex repairs with atrial or ventricular baffles are frequent. Arrhythmias were common and pose a concern late after repair.

Improving results of atrioventricular valve repair in challenging patients with heterotaxy syndrome

OBJECTIVES

Heterotaxy syndrome, which is often associated with atrioventricular valvar regurgitation, has been considered a risk factor for the surgical repair for Fontan candidates. The results of atrioventricular valve repair in this challenging patient population remain largely unknown.

METHODS

From July, 1994 to January, 2007, 25 patients with the heterotaxy syndrome consisting of 22 right isomerism and three left isomerism presented to the Shizuoka Children's Hospital Japan with significant (3-4+) atrioventricular valvar regurgitation necessitating atrioventricular valve repair. The clinical and Doppler/echocardiographic data were retrospectively reviewed to determine the efficacy of the repair and patient outcome.

RESULTS

Patients were divided into two groups on the basis of atrioventricular valvar regurgitation at the most recent follow-up: those with a successful late outcome, (0-2) and those with a poor outcome (3-4). There were 17 (67%) patients with a successful outcome and 8 (33%) with a poor outcome. The repair technique including leaflet apposition was predictive of a successful outcome (p = 0.003). Overall survival was 64% (16/25). Survival was 88.2% (15/17) for patients with a successful result versus 12.5% (1/8) for those with a poor outcome (p = 0.0007). Of the 15 survivors, 13 have reached final completion of the Fontan circulation, and two currently remain at the bi-directional Glenn shunt stage.

CONCLUSION

Atrioventricular valve repair can be accomplished in this challenging patient population with excellent results. The combination of the leaflet apposition technique and the Kay suture can be performed with an excellent outcome in the majority of patients with heterotaxy syndrome, even with significant atrioventricular valvar regurgitation.

Long-term clinical outcome of atrial isomerism after univentricular repair

OBJECTIVES

We retrospectively reviewed the long-term outcome of atrial isomerism patients after Fontan completion.

METHODS

Since 1972, 58 patients underwent a palliative procedure prior to the Fontan-type operation. Twenty-eight out of 58 patients could not reach Fontan-type operation. Twenty-five patients underwent Fontan-type operation, and 12 of them expired less than five years after the Fontan completion. Eleven patients survived more than five years after the Fontan completion and were identified as long-term survivors. The mean follow-up period was 13+/-5 years.

RESULTS

During follow-up period, four of the 11 patients expired. The actuarial survival rates at 10, 15, and 20 years after univentricular repair (UVR) were 100%, 71.4%, and 53.6%, respectively. The significant predictors of long-term survival by univariate analysis were the staged strategy (p=0.019), total cavo-pulmonary connection with extracardiac conduit (p=0.019), and the absence of postoperative common atrioventricular valve regurgitation (p=0.040). Six out of the seven present survivors showed New York Heart Association class I activity. All present survivors' mean percutaneous oxygen saturation, mean pulmonary arterial pressure, pulmonary capillary wedge pressure, single ventricular end diastolic volume index, and single ventricular ejection fraction were 88.8+/-6.8%, 11.0+/-2.6 mmHg, 5.8+/-2.0 mmHg, 104+/-37 mL/m2, and 52.0+/-6.5%, respectively.

CONCLUSIONS

There are still life-threatening problems 10 years after the UVR. However, the excellent performance status of the present long-term survivors suggests that these problems can all be overcome by the present strategies established for the Fontan-type operation.

Importance of totally anomalous pulmonary venous connection and postoperative pulmonary vein stenosis in outcomes of heterotaxy syndrome

Historically, outcomes of patients with heterotaxy syndrome and congenital heart disease have been poor. Published series include patients treated over many decades or focus on specific patient/operative subgroups. This study was performed to evaluate midterm outcomes and determine anatomic risk factors for death in patients with all types of heterotaxy syndrome treated after 1985. We reviewed all infants with heterotaxy born between 1985 and 1997, presenting to one institution at <6 months age, followed for > or =5 years. Of 102 study patients (46 with asplenia phenotype, 56 with polysplenia phenotype), 48 (47%) died at a median age of 0.6 months, 12 without intervention. Survivors were followed for a median of 12.8 years (5-21.7 years). Independent predictors of mortality included obstructed totally anomalous pulmonary venous connection (TAPVC) (OR, 7.8; 95% CI, 1.9-32.9; p = 0.005), mild or greater atrioventricular (AV) valve regurgitation at presentation (OR, 3.5; 95% CI, 1.0-12.1; p = 0.03), and common AV canal (OR, 3.1; 95% CI, 1.1-8.5; p = 0.03). Sixteen patients developed pulmonary vein stenosis at a median age of 2 months, with 5 (31%) alive at follow-up. In patients with TAPVC, the mean indexed sum of pulmonary vein diameters was lower among patients who died than in survivors (42.3 +/- 8.3 vs 49.5 +/- 10.1 mm/m2; p = 0.02). Mortality remains high among patients with heterotaxy treated in the modern surgical era, particularly those with obstructed TAPVC. Pulmonary vein stenosis is common after repair of TAPVC in patients with heterotaxy, may be diagnosed beyond infancy, and is associated with poor outcomes.

Functional state of patients with heterotaxy syndrome following the Fontan operation

BACKGROUND

Children born with heterotaxy syndromes have poorer outcomes compared with children born with comparable cardiac lesions requiring similar surgical palliation. Heterotaxy has been reported as a separate risk factor for mortality and increased morbidity in a series of Fontan operations reported from single centres. Little is known, however, about the functional state of surviving patients with heterotaxy following a Fontan operation.

METHODS

In the multicentric cross-sectional study carried out by the Pediatric Heart Network of 546 survivors of the Fontan procedure, the patients, aged from 6 to 18 years, underwent evaluation by echocardiography, exercise testing, electrocardiography, magnetic resonance imaging, and functional health status questionnaires compiled by the patients and their parents. Heterotaxy was identified in 42 patients (8%). Medical and patient characteristics were compared between those with heterotaxy and the remaining 504 patients who did not have heterotaxy.

RESULTS

Patients with heterotaxy had their Fontan procedure performed at a later age, with a median of 3.9 years versus 2.8 years (p=0.001) and had volume-unloading surgery performed later, at a median age of 1.4 versus 0.9 years (p=0.008). These patients had significantly different ventricular and atrioventricular valvar morphology, as well as a higher incidence of systemic and pulmonary venous abnormalities. They had a higher incidence of prior surgery to the pulmonary veins, at 21 versus 0.4%. The type of Fontan procedure was different, but no difference was detected in length of stay in hospital, or the number of postoperative complications. Sinus rhythm was less common, at 44 versus 71%, (p=0.002), and history of atrial arrhythmias more common, at 19 versus 8%, (p=0.018) in those with heterotaxy. Echocardiography revealed a greater degree atrioventricular valvar regurgitation, lower indexed stroke volume, and greater Tei index. Exercise performance, levels of brain natriuretic peptide in the serum, and summary and domain scores from health status questionnaires, were not different from those not having heterotaxy.

CONCLUSIONS

The study illustrates a profile of characteristics, medical history, functional health state, and markers of ventricular performance in patients with heterotaxy after the Fontan procedure. Despite obvious anatomic differences, and some differences in echocardiography and heart rhythm, there were no important differences in exercise performance or functional health state between these patients and other survivors of the Fontan procedure.

Controversies, genetics, diagnostic assessment, and outcomes relating to the heterotaxy syndrome

How best to analyse and describe the features of the situation commonly known as "visceral heterotaxy" remains controversial. Much of the disagreement devolves on how to deal with the concept of isomerism. In the opinion of some, the concept of bilateral right-sidedness and bilateral left-sidedness, while useful in helping to remember which abnormalities are likely to occur in asplenia or polysplenia, should not be granted the status of a specific "situs", since there are numerous examples of exceptions to these patterns. On the other hand, those who favour the concept of isomerism point out that, when describing only the heart, and taking the structure of the atrial appendages as the starting point for analysis, basing this on the extent of the pectinate muscles relative to the atrioventricular junctions, then the only possible arrangements for the appendages are the usual one, its mirror-image, and the two situations in which appendages of comparable morphology are found on both sides of the heart, these being the arrangements of right or left isomerism. It is certainly the case that the arrangement of the organs is not always in harmony with the arrangement of the atrial appendages, but those circumstances, in which there is disharmony, can readily be described by paying specific attention to each series of organs. On this basis, in this review, we describe the approach to heterotaxy, and isomerism of the atrial appendages, in terms of the genetic background, the diagnosis, and outcomes after cardiac surgery. Attention is given to the various diagnostic modalities, including fetal and postnatal echocardiography, recent tomographic and magnetic resonance imaging techniques, and the time-honoured approach using angiography.

Progressive fetal atrioventricular block in heterotaxy syndrome

We report a fetus with left isomerism, in whom the atrioventricular block progressed from low grade second degree to complete block and fetal hydrops. While it is known that there is a high incidence of heart block in the fetus with left isomerism, as far as we are aware, ours is the first report of Wenckebach type block documented in the fetus by Doppler echocardiography, and demonstration of the progression of heart block during fetus life in the setting of left isomerism.

Clinical investigations over 13 years to establish the nature of the cardiac defects in patients having abnormalities of lateralization

INTRODUCTION

The first step in diagnosing congenital cardiac malformations is to assess the arrangement of the atrial appendages. In patients with abnormal lateralization of the organs of the body, the arrangement of atrial appendages is neither normal, nor a mirror image of normal. There are 2 categories of abnormal arrangement based on the morphology of the atrial appendices, namely right isomerism and left isomerism, and in almost all instances these are found in the setting of so-called heterotaxy syndromes.

OBJECTIVE

To evaluate the various congenital cardiac malformations those are associated with abnormalities of lateralization, and to discuss the diagnostic tools, therapeutic options, and outcome for these patients.

PATIENTS AND METHODS

We studied 134 patients, who had been admitted to our department of paediatric cardiology with known abnormalities of lateralization and congenital cardiac defects between 1990 and 2003. The data relating to each patient was evaluated retrospectively. The arrangement of the atrial appendages was established echocardiographically, and/or angiographically, and/or on the basis of morphologic investigations during the operation. These studies showed that 43 (32.1%) of the patients had right isomerism, and 88 (65.7%) had left isomerism. In 2 (1.5%), there was mirror-imaged arrangement, while in the final patient (0.07%), we were unable to determine sidedness with certainty. The median age at diagnosis was 0.66 years, and the females outnumbered the males in a ratio of 3 to 1. Patients in the 2 isomeric groups were compared with regard to age, cardiac defects, diagnostic tools and outcomes.

RESULTS

The difference in mean ages of the two groups of patients was statistically significant, those with right isomerism being 1.0 minus or plus 1.5 years, as opposed to those with left isomerism being 3.3 minus or plus 4.7 years (P is less than 0.005). Of the patients with right isomerism, 32 (74.4%) had left-sided, and 11 (25.6%) right-sided hearts, whereas in those with left isomerism, the hearts were left-sided in 65 (73.9%), and right-sided in 21 (23.9%), with 2 (2.2%) positioned in the midline. Extracardiac totally anomalous pulmonary venous connection was more common in those with right isomerism, being found in 13 patients (30.2%) as opposed to 5 patients (5.7%) with left isomerism. In only 8 of those with right isomerism did we find two perforate atrioventricular valves (18.6%), this arrangement being found in 34 (38.6%) of those with left isomerism. Pulmonary atresia and stenosis were present in 40 (93.0%) of those with right isomerism, but also in 41 (46.6%) of the patients with left isomerism. Angiographic and echocardiographic investigations were concordant in about three-quarters of patients with both right and left isomerism. All patients with extracardiac totally anomalous pulmonary venous connection died. Overall, 22 of the patients with right isomerism died (51.2%), as opposed to 20 (22.7%) of those with left isomerism.

CONCLUSION

Our experience confirms that patients with right isomerism have more complex cardiac defects than those with left isomerism. Overall, the presence of isomerism carries a poor prognosis, the more so for right isomerism, with this related to the complex cardiac abnormalities. In our cohort, extracardiac totally anomalous pulmonary venous connection with pulmonary arterial obstruction was always a fatal combination. The mapping of cardiac and abdominal morphologies is still essential for proper diagnosis of these syndromes, especially in fetal life.

Congenital heart disease and other heterotaxic defects in a large cohort of patients with primary ciliary dyskinesia

BACKGROUND

Primary ciliary dyskinesia (PCD) is a recessive genetic disorder that is characterized by sinopulmonary disease and reflects abnormal ciliary structure and function. Situs inversus totalis occurs in approximately 50% of PCD patients (Kartagener's syndrome in PCD), and there are a few reports of PCD with heterotaxy (situs ambiguus), such as cardiovascular anomalies. Advances in diagnosis of PCD, such as genetic testing, allow the systematic investigation of this association.

METHODS AND RESULTS

The prevalence of heterotaxic defects was determined in 337 PCD patients by retrospective review of radiographic and ultrasound data. Situs solitus (normal situs) and situs inversus totalis were identified in 46.0% and 47.7% of patients, respectively, and 6.3% (21 patients) had heterotaxy. As compared with patients with situs solitus, those with situs abnormalities had more ciliary outer dynein arm defects, fewer inner dynein arm and central apparatus defects (P<0.001), and more mutations in ciliary outer dynein arm genes (DNAI1 and DNAH5; P=0.022). Seven of 12 patients with heterotaxy who were genotyped had mutations in DNAI1 or DNAH5. Twelve patients with heterotaxy had cardiac and/or vascular abnormalities, and most (8 of 12 patients) had complex congenital heart disease.

CONCLUSIONS

At least 6.3% of patients with PCD have heterotaxy, and most of those have cardiovascular abnormalities. The prevalence of congenital heart disease with heterotaxy is 200-fold higher in PCD than in the general population (1:50 versus 1:10 000); thus, patients with PCD should have cardiac evaluation. Conversely, mutations in genes that adversely affect both respiratory and embryological nodal cilia are a significant cause of heterotaxy and congenital heart disease, and screening for PCD is indicated in those patients.

Anatomical and functional evaluation of pulmonary veins in children by magnetic resonance imaging

Pulmonary vein pathologies often present a diagnostic challenge. Among the different imaging modalities used for the evaluation of pulmonary veins, magnetic resonance is the most comprehensive in assessing anatomy and pathophysiology at the same time. Bright blood cine sequences and contrast-enhanced magnetic resonance angiography outline the course and connections of the pulmonary veins. Phase-contrast velocity mapping measures flow patterns, velocities, and volumes throughout the pulmonary circulation. This paper reviews contemporary utilization of magnetic resonance in the evaluation of pulmonary venous abnormalities in children, based on our experience over the last 5 years and on that of other investigators. We summarize how magnetic resonance imaging enhances our understanding of pulmonary vein physiology and how it can influence the diagnostic approach to children and adults with a pulmonary venous pathology, and we discuss its limitations.

Early and Late Results of the Modified Fontan Operation for Heterotaxy Syndrome

OBJECTIVES

We sought to evaluate the early and late results of the modified Fontan operation for patients with heterotaxy syndrome, assess variables traditionally known to correlate with poor outcome, and assess current health status of survivors after the Fontan procedure.

BACKGROUND

The natural history of unoperated cardiac lesions in heterotaxy is known to be poor. Therefore, the Fontan operation has been proposed to improve survival.

METHODS

Patients with heterotaxy were identified from the Mayo Clinic Fontan database. Hospital and outpatient records were abstracted for preoperative, operative, and postoperative clinical and hemodynamic data. All patients not known to be deceased were sent health status questionnaires.

RESULTS

A total of 142 patients with heterotaxy syndrome had a modified Fontan operation. Asplenia was present in 76 patients (54%). Median age at operation was 9 years (range 2 to 35 years). Median follow-up was 4 years (range 0 to 23 years). There were a total of 61 deaths (43%), with 32 (23%) within 30 days of operation or before hospital discharge. The 5-, 10-, and 15-year survival was 64%, 57%, and 53%, respectively. In the modern era (1995 to 2004) early mortality was 10%. Of the 81 survivors, questionnaires were available from 41 (51%). Eighty percent reported having no or mild symptoms. However, 19 (46%) had arrhythmias, 5 (12%) had a thromboembolic event, and 1 (2%) developed protein-losing enteropathy.

CONCLUSIONS

Early survival has improved for heterotaxy patients after the Fontan operation; however, late morbidity and mortality remain substantial. Better strategies for long-term treatment of this high-risk group need to be identified.

Heterotaxy syndrome with functional single ventricle: does prenatal diagnosis improve survival?

BACKGROUND

Despite improved outcome for many single ventricle lesions, staged reconstruction for heterotaxy syndrome with a functional single ventricle continues to have a high mortality. Prenatal identification of heterotaxy syndrome may improve long-term survival.

METHODS

Our database was reviewed from January 1996 to December 2004 for patients with heterotaxy syndrome. Assessment was made for prenatal diagnosis and echocardiographic characteristics of heterotaxy syndrome. We sought to assess the accuracy of fetal echocardiography in the diagnosis of heterotaxy syndrome and determine whether prenatal diagnosis and other risk factors have an impact on survival in patients with heterotaxy syndrome.

RESULTS

Of 81 patients that met criteria, 43 (53%) had prenatal diagnosis. Prenatal diagnosis had high specificity and positive predictive value for all findings but had low sensitivity for anomalous pulmonary veins. Among the 70 patients born alive, survival was 60% with median follow-up of 51.4 months (range, 6.5 to 109.7 months). Prenatal diagnosis did not improve survival (p = 0.09). None of the 11 patients with complete heart block (CHB) survived past 3 months of age. Two patients underwent heart transplantation as their first intervention and have survived. CHB and anomalous pulmonary venous connection were associated with shorter duration of survival.

CONCLUSIONS

Prenatal diagnosis of heterotaxy syndrome does not improve survival in patients who undergo single ventricle reconstruction. The most potent risk factors for poor outcome (CHB, anomalous pulmonary veins) are likely not impacted by identification in utero. In light of the poor outcome, cardiac transplantation as an initial therapy may be a viable option for some patients.