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

A multi-disciplinary, comprehensive approach to management of children with heterotaxy

Heterotaxy (HTX) is a rare condition of abnormal thoraco-abdominal organ arrangement across the left-right axis of the body. The pathogenesis of HTX includes a derangement of the complex signaling at the left-right organizer early in embryogenesis involving motile and non-motile cilia. It can be inherited as a single-gene disorder, a phenotypic feature of a known genetic syndrome or without any clear genetic etiology. Most patients with HTX have complex cardiovascular malformations requiring surgical intervention. Surgical risks are relatively high due to several serious comorbidities often seen in patients with HTX. Asplenia or functional hyposplenism significantly increase the risk for sepsis and therefore require antimicrobial prophylaxis and immediate medical attention with fever. Intestinal rotation abnormalities are common among patients with HTX, although volvulus is rare and surgical correction carries substantial risk. While routine screening for intestinal malrotation is not recommended, providers and families should promptly address symptoms concerning for volvulus and biliary atresia, another serious morbidity more common among patients with HTX. Many patients with HTX have chronic lung disease and should be screened for primary ciliary dyskinesia, a condition of respiratory cilia impairment leading to bronchiectasis. Mental health and neurodevelopmental conditions need to be carefully considered among this population of patients living with a substantial medical burden. Optimal care of children with HTX requires a cohesive team of primary care providers and experienced subspecialists collaborating to provide compassionate, standardized and evidence-based care. In this statement, subspecialty experts experienced in HTX care and research collaborated to provide expert- and evidence-based suggestions addressing the numerous medical issues affecting children living with HTX.

Predictive factors contributing to prolonged recovery in patients after Fontan operation

Background

Prolonged recovery is a severe issue in patients after Fontan operation. However, predictive factors related to this issue are not adequately evaluated. The present study aimed to investigate potential predictive factors which can predict Fontan postoperative recovery.

Methods

We retrospectively reviewed the perioperative medical records of patients with Fontan surgery between January 2015 and December 2018, and divided patients with > 75%ile cardiac intensive care unit stay into prolonged recovery group. The others were assigned to standard recovery group. Patients that died or underwent a Fontan takedown were excluded. Statistical analysis was performed to compare data difference of the two groups.

Results

282/307 cases fulfilled the inclusion criteria. Seventy patients were considered in prolonged recovery and 212 patients were defined as standard recovery. Pre- and intra-operative data showed a higher incidence of heterotaxy syndrome, longer cardiopulmonary bypass and aortic cross-clamp time in the prolonged recovery group. Postoperative information analysis displayed that ventilation time, oxygen index after extubation, hemodynamic data, inotropic score (IS), drainage volume, volume resuscitation, pulmonary hypertension (PH) treatment, and surgical reintervention were significantly different between the two groups. Higher IS postoperatively, and PH treatment and higher fluid resuscitation within two days were independent predictive factors for prolonged recovery in our multivariate model. C-statistic model showed a high predictive ability in prolonged recovery by using the three factors.

Conclusions

Ventilation time, higher IS in postoperative day, and PH treatment and higher fluid resuscitation within two days were independent risk factors and have a high predictability for Fontan prolonged recovery.

Outcomes of the Surgical Management of Atrial Isomerism and Functional Single Ventricle: A Single-Centered Cohort From China

Objectives: The management of atrial isomerism with complex congenital heart disease remains challenging. Experience has been largely obtained in advanced countries. The clinical diversity is greater in China. We evaluated the early- and medium-term outcomes of surgical treatment of these patients. Methods: We reviewed 86 patients of atrial isomerism with complex congenital heart disease undergoing varied surgeries in our center in 2008-2020. Cox regression models were used to analyze the risk factors for mortality. Results: There were 75 cases of right and 11 of left atrial isomerism. Eighty-three (96.5%) patients underwent single-ventricle staged palliation approach, with 10 early and 7 late deaths. The overall 1-, 5-, and 10-year survival rates were 84.7, 79.3, and 79.3%, respectively. Thirty-six (43.4%) patients completed the Fontan procedure with median age of 48 months and freedom from death or Fontan failure at 1-, 5-, and 8-years were 94.4, 87.4, and 80.7%, respectively. Concomitant total anomalous pulmonary venous connection [hazard ratio (HR): 5.15 (1.95-12.94), p = 0.008], more than moderate atrioventricular valve regurgitation [HR: 4.82 (2.42-6.79), p = 0.003], and the need for first-stage palliative surgery [HR: 4.58 (1.64-10.76), p = 0.015] were independent risk factors for mortality. Conclusions: Despite even greater clinical diversity, the surgical outcomes of atrial isomerism with complex congenital heart disease are improving in China. The early and intermediate outcomes are comparable to many previous reports. Concomitant total anomalous pulmonary venous connection, moderate or severe atrioventricular valve regurgitation, and the need for a first-stage palliative surgery are still independent risk factors for mortality.

Echocardiographic Identification of Pulmonary Artery Flow Reversal: An Indicator of Adverse Outcomes in Single Ventricle Physiology

Individuals with single ventricle congenital heart disease (CHD) undergo multiple staged surgical palliations. Staged single ventricle palliation with a superior cavopulmonary connection (SCPC) in infancy followed by a Fontan in early childhood relies on passive, unobstructed pulmonary blood flow and normal pulmonary vasculature. We hypothesized that patients with echocardiographic identification of retrograde flow in a branch pulmonary artery (PA) after SCPC or Fontan are at increased risk for adverse outcomes. We conducted a retrospective chart review of patients seen at Children's Wisconsin from 1999 to 2019. Inclusion criteria included a history of single ventricle congenital heart disease and surgical palliation with a superior cavopulmonary connection (SCPC). We created two cohorts based on transthoracic echocardiographic identification of branch PA flow patterns: those with color Doppler-defined pulmonary artery flow reversal (PA reversal cohort) and those with normal anterograde flow (Non-reversal cohort). We identified 21 patients in the PA reversal cohort and 539 patients in the Non-reversal cohort. The PA reversal cohort had increased hospital length of stay after SCPC palliation (p < 0.001) and decreased transplant-free survival (p = 0.032), but there was no difference in overall survival (p = 0.099). There was no difference in hospital length of stay after Fontan (p = 0.17); however, the PA reversal cohort was significantly less likely to progress to Fontan palliation during early childhood (p = 0.005). Echocardiographic color Doppler identification of branch PA flow reversal in patients with single ventricle physiology is a high-risk indicator for adverse short- and long-term outcomes.

The Spectrum of Cardiac Anomalies Associated with Heterotaxy: A Single-Center Study of a Large Series Based on Computed Tomography

The aim of the study was to identify and correlate the anatomical variants of cardiac structures among patients with heterotaxy. In this retrospective cross-sectional analysis of 13 years duration, 302 patients of congenital heart diseases associated with heterotaxy were studied. All these patients had undergone a meticulous clinical evaluation, echocardiography, and cardiac computed tomography. The mean age of the cohort was 38.4 months, with 180 males and 122 females. The cohort had 184 patients of right isomerism and 118 of left isomerism. More than half of the cohort had abnormal pulmonary veins. Over 75% of the cohort had low pulmonary blood flow. Abnormal relationship of great arteries was seen in nearly 69% of the cohort. Atrio-venticular canal defect was the commonest anatomical variant. Overall, 43% of the cohort had single ventricle physiology, predominantly associated with right isomerism. Heterotaxy forms a difficult anatomical subset to comprehend due to the plethora of possible abnormalities. However, unless the cardiac and visceral anatomy is delineated well, the surgical plan becomes suboptimal and often elusive, leaving tough choices for cardiac surgeon. It is essential to obtain all the possible anatomical information using additional imaging modalities to devise a basis for a comprehensive plan for medical and surgical management. A better understanding of the genetic and molecular factors in the etiology, coupled with the application of state-of-the-art imaging techniques, is likely to add to our knowledge of heterotaxy to bring about improved surgical outcomes and a better quality of life for patients suffering from this complex entity.

Identification of novel candidate genes in heterotaxy syndrome patients with congenital heart diseases by whole exome sequencing

Heterotaxy syndrome (HS) involves dysfunction of multiple systems resulting from abnormal left-right (LR) body patterning. Most HS patients present with complex congenital heart diseases (CHD), the disability and mortality of HS patients are extremely high. HS has great heterogeneity in phenotypes and genotypes, which have rendered gene discovery challenging. The aim of this study was to identify novel genes that underlie pathogenesis of HS patients with CHD. Whole exome sequencing was performed in 25 unrelated HS cases and 100 healthy controls; 19 nonsynonymous variants in 6 novel candidate genes (FLNA, ITGA1, PCNT, KIF7, GLI1, KMT2D) were identified. The functions of candidate genes were further analyzed in zebrafish model by CRISPR/Cas9 technique. Genome-editing was successfully introduced into the gene loci of flna, kmt2d and kif7, but the phenotypes were heterogenous. Disruption of each gene disturbed normal cardiac looping while kif7 knockout had a more prominent effect on liver budding and pitx2 expression. Our results revealed three potential HS pathogenic genes with probably different molecular mechanisms.

Outcomes in adults with congenital heart disease and heterotaxy syndrome: A single-center experience

BACKGROUND

Heterotaxy syndrome (HS) is a condition in which the thoracoabdominal organs demonstrate an abnormal lateral arrangement and is often associated with congenital heart disease (CHD). Little is known about the adult HS population with CHD.

OBJECTIVE

To describe the outcomes and sociodemographics of the adult CHD population with HS.

METHODS

Records of patients 18 years of age or older with diagnoses of both CHD and HS at Texas Children's Hospital from 1964 to 2018 were reviewed.

RESULTS

Sixty-two patients met inclusion criteria. Median age was 22.7 [IQR 19.6-30.0] years; 26 (42%) were female; and 13 (21%) of patients had a gap in care of >3 years. Median follow-up time in adulthood was 2.9 [IQR 1.3-8.2] years. Forty-three (69%) of patients had single ventricle heart disease, 31 (71%) of whom completed Fontan circulation. A total of 36 interventions occurred in 24 patients which included 16 cardiac catherization interventions, 13 electrophysiology-related procedures, and 18 surgical procedures including 2 orthotopic heart transplants. The median age for death or heart transplant was 45.3 (95%CI 34.3-56.1) years. Heart failure-free survival was 80.8 ± 5.2%, 58.7 ± 11.0%, and 31.1 ± 15.7% at 20, 30, and 40 years old, respectively. Cerebrovascular accident-free survival was 84.3 ± 5.1%, 54.2 ± 11.3%, and 40.6 ± 14.5% at 20, 30, and 40 years old, respectively. Tachyarrhythmia-free survival was 54.0 ± 7.1%, 29.2 ± 8.3%, and 19.5 ± 9.7% at 20, 30, and 40 years old and bradyarrhythmia-free survival was 66.0 ± 6.3%, 41.7 ± 9.4%, and 33.4 ± 10.6% at ages 20, 30, and 40 years, respectively.

CONCLUSIONS

At a tertiary referral center, adult patients with CHD and HS have high rates of comorbidities and early death or heart transplant. Longitudinal surveillance and further exploration into factors associated with improved survival in this population are warranted.

Impact of Era, Type of Isomerism, and Ventricular Morphology on Survival in Heterotaxy: Implications for Therapeutic Management

BACKGROUND

Heterotaxy has been demonstrated to reduce survival. There are several different subgroups of patients, however, and no single study has had a large number of patients and analyzed survival across the different subgroups such as patients born in different eras, patients with right and left isomerism, and patients with biventricular or functionally univentricular hearts. This study pools previously reported data from Kaplan-Meier curves and performs such subgroup analysis.

METHODS

A systematic review of the literature was performed to identify studies reporting survival of patients with the so-called "heterotaxy" by means of Kaplan-Meier survival curves. Data were extracted from these survival curves and then pooled together. A polynomial regression was then used to generate a pooled survival curve. This was done for all patients, those born in a more recent era, those with right and left isomerism, and those with biventricular or functionally univentricular hearts.

RESULTS

Those born in the more recent era (after 2000) had increased survival compared to the overall cohort. Those with left isomerism tended to have a survival benefit compared to those with right isomerism until about 16 years of age, beyond which those with right isomerism developed a survival benefit. Those with biventricular hearts had a survival benefit compared to those with left isomerism.

CONCLUSION

Survival in the so-called heterotaxy syndrome is based on several factors, which include era of birth, sidedness of isomerism, and whether the heart is biventricular or functionally univentricular.