Heterotaxy syndrome: Prenatal diagnosis, concomitant malformations and outcomes

Early and long-term outcomes following cardiac surgery for patients with heterotaxy syndrome

Objective

Heterotaxy syndrome is a complex multisystem abnormality historically associated with high morbidity and mortality. We sought to evaluate the early and long-term outcomes after cardiac surgery in heterotaxy syndrome.

Methods

This is a single-center retrospective review of patients with heterotaxy syndrome undergoing single-ventricle palliation or primary or staged biventricular repair from 1998 to 2018. Patients were stratified by single ventricle versus biventricular physiology, and the severity of atrioventricular valve regurgitation. Demographics, anatomic characteristics, and early and late outcomes, including the length of stay, mortality, and surgical or catheter reinterventions, were analyzed.

Results

Among 250 patients, 150 (60%) underwent biventricular repair. In-hospital mortality was 7.6% (n = 19). Median follow-up was 5.2 (range, 0-16) years. Among survivors to discharge, mortality was 19% (n = 44) and reintervention was 52% (n = 120). Patients with moderate/severe atrioventricular valve regurgitation were older (32 vs 16 months, P = .02), were more likely to experience adverse events during their index surgical admission (72% vs 46%, P < .001), and had longer in-hospital length of stay (20 vs 12 days, P = .009). Among patients with moderate to severe atrioventricular valve regurgitation, single-ventricle palliation is associated with a greater risk of unplanned reintervention compared with patients undergoing biventricular repair (hazard ratio, 2.13; CI, 1.10-4.12; P = .025).

Conclusions

There was no significant difference in early or late outcomes in single-ventricle versus biventricular repair strategies in heterotaxy. In the subgroup of patients with moderate/severe atrioventricular valve regurgitation, patients who underwent single-ventricle palliation were 2.5 times more likely to need a late reintervention compared with those undergoing biventricular repair.

Prenatal diagnosis of right aortic arch: associated anomalies and fetal prognosis according to different subtypes

OBJECTIVES

Right aortic arch (RAA) is a rare anomaly with an incidence of 0.1 % in the adult population and low-risk fetuses. Our aim in this study was to evaluate associated anomalies and conditions according to subtypes.

METHODS

This was a retrospective study examining consecutive pregnancies diagnosed with RAA in our hospital between 2018 and 2022. Fetuses with RAA were divided into three groups, RAA with right-sided ductus arteriosus (RAA-RDA), RAA with left-sided ductus arteriosus (RAA-LDA), and RAA with a double aortic arch (RAA-DAA).

RESULTS

A total of 81 fetuses were diagnosed as having RAA during the study period. The rate of cardiac anomalies (82.8 %) in the RAA-RDA group was higher than in the RAA-LDA (17.6 %) and RAA-DAA (22.2 %) groups (p<0.001). No statistically significant difference was found between the groups in terms of maternal age, diagnosis week, pregnancy outcome, extracardiac anomalies, and genetic anomalies. Three (8 %) of 36 fetuses with isolated RAA who resulted in live birth developed symptoms related to the vascular ring, and one (2.7 %) newborn with RAA-DAA underwent surgery.

CONCLUSIONS

The incidence of cardiac anomalies is high in fetuses with RAA-RDA. Ultrasound examinations should be performed for cardiac anomalies and additional structural anomalies. Vascular ring formation is a rare but important complication due to compression risk to the trachea and esophagus.

Navigating the spectrum of double-outlet right ventricle presentations: Outcomes from a contemporary cohort based on subtypes

PURPOSE

Our aim in this study was to investigate the prenatal and postnatal prognosis of double outlet right ventricle (DORV) cases diagnosed prenatally by analyzing the outcomes based on the subtype.

METHODS

This study is a retrospective chart review. Cases diagnosed with fetal DORV by prenatal ultrasound in the maternal-fetal medicine department of our hospital between 2014 and 2022 were included. Data on maternal characteristics, fetal echocardiographic features (type of DORV), pregnancy and neonatal outcomes (termination of pregnancy [TOP], intrauterine fetal death [IUD], neonatal death [NND], death in infancy (IND), survival) were collected and analyzed.

RESULTS

Ninety-nine cases of prenatally diagnosed cases of DORV were included. The prenatal diagnosis was right in 97% of the liveborn fetuses. The cases were classified into subtypes, including transposition of great arteries (TGA), Fallot, ventricular septal defect (VSD), remote, and heterotaxy types. The cohort consisted of 32.3% TGA type, 19.1% fallot type, 11.1% VSD type, 2% remote type, and 35.3% heterotaxy type of DORV. An additional cardiac anomaly was observed in 87% and an extra-cardiac anomaly was observed in 54% of the cases. When we excluded the cases with heterotaxy type but without any chromosomal abnormality, additional genetic abnormalities were detected in 42% of the remaining cases. Outcome of pregnancy was livebirth in 68/99 (68.7%), IUFD in 5/99 (5.1%), and TOP in 26/99 (26.3%). Postnatal cardiac surgical repair was performed in 48 cases. Survival among livebirths was 39/68 (57.3%). Twenty-nine neonates or infants who had additional cardiac anomalies and/or genetic abnormalities died before any surgical intervention. The postoperative survival rate was 39/48 (81.2%).

CONCLUSION

The prognosis in DORV depends on the anatomical subtype, the presence, and severity of associated anomalies. Survival increases in isolated cases without any additional structural or genetic anomalies.

Characterization of ultrasound and postnatal pathology in fetuses with heterotaxy syndrome

Background

To explore the diagnostic clues and abnormality spectrum of heterotaxy syndrome by prenatal ultrasonography and postnatal verification.

Methods

The prenatal ultrasonic data of 88 heterotaxy syndrome fetuses were analyzed retrospectively as left isomerism (LI) and right isomerism (RI). Prenatal ultrasound compared with the anatomical casting of the fetal body after labor induction, and the confirmatory postnatal diagnosis after delivery.

Results

Fetal LI showed typical malformations of gastric vesicles on different sides from the heart, absence of hepatic segment of the inferior vena cava (IVC), abdominal aorta (AO) parallel with the azygos vein (AV), bilateral left bronchus, bilateral left atrial appendages, and polysplenia; intracardiac malformations of AV septal defects (AVSD), single atrium (SA), left ventricular outflow tract obstruction (LVOTO), and double-outlet right ventricle (DORV); and cardiac conduction abnormalities of sinus bradycardia and AV blockage. Fetal RI reported typical malformations of gastric vesicles on different sides from the heart, juxtaposition of the IVC with AO, anomalous pulmonary venous connection (APVC), asplenia, and bilateral right atrial appendages; intracardiac malformations of AVSD, SA, single ventricle, pulmonary atresia and stenosis, and DORV. The postnatal verification revealed 3 malformations misdiagnoses and 4 malformations missed diagnoses in LI fetuses and 10 misdiagnoses and 8 missed diagnoses in RI fetuses.

Conclusions

The proposed five-step prenatal ultrasonography has an important diagnostic value for the identification and classification of heterotaxy syndrome. The different sides of gastric vesicles and cardiac apex are important diagnostic clues for heterotaxy syndrome, featuring disconnected or hypoplastic IVC, typical complex cardiac malformation, and atrioventricular block in fetal LI, and shown APVC, juxtaposition of IVC and AO, and intracardiac malformations such as AVSD, DORV, and LVOTO in fetal RI.

CRISPR/CAS9: A promising approach for the research and treatment of cardiovascular diseases

The development of gene-editing technology has been one of the biggest advances in biomedicine over the past two decades. Not only can it be used as a research tool to build a variety of disease models for the exploration of disease pathogenesis at the genetic level, it can also be used for prevention and treatment. This is done by intervening with the expression of target genes and carrying out precise molecular targeted therapy for diseases. The simple and flexible clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 gene-editing technology overcomes the limitations of zinc finger nucleases (ZFNs) and transcription activator-like effector nucleases (TALENs). For this reason, it has rapidly become a preferred method for gene editing. As a new gene intervention method, CRISPR/Cas9 has been widely used in the clinical treatment of tumours and rare diseases; however, its application in the field of cardiovascular diseases is currently limited. This article reviews the application of the CRISPR/Cas9 editing technology in cardiovascular disease research and treatment, and discusses the limitations and prospects of this technology.

Discordant Post-natal Patterns in Fetuses With Heterotaxy Syndrome: A Retrospective Single-Centre Series on Outcome After Fetal Diagnosis

OBJECTIVE

Cardiac and extra-cardiac anomalies in 46 pre-natally diagnosed cases of heterotaxy were compared to post-natal anatomical patterns in order to reveal discordant findings. Second, the outcome of these fetuses was evaluated.

METHODS

Fetuses with heterotaxy, diagnosed in a tertiary referral centre, were analysed retrospectively. Based on the foetal abdominal situs view, right atrial isomerism (RAI) and left atrial isomerism (LAI) were defined as foetal sub-types. Post-natally, discordant anatomical patterns for broncho-pulmonary branching, atrial appendage morphology, and splenic status were further clarified with CT scans. In summary, the spectrum of pre-natally and post-natally detected cardiac and extra-cardiac anomalies is systematically reviewed. Necessary surgical interventions and mid-long-term outcomes were compared between the two sub-types in surviving infants.

RESULTS

A total of 46 fetuses with heterotaxy were included; LAI was diagnosed in 29 (63%) fetuses and RAI was diagnosed in 17 (37%) fetuses. Extra-cardiac anomalies were noted in 35% of fetuses. Seven out of the 29 fetuses (24%) with LAI had atrio-ventricular block (AVB) and four of these cases presented with hydrops. Twenty nine out of the 46 participating fetuses (63%) were live births, with 62% in the LAI group and 65% in the RAI group. Five fetuses were lost to follow-up. At the age of 1 year, the overall survival of live births [estimate (95% CI)] was 67% (48; 92%) in patients with LAI and 55% (32; 94%) in patients with RAI. At the age of 5 years, the estimates were 67% (48; 92%) in the LAI group and 46% (24-87%) in the RAI group. The median survival (first quartile; third quartile) was 11.1 (0.1; 14) years for patients with LAI and 1.3 (0.09; NA) years for patients with RAI. Of 17 children who had undergone cardiac surgery, five (29%) children achieved a bi-ventricular repair and 12 (70%) children achieved a uni-ventricular palliation. Three were primarily palliated, but converted to bi-ventricular thereafter. Foetal subtype definition of heterotaxy based on the abdominal situs and post-natal thoracic imaging studies showed a discordant pattern of broncho-pulmonary branching and atrial appendage anatomy in 40% of our live-born children.

CONCLUSION

Heterotaxy is a rare and complex condition with significant morbidity and mortality related to severe cardiac and extra-cardiac associations. Accurate pre-natal diagnosis can help identify the fetuses at risk and allow for timely intervention in a multi-disciplinary setting. Further studies are warranted to shed light on the exact sub-type definition in fetuses with heterotaxy and the presence of discordant post-natal patterns.