Malformaciones cardíacas, heterotaxia y lateralidad

Cardiac Laterality: Surgical Results of Right Atrial Isomerism

Right atrial isomerism (RAI) is a complex entity with varying diagnostic and treatment outcomes due to its rarity. Treatment options range from palliative to corrective surgeries, resulting in heterogeneous outcomes. The aim of this study was to analyze the results obtained after cardiac surgery in patients with RAI. A retrospective study was conducted, including patients diagnosed with RAI who underwent cardiac surgery. Their follow-up was from 1 January 2010 to 31 March 2020. Demographic characteristics and perioperative conditions were described. Thirty-eight patients were included, the median age was 4 years (IQR 2-9.2) and 57.9% were men. The main diagnoses were atrioventricular canal (63.2%) and pulmonary stenosis (55.3%). The most common surgical procedures were modified Blalock-Taussig shunt (65.8%) and total cavopulmonary connection with an extracardiac conduit fenestrated without cardiopulmonary bypass (15.9%). We did not find any factors associated with negative outcomes in these patients. The overall survival was 86.8%, with a better outcome in those who did not require reintubation (log rank, p < 0.01). The survival of RAI was similar to other centers. Individuals with RAI should be evaluated rigorously to determine an adequate repair strategy, considering high morbidity and mortality.

Cardiac surgery in patients with atrial isomerism: Long-term results and outcomes

PURPOSE

The aim of the study was to identify, determine, and analyze the clinical and surgical outcomes of patients with atrial isomerism (AI) undergoing cardiac surgery.

METHODS

A retrospective study was carried out. Patients with diagnosis of AI undergoing cardiac surgery at the National Institute of Cardiology Ignacio Chávez, from January 1, 2010 and March 31, 2020 were included; demographic characteristics and perioperative conditions of the patients were considered.

RESULTS

Sixty-five patients were included, with an average age of 6.4 ± 4.9 years, 50.8% males. Thirty-eight (58.5%) had right atrial isomerism (RAI) and 27 (41.5%) had left atrial isomerism (LAI); univentricular physiology (78.5%) predominated. Atrioventricular septal defect (AVSD) in RAI and septal defects in LAI were identified as the main associated defects. The most common surgical procedures performed were modified Blalock-Taussig shunt (MBTS) (27.6%), MBTS with total anomalous pulmonary venous connection (TAPVC) repair (15.3%) and total cavopulmonary connection (TCPC) with an extracardiac conduit fenestrated (10.8%); 100% RAI required a univentricular approach, while in LAI it was 48.1%. Overall survival was 92.3%, with 100% survival in LAI with biventricular physiology and 86.8% in RAI with univentricular physiology.

CONCLUSIONS

The survival of our institution is similar to that of other referral centers, where patients with LAI had a better evolution than RAI; in addition, the univentricular approach was required in all with RAI. Patients with AI must undergo a rigorous evaluation to determine an adequate repair strategy, considering univentricular RAI with a high possibility of morbidity and mortality.

Functional study of DAND5 variant in patients with Congenital Heart Disease and laterality defects

BACKGROUND

Perturbations on the Left-Right axis establishment lead to laterality defects, with frequently associated Congenital Heart Diseases (CHDs). Indeed, in the last decade, it has been reported that the etiology of isolated cases of CHDs or cases of laterality defects with associated CHDs is linked with variants of genes involved in the Nodal signaling pathway.

METHODS

With this in mind, we analyzed a cohort of 38 unrelated patients with Congenital Heart Defects that can arise from initial perturbations in the formation of the Left-Right axis and 40 unrelated ethnically matched healthy individuals as a control population. Genomic DNA was extracted from buccal epithelial cells, and variants screening was performed by PCR and direct sequencing. A Nodal-dependent luciferase assay was conducted in order to determine the functional effect of the variant found.

RESULTS

In this work, we report two patients with a DAND5 heterozygous non-synonymous variant (c.455G > A) in the functional domain of the DAND5 protein (p.R152H), a master regulator of Nodal signaling. Patient 1 presents left isomerism, ventricular septal defect with overriding aorta and pulmonary atresia, while patient 2 presents ventricular septal defect with overriding aorta, right ventricular hypertrophy and pulmonary atresia (a case of extreme tetralogy of Fallot phenotype). The functional analysis assay showed a significant decrease in the activity of this variant protein when compared to its wild-type counterpart.

CONCLUSION

Altogether, our results provide new insight into the molecular mechanism of the laterality defects and related CHDs, priming for the first time DAND5 as one of multiple candidate determinants for CHDs in humans.

Genetic variance of transforming growth factor β2 gene in conotruncal heart defects

OBJECTIVE

The aim of this study was to evaluate the association between two haplotype-tag single nucleotide polymorphisms (SNPs) (rs6658835 and rs10495098) of TGF-β2 and conotruncal heart defects (CTDs).

METHODS

Two polymorphisms of TGF-β2 gene were genotyped by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) from 259 CTDs patients and 310 control subjects.

RESULTS

The association between SNP rs6658835 in TGF-β2 and CTDs has been found. The frequency of G allele in CTDs patients was significantly higher than that in control subjects (52.7% versus 40.3%, p < 0.001, OR =1.649).

CONCLUSION

TGF-β2 gene polymorphisms may serve as a novel genetic marker for the risk of CTDs.

Inner ventricular structures and valves of the heart in white rhinoceros (Ceratotherium simum)

In this study, we describe the internal structures of both ventricles and the valvular apparatus of the heart of the white rhino. In the right of the heart, three papillary muscles were found in septal and marginal walls and m. papillaris magnus was the biggest. There was only one m. papillaris parvus in the right ventricle. The right atrioventricular valve was tricuspid, and the parietal cusp was longest. In the left of the heart, two papillary muscles were found on the septal wall and the subauricular was the biggest. The left atrioventricular valve was bicuspid and the parietal cusp was longest. There were no nodules in the valves of the pulmonary trunk and aorta, and the semilunar valves had many fibrous folds and transparent parts. Within the cardiac skeleton there was a cartilago cordis which occupied a small part of the right fibrous trigone. While the right ventricle included only one septomarginal trabecula, there were many trabeculae in the left ventricle. In both ventricles, the endocardium was thin and the subendocardial network was visible, also their continuation with the septomarginal trabeculae. We also found many trabeculae carneae in the dorsal part of the ventricles.