Early and late results of repair of tetralogy of Fallot with subarterial ventricular septal defect. A comparative evaluation of tetralogy with perimembranous ventricular septal defect

Conal Septal Hypoplasia in Tetralogy of Fallot-Impact on Clinical Course, Treatment Strategies, and Outcomes After Surgical Intervention

We sought to characterize the clinical course and outcomes of intervention for Tetralogy of Fallot (TOF) with associated conal septal hypoplasia (CSH) compared to those with identifiable conal septum on initial newborn echocardiogram. We performed a retrospective, 1:2 case-control study of children with TOF anatomy, 33 with CSH and 66 with typical TOF, who underwent surgical repair from 1991-2019 at Children's Wisconsin. Data on echocardiographic anatomic features, systemic oxygen saturations, medical therapies, admissions, palliative interventions, operative strategies, and long-term follow-up were compared. The CSH group had fewer hypercyanotic spells (6% vs 42%, p < 0.001), beta-blockers prescribed (12% vs 41%, p = 0.005), and hospital admissions for cyanosis (12% vs 44%; p = 0.001) prior to any intervention. Of 14 who required palliative intervention, 8 had balloon pulmonary valvuloplasty (BPV) (7 from the CSH group and 1 from the control group), and 6 had systemic-to-pulmonary artery shunts (all from the control group). Definitive repair was performed at a significantly older age in the CSH group (10.2 ± 10 vs 5.6 ± 5.9 months, p = 0.011), with less subpulmonary muscle resection (57.6% in vs 92.4%, p < 0.001) and higher use of a transannular patch (84.8% vs 65.2%, p = 0.040). The average time to surgical reintervention was similar in both groups (9.7 ± 5.9 vs 8.6 ± 6.4 years in controls). We conclude that infants with TOF and CSH have a milder preoperative clinical course with fewer hypercyanotic spells or need for medical therapy. They also respond well to palliative BPV and can safely undergo later definitive repair compared to typical TOF with a well-developed conal septum.

Identification of Novel Rare Copy Number Variants Associated with Sporadic Tetralogy of Fallot and Clinical Implications

Tetralogy of Fallot (TOF) is the most common cyanotic congenital heart disease. Highly penetrant copy number variants (CNVs) and genes related to the etiology of TOF likely exist with differences among populations. We aimed to identify CNV contributions to sporadic TOF cases in Han Chinese. Genomic DNA was extracted from peripheral blood in 605 subjects (303 sporadic TOF and 302 unaffected Han Chinese [Control] from cardiac centers in China and analyzed by genome-wide association study (GWAS). The GWAS results were compared to existing Database of Genetic Variants. These CNVs were further validated by qPCR. Bioinformatics analyses were performed with Protein-Protein Interaction (PPI) network and KEGG pathway enrichment. Across all chromosomes 119 novel "TOF-specific CNVs" were identified with prevalence of CNVs of 21.5% in chromosomes 1-20 and 37.0% including Chr21/22. In chromosomes 1-20, CNVs on 11q25 (encompasses genes ACAD8, B3GAT1, GLB1L2, GLB1L3, IGSF9B, JAM3, LOC100128239, LOC283177, MIR4697, MIR4697HG, NCAPD3, OPCML, SPATA19, THYN1, and VPS26B) and 14q32.33 (encompasses genes THYN1, OPCML, and NCAPD3) encompass genes most likely to be associated with TOF. Specific CNVs found on the chromosome 21 (6.3%) and 22(11.9%) were also identified in details. PPI network analysis identified the genes covering the specific CNVs related to TOF and the signaling pathways. This study for first time identified novel TOF-specific CNVs in the Han Chinese with higher frequency than in Caucasians and with 11q25 and 14q32.33 not reported in TOF of Caucasians. These novel CNVs identify new candidate genes for TOF and provide new insights into genetic basis of TOF.

Histological and biomechanical characterization of decellularized porcine pericardium as a potential scaffold for tissue engineering applications

BACKGROUND

Each year, more than 800,000 vascular and cardiac surgeries are performed therefore, there is a great need for suitable material for bioprosthetic operations. Porcine pericardium is a double-walled sac that covers the heart and can be used in vascular and cardiac thoracic surgery.

OBJECTIVE

The aim of the present study was to evaluate the decellularization process and biomechanical properties in porcine pericardial tissue after the decellularization treatment.

METHODS

A detergent based protocol was used for the decellularization of porcine pericardium. Histological analysis and contact cytotoxicity assay were performed. Additionally, biomechanical testing and in vivo biocompatibility by implantation into Wistar Rats were performed.

RESULTS

The histological analysis showed the preservation of the extracellular matrix, without any observable cellular remnants. No toxic effects were noticed when contact cytotoxicity assay performed. The decellularized tissues, after implantation in Wistar Rats, remained for up to 12 weeks without being rejected. Finally, the biomechanical testing showed no significant differences between native and decellularized tissues.

CONCLUSION

In this study, the decellularization of the porcine pericardium produced a non toxic scaffold, free of any cellular remnants, thus serving as an alternative material for tissue engineering applications including heart valve and vascular patch development.

Tetralogy of Fallot with subarterial ventricular septal defect: Surgical outcome in the current era

Background:

Tetralogy of Fallot (TOF) with subarterial ventricular septal defect (VSD) is more common among Asians than Caucasians. Compared with the regular subaortic VSD postoperative right ventricular outflow obstruction is more common because of the sub-pulmonary extension of the defect. The objective of this study is to analyze the surgical implications and outcomes of patients with TOF - subarterial VSD in the current era.

Patients and Methods:

In all, 539 consecutive operated patients with TOF from May 2005 to September 2012 were retrospectively reviewed. Eighty-five patients had subarterial VSD. Seventy-nine of these underwent intracardiac repair. Preoperative clinical, echocardiographic features, operative and postoperative variables were assessed.

Results:

The median age at surgery was 6 years and the median weight was 14 kilograms. The male to female ratio was 1.7:1. TOF with subarterial VSD was associated with frequent use of transannular patch (74.6%). The early mortality was 2.5%. Follow up was 92% complete with a mean duration of 20 months with actuarial survival of 97.3% at 5 years. Two patients required reoperation for significant right ventricular outflow tract obstruction (RVOTO) at one year and three years, respectively.

Conclusions:

Intra cardiac repair for TOF with subarterial VSD has low perioperative mortality and morbidity. Transannular patch augmentation of the right ventricular outflow tract (RVOT) is required in a significant proportion of these patients. Precise suturing of the VSD patch, adequate infundibular resection and lower threshold for a transannular patch placement ensures a smooth early postoperative recovery.

Prosthetic reconstruction of bicuspid pulmonary valve in tetralogy of Fallot

BACKGROUND

Various techniques have been described for preserving pulmonary valve function in tetralogy of Fallot repair. In selected substrates, the pulmonary valve can be bicuspidized and preserved using polytetrafluoroethylene pericardial membrane.

METHODS

This study was a retrospective review of 20 patients aged 11 months to 31 years with tetralogy of Fallot and a bicuspid pulmonary valve (with anteroposterior cusps) who underwent intracardiac repair from August 2010 to January 2013. The anterior cusp was augmented using polytetrafluoroethylene pericardial membrane to preserve the valve hinge. A transannular patch was used in all cases. Data relating to surgical outcome, intensive care unit course, pulmonary regurgitation, and right ventricular outflow tract gradient were collected.

RESULTS

There was no mortality. Predischarge pulmonary regurgitation was ≤grade 2 in 18 (90%) patients. One patient had an outflow gradient >40 mm Hg. On follow-up of 3-24 months, there was no increase in outflow gradient; 18.7% had progression of pulmonary regurgitation.

CONCLUSION

In selected substrates, this technique is associated with minimization of pulmonary regurgitation and an excellent functional outcome. The utility of this technique needs to be validated over a longer time scale in a larger series.

Early and late outcomes of total repair of tetralogy of Fallot: risk factors for late right ventricular dilatation

OBJECTIVES

This study was undertaken to assess the early and long-term results of total repair of tetralogy of Fallot (TOF) and to identify the risk factors associated with late right ventricular (RV) dilatation.

METHODS

The medical records of 326 patients (male:female = 192:134) who underwent total repair of TOF at Pusan National and Dong-A University Hospitals between July 1991 and May 2011 were retrospectively reviewed. Median age and weight at the time of operation were 13.0 months and 8.7 kg, respectively. Right ventricular end-diastolic dimensions and left ventricular end-diastolic dimensions were obtained during follow-up echocardiography to identify the risk factors associated with late RV dilatation.

RESULTS

There were one operative death (0.3%) and 8 late deaths (2.5%). Of late deaths, two were related to operation-related cardiac problems. Overall survival rates at 5, 10, and 15 years were 97.0%, 95.4%, and 95.4%, and the corresponding freedom from cardiac death were 98.8%, 98.8%, and 98.8%, respectively. Freedom from re-operation and re-intervention were 84.4%, 74.2% and 74.2%. Six patients underwent pulmonary valve replacement during the follow-up period. Transannular patch (P = 0.036) and postoperative ventilator support period (P < 0.001) were found to be significant risk factors of late RV dilatation in multivariate analysis.

CONCLUSIONS

Total correction of TOF can be performed with a very low mortality rate. However, the postoperative re-operation or re-intervention rates remain relatively high. Late RV dilatation after total repair of TOF was found to be associated with transannular patch enlargement and a longer postoperative ventilator support period.

Cardiac defects and results of cardiac surgery in 22q11.2 deletion syndrome

Specific types and subtypes of cardiac defects have been described in children with 22q11.2 deletion syndrome as well as in other genetic syndromes. The conotruncal heart defects occurring in patients with 22q11.2 deletion syndrome include tetralogy of Fallot, pulmonary atresia with ventricular septal defect, truncus arteriosus, interrupted aortic arch, isolated anomalies of the aortic arch, and ventricular septal defect. These conotruncal heart defects are frequently associated in this syndrome with additional cardiovascular anomalies of the aortic arch, pulmonary arteries, infundibular septum, and semilunar valves complicating cardiac anatomy and surgical treatment. In this review we describe the surgical anatomy, the operative treatment, and the prognostic results of the cardiac defects associated with 22q11.2 deletion syndrome. According to the current literature, in patients with tetralogy of Fallot with/without pulmonary atresia and truncus arteriosus, in spite of the complex cardiac anatomy, the presence of 22q11.2 deletion syndrome does not worsen the surgical prognosis. On the contrary in children with pulmonary atresia with ventricular septal defect and probably in those with interrupted aortic arch the association with 22q11.2 deletion syndrome is probably a risk factor for the operative treatment. The complex cardiovascular anatomy in association with depressed immunological status, pulmonary vascular reactivity, neonatal hypocalcemia, bronchomalacia and broncospasm, laryngeal web, and tendency to airway bleeding must be considered at the time of diagnosis and surgical procedure. Specific diagnostic, surgical, and perioperative protocols should be applied in order to provide appropriate treatment and to reduce surgical mortality and morbidity.

Tetralogy of fallot with subarterial ventricular septal defect

BACKGROUND

Tetralogy of Fallot with subarterial ventricular septal defect is frequently seen among Asians. Compared with infracristal ventricular septal defect, postoperative right ventricular outflow obstruction is more likely because of subpulmonary extension of the defect. Moreover the incidence of aortic regurgitation is a concern because of the absence of a supporting infundibulum.

METHODS

Four hundred cases of classic tetralogy were reviewed, 61 of which had subarterial ventricular septal defect.

RESULTS

Aortic regurgitation (of more than mild degree) was identified in 7 cases with subarterial and 7 with infracristal ventricular septal defects. The mechanism of infracristal defect was predominantly an annular dilation before surgery. In contrast 5 cases with subarterial defect had progression of aortic regurgitation after operation yielding an actuarial incidence of 29.7% at 20 years. In 2 patients the cause seemed to be fixation or plication of the aortic valve annulus by the ventricular septal patch. Compared with infracristal defect, subarterial defect was associated with increased incidence of reoperation (12.0% versus 1.9% at 10 years, p = 0.01), frequent use of transannular patch (70.5% versus 45.7%, p = 0.0004), and worse New York Heart Association (NYHA) functional class (p = 0.007). Right ventricular outflow obstruction was the reason for reoperation in 3 patients with subarterial defect and was associated with worse NYHA classification in the long-term, on multivariate analysis (p = 0.0002).

CONCLUSIONS

Tetralogy with subarterial ventricular septal defect was associated with worse functional outcome. To prevent adverse outcomes, precise suturing of the distal ventricular septal patch, extensive infundibulectomy, lower threshold for transannular incision, and smaller-sized ventricular septal patch placement are warranted.

Indication and technique of total correction of tetralogy of Fallot in 228 patients

BACKGROUND

Several factors, such as old age, high hemoglobin level, pulmonary artery hypoplasia, and diminutive left ventricle, have been identified as high risk factors for operative mortality. This group of patients includes all these factors.

METHODS

Between September 1987 and March 1995, I performed total correction of tetralogy of Fallot on 228 unselected consecutive patients at Fu Wai Hospital in Beijing. There were 140 male and 88 female patients.

RESULTS

Only 2 patients died of nonsurgical causes postoperatively. The mortality was 0.9%. The remaining patients recovered uneventfully. The late mortality was 1.8% (4/228).

CONCLUSIONS

The results suggested that hypoplastic pulmonary artery and left ventricle were not an absolute contraindication of total correction of tetralogy of Fallot. High hematocrit and old age were also not high risk factors causing death. The key factor was to correct the pathology completely and manage the complications properly.

Associated cardiac anomalies in isolated and syndromic patients with tetralogy of Fallot

To detect in children with tetralogy of Fallot (ToF) the prevalence of associated cardiac anomalies in syndromic and isolated cases, the additional cardiac defects of 150 consecutive patients with ToF (102 isolated and 48 syndromic cases) were evaluated by review of echocardiographic, angiocardiographic, and surgical reports. Syndromic patients were classified into groups with branchial arch defects, Down syndrome, and other genetic conditions. ToF is significantly associated with additional cardiac malformations in patients with branchial arch (11 of 21, p <0.01) and Down (10 of 20, p <0.0001) syndromes. The subarterial ventricular septal defect with deficiency of the infundibular septum (4 of 21, p <0.01) and the right aortic arch (6 of 21, p <0.05) were prevalent in patients with branchial arch syndromes, whereas atrioventricular canal (10 of 20, p <0.0001) was associated with ToF in patients with Down syndrome. Peculiar anatomic cardiac patterns are present in children with ToF and may alert the cardiologist to look at additional cardiac anomalies. Moreover, the presence of some associated cardiac anomalies may suggest careful clinical evaluation for genetic syndromes.