Echocardiographically guided repair of tetralogy of Fallot

Contemporary multimodality non-invasive cardiac imaging protocols for tetralogy of Fallot

Tetralogy of Fallot is the most prevalent cyanotic congenital heart disease, requiring lifelong multimodality non-invasive cardiac imaging, such as echocardiography, cardiothoracic computed tomography, and cardiac magnetic resonance imaging. As imaging techniques continuously evolve and are gradually integrated into clinical practice, there is a critical need to update multimodality imaging protocols. Over the last two decades, cardiothoracic computed tomography imaging techniques have advanced remarkably, significantly enhancing its role in evaluating patients with tetralogy of Fallot. In this review, we describe contemporary multimodality non-invasive cardiac imaging protocols for tetralogy of Fallot, emphasizing the expanding role of cardiothoracic computed tomography. Additionally, we present standardized reporting forms designed to facilitate the clinical adoption of these protocols.

Comparison of non-invasive assessment for pulmonary vascular indices by two-dimensional echocardiography and cardiac computed tomography angiography with conventional catheter angiocardiography in unrepaired Tetralogy of Fallot physiology patients weighing more than 10 kg: a retrospective analysis

AIMS

Assessment of pulmonary vascular dimensions (PVDs) in Tetralogy of Fallot (TOF) is an integral part of planning transcatheter and surgical interventions. We sought to examine the reliability and correlation of echocardiography (ECHO) and computed tomography angiography (CTA) measurements with those obtained by cardiac catheterization and angiography (CCA).

METHODS AND RESULTS

Tetralogy of Fallot physiology patients undergoing ECHO, CTA, and CCA within a month prior to surgical correction during 2018-2020 were retrospectively enrolled. Indexed diameter of pulmonary annulus (iPAnn), indexed right pulmonary artery (iRPA), indexed left pulmonary artery (iLPA) and indexed descending aorta (iDA) were measured using ECHO and CTA followed by derivation of Nakata index (NI), McGoon's ratio (MGR), ratio of predicted peak right ventricular (RV) and left ventricular (LV) pressures (pRV/pLV) and Z-scores. Comparison with CCA-derived measurements was made and correlational equations were subsequently deduced. Pulmonary vascular dimensions for 54 patients with mean age of 15.5 ± 9.3 years (range: 3-34 years) were analysed. Computed tomography angiography and CCA measurements for iPAnn, iRPA, NI, MGR, pRV/pLV, and Z-score were comparable with each other while ECHO parameters were significantly lower than CCA. However, iLPA diameter was significantly underestimated by ECHO and overestimated by CTA. Correlational analysis showed stronger correlation between CTA- and CCA-derived PVD as against ECHO measurements except for iDA, pRV/pLV, and Z-score.

CONCLUSIONS

For unrepaired TOF physiology patients weighing more than 10 kg, CTA-acquired PVD are reliable and comparable with CCA except for DA for which ECHO is non-inferior. Non-invasive modalities though are inferior to CCA for LPA sizing. Utilizing derived equations, precise estimation of PVD can be carried out using non-invasive tools.

Tetralogy of Fallot with coronary crossing the right ventricular outflow tract: A tale of a bridge and the artery

A coronary artery crossing the right ventricular outflow tract is a subset of a larger pathomorphological cohort known as an anomalous coronary artery (ACA) in the tetralogy of Fallot (TOF). The best possible outcome in a patient with TOF and ACA is decided by judicious selection of optimum preoperative investigative information, the timing of surgery, astute assessment of preoperative surgical findings, and appropriate surgical technique from a wide array of choices. In most instances, the choice of surgical technique is determined by the size of the pulmonary annulus and the anatomical relation of ACA to the pulmonary annulus. In the present era, complete, accurate preoperative diagnosis and primary repair is a routine procedure with strategies to avoid a right ventricle-to-pulmonary artery conduit.

Diagnostic assessment before Fontan operation in patients with bidirectional cavopulmonary anastomosis: are noninvasive methods sufficient?

OBJECTIVES

This study was designed to determine if a subset of patients who have undergone bidirectional cavopulmonary anastomosis could be identified in which catheterization was of little benefit before completion of the Fontan procedure.

BACKGROUND

Diagnostic evaluation before Fontan procedure has typically included cardiac catheterization. However, the overall management strategy for patients with functional single ventricle has evolved to include staging bidirectional cavopulmonary anastomosis in most, and it has become uncommon to exclude patients from Fontan based on catheterization data.

METHODS

Patients who underwent bidirectional cavopulmonary anastomosis and had complete echocardiograms and catheterizations within three months of each other between January 1992 and October 1997 were evaluated with a series of clinical and echocardiographic characteristics to identify a subset in whom catheterization was predicted to be of little added value ("no-cath" group). The predictive value and sensitivity of these criteria in excluding patients who required additional intervention, were excluded from Fontan, or died within 30 days of Fontan was determined.

RESULTS

A total of 99 patients who underwent bidirectional cavopulmonary anastomosis at 6.7 months (range 2.9 months to 14 years) were studied; 46 met criteria for the "no-cath" group. Noninvasive criteria stratified all patients who died (n = 5) or did not proceed to Fontan (n = 1) and 9 of 11 who required additional interventions to the "cath" group. Thus, the negative predictive value of these criteria was 93%.

CONCLUSIONS

Our data suggest that catheterization before Fontan could be avoided in a large percentage of patients without adversely affecting outcome; prospective evaluation of this strategy is warranted.

Congenital heart disease and genetic syndromes: specific correlation between cardiac phenotype and genotype

The increasing role of genetic factors in the etiology of congenital heart defects is shown by the high frequency of genetic syndromes and extracardiac malformations in these patients. The accurate study of cardiac anatomy disclosed that peculiar morphologic subtypes of heart defects are related to specific genetic conditions. The correlation between anatomic cardiac patterns and some genetic anomalies (trisomy, deletion, mutation) suggests that specific morphogenetic mechanisms put in motion by gene(s) can result in a specific cardiac phenotype. In this review we analyze the cardiac morphology and the frequent genetic syndromes in five groups of congenital heart diseases: right-sided obstructions, left-sided obstructions, atrioventricular canal defects, ventricular septal defects, and conotruncal defects. Progress in this field is due not only to new research in molecular biology, but also to the attention of clinicians to a detailed cardiac diagnosis and to specific correlations between genotype and phenotype.

Coronary echocardiography in tetralogy of fallot: diagnostic accuracy, resource utilization and surgical implications over 13 years

OBJECTIVES

This study sought to determine the diagnostic accuracy and impact of the systematic use of coronary echocardiography in a large group of preoperative patients with tetralogy of Fallot (TOF).

BACKGROUND

Accurate preoperative identification of an anomalous coronary artery crossing the right ventricular outflow tract (RVOT) in patients with TOF is important to prevent coronary injury during surgical repair.

METHODS

A retrospective review identified 598 patients with TOF between 1983 to 1995 who underwent an echocardiogram at <2 years old before complete surgical repair. Associated diagnoses included pulmonary stenosis (n = 433), pulmonary atresia (n = 121), common atrioventricular canal (n = 17), absent pulmonary valve syndrome (n = 24) and aortopulmonary window (n = 3).

RESULTS

Based on intraoperative findings, 32 patients (5.4%) were found to have a major coronary artery crossing the RVOT. The use and diagnostic performance of coronary echocardiography increased over time, while the number of patients undergoing preoperative cardiac catheterization declined. During the most recent study period (1991 to 1995, n = 274), 97% of patients underwent coronary echocardiography yielding a sensitivity of 82%, specificity of 99% and accuracy of 98.5%. Of the 18 patients with TOF and pulmonary stenosis who had abnormal coronary arteries during this period, only 6 (33%) required an extracardiac conduit as part of their complete repair.

CONCLUSIONS

Coronary echocardiography is an accurate noninvasive tool to delineate coronary anatomy in infants with TOF before complete repair. Routine preoperative cardiac catheterization solely for diagnosis of coronary anatomy is not necessary. The use of an extracardiac conduit can be avoided in the majority of patients with TOF and pulmonary stenosis who have a major coronary artery crossing the RVOT.

Pediatric cardiac surgery after exclusively echocardiography-based diagnostic work-up

This study was performed to evaluate the accuracy of exclusively non-invasive preoperative diagnostic work-up based on echocardiography and to assess the safety of cardiac surgery using this diagnostic approach in children with heart disease. During a 3. 5-year period, accuracy of preoperative (invasive and non-invasive) diagnostic work-up was prospectively tested by comparison with the intraoperative findings obtained by surgical inspection and transoesophageal echocardiography. Included were all consecutive 358 children undergoing cardiac surgery (except pulmonary artery bandings and ductus ligations) during the study period at our institution. Of the patients, 44% were operated on in infancy, 84% of procedures were on cardiopulmonary bypass. Echocardiography as the only preoperative imaging modality was used in 231 patients (65%), in the other children, a diagnostic catheter was done. Diagnostic errors occurred in 3.9% (n=5) of patients after diagnostic catheter and in 6.9% (n=16) of patients with echocardiography only. Major diagnostic errors (resulting in prolongation of cardiac bypass time) were observed at equal frequency in both groups (1.7% or four children in the echo-only group and 1.6% or two patients in the catheter group). In no case was the outcome affected by the previously unrecognized findings. It was shown that diagnostic cardiac catheterization could be avoided in a majority of pediatric patients prior to surgical palliation or correction of cardiac defects, without increasing the risk of complications or the overall outcome.

Pediatric open heart operations without diagnostic cardiac catheterization

BACKGROUND

Echocardiography allows for an adequate noninvasive preoperative evaluation in an increasing proportion of pediatric patients before open heart operations. The present study assessed the diagnostic accuracy of both invasive and noninvasive preoperative evaluation in children with congenital heart disease.

METHODS

We prospectively evaluated the accuracy of preoperative noninvasive or invasive diagnostic methods. Preoperatively established diagnosis was compared with the intraoperative diagnosis made by surgical inspection and routine perioperative transesophageal echocardiography.

RESULTS

During the study period of 30 months (ending in December 1997) 209 open-heart procedures were performed. Eighty-one patients (39%) were in the first year of life at the time of surgery, and 43% of all patients had symptoms. Noninvasive preoperative diagnosis using echocardiography was done exclusively in 142 patients (68%). Of the 67 children who had preoperative catheterization, 4 (6%) showed an additional intraoperative finding that modified the surgical approach in 2 of them. In the 142 patients who had echocardiographic preoperative assessment, the surgeons were confronted with a previously undiagnosed finding in 12 patients (8.5%). The finding was considered significant (prolongation of cardiopulmonary bypass time) in 2 patients and might have affected the outcome in 1 of them, a neonate with transposition of the great arteries and a preoperatively undiagnosed intramural coronary artery, who died postoperatively despite a technically adequate repair.

CONCLUSIONS

In many infants and children, diagnostic work-up before open heart operations could be adequately based on an exclusively noninvasive basis by relying on echocardiography alone.

Echocardiographic diagnosis alone for the complete repair of major congenital heart defects

OBJECTIVES

The study was done to determine the diagnostic accuracy of echocardiography alone in the preoperative diagnosis of children with major congenital heart defects undergoing primary complete repair.

BACKGROUND

Although echocardiography is well established as the first-line imaging technique for the diagnosis of all forms of congenital heart disease, most institutions continue to perform cardiac catheterization prior to complete repair of more complex defects.

METHODS

To determine the diagnostic accuracy of echocardiography alone and echocardiography plus catheterization, we reviewed the records of 503 children with major congenital heart defects who underwent primary complete repair at our institution between July 1992 and June 1997. We included children with transposition of the great arteries, tetralogy of Fallot, double-chamber right ventricle, interrupted aortic arch, aortic coarctation, atrioventricular septal defect, truncus arteriosus, aortopulmonary septal defect, and totally anomalous pulmonary venous return. We excluded children with less complex defects such as isolated shunt lesions, as well as those with the most complex defects that would require surgical palliation (e.g., functional univentricular heart). We defined major errors as those that increased the surgical risk and minor errors as those that did not. Errors in diagnosis were determined at surgery.

RESULTS

Eighty-two percent of children (412 of 503) underwent surgery after preoperative diagnosis by echocardiography alone. There were 9 major (2%) and 10 minor errors in the echocardiography alone group and 7 major and 5 minor errors in the echocardiography plus catheterization group. The most common type of error was misidentification of coronary artery anatomy in patients with transposition of the great arteries. No error in either group resulted in surgical morbidity or mortality.

CONCLUSIONS

This study suggests that echocardiography alone is an accurate tool for the preoperative diagnosis of major congenital heart defects in most children undergoing primary complete repair, and may obviate the need for routine diagnostic catheterization.

Coronary arterial anatomy in tetralogy of Fallot: morphological and clinical correlations

OBJECTIVE

To clarify the problems in angiographic diagnosis of major coronary arteries crossing the right ventricular outflow tract.

DESIGN

A retrospective study with clinicomorphological correlations to ascertain any aberrant coronary arteries and variations in distribution of the normal right coronary arterial branches.

SETTING

Tertiary referral centre.

SUBJECTS

36 necropsy specimens together with the aortograms and surgical reports from 130 patients with tetralogy of Fallot.

RESULTS

A preventricular branch was found in 19% of cases with tetralogy of Fallot, but in none of 13 normal hearts. Aberrant origin of the anterior interventricular coronary artery was found in 14% of the specimens. The combination of "laid back" and straight lateral views, when reviewed retrospectively, identified this anomaly correctly in nine of 16 patients, with these findings confirmed at surgery in seven patients. A major branch initially thought to cross the outflow tract was shown retrospectively to be an infundibular artery in six, with surgical confirmation in four. It was a preventricular branch in another patient.

CONCLUSIONS

Using the laid back view alone, infundibular and preventricular branches may be mistaken for a major aberrant artery. A combination of laid back and straight lateral views is needed to avoid false positive diagnosis.

Pitfalls in echocardiographic-based repair of aortic coarctation

The knowledge of echocardiographic pitfalls, which may impair the correct indication for surgery of aortic coarctation, is of great importance to pediatric cardiologists. We believe that only the suspicion of coronary artery anomalies is a clear indication to perform a cardiac catherization.

Primary repair of isolated ventricular septal defect in infancy guided by echocardiography

Between 1989 and 1995, 96 consecutive infants affected by isolated ventricular septal defect (VSD) were submitted for primary correction at a median age of 4 months. Of the 96, 60 (group I) underwent surgery on the base of a 2-dimensional Doppler echocardiographic (DD echo) test alone. The preoperative DD echo anatomic definition of the type of VSD was confirmed at surgery in all 60 patients without false-positive results in terms of additional cardiac anomalies. There were 2 false-negatives: in 2 patients an associated cardiac anomaly was not detected by DD echo and required a second surgical procedure after postoperative cardiac catheterization. During the same period 36 infants (group II) underwent surgical closure of isolated VSD on the basis of cardiac catheterization and angiocardiography in addition to DD echo. The retrospective comparison between the 2 groups revealed no significant difference in terms of sensitivity and specificity of the diagnostic tools, early and late mortality after surgical correction, postoperative hospital stay, and need for late cardiac catheterization and surgery. We conclude that after an accurate selection, most of the infants with uncomplicated VSD can safely undergo primary repair on the basis of DD echo alone.

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.