Tetralogy of Fallot: Preoperative assessment with MR and CT imaging.

Tetralogy of Fallot has a broad anatomical spectrum. In mild forms of the condition the obstruction is only located in the right ventricular infundibulum, whereas in severe forms the pulmonary valve is atretic, the pulmonary arteries are absent and the lung is supplied by aorto-pulmonary collateral arteries. Surgical management differs from conventional surgery in the former situation, whereas in the latter it is complex and requires reconstruction of the pulmonary arteries (unifocalization) carried out in more than one stage and with a high morbidity rate. The key factors to establish before corrective surgery are the levels and degree of obstruction of the right ventricular outflow tract, the development of the pulmonary arteries and the presence of collateral arteries. The main role of magnetic resonance imaging along with that of computed tomography angiography are discussed and illustrated.

Anatomy of the ventricular septal defect in outflow tract defects: similarities and differences.

OBJECTIVE: The study objective was to analyze the anatomy of the ventricular septal defect found in various phenotypes of outflow tract defects. METHODS: We reviewed 277 heart specimens with isolated outlet ventricular septal defect without subpulmonary stenosis (isolated outlet ventricular septal defect, 19); tetralogy of Fallot (71); tetralogy of Fallot with pulmonary atresia (51); common arterial trunk (54); double outlet right ventricle (65) with subaortic, doubly committed, or subpulmonary ventricular septal defect; and interrupted aortic arch type B (17). Special attention was paid to the rims of the ventricular septal defect viewed from the right ventricular side and the relationships between the tricuspid and aortic valves. RESULTS: The ventricular septal defect was always located in the outlet of the right ventricle, between the 2 limbs of the septal band. There was a fibrous continuity between the tricuspid and aortic valves in 74% of specimens with isolated outlet ventricular septal defect, 66% of specimens with tetralogy of Fallot, 39% of specimens with tetralogy of Fallot with pulmonary atresia, 4.6% of specimens with double outlet right ventricle, 1.8% of specimens with common arterial trunk, and zero of specimens with interrupted aortic arch type B (P < .005). When present, this continuity always involved the anterior tricuspid leaflet. CONCLUSIONS: The ventricular septal defect in outflow tract defects is always an outlet ventricular septal defect, cradled between the 2 limbs of the septal band. However, there are some differences regarding the posteroinferior and superior rims of the ventricular septal defect. These differences suggest an anatomic continuum from the isolated outlet ventricular septal defect to the interrupted aortic arch type B rather than distinct physiologic phenotypes, related to various degrees of abnormal rotation of the outflow tract during heart development: minimal in isolated outlet ventricular septal defect; incomplete in tetralogy of Fallot, tetralogy of Fallot with pulmonary atresia, and double outlet right ventricle; absent in common arterial trunk; and excessive in interrupted aortic arch type B.

Double outlet right ventricle versus aortic dextroposition: morphologically distinct defects.

This study concerns the morphological differentiation between double outlet right ventricle (DORV) and aortic dextroposition (AD) defects, namely tetralogy of Fallot and Eisenmenger anomaly. Indeed, despite the similar condition in terms of sequential ventriculo-arterial connections, DORV and AD are two distinct morphological entities. It is proposed that the borderline between these two groups of malformations is represented by the specific insertion of the infundibular septum into the left anterior cranial division of the septomarginal trabeculation (or septal band) occurring in ADs and lacking in DORV. Furthermore, the spiraliform versus straight parallel arrangement of the great arteries in the two groups of anomalies is emphasized as an additional and distinctive morphological feature. Emphasis is also given to the association of straight parallel great arteries conotruncal malformations, DORV and transposition of the great arteries, with the asplenia type of heterotaxy laterality defects. Within this context, the absence of subaortic ventricular septal defect and concomitantly of spiraliform great arteries in the asplenia group of heterotaxy anomalies, as detected by this study, further substantiates our belief of not mixing collectively the ADs with the DORV in clinico-pathological diagnosis.

Use of diagnostic information submitted to the United Kingdom Central Cardiac Audit Database: development of categorisation and allocation algorithms.

OBJECTIVE: To categorise records according to primary cardiac diagnosis in the United Kingdom Central Cardiac Audit Database in order to add this information to a risk adjustment model for paediatric cardiac surgery. DESIGN: Codes from the International Paediatric Congenital Cardiac Code were mapped to recognisable primary cardiac diagnosis groupings, allocated using a hierarchy and less refined diagnosis groups, based on the number of functional ventricles and presence of aortic obstruction. SETTING: A National Clinical Audit Database. Patients Children undergoing cardiac interventions: the proportions for each diagnosis scheme are presented for 13,551 first patient surgical episodes since 2004. RESULTS: In Scheme 1, the most prevalent diagnoses nationally were ventricular septal defect (13%), patent ductus arteriosus (10.4%), and tetralogy of Fallot (9.5%). In Scheme 2, the prevalence of a biventricular heart without aortic obstruction was 64.2% and with aortic obstruction was 14.1%; the prevalence of a functionally univentricular heart without aortic obstruction was 4.3% and with aortic obstruction was 4.7%; the prevalence of unknown (ambiguous) number of ventricles was 8.4%; and the prevalence of acquired heart disease only was 2.2%. Diagnostic groups added to procedural information: of the 17% of all operations classed as "not a specific procedure", 97.1% had a diagnosis identified in Scheme 1 and 97.2% in Scheme 2. CONCLUSIONS: Diagnostic information adds to surgical procedural data when the complexity of case mix is analysed in a national database. These diagnostic categorisation schemes may be used for future investigation of the frequency of conditions and evaluation of long-term outcome over a series of procedures.

Tetralogy of Fallot: nosological, morphological, and morphogenetic considerations.

It is timely, in the 125th anniversary of the initial description by Fallot of the hearts most frequently seen in patients presenting with "la maladie bleu", that we revisit his descriptions, and discuss his findings in the light of ongoing controversies. Fallot described three hearts in his initial publication, and pointed to the same tetralogy of morphological features that we recognise today, namely, an interventricular communication, biventricular connection of the aorta, subpulmonary stenosis, and right ventricular hypertrophy. In one of the hearts, he noted that the aorta arose exclusively from the right ventricle. In other words, one of his initial cases exhibited double-outlet right ventricle. When we now compare findings in hearts with the features of the tetralogy, we can observe significant variations in the nature of the borders of the plane of deficient ventricular septation when viewed from the aspect of the right ventricle. We also find that this plane, usually described as the ventricular septal defect, is not the same as the geometric plane separating the cavities of the right and left ventricles. This means that the latter plane, the interventricular communication, is not necessarily the same as the ventricular septal defect. We are now able to provide further insights into these features by examining hearts prepared from developing mice. Additional molecular investigations will be required, however, to uncover the mechanisms responsible for producing the morphological changes underscoring tetralogy of Fallot.

Risk factors for sudden death after repair of tetralogy of Fallot.

BACKGROUND: Sudden cardiac death remains the most common cause of death after repair of tetralogy of Fallot. It has been suggested that sudden cardiac death is related to right ventricular hypertrophy or dilation. However, it is uncertain whether the preoperative patient status or operative techniques predispose for sudden cardiac death. METHODS: From 1958 to 1977, 658 patients underwent repair of tetralogy of Fallot at our institution at a median age of 12.2 +/- 8.6 years. One third had at least one previous palliative operation 4.6 +/- 2.5 years earlier. A total of 490 patients survived the first postoperative year and were analyzed for sudden cardiac death. During a follow-up period of 25.3 +/- 5.8 years (range, 1.0 to 35.5 years), 42 patients died, and 15 (36%) of those deaths were as a result of sudden cardiac death. RESULTS: Actuarial 10-year, 20-year, and 30-year survival rates were 97%, 94%, and 89%. Freedom from sudden cardiac death was 99%, 98%, and 95% after 10, 20, and 30 years. The risk of sudden cardiac death increased after 10 years from 0.06%/y to 0.20%/y. Univariate predictors (p < 0.1) of sudden cardiac death were use of an outflow tract patch (p = 0.068), male sex (p = 0.048), no previous palliation (p = 0.013), and higher preoperative New York Heart Association status (p = 0.014). Multivariate analysis confirmed these risk factors except use of an outflow tract patch. CONCLUSIONS: The most important risk factors for sudden cardiac death were higher preoperative New York Heart Association class and no previous palliation. Thus, early surgical intervention is recommended. The risk of sudden cardiac death increases with time, suggesting that long-term follow-up by specialized cardiologists or pediatricians should be intensified. However, all patients who died suddenly had at least two risk factors at the time of surgery.

Angiographic classification of ventricular septal defects in tetralogy of Fallot.

The ventricular septal defect (VSD) in Fallot's tetralogy (TF) was classified into four types: perimembranous (PM), muscular outlet (MO), doubly committed subarterial (DS), and DS with perimembranous extension. From July 1990 to June 1992, we used angiocardiography to define preoperatively the types of VSD in 30 cases of TF, and correlated them with the operative findings. The angiographic images used to identify the types of VSDs were anteroposterior (AP) plus cranial tilting 20-30 degrees, right anterior oblique 30 degrees plus cranial tilting 30 degrees (elongated RAO view) and true lateral view of right ventricular (RV) angiography. DS type and MO type had a shadow of muscle bar postero-inferiorly in the AP and elongated RAO views, while perimembranous type and MO superiorly in the lateral view. DS with perimembranous extension type was devoid of both shadows. The results revealed 73% accuracy rate of prediction by angiocardiography. Most of the incorrectly predicted cases were attributed to a tiny inferior muscle bar in MO type and was mistaken as pm type VSD. We conclude that routine RV angiography before correction of tetralogy of Fallot to identify the types of VSDs is feasible. This information facilitates planning of surgical strategy.

A correlative study of the functional class and hemodynamic status following intracardiac repair of tetralogy of Fallot.

An attempt was made to correlate the NYHA Functional class with the hemodynamic status of 196 patients at an average of 21.2 months following the intracardiac repair of tetralogy of Fallot. 171 patients were in Functional class I (87.2%), 9 in class III (4.5%), 5 in class II (2.5%) and 11 in class IV (5.6%). Right and left heart catheterisation and cardiac angiography revealed the hemodynamic status of these patients to be excellent in 92 (46.4%), good in 37 (18.8%), satisfactory in 6 (3.0%) and unsatisfactory in 61 (31.6%). Whereas all patients in Functional class II, III and IV had unsatisfactory hemodynamic findings, patients in Functional Class I were hemodynamically heterogeneous and included excellent (53.8%), good (21.6%), satisfactory (3.5%) and unsatisfactory (21%) groups. The surgical technique did not seem to determine the functional status. While early reoperation is advisable for patients with functional disability, caution is necessary in considering reoperation for patients in Functional class I who have hemodynamic findings which are classified as unsatisfactory.

Early and late results after repair of tetralogy of Fallot.

Between January 1, 1975, and December 31, 1988, 233 patients were operated on for correction of tetralogy of Fallot (TOF). Mean follow-up was 13.9 years (median 7.65 years) and was 99.6% complete. Actuarial survival was 84 +/- 3%. The risk of death decreased gradually to a constant rate of 0.00034 deaths/month by the 6th postoperative month. There were 22 early deaths, due mostly to Low Output Syndrome. The principal incremental risk factor was the postrepair ventricular pressure ratio (PRV/LV) (P less than 0.0001). Other factors were: patent ductus arteriosus (PDA; P = 0.02), other associated anomalies (P = 0.005), higher preoperative hemoglobin levels (P = 0.06) and use of transannular patches (P = 0.02). The operative risk was significantly reduced by a recent operative date (P = 0.01) and by an older age at operation (P = 0.12). Among 8 late deaths, 2 were unrelated to the cardiac condition, 2 occurred suddenly, 3 were due to congestive heart failure and the last was due to reoperation for patch endocarditis. The risk of late death was significantly higher in patients operated on at an older age (P = 0.04). There were 10 open heart reoperations: 5 for patch dehiscence, 4 for residual pulmonary stenosis and 1 for residual atrial septal defect. The reoperation-free actuarial survival was 82 +/- 3%. With the present operative standards, the parametric operative risk of an average patient with simple TOF (hemoglobin = 12 g, PRV/LV = 0.5) is 0.7%. Where the TOF is severely cyanotic (hemoglobin = 25 g) and the pulmonary arteries are severely restricted, the average mortality is 30%.(ABSTRACT TRUNCATED AT 250 WORDS)

Etienne-Louis Arthur Fallot and his tetralogy: a new translation of Fallot's summary and a modern reassessment of this anomaly.

As this translation of Fallot's conclusions makes clear, he emphasized the clinical diagnostic usefulness of his findings because of the high frequency of this malformation in cyanotic congenital heart disease. Terming this anomaly "tetralogy," he clearly and simply delineated its four cardinal features. He stated that cyanosis was not due to a patent foramen ovale. He attributed the morphogenesis of the tetralogy to an intrauterine pathologic process at the level of the pulmonary valve leaflets and the subpulmonary infundibulum. The tetralogy and Fallot's contribution are reassessed in the light of present understanding.

Classification of hearts with overriding aortic and pulmonary valves.

Despite the clarity of the sequential segmential segmental approach to complex congenital heart malformations, the classification of hearts with overriding arterial valves remains contentious. A series of 67 hearts, all with overriding arterial valves, has therefore been studied in an attempt to provide clear and unambiguous criteria for their classification. There were 51 hearts with an overriding aortic valve, 13 hearts with an overriding pulmonary valve and 3 specimens with overriding of both valves. In each of these categories the degree of override and the underlying morphology varied considerably. The options to classify these hearts are limited. Using the "50 per cent rule" as a device to catalogue the type of connexion - irrespective of the morphology - all hearts were described in unambiguous fashion. A comparison with synonyms, as frequently used for purposes of classification, revealed that the latter are often insufficient properly to classify the basic abnormality. By classifying the type of connexion and describing the morphology separately, no basic problem remains in distinguishing between hearts with double outlet right ventricle and subpulmonary ventricular septal defect and hearts with the morphology of Fallot's tetralogy with an aorta almost exclusively arising from the right ventricle. Similarly, the classification of hearts with complete transposition and subpulmonary defect in the setting of the so-called Taussig-Bing heart is brought back to its proper perspective. Proper and consistent application of the sequential segmental approach leaves no room for ambiguity, even in complicated hearts with overriding arterial valves.

[Reoperations after surgical correction of tetralogy of Fallot]. / Réopérations après correction chirurgicale de tétralogie de Fallot.

Between 1970 and 1981, 40 patients (6%) were reoperated after surgical correction of Fallot's tetralogy. The average age of these patients was 7,5 years (range 2 months to 37 years). The usual anatomical form was present in 30 cases and severe forms accounted for the other 10 cases (pulmonary atresia with septal defect were excluded). The 40 patients were divided into 3 groups according to the anatomical lesions corrected at reoperation: Group I: 16 patients with a residual isolated VSD; Group II: 14 patients with one or two residual right heart anomalies (RRHA) but without a septal defect; Group III: 10 patients with a residual VSD and RRHA. The only clinical difference between the patients of these 3 groups was the delay of onset of symptoms: the patients with residual VSD (Groups I and III) often developed cardiac failure immediately, whilst in those without residual VSD (Group II) cardiac failure was usually observed secondarily. Four patients (10%) died early after reoperation (less than 1 month). Three others died later, two during a third operation. The total mortality was similar in the three groups. The surgical result was assessed clinically after an average follow-up of 4,5 +/- 3 years: patients with a residual isolated VSD (Group I) had the best long-term results. In 12 patients, M mode and 2D echocardiography showed normal left ventricular function but the ratio of end diastolic right ventricular and left ventricular dimensions was increased to an average of 0,72 +/- 0,2.(ABSTRACT TRUNCATED AT 250 WORDS)

[Two-dimensional echocardiographic diagnosis of tetralogy of Fallot with a total conus defect].

Tetralogy of Fallot (TOF) with a total conus defect has some characteristics different from classical TOF in respect to its morphogenesis and clinical features. This anomaly, although rare in Europe, constitutes approximately 10% of all types of TOF in Japan. In this report, we studied 30 cases of TOF with angiographic or surgical documentation in order to investigate two-dimensional echocardiography as a possible mean of detecting a conus defect in TOF. We classified the entire group into three types according to the location of a ventricular septal defect (VSD): subpulmonic VSD (six cases, I), infundibular muscular VSD (11 cases, II) and perimembranous VSD (13 cases, III). A long-axis view along the right ventricular outflow tract rather than a short-axis view at the level of the aortic root was adopted as a useful examination for viewing VSDs. Using the former image, we could observe precisely a VSD just below the pulmonary valve in all six cases of Type I and three of Type II, but none of Type III. Three cases of Type II which had a short infundibular septum of several millimeters in length with surgical confirmation were very similar to cases of Type I. The discontinuity between the interventricular septum and the pulmonary valve was confirmed to be identical with subpulmonic VSD by angiographic and pathological studies. In conclusion, we could differentiate TOF with a total conus defect from the other types of TOF by detecting the echo defect in the septum just below the pulmonary valve with the aid of a long-axis view of the right ventricular outflow defect.