COMPLETE AND INVERTED TRANSPOSITION OF THE GREAT VESSELS

Computational Study of Pulmonary Flow Patterns After Repair of Transposition of Great Arteries

Patients that undergo the arterial switch operation (ASO) to repair transposition of great arteries (TGA) can develop abnormal pulmonary trunk morphology with significant long-term complications. In this study, cardiovascular magnetic resonance was combined with computational fluid dynamics to investigate the impact of the postoperative layout on the pulmonary flow patterns. Three ASO patients were analyzed and compared to a volunteer control. Results showed the presence of anomalous shear layer instabilities, vortical and helical structures, and turbulent-like states in all patients, particularly as a consequence of the unnatural curvature of the pulmonary bifurcation. Streamlined, mostly laminar flow was instead found in the healthy subject. These findings shed light on the correlation between the post-ASO anatomy and the presence of altered flow features, and may be useful to improve surgical planning as well as the long-term care of TGA patients.

Fetal and postnatal echocardiographic imaging of transposition of the great arteries with the aortic valve posterior to the pulmonary valve

Transposition of the great arteries (TGA) with a posterior aorta is an uncommon but historically important variant of TGA. In this arrangement, the aorta is posterior to the pulmonary valve, maintains fibrous continuity with the mitral valve, and arises from the right ventricle. We present a case of fetal echocardiography demonstrating TGA with a posterior aorta. Postnatal transthoracic echocardiography and intra-operative assessment confirm the anatomy. To the best of our knowledge, this is the first published case of this anatomic lesion by fetal echocardiography.

The nomenclature, definition and classification of discordant atrioventricular connections

During the process of creation of a bidirectional crossmap between the system emerging, on the one hand, from the initiative sponsored by the Congenital Heart Committees of the European Association for Cardio-Thoracic Surgery and the Society of Thoracic Surgeons, and on the other hand, from that formulated by the Coding Committee of the European Association for Pediatric Cardiology, the Nomenclature Working Group has successfully created the International Paediatric and Congenital Cardiac Code. As would be expected, during the process of crossmapping it became clear that, for most lesions, the European Pediatric Cardiac Code was more complete in its description of the diagnoses, while the International Congenital Heart Surgery Nomenclature and Database Project was more complete in its description of the procedures. This process of crossmapping exemplifies the efforts of the Nomenclature Working Group to create a comprehensive and all-inclusive international system for the naming of paediatric and congenital cardiac disease, the International Pediatric and Congenital Cardiac Code. Although names and classification for paediatric and congenital cardiac disease will continue to evolve over time, we are now closer than ever to reaching uniform international agreement and standardization. The International Paediatric and Congenital Cardiac Code can be downloaded from the Internet, free of charge, at www.ipccc. net.

Modified arterial switch operation by spiral reconstruction of the great arteries in transposition

BACKGROUND

Spiral relationship of the normally related great arteries (SRGA) has never been reconstructed in an arterial switch operation.

METHODS

From March 1998 to April 1999, 9 consecutive cases of transposition of the great arteries (TGA) family (from 2 days to 1.6 years old) underwent arterial switch operations with SRGA at our hospital. Two had a congenitally corrected TGA (plus atrial redirection). Lecompte maneuver was not used in all. The posterior wall of pulmonary trunk was not divided but three were reattached, two of whom had had previous pulmonary trunk banding. Thus the wall was shared between the great arteries facing each other.

RESULTS

All survived the operation. Supraaortic stenosis was balloon-dilated in 2 cases of early series, but technical modifications later were able to avoid it. Angiogram showed smooth flow into SRGA without upward and anterior tilting of the pulmonary bifurcation. All great and coronary arteries were patent. All were doing well on follow-up (16.5 +/- 4.2 months).

CONCLUSIONS

We concluded that the techniques to relocate the coronary arteries using common wall and in situ switch could also be applied to pulmonary arterial reconstruction, so that SRGA can be resumed in TGA.

Congenital Heart Surgery Nomenclature and Database Project: corrected (discordant) transposition of the great arteries (and related malformations)

The extant nomenclature for congenitally corrected transposition of the great arteries is reviewed for the purpose of establishing a unified reporting system. The subject was debated and reviewed by members of the STS-Congenital Heart Surgery Database Committee and representatives from the European Association for Cardiothoracic Surgery. All efforts were made to include all relevant nomenclature categories using synonyms where appropriate. Congenitally corrected transposition of the great arteries is a complex cardiac lesion that is associated with ventricular septal defect, left ventricular outflow tract obstruction, and tricuspid valve abnormalities. Nomenclature for this lesion has been variable and confusing. Herein we attempt to clarify the terminology, with an emphasis on identification of synonymous and nonsynonymous appellations. A comprehensive database set is presented that is based on a hierarchical scheme. Data are entered at various levels of complexity and detail that can be determined by the clinician. These data can lay the foundation for comprehensive risk stratification analyses. A minimum database set is also presented that will allow for data sharing and would lend itself to basic interpretation of trends. Outcome tables relating diagnoses, procedures, and various risk factors are presented.

A SIMPLIFIED BASIC CLASSIFICATION OF SPATIAL ALIGNMENTS OF THE HEART, ITS CHAMBERS, AND THE GREAT VESSELS

The problems resulting from a lack of accepted terminology and a basic classification system for the various spatial alignments of the heart, its chambers and great vessels are reviewed. A basic simplified classification system founded on fundamental embryologic, clinical, and roentgenologic considerations is proposed. Terminology employed is precisely defined. The clinical studies needed to place patients in their category are enumerated and discussed. It is recognized that some forms of spatial derangement defy classification within this system. Nevertheless, this classification system with the suggested terminology, however inadequate, is offered as a means to promote clinical definition of these entities and to encourage clear discussion and a better understanding of these conditions. It is hoped that future study will add to our knowledge of the embryologic mechanisms involved and eventually lead to a more comprehensive classification embracing a larger number of congenital cardiac anomalies.

Conal anatomy in 119 patients with d-loop transposition of the great arteries and ventricular septal defect: an echocardiographic and pathologic study

OBJECTIVES

We sought to study the range of conal morphology in transposition of the great arteries with ventricular septal defect and their embryologic and surgical implications.

BACKGROUND

Conal anatomy in transposition of the great arteries and ventricular septal defect is variable and might affect surgical repair.

METHODS

Conal anatomy was explored using two-dimensional echocardiography in 119 patients with transposition of the great arteries and a large ventricular septal defect who presented between 1984 and 1991. The influence of conal anatomy on surgical technique was determined by review of the operative reports. Specimens of transposition of the great arteries with unusual conal anatomy were selected from the Cardiac Registry for comparison with the echocardiograms.

RESULTS

One hundred five patients (88.2%) had subaortic conus only with no subpulmonary conus (Group 1). Subarterial conus was present bilaterally in eight patients (6.7%) (Group 2). Four patients (3.4%) had only subpulmonary conus with no (or minimal) subaortic conus (Group 3). Among these four patients, the aorta was posterior to the pulmonary artery in one patient, side by side relative to the pulmonary artery in two patients and slightly anterior in the fourth patient. Subarterial conus was absent bilaterally in two patients (1.7%) (Group 4); the aorta was slightly posterior in one and side by side with the pulmonary artery in the other.

CONCLUSIONS

This variability of conal anatomy in transposition of the great arteries with ventricular septal defect implies four mechanisms by which transposition can occur. The conal anatomy appeared to affect surgical repair in Groups 1 and 2 insofar as it influenced ventricular outflow tract obstruction. In Groups 3 and 4, an arterial switch operation was performed in four of the six patients. The posterior location of the aorta obviated the need for the Lecompte maneuver in two of these four patients. In the remaining two cases in Groups 3 and 4, the condition was repaired by directing the left ventricular outflow across the ventricular septal defect to the aorta using a patch, with or without placement of a conduit from the right ventricle to the pulmonary artery.

Corrected transposition of the great vessels: a vectorcardiographic study

The vectorcardiograms (VCGs) of two groups of patients with corrected transposition of the great vessels (CTGV) were studied; the first, group A, included 17 patients with CTGV in "situs solitus,", characterized by leftward orientation of the cardiac apex; the second group, group B, with three patients, presented CTGV in "situs solitus" and apex to the right. All cases had one or more associated defects: ventricular septal defect, atrial septal defect, pulmonic stenosis or tricuspid insufficiency.

'Posterior' transposition reconsidered

Seven cases of transposition with an unusually posterior aorta and mitral-aortic fibrous continuity are described. The cases are similar to four cases published by Van Praagh et al. in 1971. The use of the term 'p' transposition is suggested to distinguish this unusual form of transposition from cases with a subaortic conus ('d' and 'l' transposition). The use of the term 'transposition' is considered justifiable on both semantic and morphogenetic grounds and a possible common embryological mechanism for all forms of transposition is discussed.

The differential diagnosis of levo-transposed or malposed aorta. An angiocardiographic study

The levo-transposed aorta has previously been considered diagnostic of corrected transposition of the great arteries and hence ventricular inversion in situs solitus. Increasing experience with conotruncal abnormalities has shown that an abnormally leftward aorta may be found in patients with normally related ventricles (D-ventricular loop) and hemodynamically complete transposition of the great arteries; anatomically corrected L-malposition of the great arteries; and rarely in patients with D-ventricular loop, double outlet right and left ventricles. Thus the levo-positioned aorta should suggest a wider spectrum of cardiovascular abnormalities than previously thought. The specific angiocardiographic features of levo-transposition, anatomically corrected malpositions, and D-ventricular loop with levo-transposed aorta are presented in detail; and their differential diagnosis from the very uncommon D-loop, double outlet right and left ventricles with an L-malposed aorta is considered. The role of selective biplane angiocardiography in the assessment of these conotruncal abnormalities is stressed.

Pathologic anatomy of dextrocardia and its clinical implications

This is a morphologic study of 41 cases of dextrocardia for the purpose of clarifying terminology and evaluating the clinical import of the morphologic data. Dextrocardias are classified as dextroversion, mirror-image dextrocardia, and mixed dextrocardia. When the atrial septum does not identify the atria, it was found possible to make the presumptive diagnosis of dextroversion or mirror-image dextrocardia. The mutual relations of the visceral situs with the atrial situs, the presence or absence of splenic abnormalities, the type of dextrocardia, and the systemic and pulmonic venous return were investigated, as well as the type of complex that is characteristic of each type of dextrocardia. The most important morphologic data useful for clinical application were found to be the position of the aortic and pulmonic annuli, the course of the pulmonary trunk, the entry of the inferior and superior venae cavae, and the course of the anterior descending coronary artery.

Truncal inversion with biventricular pulmonary trunk and aorta from right ventricle (variant of Taussig-Bing complex)

A heart is described pathologically in which the aorta emerged from the right ventricle and was not related to the ventricular septal defect, while the pulmonary trunk emerged from both ventricles, but mostly the right, and was related to the ventricular septal defect. This Taussig-Bing arrangement of vessels was coupled with the presence of the aortic orifice to the left and the pulmonic orifice to the right, which is an inverted position. The anatomic concept of inversion is an abnormality in position from the standpoint of laterality. A careful study of the conal regions of the left and right ventricles showed that those regions were not inverted. Therefore, this represents a case of Taussig-Bing complex with exclusively truncal inversion, which is unique. This may be explained on the basis of opposite metameric contribution to the development of the truncus.

The electrocardiogram in complete transposition of the great vessels

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