TAPVR: Molecular Pathways and Animal Models.

The venous pole of the heart where the pulmonary veins will develop encompasses the sinus venosus and the atrium. In the fourth week of development, the sinus venosus consists of a left and a right part receiving blood from the common cardinal vein, the omphalomesenteric and umbilical veins. Asymmetrical expansion of the common atrium corresponds with a rightward shift of the connection of the sinus to the atrium. The right-sided part of the sinus venosus including its tributing cardinal veins enlarges to form the right superior and inferior vena cava that will incorporate into the right atrium. The left-sided part in human development largely obliterates and remodels to form the coronary sinus in adults. In approximately the same time window (4th-fifth weeks), a splanchnic vascular plexus surrounds the developing lung buds (putative lungs) with a twofold connection. Of note, during early developmental stages, the primary route of drainage from the pulmonary plexus is toward the systemic veins and not to the heart. After lumenization of the so-called mid-pharyngeal endothelial strand (MPES), the first anlage of the pulmonary vein, the common pulmonary vein can be observed in the dorsal mesocardium, and the primary route of drainage will gradually change toward a cardiac drainage. The splanchnic pulmonary venous connections with the systemic cardinal veins will gradually disappear during normal development. In case of absence or atresia of the MPES, the pulmonary-to-systemic connections will persist, clinically resulting in total anomalous pulmonary venous return (TAPVR). This chapter describes the developmental processes and molecular pathways underlying anomalous pulmonary venous connections.

Prenatal diagnosis of total anomalous pulmonary venous connection by 2D and 3D fetal echocardiography.

OBJECTIVE: Prenatal diagnosis of total anomalous pulmonary venous connection (TAPVC) by fetal echocardiography (FE) remains a challenge. We sought to ascertain the diagnostic accuracy of 2D and 3D spatiotemporal image correlation (STIC) FE and the potential incremental value of 3D STIC FE for prenatal diagnosis and assessment of TAPVC. METHODS: This study was conducted retrospectively in a single tertiary referral center. The study population consisted of 74 TAPVC from 17 063 fetuses by FE from August 2010 to April 2016. The 3D volume acquisition was also performed by STIC. RESULTS: A total of 17 063 fetal echocardiograms in our institution were queried and 74 (0.4%) were identified with TAPVC. In the TAPVC group, 11 had postnatal echocardiographic study, 25 had autopsies, 36 declined autopsy and 2 lost for follow-up. The sensitivity of FE for diagnosis of TAPVC was 97.14%, specificity 99.98%, respectively. In our cohort, 31 fetuses were evaluated by both 2D and 3D STIC and were confirmed by postnatal echocardiography or autopsies. TAPVC was diagnosed in all 31 patients (100%) by both 2D FE and 3D STIC. Furthermore, the classification of subtypes of TAPVC and accurate diagnosis of the drainage pathway was correct in 26 (83.9%) and 24 (77.4%) cases by 2D FE, respectively; but in 31 (100%) and 31 (100%) cases by 3D STIC. CONCLUSION: 2D and 3D STIC FE provide accurate diagnosis of TAPVC with excellent sensitivity and specificity. 3D STIC FE has incremental value in further evaluation of classification of TAPVC types and drainage pathways.

Role of four-dimensional echocardiography with high-definition flow imaging and spatiotemporal image correlation in detecting fetal pulmonary veins.

BACKGROUND: Prenatal diagnosis of fetal total anomalous pulmonary vein connection (TAPVC) remains challenging for most screening sonographers. The purpose of this study was to evaluate the use of four-dimensional echocardiography with high-definition flow imaging and spatiotemporal image correlation (4D-HDFI) in identifying pulmonary veins in normal and TAPVC fetuses. MATERIAL & METHODS: We retrospectively reviewed and performed 4D-HDFI in 204 normal and 12 fetuses with confirmed diagnosis of TAPVC. Cardiac volumes were available for postanalysis to obtain 4D-rendered images of the pulmonary veins. For the normal fetuses, two other traditional modalities including color Doppler and HDFI were used to detect the number of pulmonary veins and comparisons were made between each of these traditional methods and 4D-HDFI. RESULTS: For conventional echocardiography, HDFI modality was superior to color Doppler in detecting more pulmonary veins in normal fetuses throughout the gestational period. 4D-HDFI was the best method during the second trimester of pregnancy in identifying normal fetal pulmonary veins. 4D-HDFI images vividly depicted the figure, course, and drainage of pulmonary veins in both normal and TAPVC fetuses. CONCLUSION: HDFI and the advanced 4D-HDFI technique could facilitate identification of the anatomical features of pulmonary veins in both normal and TAPVC fetuses; 4D-HDFI therefore provides additional and more precise information than conventional echocardiography techniques.

Prenatal diagnoses of an uncommon isolated obstructed supracardiac total anomalous pulmonary venous connection: Case report and review of the literature (CARE compliant).

INTRODUCTION: Total anomalous pulmonary venous connection is an uncommon congenital heart disease. Four types are described based on the site of pulmonary venous drainage: supracardiac, cardiac, infradiaphragmathic, and mixed connection. In most cases of supracardiac type, the common venous confluence drains through an ascending left vertical vein into the brachiocephalic vein, right superior vena cava, and then into the right atrium. Anomalous connection of the pulmonary venous confluence directly to the right SVC, especially the obstructed form is an unusual and severe supracardiac variant. The prenatal diagnosis is challenging. PATIENT CONCERNS: We present a case report of a fetus diagnosed with TAPVC at 23 gestational weeks. DIAGNOSIS INTERVENTIONS: The 4-chamber view showed a small left atrium, with a "smooth" posterior wall and the absence of pulmonary vein connection. This is the first case of prenatally diagnosed isolated, obstructed supracardiac type with drainage directly into the right superior vena cava. CONCLUSION: The obstetrician and fetal cardiologist should be cautious at the direct and indirect echocardiographic signs of this condition. A prenatal diagnose of isolated, obstructed form is important for adequate planning of delivery and postnatal surgery in a tertiary center.

Síndrome de la cimitarra. Correlación anatomoembriológica / Scimitar syndrome. Correlation anatomo-embryological

Resumen Objetivos Describir morfológicamente un bloque visceral toracoabdominal de un caso de síndrome de la cimitarra. Proponer una hipótesis patogenética que explique el desarrollo de las conexiones venosas pulmonares de este síndrome. Método El espécimen anatómico se describió con el sistema secuencial segmentario. Se determinó el situs, las conexiones entre los segmentos cardíacos y las anomalías agregadas. Se describió la anatomía de ambos pulmones, incluida la conexión venosa pulmonar. Se elaboró una hipótesis patogenética que explica la conexión venosa pulmonar a través de una correlación entre la patología del síndrome y el desarrollo normal de las venas pulmonares. Resultados El situs fue solitus, las conexiones entre los segmentos cardíacos fueron normales, existió hipoplasia y displasia del pulmón derecho con secuestro del lóbulo inferior; las venas pulmonares derechas drenaron a un colector curvo en la porción suprahepática de la vena cava inferior y las venas pulmonares izquierdas lo hicieron a la aurícula izquierda. El secuestro pulmonar recibió irrigación a través de una colateral aortopulmonar. Existió una comunicación interauricular. Conclusiones La hipótesis patogenética propone que las conexiones venosas pulmonares de este síndrome representan la persistencia del horizonte XIV de Streeter (28-30 días de desarrollo), período en el que el seno de las venas pulmonares presenta conexión venosa doble con la aurícula izquierda y con un colector de la conexión primitiva que desemboca en la vitelina derecha de la que se deriva la porción suprahepática de la vena cava inferior.

Abstract Objectives To describe morphologically a toracoabdominal visceral block of a scimitar's syndrome case. We propose a pathogenetic theory wich explains the development of the pulmonary venous connection in this syndrome. Method The anatomic specimen was described with the segmental sequential system. The situs was solitus, the connections between the cardiac segments and the associated anomalies were determined. The anatomy of both lungs, including the venous pulmonary connection, was described. A pathogenetic hypothesis was made, which explains the pulmonary venous connection throw a correlation between the pathology of this syndrome and the normal development of the pulmonary veins. Results The situs was solitus, the connections of the cardiac chambers were normal; there were hypoplasia and dysplasia of the right lung with sequestration of the inferior lobe; the right pulmonary veins were connected with a curved collector which drainaged into the suprahepatic segment of the inferior vena cava; the left pulmonary veins were open into the left atrium. The sequestered inferior lobe of the right lung received irrigation throw a collateral aortopulmonary vessel. There was an atrial septal defect. Conclusions The pathogenetic hypothesis propose that the pulmonary venous connection in this syndrome represent the persistent of the Streeter's horizon XIV (28-30 days of development), period in which the sinus of the pulmonary veins has double connection, with the left atrium and with a primitive collector into the right viteline vein which forms the suprahepatic segment of the inferior vena cava.

Anomalous Pulmonary Venous Return: Insights Into Prenatal Detection.

OBJECTIVES: To review all cases of total anomalous pulmonary venous return (TAPVR) or partial anomalous pulmonary venous return (PAPVR) identified prenatally or postnatally at a single institution and to identify factors that may lead to a correct or missed diagnosis in both high- and low-risk fetuses on screening examinations. METHODS: Fetal images from 16 cases of prenatally or postnatally diagnosed T/PAPVR were retrospectively reviewed to analyze factors that influenced interpretations and diagnoses. RESULTS: Sixteen diagnoses of T/PAPVR were made, with a final number of 10 confirmed cases, 1 of which was PAPVR. Ten fetuses with a presumptive diagnosis of T/PAPVR before delivery were at an average gestational age of 24.7 weeks, with 5 cases diagnosed postnatally. None of the diagnoses of isolated TAPVR were made during a screening examination. Twelve of the pregnancies were complicated by complex cardiac defects, including 6 with heterotaxy syndromes. Of the 5 abnormal cases identified in the postpartum period, 3 had isolated TAPVR. In the 3 patients with isolated defects, prenatal echocardiography was not performed; the anatomy scan interpretations were confounded by multiple factors. In retrospect, there was no obvious sonographic evidence of TAPVR in these patients; however, color flow Doppler imaging of the pulmonary veins was not performed on any of them. CONCLUSIONS: Although fetal echocardiography has improved the overall detection of TAPVR or PAPVR, this abnormality continues to elude prenatal diagnosis during screening in both low- and high-risk patients. We hypothesize that the use of color flow Doppler imaging in the 4-chamber view may assist in diagnosing TAPVR in screening low-risk patients, especially in those with difficult scans.

[Scimitar syndrome. Correlation anatomo-embryological]. / Síndrome de la cimitarra. Correlación anatomoembriológica.

OBJECTIVES: To describe morphologically a toracoabdominal visceral block of a scimitar's syndrome case. We propose a pathogenetic theory wich explains the development of the pulmonary venous connection in this syndrome. METHOD: The anatomic specimen was described with the segmental sequential system. The situs was solitus, the connections between the cardiac segments and the associated anomalies were determined. The anatomy of both lungs, including the venous pulmonary connection, was described. A pathogenetic hypothesis was made, which explains the pulmonary venous connection throw a correlation between the pathology of this syndrome and the normal development of the pulmonary veins. RESULTS: The situs was solitus, the connections of the cardiac chambers were normal; there were hypoplasia and dysplasia of the right lung with sequestration of the inferior lobe; the right pulmonary veins were connected with a curved collector which drainaged into the suprahepatic segment of the inferior vena cava; the left pulmonary veins were open into the left atrium. The sequestered inferior lobe of the right lung received irrigation throw a collateral aortopulmonary vessel. There was an atrial septal defect. CONCLUSIONS: The pathogenetic hypothesis propose that the pulmonary venous connection in this syndrome represent the persistent of the Streeter's horizon xiv (28-30 days of development), period in which the sinus of the pulmonary veins has double connection, with the left atrium and with a primitive collector into the right viteline vein which forms the suprahepatic segment of the inferior vena cava.

The clinical anatomy of the inferior vena cava: a review of common congenital anomalies and considerations for clinicians.

Anomalies in the course and drainage of the Inferior Vena Cava (IVC) may complicate normal functioning, correct diagnosis, and therapeutic interventions within the abdomen. Development of the IVC occurs during the 4th to 8th week of gestation, and due to its developmental complexity, there are many opportunities for malformations to occur. Although most IVC anomalies are clinically silent and are usually discovered incidentally on abdominal imaging, aberrations may be responsible for formation of thrombosis, back pain, and anomalous circulation of blood to the heart. In this review, we will discuss the most common variations and abnormalities of the IVC, which include the posterior cardinal veins, the subcardinal veins, the supracardinal veins, persistent left IVC, IVC duplication, situs inversus, left retroaortic renal vein, left circumaortic renal collar, scimitar syndrome, and IVC agenesis. For each abnormality outlined above, we aim to discuss relevant embryology and potential clinical significance with regards to presentation, diagnosis, and treatment as is important for radiologists, surgeons, and clinicians in current clinical practice.

Prenatal findings and differential diagnosis of scimitar syndrome and pulmonary sequestration.

OBJECTIVES: Scimitar syndrome and pulmonary sequestration (PS) have overlapping features. This accounts for postnatal descriptions of a 'sequestrated lung' in scimitar-syndrome patients. We review the similarities and differences in these two conditions, and the antenatal ultrasound findings that allow correct prenatal identification and differential diagnosis. METHODS: This was a retrospective analysis of prenatally diagnosed cases of scimitar syndrome or PS that underwent fetal echocardiography between January 1995 and November 2004. RESULTS: There were five cases of PS and six of scimitar syndrome. Right-sided mediastinal shift (ipsilateral relative to the affected lung) was the commonest indication for referral in scimitar syndrome whereas in sequestration, referral was because of hyperechogenic lung and contralateral mediastinal shift. Lung echogenicity was normal in scimitar syndrome but focally increased in PS. Abnormal, unobstructed pulmonary venous drainage was identified prenatally in four cases of scimitar syndrome. It was normal in three fetuses with sequestration but abnormal and obstructed in the other two cases complicated by hydrothorax. Abnormal systemic arterial supply to the affected lung was easily demonstrated in all fetuses with PS, but could not be shown prenatally in scimitar-syndrome fetuses. Postnatal embolization was warranted in one case with PS and four with scimitar syndrome, one each in the neonatal period. CONCLUSION: Prenatally, scimitar syndrome and PS are clearly distinct entities based on lung echogenicity and laterality of mediastinal shift. Hyperechogenic lung and dextrocardia indicate the possibility of PS and scimitar syndrome, respectively. Complete delineation of the vascular pattern should be attempted in all, but is more challenging in scimitar syndrome. Obstructed venous return in PS may identify fetuses at risk of developing hydrothorax.

Scimitar syndrome.

Scimitar syndrome is a rare congenital anomaly consisting in part of right pulmonary venous return to the inferior vena cava. There is a clear bimodal presentation of this syndrome with either an infantile manifestation or a pediatric/adult form. The infantile variant is marked by a higher incidence and severity of associated defects, heart failure, pulmonary hypertension, and significant mortality. The patient with the pediatric/adult form is less severely affected and may be asymptomatic on diagnosis. In this article, we review the historical aspects, presentation, and pathophysiology of Scimitar syndrome and discuss available treatment strategies. We emphasize the safe and effective approach developed at Indiana University that obviates both the need for an intra-atrial baffle or use of cardiopulmonary bypass. The results with our alternative approach to Scimitar syndrome are summarized and they compare favorably with other published reports.

[Anatomo-echocardiographic correlation of scimitar syndrome in adults]. / Correlación anatomo-ecocardiográfica del síndrome de cimitarra en el adulto y comentario embriológico.

It is a retrospective study of 7 patients with clinical and echocardiographic assessment, the last was correlated with morphologic features of one equivalent anatomic specimen. The results are: respiratory infections and dyspnea in 90% of cases, scimitar sign in four (57%), interatrial septal defect in five (71%), one of them with patent ductus arteriosus, two (28.6%) only with patent ductus arteriosus. Dextrocardia was found in 5 (71%), dilation of the right cavities in 5 (71%) and blunt edge in 6 (85.7%). In two the colector drained into the right atrium, in one to the junction of the right atrium and inferior vena cava and in the other three into the inferior vena cava through the colector. Six patients with cardiac abnormalities went to surgery. The correlation shows agreement between the echocardiographic image and the anatomic specimen. Scimitar syndrome is a rare entity, which diagnosis and follow up can be performed by echocardiography in a great percentage (86%). The embryologic basis of this syndrome is enhanced.

Correlación anatomo-ecocardiográfica del síndrome de cimitarra en el adulto y comentario embriológico / Anatomo-echocardiographic correlation of Scimitar Syndrome in adults

Estudio retrospectivo de 7 pacientes adultos con síndrome de cimitarra mediante examen clínico y ecocardiográfico, este último se correlacionó con un espécimen anatómico equivalente. Los resultados fueron: Infección respiratoria y disnea de medianos esfuerzos en el 90%, signo de Cimitarra en 4 (57%), comunicación interatrial en 5 (71 %), uno de ellos con persistencia de conducto arterioso; dos (28.6%) sólo con persistencia de conducto arterioso, dextrocardia en 5 (71%), dilatación de cavidades derechas en 5 (71%) y borde romo en 6 (85.7%). En 2 el colector drenó a la porción baja de la aurícula derecha, en tres a la unión del atrio derecho con la vena cava inferior y en 2 a la vena cava inferior a través de un colector. Seis fueron a cirugía. La correlación mostró concordancia entre la imagen ecocardiográfica y el espécimen anatómico. El síndrome de la Cimitarra es raro, su diagnóstico y seguimiento se puede realizar mediante ecocardiografía en un alto porcentaje (86%). Se resalta la base embriológica de este síndrome.

It is a retrospective study of 7 patients with clinical and echocardiographic assessment, the last was correlated with morphologic features of one equivalent anatomic specimen. The results are: respiratory infections and dyspnea in 90% of cases, scimitar sign in four (57%), interatrial septal defect in five (71%), one of them with patent ductus arteriosus, two (28.6%) only with patent ductus arteriosus. Dextrocardia was found in 5 (71 %), dilation of the right cavities in 5 (71%) and blunt edge in 6 (85.7%). In two the colector drained into the right atrium, in one to the junction of the right atrium and inferiorvena cava and in the other three into the inferior vena cava through the colector. Six patients with cardiac abnormalities went to surgery. The correlation shows agreement between the echocardiographic image and the anatomic specimen. Scimitar syndrome is a rare entity, which diagnosis and follow up can be performed by echocardiography in a great percentage (86%). The embryologic basis of this syndrome is enhanced. (Arch Cardiol Mex 2005; 75: 165-169).