total anomalous pulmonary venous connection ( tapvc ) is an uncommon congenital heart disease , with an incidence of about 0.6 to 1.2/10.000 live birth and accounting for about 0.7 to 1.5% of all cardiac defects . tapvc is a result of the nonfusion of the confluence of the pulmonary venous drainage and the left atrium . darling described 4 types of tapvc based on the site of pulmonary venous drainage : supracardiac ( type i ) , cardiac ( type ii ) , infradiaphragmathic ( type iii ) , and mixed connection ( type iv ) . in most cases of supracardiac tapvc , there is an anomalous connection of the common venous confluence with a persistent left superior vena cava ( svc ) , also named ascending left vertical vein , which further drains into the brachiocephalic vein , right svc , and then into the right atrium . the connection of the pulmonary venous confluence directly into the right svc is an uncommon condition . the symptoms of tapvc vary from mild cyanosis to severe cyanosis , respiratory distress , and acidosis even in the first hours of life . these symptoms depend mostly on the degree of venous obstruction ; therefore , the symptoms will increase in severity at the same time with the degree of venous obstruction . the supracardiac type of tapvc will present pulmonary venous obstruction less frequently than the infracardiac type . the obstructive forms of tapvc present more rapidly respiratory disorders , hypoxia , pulmonary hypertension , even cardio - respiratory failure , and distress - syndrome - like pattern . the 2-dimensional echocardiography is the one that usually establishes the diagnosis of this rare cardiac congenital condition . other therapeutic measures , such as atrial septostomy , can be performed by cardiac catheterization . the surgical treatment consists in ligaturation of the vertical vein in order to prevent the residual left - to - right shunt . heritable cases of tapvc have also been described in the literature ; therefore , the physician must always take into consideration the referral of the family for genetic assessment and advice . the informed consent was given by the patient 's parents ( legal guardians ) for publication of this case report . a 26-year - old primigravid woman , without relevant history , was referred for fetal echocardiography at 26 weeks of gestation , after the second trimester fetal echocardiography screening revealed tapvc in the fetus . cardiac examination was carried out by a pediatric cardiologist and a gynecologist with experience in fetal echocardiography . the 4-chamber view revealed a right - to - left chamber discrepancy , a small left atrium , with a smooth  posterior wall . also , the 2d image raised the suspicion of absent pulmonary vein connection ( fig . low - flow color mapping identified pulmonary veins draining into a common confluence behind the small left atrium . three vessel - trachea ( 3vt ) view revealed a dilated right svc , with normal innominate vein . no vertical vein was detected on 3 vessel ( 3  v ) or 3vt view ( fig . 2 ) . low - flow color doppler imaging revealed a turbulent flow in right svc at the drainage site of the common confluence ( fig . a very narrow opening of the confluence into the right svc was detected ( fig . 4c view = 4 chamber view , cc = common venous confluence , la = left atrium , svc = superior vena cava . prenatal echocardiography . a 3 vessel trachea view ( 3vtv ) with color doppler flow mapping . 3vtv = 3 vessel trachea view , ao arch = aortic arch , duct art . dilated svc due to the drainage of the common venous confluence through a narrow opening . cc = common venous confluence , ivc = inferior vena cava , ra = right atrium , svc = superior vena cava . at 38 weeks of gestation , a male neonate was born in a tertiary cardiovascular center by cesarean section due to cephalous - pelvic disproportion . his birth weight was 3700  g , length was 57  cm , and head girth was 34  cm . the apgar score at 1 and 5 minutes after birth was 8 and 9 , respectively . he presented cyanosis , with tachypnea , a respiratory rate of 60 to 70  breath / min , suprasternal and subcostal retractions . this revealed an enlarged right heart ( atrium and ventricle ) and ostium secundum type atrial septal defect of 6  mm , with right - to - left shunt . the 4 pulmonary veins drained into a common confluence localized behind the left atrium , which opened directly into the right svc , without an ascending vertical vein . the color flow mapping of the confluence opening into the right svc showed a critical obstruction ( fig . pulsed doppler evaluation of the pulmonary venous confluence opening into the superior vena cava showed a maximal velocity of 21  cm / s and maximal gradient of 18 mm hg , suggesting obstruction at that level ( fig . a computer tomography angiography was performed , which revealed similar findings ( figs . 7 and 8) . postnatal echocardiography . ( b ) color - doppler flow mapping of the confluence opening into the right svc showed a high turbulence suggestive for critical obstruction . 2d = bi - dimensional , ao = aorta , cc = common venous confluence , pa = pulmonary artery , svc = superior vena cava . postnatal echocardiography . pulsed doppler evaluation of the pulmonary venous confluence opening into the svc showed a maximal velocity of 21  cm / s and maximal gradient of 18 mm hg , suggesting obstruction at that level . common confluence of the 4 pulmonary veins , opening directly into the right svc : angioct = computer tomography angiography , cc = common venous confluence , svc = superior vena cava , v = pulmonary veins ,  drainage site of the common venous confluence into the svc . common pulmonary venous confluence opening into the right svc : angioct = computer tomography angiography , cc = common pulmonary venous confluence , svc = superior vena cava ,  drainage site of the common venous confluence into the svc . the neonate underwent an emergency open heart surgery by performing a side - to - side anastomosis between the pulmonary venous confluence and left atrium . the postoperative recovery was complicated by pulmonary arterial hypertension , right ventricular myocardial dysfunction with hemodynamic failure , and unfortunately the newborn died 3 days after surgery . anomalous connection of the pulmonary venous confluence directly to the right svc , especially the obstructed form is an unusual supracardiac variant . in a retrospective , collaborative study involving 19 pediatric cardiac centers from the united kingdom , ireland , and sweden the incidence of tapvc was about 7.1/100.000 live births . this incidence is higher compared to 6.8 in the baltimore - washington infant study or 5.9 in the new england regional infant cardiac program . several studies have reported case series with prenatally diagnosed supracardiac tapvc , some of them with drainage direct into the right svc . this is the first case of prenatally diagnosed isolated , obstructed supracardiac tapvc with drainage directly into the right svc , identified by us in the literature . this fact can be explained by the particularities of the fetal pulmonary circulation : low pulmonary blood flow , due to high pulmonary vascular resistance . however , rasanen et al showed that during the pregnancy there is a slight increase of pulmonary blood flow compared with the combined cardiac output , from 13% at 20 weeks of gestation to 25% at 30 weeks of gestation , with no changes in the last semester . this pulmonary flow increase can explain the right - left ventricular discrepancy after 28 weeks of gestation . after postnatal transition , the pulmonary blood flow increases and as a result of systemic and pulmonary venous flow mixing in the right heart , the neonate will be cyanotic . some indirect and direct signs suggesting the prenatal diagnose of isolated supracardiac tapvc , are described in the literature . the initial sign that can become obvious in the third trimester of pregnancy is the right ventricular predominance , with increase of pulmonary blood flow . another indirect sign detectable in 4-chamber view is a small left atrial size and  smooth  posterior aspect of it . dilation of the svc and detection of an additional vein ( vertical vein  in typical supracardiac tapvc ) in 3 vtv is helpful . low - flow color mapping in order to identify pulmonary veins could be helpful for diagnosis improvement . also , abnormal pulsed doppler flow in pulmonary veins can give important information . because of the low pulmonary blood flow in fetus , obstruction of the pulmonary venous confluence may be difficult to detect . a4c and 3vt view are of great importance and compulsory in diagnosing isolated supracardiac tapvc beside doppler color and pulsed doppler flow imaging of pulmonary veins . however , in our particular supracardiac tapvc case , there was no additional vessel in the 3 vtv , because of the direct drainage of the common pulmonary venous confluence into the right svc . we noticed a dilated right svc at the site of the pulmonary venous drainage in 3vtv , with a turbulent doppler color flow at that level . further careful assessment of the right svc allowed identification of the drainage site of the common confluence . recently , it was described a case of a 4-month - old infant without any pathological history , admitted for perioral cyanosis and poor feeding , who was diagnosed with tapvc , which was successfully repaired by surgical intervention . zhang et al in their study showed that comparing with surgical or angioct results , the postnatal echocardiography had a sensitivity of 97.6% and a specificity of 99.9% . unfortunately , even though we diagnosed our patient in utero , he died after surgery . on the other hand , a study performed on patients with mixed - type tapvc , underlined the fact that the mortality during the first year after surgery is high , but those who survive past the 1st year , usually present a good prognosis , without sequelae . tapvc can be associated with other cardiac malformations , such as in the case described by ide et al about a neonate diagnosed with a single ventricle , right atrial isomerism , pulmonary atresia with major aortopulmonary collateral arteries , a small central pulmonary artery and a supracardiac tapvc , who underwent an uneventful surgical repair . even though , complications after surgical repair , such as pulmonary arterial hypertension usually appear in the first 6 months after surgery , this can appear also later on life , like in the case described by martinez  quintana about a teenager who developed pulmonary venous obstruction and severe secondary pulmonary arterial hypertension after a surgical intervention for tapvc during infancy . in the case described above , severe pulmonary arterial hypertension appeared very quickly after the surgical intervention and led to the newborn 's death on the 3rd day after surgery . other rare cases involving tapvc were also reported in the specialty literature , such as the association between tetralogy of fallot with anomalous left coronary artery from pulmonary artery and totally anomalous pulmonary venous connection , or the coexistence of tapvc and persistent left superior vena cava . according to shi et al obstructed tapvc was discovered in 25% of newborns , the mean surgical age were about 215 days of life with 51 deaths of the 768 cases with different types of anomalous pulmonary venous connection . although our case had a severe obstructed form and unfortunately died after surgery , we can emphasize that a prenatal diagnosis of isolated , obstructed tapvc is important for adequate postnatal planning of delivery and surgery in a tertiary center . a 26-year - old primigravid woman , without relevant history , was referred for fetal echocardiography at 26 weeks of gestation , after the second trimester fetal echocardiography screening revealed tapvc in the fetus . cardiac examination was carried out by a pediatric cardiologist and a gynecologist with experience in fetal echocardiography . the 4-chamber view revealed a right - to - left chamber discrepancy , a small left atrium , with a smooth  posterior wall . also , the 2d image raised the suspicion of absent pulmonary vein connection ( fig . low - flow color mapping identified pulmonary veins draining into a common confluence behind the small left atrium . three vessel - trachea ( 3vt ) view revealed a dilated right svc , with normal innominate vein . no vertical vein was detected on 3 vessel ( 3  v ) or 3vt view ( fig . 2 ) . low - flow color doppler imaging revealed a turbulent flow in right svc at the drainage site of the common confluence ( fig . a very narrow opening of the confluence into the right svc was detected ( fig . 4c view = 4 chamber view , cc = common venous confluence , la = left atrium , svc = superior vena cava . prenatal echocardiography . a 3 vessel trachea view ( 3vtv ) with color doppler flow mapping . 3vtv = 3 vessel trachea view , ao arch = aortic arch , duct art . dilated svc due to the drainage of the common venous confluence through a narrow opening . cc = common venous confluence , ivc = inferior vena cava , ra = right atrium , svc = superior vena cava . at 38 weeks of gestation , a male neonate was born in a tertiary cardiovascular center by cesarean section due to cephalous - pelvic disproportion . his birth weight was 3700  g , length was 57  cm , and head girth was 34  cm . the apgar score at 1 and 5 minutes after birth was 8 and 9 , respectively . he presented cyanosis , with tachypnea , a respiratory rate of 60 to 70  breath / min , suprasternal and subcostal retractions . this revealed an enlarged right heart ( atrium and ventricle ) and ostium secundum type atrial septal defect of 6  mm , with right - to - left shunt . the 4 pulmonary veins drained into a common confluence localized behind the left atrium , which opened directly into the right svc , without an ascending vertical vein . the color flow mapping of the confluence opening into the right svc showed a critical obstruction ( fig . pulsed doppler evaluation of the pulmonary venous confluence opening into the superior vena cava showed a maximal velocity of 21  cm / s and maximal gradient of 18 mm hg , suggesting obstruction at that level ( fig . a computer tomography angiography was performed , which revealed similar findings ( figs . 7 and 8) . postnatal echocardiography . ( b ) color - doppler flow mapping of the confluence opening into the right svc showed a high turbulence suggestive for critical obstruction . 2d = bi - dimensional , ao = aorta , cc = common venous confluence , pa = pulmonary artery , svc = superior vena cava . pulsed doppler evaluation of the pulmonary venous confluence opening into the svc showed a maximal velocity of 21  cm / s and maximal gradient of 18 mm hg , suggesting obstruction at that level . common confluence of the 4 pulmonary veins , opening directly into the right svc : angioct = computer tomography angiography , cc = common venous confluence , svc = superior vena cava , v = pulmonary veins ,  drainage site of the common venous confluence into the svc . common pulmonary venous confluence opening into the right svc : angioct = computer tomography angiography , cc = common pulmonary venous confluence , svc = superior vena cava ,  drainage site of the common venous confluence into the svc . the neonate underwent an emergency open heart surgery by performing a side - to - side anastomosis between the pulmonary venous confluence and left atrium . the postoperative recovery was complicated by pulmonary arterial hypertension , right ventricular myocardial dysfunction with hemodynamic failure , and unfortunately the newborn died 3 days after surgery . anomalous connection of the pulmonary venous confluence directly to the right svc , especially the obstructed form is an unusual supracardiac variant . in a retrospective , collaborative study involving 19 pediatric cardiac centers from the united kingdom , ireland , and sweden the incidence of tapvc was about 7.1/100.000 live births . this incidence is higher compared to 6.8 in the baltimore - washington infant study or 5.9 in the new england regional infant cardiac program . several studies have reported case series with prenatally diagnosed supracardiac tapvc , some of them with drainage direct into the right svc . this is the first case of prenatally diagnosed isolated , obstructed supracardiac tapvc with drainage directly into the right svc , identified by us in the literature . this fact can be explained by the particularities of the fetal pulmonary circulation : low pulmonary blood flow , due to high pulmonary vascular resistance . however , rasanen et al showed that during the pregnancy there is a slight increase of pulmonary blood flow compared with the combined cardiac output , from 13% at 20 weeks of gestation to 25% at 30 weeks of gestation , with no changes in the last semester . this pulmonary flow increase can explain the right - left ventricular discrepancy after 28 weeks of gestation . after postnatal transition , the pulmonary blood flow increases and as a result of systemic and pulmonary venous flow mixing in the right heart , the neonate will be cyanotic . prenatal diagnosis of isolated tapvc is challenging . some indirect and direct signs suggesting the prenatal diagnose of isolated supracardiac tapvc , the initial sign that can become obvious in the third trimester of pregnancy is the right ventricular predominance , with increase of pulmonary blood flow . another indirect sign detectable in 4-chamber view is a small left atrial size and  smooth  posterior aspect of it . dilation of the svc and detection of an additional vein ( vertical vein  in typical supracardiac tapvc ) in 3 vtv is helpful . low - flow color mapping in order to identify pulmonary veins could be helpful for diagnosis improvement . also , abnormal pulsed doppler flow in pulmonary veins can give important information . because of the low pulmonary blood flow in fetus , obstruction of the pulmonary venous confluence may be difficult to detect . a4c and 3vt view are of great importance and compulsory in diagnosing isolated supracardiac tapvc beside doppler color and pulsed doppler flow imaging of pulmonary veins . however , in our particular supracardiac tapvc case , there was no additional vessel in the 3 vtv , because of the direct drainage of the common pulmonary venous confluence into the right svc . we noticed a dilated right svc at the site of the pulmonary venous drainage in 3vtv , with a turbulent doppler color flow at that level . further careful assessment of the right svc allowed identification of the drainage site of the common confluence . recently , it was described a case of a 4-month - old infant without any pathological history , admitted for perioral cyanosis and poor feeding , who was diagnosed with tapvc , which was successfully repaired by surgical intervention . zhang et al in their study showed that comparing with surgical or angioct results , the postnatal echocardiography had a sensitivity of 97.6% and a specificity of 99.9% . unfortunately , even though we diagnosed our patient in utero , he died after surgery . on the other hand , a study performed on patients with mixed - type tapvc , underlined the fact that the mortality during the first year after surgery is high , but those who survive past the 1st year , usually present a good prognosis , without sequelae . tapvc can be associated with other cardiac malformations , such as in the case described by ide et al about a neonate diagnosed with a single ventricle , right atrial isomerism , pulmonary atresia with major aortopulmonary collateral arteries , a small central pulmonary artery and a supracardiac tapvc , who underwent an uneventful surgical repair . even though , complications after surgical repair , such as pulmonary arterial hypertension usually appear in the first 6 months after surgery , this can appear also later on life , like in the case described by martinez  quintana about a teenager who developed pulmonary venous obstruction and severe secondary pulmonary arterial hypertension after a surgical intervention for tapvc during infancy . in the case described above , severe pulmonary arterial hypertension appeared very quickly after the surgical intervention and led to the newborn 's death on the 3rd day after surgery . other rare cases involving tapvc were also reported in the specialty literature , such as the association between tetralogy of fallot with anomalous left coronary artery from pulmonary artery and totally anomalous pulmonary venous connection , or the coexistence of tapvc and persistent left superior vena cava . according to shi et al obstructed tapvc was discovered in 25% of newborns , the mean surgical age were about 215 days of life with 51 deaths of the 768 cases with different types of anomalous pulmonary venous connection . although our case had a severe obstructed form and unfortunately died after surgery , we can emphasize that a prenatal diagnosis of isolated , obstructed tapvc is important for adequate postnatal planning of delivery and surgery in a tertiary center . prenatal diagnosis of isolated obstructed supracardiac tapvr with drainage into the right svc is possible by careful assessment of direct and indirect signs .
abstractintroduction : 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 .