Obstructive total anomalous pulmonary venous drainage

Obstructive total anomalous pulmonary venous drainage (TAPVD) has a florid presentation in the neonatal period from the resulting pulmonary edema. A complete anatomical and functional diagnosis is usually possible by transthoracic color Doppler echocardiography, and cardiac catheterization with its attendant risks can usually be avoided in the sick neonate. Currently balloon atrial septostomy has a limited role in palliation of these neonates. Corrective surgery on urgent basis has gratifying results and prevents progression of pulmonary vascular occlusive disease. Pulmonary hypertensive crisis in the early post-operative course needs to be avoided and treated vigorously if it were to develop. Late post-operative course can be complicated by anastomotic obstruction or progressive narrowing of the individual pulmonary veins. Although the former can be dealt successfully by re-operation, surgical treatment of the latter is not satisfactory. Balloon dilatation of the obstructed pulmonary venous pathway, native and post-operative, has been reported with equivocal results. Infant heart-lung transplant is a viable option in patients with diffusely narrow pulmonary veins or complex TAPVDs.     

Progressive pulmonary venous obstruction and pulmonary interstitial fibrosis associated with tetralogy of Fallot

Summary Stenosis of individual pulmonary veins is a rare condition associated with a very high mortality. The present report is the first known case of progressive pulmonary venous obstruction associated with the tetralogy of Fallot. This clinical and anatomical study suggests that initial dynamic and possibly reversible occlusion occurs at the junction of the pulmonary vein and left atrium. Anatomical lesions in pulmonary veins then develop, possibly secondary to functional stenosis. The usually fatal outcome of these cases is due to the development of fixed pulmonary venous occlusion and possibly pulmonary interstitial fibrosis. The rapid progression of pulmonary venous stenosis strongly suggests that discrete veno-atrial stenosis should be surgically corrected as early as possible to prevent the irreversible diffuse pulmonary venous obstruction associated with an invariably fatal prognosis.     

Functional total anomalous pulmonary venous connection via levoatriocardinal vein

We report a fetal case of double outlet right ventricle, mitral atresia, and intact atrial septum. Although the pulmonary veins were connected to the left atrium, pulmonary venous blood drained into the right superior vena cava via the stenotic levoatriocardinal vein (LACV), which resulted in a circulation resembling total anomalous pulmonary venous connection (TAPVC) with pulmonary venous obstruction. Since the pulmonary veins were connected to both the stenotic LACV and the “dead‐end” left atrium, the pulmonary venous flow had a to‐and‐fro pattern along with atrial relaxation and contraction. Postnatal echocardiography and computed tomography confirmed the diagnosis of normally connected but anomalously draining pulmonary veins via the LACV. Surgical creation of an atrial septal defect on the day of birth successfully relieved pulmonary venous obstruction. Normally connected but anomalously draining pulmonary veins via the LACV should be considered for TAPVC differential diagnosis in fetuses with a left‐side heart obstruction.     

Common pulmonary vein atresia without anomalous pulmonary venous connection

Common pulmonary vein atresia without pulmonary venous connection is a rare form of congenital heart disease. No communication exists between the confluence of the pulmonary veins and the heart or a major systemic vessel. A case diagnosed antemortem is presented. Correct early diagnosis is imperative as surgery may be corrective.     

Contrast-enhanced MR angiography of pulmonary venous abnormalities in children

BACKGROUND: Echocardiography and X-ray angiography have been considered as gold standards for evaluation of pulmonary venous abnormalities. However, each technique has its own limitations, such as limitation in visualization of the pulmonary veins within the lungs by echocardiography, and the invasive nature of and use of ionizing radiation in X-ray angiography. Contrast-enhanced MR angiography (MRA) is a fast noninvasive method of visualization of the vessels including the pulmonary arteries and veins. OBJECTIVES: To evaluate the utility of contrast-enhanced MRA in the evaluation of pulmonary venous abnormalities in pediatric patients and to compare its diagnostic accuracy with that of transthoracic echocardiography. MATERIALS AND METHODS: In 30 pediatric patients 31 contrast-enhanced MRA studies were performed for evaluation of pulmonary venous abnormalities. Each of 124 pulmonary veins was evaluated for site of connection, course within the lung, presence of obstruction, and topographic relationship with the adjacent structures. The findings of MRA were compared with echocardiographic findings for 116 veins in 29 studies in 28 patients. RESULTS: Contrast-enhanced MRA visualized 99% (123 of 124) of the pulmonary veins investigated, while echocardiography visualized 89% (103 of 116). Exact agreement was found between the two methods in 72% of the veins with a weighted kappa of 0.60 (0.47-0.73, 95% CI). Echocardiography failed to diagnose an abnormal connection in 2 of 15 pulmonary veins, a discrete stenosis in 2 of 19 veins, and diffuse hypoplasia in 10 of 14 veins. In 29% of patients, MRA made the uncertain echocardiographic findings clear. In another 29%, MRA provided a new diagnosis. CONCLUSIONS: Contrast-enhanced MRA is a powerful, safe, and accurate fast-imaging technique for the anatomical evaluation of pulmonary venous abnormalities. MRA may obviate the need for conventional X-ray angiography. Cardiac catheterization may be reserved for those patients in whom pulmonary vascular resistance needs to be determined.     

Successful balloon dilatation of ascending vein stenosis in obstructed supracardiac total anomalous pulmonary venous connection

Summary A newborn infant presenting with severe hypoxia and pulmonary edema was found to have supracardiac total anomalous pulmonary venous connection (TAPVC). There was a severe localized stenosis (gradient >30 mmHg) of the vein ascending from the pulmonary venous confluence. Balloon dilatation of the stenosis provided immediate and effective relief of the obstruction (gradient 4 mmHg) until surgery was performed. In sick neonates with discretely obstructed anomalous pulmonary venous connection, short-term hemodynamic stability may be achieved by balloon angioplasty of the site of obstruction.     

Radiological evaluation of pulmonary vein obstruction including two examinations by magnetic resonance imaging

Congenital obstruction of the pulmonary vein without anomalous drainage can cause long-standing pulmonary congestion and pulmonary arterial hypertension, and it may include stenosis of individual pulmonary veins and pulmonary vein atresia. We reviewed seven cases of pulmonary vein obstruction, five of which were accompanied by other cardiac anomalies. Right pulmonary veins were involved in all seven cases; one case was bilateral. Pulmonary veins were occluded totally in five and partially in three lungs. Diagnostic pulmonary catheterization and angiography were performed. Chest radiographs of total occlusion cases showed decreased lung volume, features of pulmonary edema, interstitial lesions, and pleural changes, which were quite specific, whereas pulmonary venous dilatation was the dominant finding in partial obstruction cases. Pulmonary perfusion scan (n=3) showed total perfusion defects in the cases with total occlusion of pulmonary veins. Magnetic resonance (MR) imaging (n=2) demonstrated totally occluded pulmonary veins at the venoatrial junction in two lungs and membranous focal obstruction in one lung. Two children underwent pneumonectomy and had the diagnosis histologically confirmed. Although catheterization and angiography are essential for the diagnosis of pulmonary vein obstruction, MR imaging is a useful adjunct.     

完全性肺静脉异位引流病理谱及个体化手术治疗

目的 描绘完全性肺静脉异位引流(TAPVC)患儿肺静脉走行"路线图"和形态"变异图",阐明肺静脉病理谱的变化规律,促进有效个体化手术.方法 2006年4月至2009年9月,139例TAPVC患儿进行手术,心上型61例,心内型55例,心下型6例和混合型17例.病理诊断依据超声心动图、核磁共振、计算机断层扫描或心导管和心血管造影检查以及术中解剖,根据患儿TAPVC类型和解剖特点选择个体化手术方法.结果 1.病理谱:①肺静脉走行连接"路线图":心上型按照垂直静脉(VV)走行方式分为4种,左行(47例)、右行(9例)、后行(2例)和双行(3例);心内型按照肺静脉回流部位分为3种,汇入冠状静脉窦(49例)、汇入右心房(5例)和同时汇人CS和右心房(1例),再依据肺静脉开口数目分为4个开口、2个开口和1个开口三种亚型;心下型按照VV汇入体静脉方式分为4种:汇入门静脉(1例)、肝静脉(3例)、同时汇入门静脉和肝静脉(1例)以及汇入下腔静脉(1例);混合型按照肺静脉回流双侧是否对称分为双侧对称连接的"2+2"型(5例)、双侧不对称连接的"3+1"型(10例)和"怪异型"(2例).②肺静脉形态"变异图":肺静脉入口狭窄、发育不良或多分支(11例)、共汇肺静脉发育不良或伴内膜增生(4例)、VV扭曲、短小和狭窄(9例).2.手术结果:本组早期死亡6例(4.3%),其中低心排1例,肺静脉梗阻5例.中期随访因肺静脉梗阻再手术6例,术后轻微梗阻2例.结论 TAPVC患儿肺静脉病理谱广,个体差异大;按照肺静脉走行"路线图"和形态"变异图"有利术中肺静脉解剖的探查和个体化手术设计.

Abstract：

Objective To delineate the morphological spectrum of total anomalous pulmonary venous connection (TAPVC) by building the "road map" and the " variation chart" of pulmonary veins,and to advance individualized surgical treatment Methods Between April,2006 to June,2009, 139 consecutive patients with TAPVC underwent operations. There were 61 supracardiac,55 intracardiac,6 infracardiac and 17 mixed types. Pathological diagnosis was made by echocardiogram,magnetic resonance imaging, computerized tomography,or the cardiac catheterization and operative findings during operation. The option of procedure was determined by findings. Results (1) Pathological spectrum:①" the road map"of the pulmonary veins: the patients with supracardiac type were divided into 4 subtypes according to the course of vertical veins:left course (47 cases),right course (9 cases),posterior course(2 cases) and double courses (3 cases). The patients with intracardiac type were divided into 3 subtypes according to the draining site of pulmonary veins: to coronary sinus (49 cases) ,to right atrium (5 cases) or to coronary sinus and right atrium (1 case),and the openings of pulmonary veins may be 4,2 or 1 in each subtype. The patients with infracardiac type were divided into 4 subtypes according to the draining site of vertical vein:to portal vein (1 case),to hepatic vein(3 cases),to portal vein and hepatic vein (1 case) and to inferior vena cava (1 cases). The patients with mixed type were divided into 3 subtypes: bilateral and symmetrical connections "2 + 2" pulmonary venous drainage pattern; bilateral and asymmetrical connections"3 +1" pulmonary venous drainage pattern and bizarre anatomic variants. ② The morphological "variation chart" of pulmonary veins individual pulmonary vein stenosis or excessive tributary veins (11 cases) showed: hypoplastic confluence veins (4 cases) and vertical veins distortion or elongation or forming hemodynamic vise or common pulmonary vein that drained to coronary sinus or right atrium through a narrowed short vertical vein or a small window(9cases).(2)Surgical results：early death was encountered in 6 cases(4.3％).The causes included 10W cardiac output syndrome in 1 case,and pulmonary veins stenosis and associated complications in the other 5 patients.Six patients with pulmonary restenosis underwent reoperation.All survived.Two patients had mild residual obstruction during Intermediate-term follow-up.Conclusions The patients with TAPVC had a wide spectrum of pulmonary veins with high inter-individual variation.It was useful to delineate the anatomy of pulmonary veins and to plan personalized procedures during operations according to the"road map"and"variation chart"of pulmonary veins.     

Acute pulmonary edema in a newborn with infracardiac type total anomalous pulmonary venous return and surgical repair

Total anomalous pulmonary venous return (TAPVR) is a rare congenital pathology. Early diagnosis and urgent surgery are life-saving, especially in newborns with pulmonary venous obstruction, which is most commonly seen with infracardiac type. A three-day-old baby boy presented to another clinic with tachypnea and cyanosis. Initial work-up aimed at ruling out persistant pulmonary hypertension, respiratory distress syndrome and pneumonia. Acute pulmonary edema then developed, and on echocardiography obstructive type infracardiac TAPVR was suspected. Cardiac catheterization was done for definitive diagnosis. Urgent surgery was undertaken and pulmonary veins were anastomozed to left atrium with posterior approach. Patient was extubated at 10th day and discharged after three weeks. During one-year follow-up the patient was free of symptoms. Infracardiac type TAPVR is a rare pathology in which early diagnosis and urgent surgery with special postoperative case are mandatory for survival.     

Obstructed total anomalous pulmonary venous connection

Summary With the advent of echocardiography, total anomalous pulmonary venous connection (TAPVC) can be readily diagnosed without much difficulty. However, noninvasive detection of the presence of pulmonary venous obstruction in TAPVC remains a difficult issue. During a 5.5-year period, 42 patients were found to have TAPVC by catheterization, surgery, and/or autopsy: 17 had supracardiac drainage, 13 paracardiac drainage, nine infracardiac drain-age, and three mixed drainage. Obstruction to pulmonary venous drainage was found in 24 patients (57%). Patients with right isomerism tended to have a higher incidence of pulmonary venous obstruction than those with the usual atrial arrangement (80% vs. 44%,p<0.05). Color Doppler combined with cross-sectional echocardiography provided accurate delineation of drainage sites in 93% cases (39 of 42). Among the 39 cases with correct echocardiographic delineation of the drainage site, obstruction was detected by echocardiography in 22 cases with a sensitivity of 100% (22 of 22) and a specificity of 85% (17 of 20). Therefore, complete echocardiography, including cross-sectional images and color Doppler proved to be a reliable tool in the detection of drainage sites and pulmonary venous obstruction in TAPVC.     

Phase-contrast MR assessment of pulmonary venous blood flow in children with surgically repaired pulmonary veins

Background Pulmonary venous (PV) obstruction may complicate surgical repair of PV abnormalities. By combining phase-contrast cine (PC) imaging and contrast-enhanced angiography, magnetic resonance (MR) imaging can provide physiological information complementing anatomical diagnosis.Objectives To compare the PV flow pattern observed after surgical repair of PV abnormalities with normal PV flow pattern and to investigate the changes occurring in the presence of PV stenosis by using PC MR in children.Materials and methods By using PC MR, PV flow was evaluated in 14 patients (3 months-14 years) who underwent surgical repair for PV abnormalities. Eleven children (8–18 years) were studied as normal controls. Peak flow velocities and patterns were compared among three groups: normal veins (n=23), surgically repaired veins without (n=44) and with stenosis (n=10).Results Normal and unobstructed pulmonary veins after surgery showed a biphasic or triphasic flow pattern with one or two systolic peaks and a diastolic peak. Unobstructed surgically repaired veins showed decreased peak systolic velocity (P =0.001) and an increased peak diastolic velocity (P=0.005) when compared to normal values. Obstructed veins showed decreased systolic and diastolic velocities when measured upstream from the stenosis.Conclusion PC MR shows different flow patterns among normal, surgically repaired pulmonary veins with and without stenosis.     

Pulmonary venous collaterals secondary to superior vena cava stenosis: A rare cause of right-to-left shunting following repair of a sinus venosus atrial septal defect

Summary We describe a case of unusual pulmonary vein-to-vein collateral formation leading to systemic desaturation years following surgical repair of a sinus venosus atrial septal defect and partial anomalous pulmonary venous return from the right lung. At surgery, a single right upper lobe pulmonary vein branch was left draining high into the superior vena cava (SVC), resulting in a small left-to-right shunt. SVC obstruction developed at the site of the ASD repair and elevated venous pressure above the obstruction caused retrograde flow into the unincorporated pulmonary vein. Pulmonary vein-to-vein collaterals formed between this unincorporated vein and an adjacent pulmonary vein that had been surgically diverted to drain into the left atrium, resulting in a right-to-left shunt within the right lung. Normal pulmonary veins drain multiple bronchopulmonary segments, thus providing potential collateral pathways. Balloon angioplasty of the SVC stenosis successfully relieved the obstruction and abolished the right-to-left intrapulmonary shunt.     

Role of plain radiography and CT angiography in the evaluation of obstructed total anomalous pulmonary venous connection

Background

Obstructed total anomalous pulmonary venous connection (TAPVC) is frequently misdiagnosed as pulmonary disease and without operative correction early death is common. It is important to make a correct diagnosis before surgery.

Objective

The purpose of this study was to describe the chest radiographic features of obstructed TAPVC and compare CT angiography with transthoracic echocardiography in the evaluation of obstructed TAPVC.

Materials and methods

Eighteen children with obstructed TAPVC were assessed. Their clinical and imaging data were retrospectively reviewed. The characteristic radiographic findings were analyzed and compared with surgical results, and the diagnostic accuracy of CT angiography and transthoracic echocardiography was evaluated in terms of pulmonary venous drainage and obstruction detection.

Results

The common radiographic features included pulmonary venous congestion or edema or both (16 of 18 cases, 89%), and absence of cardiomegaly (12 of 18 cases, 67%). CT angiography correctly diagnosed TAPVC and clearly revealed the draining sites in all children (five with supracardiac TAPVC, three with cardiac TAPVC, eight with infracardiac TAPVC and two with mixed TAPVC). The diagnostic agreement between CT angiography and surgery was 100%. Transthoracic echocardiography only correctly revealed the draining sites in 11 children (5 with supracardiac TAPVC, 2 with cardiac TAPVC and 4 with infracardiac TAPVC). The diagnostic agreement between transthoracic echocardiography and surgery was 61%. The diagnostic accuracy of CT angiography was higher than that of transthoracic echocardiography (P?=?0.0156). Thirty-four sites of obstruction were correctly detected by CT angiography (11 in the mediastinum, 1 at the diaphragmatic level, 9 below the diaphragm and 13 stenotic individual pulmonary veins in the lung). The diagnostic agreement between CT angiography and surgery was 92%. Transthoracic echocardiography only correctly detected 15 sites of obstruction (11 in the mediastinum, 1 at the diaphragmatic level and 3 below the diaphragm). The diagnostic agreement between transthoracic echocardiography and surgery was 41%. The rate of detection for sites of obstruction with transthoracic echocardiography was much lower than that of CT angiography (P?=?0.0002).

Conclusion

In children with obstructed TAPVC, plain radiographs usually show a characteristic pattern of pulmonary venous congestion or edema, or both, and a normal cardiac silhouette. CT angiography is superior to transthoracic echocardiography in the evaluation of pulmonary venous drainage and obstruction, especially in children with infracardiac and mixed TAPVC.     

RARE VARIANT OF TOTAL ANOMALOUS PULMONARY VENOUS CONNECTION: Intrapulmonary Drainage of One Lung by the Other- A Case Report and Review of the Literature

Total anomalous pulmonary venous connection is an uncommon congenital cardiovascular anomaly but one that occurs frequently in the asplenia syndrome. We present a rare type of total anomalous pulmonary venous connection in a 4-month-old baby with the asplenia syndrome. In this patient, all of the left pulmonary veins united to form a common pulmonary vein, which crossed the mediastinum and then proceeded in an intrapulmonary fashion in the right lung. A small pulmonary vein emerged from the right upper lobe and drained into the right superior vena cava. Nine other cases have been reported, four also with asplenia, five with otherwise normal cardiac anatomy apart from an atrial septal defect. The incidence of pulmonary venous obstruction is high, at least 70 . Two cases, both with a normal heart, had corrective surgery. One with no pulmonary venous obstruction was repaired successfully. Embryologically, this type of total anomalous pulmonary venous connection represents a developmental error early in embryonic development before the venous connection between the two lungs and the cardinal veins involute.     

Congenital pulmonary vein stenosis as a rare cause of pulmonary hypertension]

We report on the history, the diagnostic, and the operative procedure in an infant with congenital stenosis of all pulmonary veins. First symptoms such as failure to thrive, tachydyspnea, tachycardia and hepatomegaly occurred in the eighth week of life. Electrocardiography, 2-dimensional echocardiography and radiography of the chest were unspecific. After recurrent episodes of pulmonary oedema cardiac catheterization was performed: bilaterally elevated pulmonary artery wedge pressure and a normal left atrial pressure proved pulmonary venous obstruction. Severe stenosis of all pulmonary veins was apparent cineangiographically only by selective injections into the right and left pulmonary artery branches in wedge position. The operation (excision of the stenotic area and reimplantation using autologous pericardium) was unsuccessful as in most cases described in the literature. Congenital stenosis of all pulmonary veins is a rapidly progressive malformation. Death occurs usually in the first year of life with and without operation.     

Late pulmonary venous obstruction after surgical repair of infradiaphragmatic total anomalous pulmonary venous return

Summary Twelve years after an apparently successful surgical correction of infradiaphragmatic (obstructed) total anomalous pulmonary venous drainage, a 12-year-old boy developed evidence of pulmonary artery hypertension secondary to pulmonary venous obstruction due to an apparent lack of growth at the anastomotic site.     

The value of early repair for total anomalous pulmonary venous drainage

Summary A total of 20 children with total anomalous pulmonary venous drainage (TAPVD) underwent complete repair within the past six years. The drainage was supracardiac in 11, infracardiac in seven, and into the coronary sinus in two. At repair mean age was nine weeks, and weight was 3.7 km. Operative technique in extracardiac types included complete mobilization of the common vein with division of anomalous channel when possible. The incision in the confluent vein was extended into the lobar veins when necessary to permit extensive incorporation of this structure into the posterior wall of the left atrium and resulted in a nonobstructing stellate-type anastomosis.Operative mortality was 10% (2 of 20). Deaths occurred only in the group of infants in whom severe obstruction to pulmonary venous return required emergency operation, and one of these patients has persistent neurologic deficit. Late cardiac catheterization has been performed in 11 of 18 survivors. Nine had no or only minor abnormalities and two required reoperation. There have been no late deaths with follow-up of 2–8 years (mean=4 years). Currently, all of the survivors are without cardiac symptoms and only one requires cardiac medication.Our experience identifies pulmonary venous obstruction with critical symptoms as the major operative risk factor in patients with TAPVD. With early operation prior to onset of critical symptoms, mortality is low and functional results are excellent.     

Pulsed wave and color doppler findings in congenital pulmonary vein stenosis

Summary A premature infant presented at 8 weeks of age with respiratory failure and pulmonary hypertension. Two-dimensional echocardiography was not diagnostic but color flow imaging and pulsed Doppler examination revealed turbulent and continuous pulmonary venous flow. Differing patterns of disturbed flow suggested varying severity of obstruction in individual pulmonary veins. The Doppler findings are compared to the angiographic and autopsy data.     

Fate of the unligated vertical vein after repair of supracardiac anomalous pulmonary venous connection

OBJECTIVE: To determine the fate of the unligated vertical vein after repair of isolated supracardiac total anomalous pulmonary venous connection (TAPVC). METHODS: We reviewed the outcome of 28 patients who were diagnosed to have isolated supracardiac TAPVC and determined the fate of the unligated vertical vein. RESULTS: Of the 28 patients, four died before surgery. The remaining 24 patients underwent surgical correction of TAPVC with (n = 5) or without (n = 19) ligation of vertical vein at a median age of 20 days (range: 1-574 days). There were no significant differences in age, weight, presence of pulmonary venous obstruction, need for preoperative inotropic and ventilatory support, cardiopulmonary bypass duration, postoperative pulmonary hypertensive crisis and requirement of peritoneal dialysis between patients with and those without vertical vein ligation. The in-hospital surgical mortality was 50% (12/24), with 83% (10/12) of deaths occurring before 1990. Patients who died after surgery were significantly younger (median age: 5.5 days vs 37 days, P = 0.005), lighter (3.3 +/- 0.5 kg vs 3.9 +/- 0.6 kg, P = 0.016), more likely to have pulmonary venous obstruction preoperatively (75% vs 12%, P = 0.039) and have undergone surgery before 1990 (83% vs 33%, P = 0.036). The 12 survivors were followed up for a median of 4.7 years (range: 2.3-18.1 years), 10 of whom had their vertical vein unligated. The vertical vein remained patent in five (50%) patients, while stenosis of pulmonary venous anastomosis was only present in one patient. Of these five patients, three had subsequently undergone surgical ligation of the vertical vein to eliminate a large left-to-right shunt. CONCLUSIONS: Patency of the unligated vertical vein is common after the repair of supracardiac TAPVC, even in the absence of pulmonary venous obstruction. The degree of left-to-right shunt through the patent vertical vein may be so significant as to warrant surgical ligation.     

Paediatric pulmonary vascular disease

Pulmonary vascular disease comprises any congenital or acquired pathology of the intrinsic pulmonary vessels with the unique feature of pulmonary arteries carrying unsaturated blood and pulmonary veins carrying oxygenated blood. Pulmonary hypertension (PH) ensues when pulmonary vascular disease affects at least 50% of the capillary resistance vessels, i.e. pulmonary pre-acinar and intra-acinar arteries (so-called pre-capillary PH), or when pressure in the pulmonary venous system distal to the capillaries rises above a mean of 15 mmHg (so-called post-capillary PH). PH is defined by a mean pulmonary arterial pressure above 25 mmHg at rest. Vasoconstriction, remodelling and thrombosis of small pulmonary arteries lead to an increase in pulmonary vascular resistance. The consequence is failure of the afterload-intolerant right ventricle. In this review, pulmonary vascular disease in children will be addressed according to the 2003 World Health Organisation (Venice) classification of PH.