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Pediatrics: Cardiac Disease and Critical Care Medicine > Cardiology
Partial Anomalous Pulmonary Venous Connection
Article Last Updated: Nov 6, 2006
AUTHOR AND EDITOR INFORMATION
Section 1 of 9  
Author: Monesha Gupta, MD, MBBS, FAAP, FACC, Assistant Professor, Division of Pediatric Pediatric Cardiology, University of Texas Medical School, Children's Memorial Hermann Hospital
Monesha Gupta is a member of the following medical societies: American Academy of Pediatrics, American College of Cardiology, American Society of Echocardiography, Medical Council of India, and Society of Pediatric Echocardiography
Coauthor(s):
David J Vaughan, MBBCh, Consultant Pediatrician, Department of Pediatrics, Our Lady of Lourdes Hospital, Ireland;
Jerry Zimmerman, MD, PhD, Professor, Department of Pediatrics/Anesthesia, University of Washington School of Medicine; Director, Division of Pediatric Critical Care Medicine, Children's Hospital of Seattle;
Ronald G Grifka, MD, Professor of Pediatrics, Michigan State University College of Human Medicine; Chief, Cardiology Division, DeVos Children's Hospital
Editors: Ira H Gessner, MD, Professor Emeritus, Pediatric Cardiology; Mary L Windle, PharmD, Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy, Pharmacy Editor, eMedicine.com, Inc; Hugh D Allen, MD, Professor, Department of Pediatrics, Division of Pediatric Cardiology and Department of Internal Medicine, Ohio State University College of Medicine; Gilbert Herzberg, MD, Assistant Professor, Department of Pediatrics, Section of Pediatric Cardiology, New York Medical College; Stuart Berger, MD, Professor of Pediatrics, Division of Cardiology, Medical College of Wisconsin; Chief of Pediatric Cardiology, Medical Director of Pediatric Heart Transplant Program, Medical Director of The Heart Center, Children's Hospital of Wisconsin
Author and Editor Disclosure
Synonyms and related keywords:
partial anomalous pulmonary venous connection, intact atrial septum, PAPVC, isolated partial anomalous pulmonary venous connection, total anomalous pulmonary venous connection, TAPVC, sinus venosus atrial septal defect, ASD
Background
Partial anomalous pulmonary venous connection (PAPVC) with intact atrial septum is a rare congenital cardiac defect. As the name suggests, in PAPVC, a few of the pulmonary veins return to the right atrium instead of the left atrium. Thus, some of the pulmonary venous flow enters the systemic venous circulation.
Embryologically, PAPVC is similar to total anomalous pulmonary venous connection (TAPVC); however, these conditions differ in that all pulmonary venous vessels connect to the right side of the heart in TAPVC.
Anatomically, PAPVC can involve a wide variety of connections, and PAPVC from the right lung is twice as common as PAPVC from the left lung. The most common form of PAPVC is one in which a right upper pulmonary vein connects to the right atrium or the superior vena cava (SVC). This form is almost always associated with a sinus venosus type of atrial septal defect (ASD).
The right pulmonary veins can also drain into the inferior vena cava. The left pulmonary veins can drain into the innominate vein, the coronary sinus, and, rarely, the cavae, right atrium, or left subclavian vein.
Pathophysiology
A number of factors determine the ratio of pulmonary blood flow (Qp) to systemic flow (Qs). The shunt magnitude, expressed as the Qp/Qs ratio, and other factors determine development of symptoms and complications.
The most important factor is the number of pulmonary veins that drain into the systemic circulation. The more veins that anomalously drain, the more blood returns to the right side of the heart. Some authors have suggested that this defect becomes clinically significant when 50% or more of the pulmonary veins anomalously return.
In addition, the source of the returning blood plays a role in determining the clinical effect of the defect. In an individual who is upright, blood flow to the lungs is primarily directed to the lower and middle lobes. Therefore, more blood returns to the systemic venous circulation in individuals in whom the anomalous connection drains into either the right middle and lower lobes or the left lower lobe of the lung.
An associated cardiac defect, such as an ASD, may either exacerbate or alleviate disease progression.
An associated noncardiac condition (eg, scimitar syndrome) may influence disease development. Scimitar syndrome, or pulmonary venolobar syndrome, is characterized by abnormal right-sided pulmonary venous drainage in the inferior vena cava and malformation and/or hypoplasia of the right lung, with abnormal arterial supply of the right lung.
Over many years, excessive pulmonary venous return to the right side of the heart causes right atrial and ventricular dilation. This has a number of consequences, including risk of arrhythmia development, right-sided heart failure, and, rarely, development of pulmonary hypertension.
Frequency
United States
Most data regarding prevalence of this condition have been garnered from autopsy series that estimate an incidence of 0.4-0.7%. However, autopsy series may overestimate the clinical significance of this condition, as many of these cases were asymptomatic; thus, the true incidence of patients who present antemortem with this condition is lower. Clinical diagnosis of isolated PAPVC is quite rare. PAPVC occurs in approximately 10% of patients with a proven ASD.
Mortality/Morbidity
Few data are available regarding mortality due to this lesion because mortality credited to the defect occurs only in adults and the diagnosis has historically been made at autopsy. Major morbidity, including arrhythmias, right-sided cardiac failure, and, rarely, pulmonary vascular disease, also primarily occurs in adults.
Race
No data exist regarding racial predilection.
Sex
No data are available regarding sexual predilection.
Age
PAPVC is a congenital defect. Clinical evidence of this congenital defect may not be apparent until the patient reaches middle age.
History
Children with partial anomalous pulmonary venous connection (PAPVC) usually remain asymptomatic and are referred based on an incidentally noted cardiac murmur. Symptoms may occur in older patients and may be secondary to right-sided volume overload or pulmonary vascular obstructive disease.
Determining the natural history of this condition was difficult before the era of direct cardiac imaging (ie, echocardiography, cardiac catheterization), as the diagnosis was made only postmortem.
The development of complications from PAPVC clearly depends on how many pulmonary veins abnormally return to the right heart. A single anomalous vein is usually not hemodynamically significant and, hence, does not produce any symptoms.
About 10% of patients with an ASD also have PAPVC and may have symptoms of right-sided overload.
- Dyspnea may occur in adults but is rare in children. A child may experience exercise intolerance as a symptom in cases in which more than 50% of pulmonary veins anomalously drain.
- Palpitations may reflect cardiac arrhythmias, which are almost always supraventricular in origin, but this is rare in childhood.
- Hemoptysis is a rare symptom that reflects either chest infection or the development of pulmonary vascular disease.
- Chest pain may be evidence of right heart ischemia but does not occur in childhood. More commonly, chest pain may be a manifestation of recurrent bronchitis.
- Associated defects (either cardiac or extracardiac) can produce symptoms.
- Peripheral edema can occur in adults with cardiac failure.
Physical
Physical examination findings are usually more revealing than the history, but positive findings depend on the volume of abnormal pulmonary venous return to the right heart. If only a single vein is anomalous, the physical examination findings may be normal. In a patient with a larger volume of abnormal veins, physical examination findings are similar to those of an uncomplicated ASD. These findings include the following:
- Left parasternal lift reflects right ventricular dilation. Impulse in the second left intercostal space reflects pulmonary artery dilation.
- A soft systolic ejection murmur is heard over the pulmonary area, reflecting turbulence in the pulmonary trunk due to increased right ventricular ejection volume. The second heart sound is always widely split but may have normal respiratory variation.
- In healthy individuals, inspiration increases systemic venous return to the right heart, causing a delay in the pulmonic closure component of the second sound. This phenomenon also occurs in patients with PAPVC who have an intact atrial septum. However, in patients with PAPVC and ASD, volume flow into the right heart is always increased, and respiration further augments that flow. Therefore, splitting of S2 proceeds from wide during expiration to wider during inspiration. This does not occur in patients with a significant ASD, in whom second heart spitting is wide and fixed. In the presence of an ASD, variations in systemic venous return during respiration are counterbalanced by reciprocal changes in flow through the ASD, maintaining total right ventricular flow more or less constant. A mid-diastolic murmur due to increased transtricuspid right ventricular filling may be heard over the tricuspid valve area at the lower left sternal border.
- Cyanosis does not occur, even in older patients in whom pulmonary hypertension develops, as a right-to-left shunt cannot develop in the absence of an atrial septal communication.
- Right-sided heart failure signs in adults include hepatomegaly, jugular venous distension, ascites, and peripheral edema.
- Pulmonary vascular disease may occur in older adults, although this is rare. Clinical signs of pulmonary hypertension include a right ventricular parasternal lift, absence of systolic murmur, narrowly split S2 with a loud pulmonic component, and, occasionally, an early, high-frequency murmur of pulmonic regurgitation. Cyanosis does not occur in the presence of an intact atrial septum.
Causes
No causes of this condition are known. No evidence has implicated common teratogens (eg, drugs, infections) in the genesis of PAPVC. No evidence for a genetic predisposition has been reported.
Atrial Septal Defect, Coronary Sinus
Atrial Septal Defect, Ostium Primum
Atrial Septal Defect, Ostium Secundum
Atrial Septal Defect, Patent Foramen Ovale
Atrial Septal Defect, Sinus Venosus
Total Anomalous Pulmonary Venous Connection
Ventricular Septal Defect, Muscular
Ventricular Septal Defect, Perimembranous
Ventricular Septal Defect, Supracristal
Imaging Studies
- Chest radiography
- Cardiomegaly noted on a chest radiograph may be the initial reason for referral of a child with partial anomalous pulmonary venous connection (PAPVC). Other findings may include a dilated main pulmonary artery and increased pulmonary arterial vascular markings. However, chest radiographic findings may be grossly normal.
- Anomalous connection of one or more veins from the left lung into a left vertical vein that drains into the left innominate vein can create widening of the left upper mediastinal shadow. Rarely, the increased flow volume may also be sufficient to dilate the SVC, widening the upper right mediastinal shadow. This can simulate the so-called "snowman" heart shape described in total anomalous pulmonary venous return to a left vertical vein.
- Scimitar syndrome, in its classic appearance, involves an anomalous vein that drains into the right lung and connects to the inferior vena cava at the diaphragmatic level. It is associated with an aberrant heart position, right lung hypoplasia, and an abnormal artery that supplies the right lung and arises from the descending aorta.
- Echocardiography
- PAPVC has been diagnosed in utero. In children, echocardiography is the study of choice.
- In most patients, transthoracic echocardiography can be performed to diagnose PAPVC and obviate the need for cardiac catheterization. A high index of suspicion for the presence of the lesion is helpful to properly diagnose the condition.
- In adults, contrast echocardiography can help with the diagnosis. Agitated saline in a left arm vein can demonstrate a negative contrast in the innominate vein at the side of the anomalous venous drainage from a left pulmonary vein.
- Transesophageal echocardiography is performed for better delineation of the veins, as well, especially in the adult population.
- Right ventricular dilation may be the first observation that indicates the presence of abnormal venous drainage. The sonographer must identify all 4 pulmonary veins and visualize their connections to the heart. The atrial septum also needs to be evaluated for defects.
- Magnetic resonance imaging
- MRI is rapidly becoming the procedure of choice for further investigation of PAPVC. While echocardiography findings suggest the PAPVC, all the pulmonary veins may not be identified, especially in adults. With refinements in technology rapidly improving the quality of images obtained, fewer children require invasive angiography. Cardiac catheterization may be a more preferable diagnostic tool in infants with complex congenital heart conditions in whom PAPVC is one component.
- Julsrud and Ehman (1985) reported that use of MRI in the imaging of PAPVC demonstrated a characteristic sign termed the "broken ring sign." In individuals with normal anatomy, a transverse MRI demonstrates a ringlike structure derived from mediastinal fat that surrounds the SVC. In healthy individuals, this ring is broken only at the point of entry of the azygous vein into the SVC. In some patients with partial anomalous pulmonary venous return, the ring of fat also appears to be breached or broken at the site of entry of the anomalous vein.
- Computed tomography: Contrast-enhanced CT is an alternative imaging modality to detect PAPVC when transthoracic images are limited, especially in older children and adults.
Other Tests
- Electrocardiography
- Electrocardiogram (ECG) findings may be normal. They may demonstrate right ventricular dilation manifested by an rSR pattern in right chest leads or right ventricular hypertrophy.
- Arrhythmias, typically atrial flutter and fibrillation, may be observed in older adult patients.
Procedures
- Cardiac catheterization is rarely necessary for precise anatomic diagnosis and hemodynamic evaluation.
- Right heart pressures are normal in the pediatric patient.
- Oxygen sampling may identify the location of an anomalous vein. Oxygen saturation in the right atrium that is higher than that found in the SVC strongly indicates PAPVC to the right atrium, provided that an ASD has been ruled out.
- Entering the anomalous vein with a catheter and injecting contrast confirms the diagnosis.
- Selective right and left pulmonary artery angiography that reveals pulmonary venous return for each lobe from each lung provides definitive anatomic diagnosis.
- Complications of catheterization include bleeding at the vascular entry site, infection, decreased pulses distal to an arterial entry site, and arrhythmia induction.
Medical Care
Medical therapy is not indicated for asymptomatic patients. Heart failure in adults can be managed with diuretics, cardiac glycosides, afterload reduction, and beta blockade. Arrhythmias should be treated appropriately.
Surgical Care
Definitive treatment for partial anomalous pulmonary venous connection (PAPVC) is surgical repair. Indications for surgical repair are controversial.
One school of thought claims that all children should undergo repair because of the exceptionally low morbidity and mortality following this surgical procedure. Others suggest that appropriate criteria include a significant left-to-right shunt, such as an entire lung that anomalously drains, before recommending surgery.
Operative technique depends on the site of the anomalous vein or veins. The usual approach is a midline sternotomy and cardiopulmonary bypass. Surgical treatment of associated lesions may be necessary.
For the PAPVC to the SVC, the repair techniques may include internal patch technique, with or without SVC enlargement, or the caval division technique with atriocaval anastomosis (Warden technique). Children with internal patch technique must be observed for obstruction of the SVC with SVC syndrome, sick sinus syndrome, obstruction of the pulmonary veins, and supraventricular tachyarrhythmias.
Consultations
- Cardiologist
- Cardiothoracic surgeon
Diet
No specific diet is recommended or prohibited.
Activity
No limitation on activity is necessary in the pediatric patient.
Further Inpatient Care
- Routine postoperative care of the patient who has undergone cardiac surgery should be performed.
- Pain control should be optimal to reduce the risk of atelectasis.
- Anticipate early extubation unless contraindications exist; these include excessive chest tube drainage, hemodynamic instability, and oversedation.
- Encourage early mobilization.
Further Outpatient Care
- Intermittent follow-up to assess right heart size and pressures and cardiac function and rhythm is necessary. Possible obstruction of the pulmonary veins should be evaluated with echocardiography.
Transfer
- Patients should be transferred to an institution skilled in pediatric cardiology and pediatric cardiac surgery for assessment and treatment.
Deterrence/Prevention
- Partial anomalous pulmonary venous connection (PAPVC) is a congenital cardiac defect with no known cause. Therefore, no preventive or deterring factors are known.
Complications
- No significant complications develop in pediatric patients who do not undergo surgery for a sinus venosus ASD repair with internal patch technique to include the right upper pulmonary vein in the left atrium. However, other types of repair may carry complications such as SVC syndrome, pulmonary venous obstruction, atrial arrhythmias, and sick sinus syndrome.
- Arrhythmias may occur in adults with unrepaired PAPVC secondary to chronic right atrial enlargement due to volume overload.
- Cardiac failure and, very rarely, pulmonary hypertension may develop in adults.
Prognosis
- Prognosis is excellent for patients with PAPVC. The perioperative mortality rate is comparable to that for ASD repair (<0.1%).
- Prognosis becomes more guarded if the lesion is undetected for a long period and if complications, particularly pulmonary hypertension, develop.
- The only postoperative death in the series by Gustafson et al involved a woman with pulmonary hypertension.
Patient Education
- Advise patient and parents regarding long-term risks if a large shunt remains unrepaired.
- If pulmonary hypertension has developed, outline the risks of pregnancy, including death.
Medical/Legal Pitfalls
- Failure to diagnose partial anomalous pulmonary venous connection (PAPVC)
- Late diagnosis of PAPVC
- Risk of pulmonary hypertension
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Partial Anomalous Pulmonary Venous Connection excerpt Article Last Updated: Nov 6, 2006
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