Left Pulmonary Artery Sling Research Articles

Diagnosis and Management of Agenesis of the Right Lung and Left Pulmonary Artery Sling

The diagnostic, developmental, and surgical aspects of left pulmonary artery sling associated with right lung agenesis in 3 patients are described. Cardiac catheterization may be avoided by the combined use of echocardiography and magnetic resonance imaging and/or computed tomography.

Left pulmonary artery sling: Diagnosis and delineation of associated tracheobronchial anomalies with MR

The left pulmonary artery sling anomaly (SLPA) has generated controversy about its diagnosis, imaging and management particularly with regard to associated tracheobronchial anomalies. Objective. To evaluate the role of MR imaging in defining airway and vascular relationships in SLPA. Retrospective review of the imaging and clinical records of three children with SLPA who underwent MRI including three dimensional image reconstruction. MR was compared and correlated with other imaging methods: plain chest radiographs (3); bronchoscopy (3); barium esophagram (1); echocardiography (2); cineangiography (2). MRI was vastly superior to other methods for clearly depicting airway and vascular anatomy and interrelationships. Good quality imaging and safe sedation was easily achieved in young infants. MR also provided accurate noninvasive evaluation of the reconstructed pulmonary artery and airway postoperatively. MR is capable of differentiating the two subtypes of SLPA. Specific delineation of vascular and airway anatomy and spatial relationships is essential for surgical management: reimplantation of LPA in type I and both LPA reimplantation and airway reconstruction in type II because of associated long segment airway stenosis.

MRI in pre- and postoperative assessment of tracheal stenosis due to pulmonary artery sling.

To evaluate the potential of MRI in the assessment of tracheal stenosis due to tracheal or vascular malformations, 45 children with severe respiratory distress were examined prospectively during a period of 1 year. Five of these children had tracheal stenosis due to a sling left pulmonary artery (SLPA). Magnetic resonance examinations of the anesthetized children were performed with a 1.5 T Siemens MR imager using electrocardiographically gated T1-weighted SE sequences in transverse and sagittal slice orientations. Slice thickness was 3 mm and each sequence was repeated after shifting the slice position by 1 mm. Monitoring during the examinations included ECG, oscillatory blood pressure, respiratory rate, and oxygen concentration. Magnetic resonance findings were compared with esophagography, selective pulmonary angiography, bronchoscopy, Doppler sonography, and surgery. All examinations were repeated after surgical therapy to assess the improvement in tracheal stenoses and the patency of the ligated and reimplanted left pulmonary arteries. Magnetic resonance imaging clearly revealed the course of the SLPA and its topographic relationship to the trachea as well as the coexistence of cardiovascular and tracheobronchial or esophageal malformations. The degree and length of tracheal stenoses, which were measured in the pre- and postoperative axial slices and graphically displayed, as well as the angles of the right and left main stem bronchi, could be accurately determined. Magnetic resonance imaging in combination with bronchoscopy yielded the necessary and sufficient information for diagnosis and aided the surgeon in planning operative strategy and in postoperative follow-up.

Branching patterns of right pulmonary artery in cardiovascular anomalies.

The branch of the right pulmonary artery (RPA) to the upper lobe of the right lung (RUL), the truncus anterior of the RPA, and the pars anterior of the left pulmonary artery, which supplies the left upper lung lobe (LUL), were demonstrated by both dissection of postmortem specimens and angiography for 20 infants and children, by angiography only for 57, and by specimen dissection only for 59 (total 136). In posteroanterior angiograms, the RUL artery branches from the RPA near the right lateral border of the vertebral column, while the LUL artery or arteries arise more laterally, near the left midclavicular plane. This pattern is reversed in situs inversus (eight patients studied). Thirty-nine patients in other categories of congenital cardiovascular disease showed an abnormal RUL or LUL arterial pattern, including pulmonary isomerism, right lung type (RUL artery pattern present bilaterally, 12 patients); pulmonary isomerism, left lung type (RUL artery pattern absent bilaterally, 11 patients); scimitar syndrome (RUL artery pattern normal, 1 patient; absent bilaterally, 4 patients); and left pulmonary artery sling (RUL artery normal, one; hypoplastic, one; absent, two patients). Five patients with tetralogy of Fallot (TOF) with right aortic arch (RAA) and 1 of 15 with RAA not TOF or situs inversus showed a relatively large RUL artery arising more laterally than usual. Three of six patients with double outlet right ventricle had the LUL artery larger than usual plus two accessory RUL arteries, and one patient with crossed pulmonary arteries showed a similar pattern. Two patients with single ventricle had an RUL artery of normal pattern although the RUL bronchus was absent, and one patient with single ventricle and situs inversus had a comparable pattern in the left lung. The ease of demonstration of the right and left upper lobe branches of the pulmonary artery by dissection or angiocardiography warrants greater attention to their patterns in patients with congenital cardiovascular disease. Dissociation of upper lobe bronchial and vascular patterns is unusual and may also be of diagnostic value.

Serial section-reconstruction of anomalous tracheobronchial branching patterns from CT scan images: Bridging bronchus associated with sling left pulmonary artery

The use of the technique of wax-plate serial section-reconstruction, based on contiguous axial plane CT images of the upper thorax, to prepare a replica of the central air-way (trachea and major bronchi) of an infant with sling left pulmonary artery type 2B, with bridging bronchus, abortive right main bronchus, and tracheal stenosis due to absence of the tracheal pars membranacea with "ring" tracheal cartilages is described. The technique is applicable to demonstration of the anatomic features of other abnormalities of branching pattern or caliber of the trachea and major bronchi.

Reconsideration of the anatomy of sling left pulmonary artery: The association of one form with bridging bronchus and imperforate anus. Anatomic and diagnostic aspects

In sling (retrotracheal) left pulmonary artery (SLPA), the tracheobronchial pattern is generally considered basically normal. Analysis of dissected specimens and/or bronchograms and other preparations from five studied and 32 reported patients suggests that there are two different forms of SLPA: (1) types 1A and B, with normal TB pattern [with (A) or without (B) a right pre-eparterial (tracheal bronchus)], and the aberrant left pulmonary artery causing TB compression. The tracheal bifurcation in type 1 SLPA is usually demonstrable at the fourth to fifth thoracic vertebral level; (2A) SLPA type 2A, with bridging bronchus (BB), in which condition the right main bronchus supplies the right upper lobe, but the bronchus supplying the right middle and lower lobes (the bridging bronchus) arises from the left main bronchus (LMB), posterior to which the SLPA courses; (2B) SLPA type 2B, with absence of the right bronchial tree, and the right lung (usually hypoplastic) supplied by a BB from the LMB, posterior to which the SLPA courses. SLPA types 2A and B have in common varying degrees of tracheal stenosis with abnormal cartilage rings and absent tracheal pars membranacea, abnormally low tracheal "bifurcation" (pseudocarina) at average level T6, increased bronchial angles with "inverted T" pattern, and lower level of anterior esophageal indentation by the SLPA than SLPA type 1. Imperforate anus occurred in 8/58 (14%) of patients with SLPA types 2A or B, but possibly in none with SLPA type 1. SLPA type 2 is the predominant form of SLPA, with the incidence of type 2B being twice that of type 2A.(ABSTRACT TRUNCATED AT 250 WORDS)

Asymptomatic form of left pulmonary artery sling

Eight patients with left pulmonary artery sling, which were asymptomatic at the time of the last consultation, are described: 2 adults and 1 child with no history of symptoms, 3 children with mild forms of airways obstruction and 2 patients with typical severe symptoms of airways obstruction in infancy. The mean follow-up of these 8 patients was 10 years (range 4 to 23), and in 1986, all were in good health and free of respiratory symptoms. The long-term prognosis is usually good.

"Horseshoe" lung: report of five new cases.

A "horseshoe" lung is a rare congenital anomaly in which the posterobasal segments of the right and left lungs are fused behind the pericardial reflection at the cardiac apex. Most patients with such pulmonary fusion share many of those cardiovascular anomalies typical of the "scimitar" or hypogenetic right lung syndrome. The clinical diagnosis of horseshoe lung can be made by pulmonary angiography, which shows a branch of the right pulmonary artery originating from its proximal but inferior aspect and coursing into the left hemithorax. Thus, there are two conditions in which an artery from the right lung supplies part or all of the left lung: errant right pulmonary artery in the horseshoe lung deformity and so-called left pulmonary artery sling.

Tracheostenosis and Bronchial Abnormalities Associated with Pulmonary Artery Sling

Three patients with aberrant left pulmonary artery (sling artery) are reported to illustrate associated tracheobronchial abnormalities. The clinical picture was that of severe episodic or progressive respiratory distress without dysphagia in early infancy. Striking narrowing of the trachea by complete "ring cartilages," unrelated to compression by the abnormal pulmonary artery, was present. Tracheotomy and intubation failed to relieve the obstruction. In one patient the bronchi and bronchial segmentation pattern were normal, but in the other two patients, bronchial abnormalities included wide irregular cartilages in the main bronchi, forming more complete rings than is normal. In both, the right main bronchus was relatively longer than normal, and the bronchus intermedius showed poor cartilage ring formation and was relatively short compared to the main bronchus. This discrepancy did not appear to be due to distal displacement of the right upper lobe bronchus. In these two patients the left main bronchus was relatively short and wide with reduced number of cartilage rings (five-six vs usual normal number of nine), so that the right and left main bronchi were almost of equal length. However, the branch patterns of the lobar bronchi were within normal range. Bronchoscopy seems essential to demonstrate such ring tracheal cartilages (absence of the pars membranacea of the trachea), which when found should alert the examiner to the possible presence of an abnormal left pulmonary artery. Since surgical correction of tracheal stenosis of this type is not possible at present, the ultimate prognosis of patients with sling artery may depend more on the severity of the tracheal anomaly rather than on success of surgical correction of the abnormal left pulmonary arterial course. Although aberrant (sling) left pulmonary artery can occur in patients without respiratory tract symptoms, tracheal stenosis due to ring tracheal cartilages occurs in a significant fraction of patients with this arterial anomaly. Bronchoscopic study of the trachea, and possibly air or contrast bronchography of right and left main bronchi, can be of aid in diagnosis of this complex.