Proximal Interruption of a Pulmonary Arch (Absence of One Pulmonary Artery): Case Report and a New Embryologic Interpretation

Proximal Interruption of Pulmonary Artery: Spectrum of Radiological Findings With Emphasis on Chest Radiograph and Contrast-Enhanced Computed Tomography (CECT)

Introduction Proximal interruption of pulmonary artery (PIPA) is a congenital anomaly presenting with aberrant termination of the pulmonary artery at the hilum. It results in a variety of radiological and clinical manifestations. Clinically, isolated PIPA can be asymptomatic till late adulthood or can present with dyspnoea, chest discomfort, hemoptysis and recurrent infections. PIPA can be associated with multiple cardiovascular anomalies such as tetralogy of Fallot (TOF), ventricular septal defects (VSD), and scimitar syndrome. We present a spectrum of cases with both isolated proximal interruption of the pulmonary artery and cases associated with other cardiovascular abnormalities. Typical chest radiographs and chest contrast-enhanced computed tomography (CECT) findings are discussed and demonstrated in detail. Proper and early diagnosis is a crucial step as it can significantly modify the treatment choice, thereby reducing morbidity. Objective To document the different presentations of the proximal arrest of pulmonary arteries, to document associations with cardiovascular and pulmonary manifestations, and to elaborate on and demonstrate the various radiological imaging findings. Material and methods All the cases that were reported with proximal interruption of pulmonary artery on the CECT studies conducted between 2019 and 2022 at a tertiary care hospital in Telangana, India. The demographic data, clinical presentation, chest radiographs, and chest CECT were collected retrospectively. Data analysis was done using Microsoft Excel 2019 to calculate descriptive statistics. A total of 22 cases were identified of which three cases were excluded of as they were previously operated and 19 cases were taken as the study population. Results Nineteen patients were included in the study. Demographic details, clinical history, CECT, and chest radiographs were collected wherever available. The majority of the cases belonged to the ≤ 10 yrs age group with the most common clinical presentation being a previous diagnosis of tuberculosis or recurrent upper respiratory tract infections. The predominant findings on chest radiographs were deviation of the trachea to the affected side, volume loss in the ipsilateral lung field, and compensatory hyperinflation of the contralateral lung field. On the CECT chest, the main findings were interrupted pulmonary artery, hypoplastic lung fields with bronchiectasis, or ground glassing. Associated cardiovascular and pulmonary malformations were identified with notable cases: TOF, right-sided aortic arch and scimitar syndrome. Their typical imaging findings have been elucidated and discussed in detail. Conclusions Patients with recurrent respiratory infections or hemoptysis having hypoplastic lung field with hyperinflation of the contralateral lung on chest radiographs should be evaluated for pulmonary artery interruptions. Chest CECT allows evaluation of the bronchial tree and lung parenchyma at the same time which helps distinguish pulmonary interruption from conditions such as Swyer-James-Macleod syndrome, pulmonary hypoplasia, thromboembolism and arteritis. Cases with PIPA can also be associated with cardiovascular and pulmonary anomalies such as TOF, partial anomalous pulmonary venous connection (PAPVC), and VSD. The knowledge of these associations is essential as they can influence the mode of treatment and can help reduce the long-term morbidity and mortality associated with the condition.

Proximal Interruption of the Pulmonary Artery: A Case Series

We present a few cases of Proximal Interruption of the Pulmonary Artery, an uncommon developmental anomaly associated with congenital heart disease. The cases had varied clinical presentations. Chest radiograph showed a hypoplastic lung with an ipsilateral small hilum on the side of the interruption and hyperinflation of the contralateral lung. Contrast CT confirmed the diagnosis, demonstrating non-visualization of the left or right pulmonary artery, and other related findings.

Imaging diagnosis of isolated proximal interruption of the right pulmonary artery in a patient presenting with respiratory complications following travel to a high-altitude region

Proximal interruption of the pulmonary artery (PA) is a rare congenital vascular anomaly with an estimated prevalence of 1 in 200,000 young adults. Patients with isolated proximal interruption of the right PA are usually asymptomatic but can present with breathlessness, haemoptysis, recurrent chest infections, pulmonary hypertension or respiratory failure. Such symptoms may be unmasked by pregnancy or at high altitude. We present a case of an isolated interruption of the right PA in a 29-year-old male with a history of cough and breathlessness, requiring hospitalization and ventilator support after travel to a hilly region. Laboratory reports showed normal haemogram and normal renal and liver function tests. Screening test for deep vein thrombosis/pulmonary embolism were negative. Echocardiogram was normal and did not show any evidence of elevated PA pressures. All serial X-rays were reviewed and showed one consistent finding: right lung volume loss with transmediastinal herniation of the left lung to the right side. We discuss the radiological and clinical features along with treatment options for the condition.

Bullous lung disease and bronchiectasis in unilateral absent right pulmonary artery

Unilateral absence of pulmonary artery is an uncommon congenital disorder. We report a case of unilateral absence of the right pulmonary artery in an adult without any other cardiovascular anomalies. We describe the clinical and radiologic presentations of this disease. Computed tomography scan and Surgery enabled us to confirm the diagnosis precisely, which was successfully treated with a right pneumonectomy for right-sided bullous lung disease and bronchiectasis. He is doing well at 2 year follow-up.

Absence of the right pulmonary artery associated with a partial anomalous pulmonary venous connection

Unilateral absence of a pulmonary artery is a rare anomaly. Patients may present with hemoptysis, recurrent respiratory infections, pulmonary hypertension, or congestive heart failure. This report describes the case of a missing right pulmonary artery associated with anomalous left pulmonary venous connection not previously described in the medical literature.

Physiologic studies in congenital absence of the left main pulmonary artery

Physiologic studies in 2 cases of congenital absence of the left pulmonary artery are presented. The significance of carbon dioxide production and oxygen uptake in the affected lung and their relationship to ventilation and perfusion are discussed. All functional and anatomic evidence points to a highly significant bronchial artery circulation substituting in part for the absent pulmonary artery.

ABSENCE OF A PRIMARY DIVISION OF THE PULMONARY TRUNK. AN ONTOGENETIC THEORY

An ontogenetic theory is proposed to explain the absence of a primary division of the pulmonary trunk on the basis of an error in the septation of the truncus arteriosus, and the two common varieties of the syndrome are discussed in detail. It is suggested that:

Both lateral pulmonary arteries are present in this syndrome, but one of them arises anomalously from the systemic circulation.

The aberrant origin of one lateral pulmonary artery derives from the dorsal shifting of one of the two ridges responsible for the septation of the truncus arteriosus. The sixth arch on the side of the dorsorotated truncal ridge then becomes incorporated into the newly formed ascending aorta.

The combination of tetralogy of Fallot, right aortic arch, and absent left primary pulmonary division results from a single primordial error: a dorsorotation of the left ridge extending throughout the truncoconus.

The initial portion of the aberrant (systemic) pulmonary artery may obliterate postnatally, thus impairing maturation of the terminal portion. This would explain the frequent failure to demonstrate the artery by angiography and, occasionally, at dissection.

Multiplane Transesophageal Echocardiographic Detection and Differential Diagnosis of Isolated Right Pulmonary Artery Agenesis

We present a case report of isolated right pulmonary artery agenesis detected by multiplane transesophageal echocardiography (TEE). A special emphasis is placed on its important role in the differential diagnosis and hemodynamic and functional evaluation of patients with unilateral pulmonary oligemia on chest radiograph. We also present a case report of pulmonary embolism with complete obstruction of the right pulmonary artery for better understanding and for comparison of TEE images in patients with pulmonary artery agenesis. (ECHOCARDIOGRAPHY, Volume 13, July 1996)

Aortic origin of the RPA: immediate resolution of severe pulmonary artery hypertension by surgical repair

Aortic origin of the right pulmonary artery (AORPA) is a rare condition requiring a high index of suspicion for diagnosis as the usual signs of structural heart disease are often absent. Ultrasound examination can strongly suggest the condition but can easily be misinterpreted. Infants should be considered "operable" even when the resistance calculations predict otherwise as there appears to be a large component of immediately reversible pulmonary artery hypertension. With technical skills learned from arterial switch operations (for transposition of the great arteries), surgical repositioning of the RPA should be possible in nearly all cases without the use of a tube graft.

The computed tomographic appearances in pulmonary artery atresia

Isolated pulmonary artery atresia is an uncommon congenital abnormality. Plain radiography and ventilation/perfusion lung scintigraphy may suggest the diagnosis but pulmonary angiography has traditionally been recommended for confirmation. The computed tomographic (CT) appearances of four patients with isolated atresia of a pulmonary artery are described. In each case the atretic segment of the abnormal vessel could be identified. Other CT findings included reduction of volume of the involved hemithorax, increased density of the affected lung, a small hilum, and an abnormal pulmonary vascular pattern thought to be due to the collateral systemic arterial supply to the intrapulmonary branches of the atretic pulmonary artery. The diagnosis of isolated pulmonary artery atresia can be made using dynamic, contrast enhanced CT without recourse to more invasive procedures.

Occult pulmonary artery associated with failure to thrive and recurrent pneumonia--a case report

Occult pulmonary artery is an uncommon cardiovascular defect. Associated symptoms include recurrent pulmonary infections and congestive heart failure. The authors describe a one-year-old boy initially diagnosed as having broncho-pulmonary dysplasia who developed severe failure to thrive, recurrent pneumonias, and pulmonary hypertension. The presence of an occult right pulmonary artery was suspected by lung perfusion scan and diagnosed by cardiac catheterization and angiography. After surgical repair, his clinical course improved and his growth and development were normal. This case demonstrates the importance of including occult pulmonary artery in the differential diagnosis of infants with failure to thrive associated with recurrent pulmonary infection.

Bilateral ductus arteriosus (or remnant): an analysis of 27 patients

Bilateral ductus arteriosus (DA) was clinically recognized in 27 patients studied angiographically from 1963 through May 1983. Distal bilateral DA origin of non-confluent pulmonary arteries was identified in 15 patients, ectopic or distal ductal origin of 1 pulmonary artery in 9 patients (5 without evidence of intracardiac disease) and isolation of the left subclavian artery in 3 (all 3 of whom had a right aortic arch). Other conditions reported to be associated with bilateral DA include interruption of the aortic arch with isolation of a subclavian artery, aortic atresia with interruption of the aortic arch in which bilateral DA supports the entire systemic circulation, bilateral DA complicating forms of congenitally malformed hearts other than those just stated, and, rarely, bilateral DA in isolation. Understanding the symmetric or paired nature of the primitive aortic arch system in the developing human heart facilitates recognition of the patterns of fourth and sixth arch anomalies seen with bilateral DA.

Surgical management of absent right pulmonary artery with associated pulmonary hypertension

A critically ill 21-month-old girl with congenital absence of the right pulmonary artery and severe pulmonary hypertension and congestive heart failure underwent conduit restoration of flow to the right lung. This patient had marked clinical improvement and reduction in pulmonary hypertension and represents the second reported surgically-treated case for absent right pulmonary artery. Reestablishment of pulmonary artery continuity is therefore recommended when cardiac failure and pulmonary hypertension occurs.

Truncus arteriosus communis. Clinical, angiocardiographic, and pathologic findings in 100 patients

Salient clinical, hemodynamic, angiocardiographic, and pathologic findings are presented in 100 patients with truncus arteriosus communis, 79 of whom were studied at autopsy. In this study of typical truncus, all had a ventricular septal defect (type A). Truncus with a partially formed aorticopulmonary septum (type A1) was much the commonest form (50%). Cases with no remnant of aorticopulmonary septum (type A2) were second in frequency (21%). The distinction between types A1 and A2 could not be made with certainty in 9%, because these types merge into one another. Cases with absence of either pulmonary artery branch (type A3) were the least frequent form (8%). Truncus with interruption, atresia, preductal coarctation, or severe hypoplasia of the aortic arch (type A4) constituted 12%. The diagnosis of truncus is primarily angiocardiographic. The plane of the truncal valve in the lateral projection is distinctive. It tilts anteriorly, facing the patient's toes, which can be of assistance in differential diagnosis. The angiocardiographic features of type A4, although unfamiliar, are pathognomonic. Since the median age at death was only 5 weeks, and in view of the difficulties associated with pulmonary artery banding, our goal should be the surgical correction of truncus during the first and second months of life.

Unilateral congenital dysplasia of lung associated with vascular anomalies

Hislop, A., Sanderson, M., and Reid, L. (1973).Thorax, 28, 435-441. Unilateral congenital dysplasia of lung associated with vascular anomalies. In three cases of unilateral lung dysplasia the structural changes have been analysed quantitatively to throw light on the nature of the anomaly and stage of its appearance. In one case the pulmonary artery was hypoplastic and the systemic supply normal but increased, suggesting onset in late intrauterine life or early childhood: in the other two cases the blood supply was only systemic, from both normal and abnormal arteries, suggesting onset in the early weeks of intrauterine development. Airway development was consistent with this interpretation. All cases had additional signs of maldevelopment of mesodermal tissue. The origin of the various types of systemic artery is discussed.

Surgical correction of absence of proximal segment of left pulmonary artery

In a 14-month-old patient who had been repeatedly hospitalized for recurrent pulmonary infections, cardiac angiography found "absence" of the left pulmonary artery, but thoracic aortography demonstrated that a rudimentary patent ductus filled a distal patent pulmonary artery. There was a coexistent vascular ring with a retroesophageal right subclavian artery.

At surgical exploration it was possible to mobilize the distal left pulmonary artery and perform a direct anastomosis between the left pulmonary artery and the main pulmonary artery. This is perhaps the first patient in whom such an operation has been performed. It is emphasized that the absence of a pulmonary artery on pulmonary angiography does not indicate that the entire pulmonary artery is absent. The presence of a patent and surgically reconstructable distal pulmonary artery can be determined only by aortography or possibly by surgical exploration.

Congenital "absence" and anomalous origin of the main pulmonary arteries. Variations of the same congenital defect

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