Unilateral absence of pulmonary artery: Pathophysiology, symptoms, diagnosis and current treatment

Abstract

Unilateral absence of pulmonary artery (UAPA) is a rare malformation that can present as an isolated lesion or may be associated with other congenital heart defects. UAPA is often associated with other congenital cardiovascular anomalies, such as tetralogy of Fallot, atrial septal defect, coarctation of aorta, right aortic arch, truncus arteriosus and pulmonary atresia. Diagnosis of UAPA is very difficult and is based on taking a complete medical history, physical examination and imaging examinations. Clinical symptoms include exercise intolerance, haemoptysis and recurrent respiratory infections. Adult patients with UAPA are often asymptomatic. There is no consensus regarding the treatment for UAPA. The therapeutic approach should be based on symptoms of the patient, pulmonary artery anatomy and associated aortopulmonary collaterals. Treatment options for these patients include partial or total pneumonectomy, closure of selected collateral arteries not solely responsible for pulmonary blood flow or a primary versus staged pulmonary artery anastomosis. This review summarizes pathophysiology, symptomatology and current diagnosis and treatment of this disease.

Definition and Management of Segmental Pulmonary Hypertension

“…The term “absent” PA is not accurate, as a hilar PA is typically present and supplied by a PDA or large collaterals but not the main PA, often leading to the development of PH in a single lung 10, 11. Several authors have used the terms “isolated PA of ductal origin” or “unilateral ductal origin of a PA” to more accurately describe this condition.…”

“…Its prevalence as an isolated lesion is estimated at 1 in 200 000‐to‐300 000 adults,10, 18, 19, 20 and 80% of reported cases involving the left PA have been associated with coexisting CHD, such as TOF or truncus arteriosus 10, 19. In 2011, a review of the literature reported 352 cases of unilateral “absence” of pulmonary artery; two thirds (n=237) were associated with other CHD 21.…”

Isolated unilateral absence of pulmonary artery in adulthood: a clinical analysis of 65 cases from a case series and systematic review

“…Early revascularization may allow the affected lung to develop more normally and improve PHT. In older patients, revascularization is not encouraged or even feasible because the intrapulmonary arteries have been found to be severely narrowed or even completely obstructed by fibrosis (6). None of the patients received surgical revascularization for PHT treatment in our study.…”

“…About 350 cases were reported in the world literature between 1868 and 2010 (2)(3)(4)(5). In most patients, UAPA is usually associated with other cardiovascular congenital abnormalities such as tetralogy of Fallot, arterial septal defect, truncus arteriosus (6) and are diagnosed in infancy or childhood due to symptoms related to associated cardiovascular abnormalities. Conversely, approximately 30% of patients with UAPA have no associated cardiovascular anomalies, this is termed isolated UAPA, and such cases generally present with a mild clinical course and can go undiagnosed until adulthood (5,7).…”

“…The chest radiograph of patients with UAPA typically shows a small hemithorax, an ipsilateral absent hilar shadow, the absence of ipsilateral pulmonary artery and ipsilateral hemidiaphragm elevation. When suspicious findings are noted on a chest radiograph, the diagnosis of UAPA can be made definitively by contrastenhanced CT or magnetic resonance angiography showing the absence of right or left pulmonary artery usually terminate within 2 cm of its expected origin from the main PA and variable systemic collateral arteries (6). Apart from these diagnostic features, lung parenchymal findings, which are thought to be related to profound, long-standing pulmonary hypoperfusion and dynamic changes in the pulmonary blood flow (9) have also been described in literature, including bronchiectasis, cystic space, and interstitial changes such as reticular opacities or honeycombing in the affected lung (7,9,10).…”