Congenital unilateral pulmonary artery anomaly resulting in pulmonary hypoplasia in a 3‐year‐old adult cat

Abstract

A 3 -year-old spayed female domestic shorthair cat was evaluated because of an acute onset of intermittently increased respiratory effort, open-mouth breathing and cough. Physical examination revealed no specific findings on auscultation, but tachypnea and laboured breathing were observed. Atelectasis of the right lung was suspected because of rightward mediastinal shift observed on thoracic radiographs ( Fig 1 A ). The cranial displacement of the right diaphragmatic crus also suggested right lung volume reduction. Thoracic CT revealed an abnormally small right lung that was well-aerated without atelectasis ( Fig 1 B ). Conventional contrast-enhanced CT ( Fig 1 C ) and three-dimensional volume rendering images ( Fig 1 D ) revealed absence of the right branch of the pulmonary artery.Congenital absence of the right pulmonary artery, which embryologically originates from the right sixth aortic arch, is seldom reported in the veterinary literature. In similarly affected humans, most patients have a relatively benign clinical course and are commonly unrecognised until adulthood. The clinical signs of unilateral absence of the pulmonary artery (UAPA) can be variable, including recurrent pulmonary infection, respiratory distress on exertion, exercise intolerance, haemoptysis or other signs associated with pulmonary hypertension.The cat's respiratory signs diminished after two weeks' treatment with enrofloxacin and metronidazole, leading to the suspicion of superimposed infection. Frequent respiratory infections have been reported in 37 to 40% of human patients with UAPA.

Pulmonary artery stenosis versus supravalvular pulmonic stenosis: Correctly describing a congenital stenosis of the pulmonic outflow tract in a domestic cat

“…Congenital heart defects include pulmonary artery stenosis, pulmonic stenosis (including what some literature describes as supravalvular pulmonic stenosis), 7 primary pulmonic infundibular stenosis, 8 double-chambered right ventricle, 13 pulmonary coarctation 10 and pulmonary artery hypoplasia. 11 Pulmonary coarctation was described in a 4year-old cat, with obstruction of the left pulmonary artery by ectopic ductal tissue; the authors described this as a pulmonary artery stenosis and therefore could be considered a synonym for the condition. 10 Acquired conditions are less likely, but consideration for vegetative endocarditis, neoplasia, granuloma, or fibrosis secondary to trauma are listed for completeness.…”

“…It is less commonly seen in veterinary medicine but can cause some clinical signs similar to those seen with pulmonic stenosis. 11 The diagnosis of pulmonary artery stenosis described in the Schrope and Kelch case series was made based on the constellation of clinical signs, electrocardiogram, radiographs and echocardiographic findings. 9 Echocardiography proved to be the most beneficial diagnostic tool by observing peak systolic and diastolic gradients across the stenosis, systolic and diastolic pressure decay half-times, and duration of antegrade flow during diastole.…”