Multimodal imaging diagnosis of concurrent left pulmonary arterial hypoplasia and right pulmonary arterial stenosis in a cat

A 10-month-old intact male British Shorthair cat weighing 4.1 kg was referred for evaluation of suspected heart disease, characterized by open-mouth respiration after physical activity. On physical examination, a grade 4/6 bilateral systolic murmur was auscultated. Thoracic radiography revealed right-sided cardiac enlargement accompanied by dilation of the main pulmonary artery. In addition, the entire left lung field appeared hyperlucent, with reduced visibility of pulmonary vasculature, decreased lung volume, and a mediastinal shift toward the left. Echocardiography demonstrated stenosis of the right proximal pulmonary artery, while the left pulmonary artery was not distinctly apparent. Computed tomography angiography further identified hypoplasia of the left pulmonary artery, resulting in hypoperfusion and reduced volume of the entire left lung, together with right proximal pulmonary artery stenosis. Unilateral pulmonary arterial hypoplasia and stenosis represent uncommon congenital cardiovascular maladies in felines, and the concurrent occurrence of both conditions is extremely unusual. Consequently, this report describes the radiographic, echocardiographic, and computed tomographic characteristics observed in a cat diagnosed with these simultaneous vascular anomalies.