Plexogenic pulmonary arteriopathy in a cat with non-restrictive ventricular septal defect and chronic pulmonary hypertension.

A 10-week-old, male, domestic long-hair cat was medically managed for congenital heart disease over a period of 8 years. Regular clinical examinations, including sequential echocardiography, documented a non-restrictive paramembranous ventricular septal defect, secundum-type atrial septal defect and aortic dextroposition. Pulmonary arterial hypertension was diagnosed by the presence of high-velocity tricuspid regurgitation, bidirectional low velocity flow across the ventricular septal defect, pulmonary arterial dilation and severe right ventricular hypertrophy without evidence of pulmonary outflow tract obstruction. The cat remained clinically stable until it died suddenly at 8 years of age. Histopathology of the lungs found evidence of plexogenic pulmonary arteriopathy. Despite severe pulmonary vascular lesions, other post-mortem evidence of right heart failure was lacking and death was attributed to a fatal cardiac arrhythmia. In this case report of a cat with chronic pulmonary hypertension over 8 years, plexogenic lesions were found on histopathology. The microscopic findings resemble those previously reported in dogs.