A Case of Congenital Pulmonary Vein Stenosis with Secondary Post-Capillary Pulmonary Hypertension and Left Sided Congestive Heart Failure in a Cat

Simple Summary Left-sided congestive heart failure and post-capillary pulmonary hypertension are commonly associated with left atrial enlargement. An instrumental step in diagnosing left-sided congestive heart in cats is confirming the presence of left atrial enlargement. However, in selected cases, left-sided congestive heart and post-capillary pulmonary hypertension may be present while the left atrium is not enlarged. This case report presents a 5-month-old Maine Coon cat with congenital pulmonary vein stenosis resulting in severe left-sided congestive heart and post-capillary pulmonary hypertension without left atrial enlargement. A five-month-old, 3.8 kg intact male Maine coon cat presented for dyspnea characterized by increased respiratory effort in addition to open-mouth breathing. Thoracic radiographs showed pectus excavatum, enlarged cardiac silhouette, and generalized interstitial patterns. Echocardiography revealed normal left atrial (LA) and left ventricular dimensions. A large tubular structure, suspected to be a distended pulmonary vein (PV), was identified as draining into the LA. Severe eccentric and concentric right ventricular hypertrophy and paradoxical septal motion were noted. Based on Doppler echocardiography, both pulmonary venous and pulmonary artery pressure was severely elevated. Clinical, radiographic, and echocardiographic abnormalities were hypothesized to result from pulmonary vein stenosis (PVS), causing severely elevated pulmonary venous pressures and resulting in clinical signs of left-sided congestive heart failure (L-CHF) and severe post-capillary pulmonary hypertension (Pc-PH). The prognosis for good quality of life was assessed as poor, and the owner elected euthanasia. Necropsy confirmed the presence of PVS with severe dilation of the PVs draining all but the left cranial lung lobe. All lung lobes except the left cranial lobe had increased tissue density and a mottled cut surface. This case report shows that, in rare cases, both L-CHF and Pc-PH may be present without LA enlargement. To the authors' knowledge, this is the first report on PVS in veterinary medicine.