Pulmonary vein to pulmonary artery ratio in healthy and cardiomyopathic cats

Abstract Introduction/Objectives Recognition of congestive heart failure (CHF) in dyspnoeic cats is crucial for correct intervention. The pulmonary vein (PV) to pulmonary artery (PA) ratio (PV/PA) has been proposed as an index that might help discriminate dogs in CHF but has never been studied in cats. We sought to determine reference intervals for various PV and PA variables in healthy cats. We then examined these variables in cats with subclinical and clinical cardiomyopathies to determine their diagnostic utility to identify CHF. Animals, Materials and Methods We prospectively enrolled 114 cats: 51 healthy cats, 32 subclinical cardiomyopathic cats and 31 cardiomyopathic cats with CHF. PV and PA were measured at the minimal and maximal diameters from M-mode images obtained from a modified right parasternal long axis view. Aorta (Ao) and left atrium were measured in 2-dimensional imaging from the right parasternal short axis view. Results Median PVmin/PAmin in healthy cats was approximately 0.51 and PVmax/PAmax was 0.67. The median distensibility of the vessels was 23% for ΔPA and 41% for ΔPV. Cats with CHF had a higher PVmin/PAmin, PVmax/PAmax, PVmin/Ao, PVmax/Ao and a smaller ΔPV than subclinical and healthy cats (p Conclusions Our study provides reference values for PV and PA variables in cats. Moreover, PV/PA variables performed better than LA:Ao in discriminating cardiomyopathic cats with and without CHF.