Novel methods to diagnose pulmonary hypertension in dogs assessed by thoracic radiography

Abstract

The objective of this retrospective study was to distinguish between dogs with pulmonary hypertension (PH)
and non-PH by using parameters obtained from thoracic radiographs. Data of 72 dogs of small breeds aged more than
1 year old and weighing less than 10 kg were retrieved. Echocardiography was used as a gold standard to diagnose PH
and separate the dogs into two groups: PH (n=15) and non-PH (n=57). Seven formulae were created from measurements
on right lateral and ventrodorsal radiographic views. Five formulae from the ventrodorsal view provided an outcome
that could differentiate PH and non-PH dogs. Two formulae are recommended including 1) the ratio of the area of the
pulmonary artery crossing the 9th rib and the area of the 9th thoracic vertebra (areaPA/areaT9) (cut-off >0.08; sensitivity
of 83% and specificity of 89.4%) and 2) the ratio of the width of the pulmonary artery crossing the 9th rib and the width
of the 9th thoracic vertebra (widthPA/widthT9) (cut-off >0.3; sensitivity of 83.3% and specificity of 78.9%). Both
measurement criteria provided high negative predictive values with moderate positive predictive values. In conclusion,
these two new formulae can be used as a screening tool for distinguishing between PH and non-PH in dogs.