Original Scientific ArticleMac Vet Rev 2016; 39 (1): [83][84][85][86][87][88][89][90] Bronchial and upper respiratory diseases have been associated with hypoxia and subsequent development of pulmonary arterial hypertension (PAH). However, there are no known studies assessing the prevalence of PAH in dogs with these conditions. The aim of this study was to assess the frequency of PAH in dogs with bronchial and upper respiratory diseases. Medical records of dogs with confirmed diagnosis (by endoscopic examination) of bronchial and/or upper respiratory diseases referred for cardiovascular investigation (January 2009 -May 2013 were retrospectively reviewed. Diagnosis of PAH was made by echocardiography (tricuspid regurgitation > 2.8 m/s and/or pulmonic regurgitation > 2.2 m/s); possible PAH was diagnosed when two or more specific echocardiographic findings were present. 52 dogs (30 with upper respiratory diseases, 17 with bronchial disease and 5 with both) were included. Diagnosis of PAH was performed in 3 dogs (5.7%). Two dogs were considered as probably affected by PAH; a total of 5 dogs (9.4%) resulted in being affected or probably affected by PAH. Our study shows that the prevalence of PAH in dogs with bronchial and/or upper respiratory diseases is low; PAH seems to occur mostly in older dogs and/or with very advanced disease: echocardiography may therefore be a useful tool in this category of patients. INTRODUCTIONIn veterinary medicine, pulmonary arterial hypertension (PAH) is defined as pulmonary arterial systolic pressure greater than 25 mmHg (1). Right-heart catheterization is considered the "gold standard" in order to diagnose PAH (2,3,4). However it is rarely performed in veterinary medicine (1,3,4). In the absence of right ventricular (RV) outfl ow tract obstruction (e.g. pulmonary stenosis) or significant right-sided volume overload (e.g. tricuspid valve dysplasia), pulmonary arterial pressure can be inferred non-invasively with Doppler echocardiography, either by calculation of RETROSPECTIVE INVESTIGATION ON THE PREVALENCE OF PULMONARY HYPERTENSION IN DOGS WITH BRONCHIAL AND UPPER RESPIRATORY DISEASESChiara Locatelli, Daniela Montrasio, Ilaria Spalla, Giulia Riscazzi, Matteo Gobbetti, Alice Savarese, Stefano Romussi, Paola G. Brambilla Milano, Via Celoria 10, 20133 Milan, Italy Received 10 October 2015; Received in revised form 11 January 2016; Accepted 20 January 2016 the maximal velocity of the regurgitant fl ow across the tricuspid (systolic pulmonary arterial pressure) or across the pulmonary valve (diastolic pulmonary arterial pressure) using the modified Bernoulli equation (4,5,6). Department of Veterinary Sciences and Public Health (DIVET), Università degli Studi diThe severity of PAH is classified as mild, moderate, and severe based on the estimated pulmonary arterial pressure, with slight variations in cut off values among reports, in dogs affected by cardiovascular diseases (6,7,8).PAH may occur through three mechanisms: increased left atrial pressure, increased pulmonary blood f...