Pulmonary arterial pulse wave velocity measurement in horses
Calcification of the tunica media of the main pulmonary arteries (PA) has been reported in a large proportion of racehorses. In humans, medial calcification is a significant cause of arterial stiffening and is implicated in the pathogenesis of cardiac, cerebral and renal microvascular diseases, as well as pulmonary hypertension. Pulse wave velocity (PWV) provides a measure of arterial stiffness. This study aimed to develop a technique to determine PA-PWV in standing sedated horses, and secondarily to investigate a potential association between PA-PWV and the presence of fibro-calcified lesions in the PA of these animals. A dual pressure sensor catheter (PSC) was placed in the main PA of 13 sedated horses. The pressure waves recorded from 10 of those horses were used to determine PWV along the PA. The method used for PWV determination was the statistical phase offset, a method developed from data collected during this study. Histological analysis of the PA was performed to investigate the presence of fibro-calcified lesions. The mean ±SD PWV was 2.3±0.7m/s in the proximal PA trunk and 1.1±0.1m/s further distal (15cm) in a main PA branch. The mean ±SD of mean arterial pressures in the proximal PA trunk was 30.1±5.2mmHg, and 22.0±6.0mmHg further distal (15cm) within the main PA branch. The mean ±SD pulse pressure in the proximal PA trunk was 15.0±4.7mmHg, and 13.5±3.3mmHg further distal (15cm) within the main PA branch. Moderate to severe lesions of the tunica media of the PAs were observed in 7/10 horses, but a correlation with PWV could not be established with the data collected. Pulmonary artery PWV may be determined in standing horses. The technique described could allow further investigation of the effect of calcification of large PAs in the pathogenesis of equine pulmonary circulatory disorders.