Canine pulmonary vein-to-pulmonary artery ratio: echocardiographic technique and reference intervals.
OBJECTIVE
The size of the pulmonary veins (PVs) and pulmonary arteries (PAs) changes in response to hemodynamic alterations caused by physiological events and disease. We sought to create standardized echocardiographic methods for imaging the right ostium of the pulmonary veins (RPVs) and the right pulmonary artery (RPA) using specific landmarks and timing to quantify vessel diameters and phasic changes during the cardiac cycle.


METHODS
Fifty client-owned healthy dogs prospectively recruited.


METHODS
M-mode and 2-dimensional images were obtained from modified right parasternal long and short axis views. Right ostium of the pulmonary veins and RPA measurements were timed with electrical [peak of the QRS complex (RPVQRSand RPAQRS) and end of T wave (RPVTand RPAT)] or mechanical events [RPV and RPA vessels at their respective maximal (RPVMAX; RPAMAX) and minimal (RPVMIN; RPAMIN) diameters]. Right ostium of the pulmonary veins and RPA measurements were also indexed to the aorta.


RESULTS
In normal dogs regardless of the echocardiographic view or time in the cardiac cycle, the RPV/RPA ratio approximated 1.0. Mechanically timed fractional changes (distensibility indices) in RPV and RPA diameters did not differ (p=0.99; 36.9% and 36.8%, respectively). ECG-timed fractional changes (distensibility indices) in RPV and RPA diameter were at least 50% smaller than mechanically timed changes (p<0.05). RPV:Ao and RPA:Ao ranged between 0.3 and 0.6, with lower values obtained in diastole and larger values in systole (p<0.0001). Multiple positive and negative deflections were identified on the RPV and RPA M-mode tracings.


CONCLUSIONS
This study provides detailed methodology and 2D and M-mode reference intervals for the RPV and RPA dimensions and the phasic changes during the cardiac cycle of the dog using echocardiography.
Department of Veterinary Medicine, University of Perugia, Perugia, Italy.
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Birettoni
Department of Veterinary Medicine, University of Perugia, Perugia, Italy.
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Caivano
Department of Veterinary Medicine, University of Perugia, Perugia, Italy.
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Patata
Department of Clinical Science, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA.
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Moïse
Department of Animal Medicine, Production and Health, University of Padua, Padua, Italy.
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Guglielmini
Veterinary Information Network, Davis, CA, USA.
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Rishniw
Department of Veterinary Medicine, University of Perugia, Perugia, Italy. Electronic address: francesco.porciello@unipg.it.
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Porciello
D000818:Animals; D004285:Dogs / Q000033:anatomy & histology*; D004452:Echocardiography / Q000379:methods / Q000662:veterinary*; D005260:Female; D008297:Male; D011446:Prospective Studies; D011651:Pulmonary Artery / Q000033:anatomy & histology*; D011667:Pulmonary Veins / Q000033:anatomy & histology*; D012016:Reference Values
Healthy dog; Index; Pulmonary artery distensibility index; Pulmonary vein distensibility index