B-MODE ULTRASONOGRAPHIC AND DOPPLERVELOCIMETRIC EVALUATION OF THE HEPATIC VEIN IN DOGS NATURALLY INFECTED BY Dirofilaria immitis (Leidy, 1856)
Heartworm, Hemodynamics, Congestion, Vascularization, Liver
Doppler ultrasonography is a modality that allows the non-invasive hemodynamic study frequently used in veterinary medicine. Among the image processing modes, pulsed Doppler presents information on blood flow in a blood vessel as a function of time. The hepatic veins are tributaries of the caudal vena cava and are responsible for draining blood from the liver. Its normal flow demonstrates a slow velocity and pulsatile pattern that reflects changes in the right atrium during the cardiac cycle. Heartworm diseasde is a disease whose etiological agent is the nematode Dirofilaria immitis, popularly known as “heartworm” that preferentially parasitizes the pulmonary arteries, and can be found in the right heart chambers and vena cava whose definitive hosts are domestic and wild canids. The presence of worms associated with vascular inflammatory changes leads to a decrease in the vessel lumen, leading to an increase in pulmonary arterial pressure, culminating in cardiac overload, right congestive heart failure (dHF) and hepatic congestion. Aiming to establish the influence of infection by D. immitis on the flow of the hepatic vein, 54 dogs naturally infected by D. immitis, carriers of antigenemia, will be submitted to physical examination and ultrasound by B-mode and pulsed Doppler of the hepatic vein in order to detect changes in the flow pattern that allow the indirect evaluation of right heart function.