This study compared uncomplicated canine babesiosis (CB) with various grades of experimentally induced normovolaemic anaemia (EA) and the physiological state (controls) in the dog using Doppler variables of the abdominal aorta and splanchnic vessels. There were 14 cases of uncomplicated CB, and each EA and control group had 11 Beagles. There were significant increases in the abdominal aorta, cranial mesenteric artery, coeliac artery and main portal vein blood flow velocities, and in portal blood flow during EA when compared with the physiological state. There were significant reductions in resistance indices of the same vessels, and those of the hilar splenic artery. Changes were most notable during severe EA and less consistent during lower grades of anaemia. Significant changes in renal haemodynamics were found only during severe acute EA. In contrast to other abdominal vessels, left renal artery pulsatility and resistive indices increased significantly during EA while those of the interlobar artery remained unchanged. There was a significant increase in peak systolic velocity and significant decrease in end diastolic velocity. Renal artery time-averaged mean velocity (TAVmean) (P < 0.008) and end diastolic velocity (P = 0.041) were significantly lower than the corresponding variables of the aorta, cranial mesenteric and coeliac arteries during the EA but not the physiological state. The TAVmean ratio was significantly (P< 0.014) lower during EA when compared to the physiological state, and significantly (P< 0.004) lower than the corresponding variables of cranial mesenteric or coeliac artery during the EA but not the physiological state. There was a striking similarity between CB and EA regarding haemodynamic change patterns of Doppler variables in all vessels. In spite of this, renal resistive indices during CB were significantly higher than during EA and the physiological state. The similarity between CB and EA haemodynamic patterns is attributed to anaemia while significant differences between them may be attributable to pathophysiological factors peculiar to CB. This observation supports the view that CB impairs renal circulation through certain mechanisms such as capillary blockage with sequestered red blood cells. Doppler ultrasonography is a useful technique for clinical investigation of haemodynamics in CB and related diseases.
Thesis (PhD (Veterinary Science))--University of Pretoria, 2005.