Biology Reference
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septum, or dilatation of the main pulmonary artery) nor pulmonary valve
regurgitant jets were registered in any dog. A tricuspid regurgitant jet having a
peak velocity of 3.3 m/s was revealed in one of two dogs with mitral valve
endocardiosis. In this dog, a systolic pressure value of 48.56 mmHg was calculated
using the modified Bernoulli equation. In all dogs, the AT index ranged from 73 to
90 ms and the AT/ET ratio ranged from 0.36 to 0.52. In particular, the AT/ET ratio
was higher than 0.42 ms in six dogs. The Tei index ranged from 0.15 to 0.48 with
only one dog showing a value higher than 0.36. The pulmonary flow profiles were
classified as pattern I in three dogs and pattern II in six dogs.
20.4 Discussion
None of the dogs included in this study showed a condition of severe PAH
associated to CanL. In one dog, a Cavalier King Charles Spaniel with mitral
valve endocardiosis (ISACH 1), a tricuspid regurgitant jet having a peak velocity
of 3.3 m/s, was registered and was considered indicative of PAH. A tricuspid
regurgitant jet peak velocity equal to or higher than 2.8 m/s is abnormal and, in
the absence of pulmonary stenosis, is indicative of PAH (Johnson et al.
1999
). The
dog was categorized as having mild PAH since the calculated systolic pressure
value was 30-55 mmHg (Pyle et al.
2004
). It is unclear whether the PAH registered
in this dog was the consequence of mitral valve insufficiency, leishmaniasis, or both
conditions. PAH can be identified in dogs with mitral valve degenerative diseases in
which the left atrium/aorta ratio is within the reference range (Serres et al.
2006
).
Other indirect Doppler echocardiographic markers were used to investigate PAH
in this study, because alterations in two-dimensional echocardiograms were
registered only during severe PAH and, in the absence of measurable tricuspid or
pulmonary regurgitant jets, assessment of pulmonary artery pressure may be
impossible (Serres et al.
2007
). Echo-Doppler variables, such as AT, AT/ET, and
TEI, are highly correlated to systolic pulmonary arterial pressures; thus, any
alteration in those measurements may raise the suspicion of PAH in animals who
do not present measurable jets (Serres et al.
2007
).
The indirect imagining markers measured and calculated in this study were not
indicative of PAH. All AT values were higher than 64 ms, a threshold previously
proposed to exclude a PAH condition (Shober and Baade
2006
). The same authors
suggested that AT/ET ratio values
0.25 were 100% specific for the diagnosis of
PAH, while values higher than 0.42 excluded PAH. In this study, the calculated AT/
ET ratio values ranged from 0.36 to 0.52, which were not indicative of PAH, as
PAH could be excluded in six dogs. Two of the remaining four dogs with interme-
diate values were the same dogs that had mitral valve degenerative disease.
Vonk et al. (
2007
) indicated that Tei-index values higher than 0.36 are predictive
of PAH, while values ranging from 0.28 to 0.36 are only indicative. In the absence
of mitral valve disease, a high Tei-index value (0.48) was registered in only one
