Page 302 - Feline Cardiology

310 Section H: Arterial Thromboembolism

AO

LA

Figure 20.5. A short-axis echocardiogram from the right para-
sternum obtained at the heart base showing the aorta and left
atrium. Note the hypoechoic thrombus (arrow) within the body of Figure 20.7. An aortogram obtained from a cat with a “saddle”
Arterial Thromboembolism to the pelvis because of a clot in the terminal aorta (arrow), and
the left atrium (LA); aorta = Ao.
embolus. Note the contrast in the aortic blood is blocked cranial
no collateral circulation is present to the pelvic limbs. Image cour-
tesy of Dr. Mark Kittleson.

TREATMENT
Acute Case Management
Acute therapy of ATE patients is directed toward manag-
ing pain, CHF, or significant arrhythmias when present;
general patient support, notably involving pain manage-
ment; and adjunctive therapies to limit thrombus growth
or future thrombus formation. In the acute phase, a 24-
hour care facility is best suited for these cases, because
there may be acute life-threatening deterioration at any
time during the first several days after ATE has occurred.
Figure 20.6. A short-axis echocardiogram from the right para- If CHF is present, therapy should be initiated similarly
sternum obtained at the heart base and showing the aorta and as in other cats with CHF (see Chapter 19 for discussion
left atrium. Note the hypoechoic or grey debris in the left atrium of CHF management). Analgesia is crucial in these
(arrows). In real time, this spontaneous contrast is visible swirl- patients, particularly for the first 24 to 48 hours, because
ing around the left atrial chamber and represents red blood cell after that time period, there is often lack of pain noted
aggregation. Left atrial smoke in the modified left parasternal in cats with a saddle embolus. In humans with periph-
long-axis view.
eral vascular disease, axonal degeneration begins after 24
hours of ischemia and severity of the pathologic change
these patients (neoplasia, systemic inflammation or is dependent on the duration of ischemia (Nakuda et al.
other systemic diseases). Neoplasia was identified as the 1996). Analgesia can be addressed with various medica-
underlying disease in 5% of the cats with ATE in one tions such as fentanyl (2–5 µg/kg/hr as a CRI for 12–18
study (Smith et al. 2003). hours until a fentanyl patch takes effect), butorphanol
Occasionally, more invasive diagnostic testing may be (0.1 to 0.2 mg/kg IV every 4 to 6 hours), or buprenor-
warranted to confirm the diagnosis of ATE. Abdominal phine (0.005 to 0.015 mg/kg IV every 6 to 8 hours). See
ultrasound, angiocardiography (Figure 20.7), and Figure 20.8 for an algorithm breaking down the acute
nuclear scintigraphy have all been used to evaluate the and long-term care of a cat with ATE.
obstructed site further. Procedures requiring sedation Vasodilators, such as acepromazine, have been sug-
should only be attempted in clinically stable patients. gested to encourage arterial vasodilation; however, arte-