Computed tomography may prove a quicker, less stressful, lower cost procedure for cats with suspected heart disease
Diagnostic imaging plays a key role in detecting and monitoring heart disease in cats. At the University of Illinois Veterinary Teaching Hospital in Urbana, clinicians are exploring whether computed tomography (CT) could provide prognostic indicators comparable to those seen in echocardiograms (heart ultrasound) for cats with heart disease. CT may be faster, less expensive, and less stressful on patients than echocardiograms and X-rays.
Hypertrophic cardiomyopathy, a condition in which the muscles of the heart thicken, is the most common heart problem in cats. This condition and others may go undiagnosed because cats with heart disease may not develop a heart murmur and may not show any signs of illness until a secondary problem, such as a blood clot, arises.
In cats with heart disease, clots may form within the heart, then dislodge and travel to other parts of the body. If a clot lodges in the hind limbs, a life-threatening problem called arterial thromboembolism may occur, causing paralysis and extreme pain.
“Currently, echocardiography—which is ultrasound imaging of the heart—is the gold standard for evaluating heart function in cats,” says Dr. Kyle Vititoe, radiology resident at the Veterinary Teaching Hospital.
“Echocardiograms are non-invasive but may require up to 30 minutes of the patient being manually restrained to complete. Very often cats that arrive in the emergency room with suspected heart disease are unstable. They need supplemental oxygen, medications, and a very low stress environment, making it risky to perform echocardiography on them,” he says.
A CT exam can take about five minutes and involves minimal stressors aside from the intravenous catheter, occasional noise and a slight movement of the table. The patient is placed in a low-stress device called the VetMouseTrap, which was invented by University of Illinois radiologist Dr. Bob O’Brien. Supportive care such as oxygen and fluids can be delivered during the exam without the use of manual restraint.
The study being conducted by Dr. Vititoe, along with veterinary cardiologist Dr. Ryan Fries, is trying to “find out if a CT exam provides useful information (specifically regarding prognosis) about cats with heart disease, especially in emergency situations where other imaging modalities aren’t practical.”
“This study will also look at whether CT can help with detecting failure of function similar to echocardiogram (e.g., heart failure) as well as identify blood clots, which will help determine the patient’s risk for arterial thromboembolism and prognosis,” says Dr. Vititoe.
When a clot is present, a cat’s prognosis is decreased. Currently, clinicians may not be able to tell if there is a clot until the day after a critical patient arrives. Having a more accurate prognosis sooner would give owners more information about the severity of the cardiac disease and allow clinicians to deliver appropriate management sooner.
If computed tomography works in accurately identifying clots, veterinarians could also use it as a way to monitor the clots in affected patients. “In cats with a cardiac clot, the patient must have frequent reexaminations by a veterinary cardiologist to monitor the size and location as well as the function of the heart,” says Dr. Vititoe.
CT imaging may also turn out to be useful for evaluating new fibrinolytics, drugs used to break down blood clots. “A CT may be a quick way to screen clots during studies of new fibrinolytics to determine how well the drug is working,” says Dr. Vititoe.
If Dr. Vititoe’s research shows that CT is as effective as echocardiography in detecting blood clots in cats as well as provides similar important prognostic indicators, clinicians will be able to offer owners a potentially quicker, less stressful, lower cost procedure for cats with suspected heart disease. CT may also be useful in the continued management of cats with heart disease.
Cats that have heart disease and have been suspected to have a cardiac clot may be eligible to take part in Dr. Vititoe’s study. Cats that fit our inclusion criteria may receive a free echocardiogram and computed tomography scan. Other hospital fees not required for imaging will still be the responsibility of the owner. Contact Dr. Kyle Vititoe at 217-649-6338 at the University of Illinois Veterinary Teaching Hospital with inquiries or schedule an appointment with Dr. Fries at 217-333-5300.
A full list of clinical trials at the hospital may be found online at http://go.illinois.edu/trials.
By Melissa Giese