Treatment of blood clots in cats with heart disease

Each year, the Winn Feline Foundation receives proposals from veterinary researchers around the world who are interested in improving feline health. To date, Winn’s cumulative total in feline health research funding exceeds $4 million. Forty-four proposals were submitted by researchers seeking funding in this review cycle. This year, our team of veterinary consultants helped Winn select 10 projects for funding, for a total of $174,018. Here is one of those projects:

W12-037

The efficacy of bosentan, a mixed ETa ETb receptor antagonist, in cats with arterial thromboembolism

Investigators: Elizabeth Rozanski, Gareth Buckley; Tufts University

A Ricky Fund Project

Hypertrophic cardiomyopathy is a very common heart disease in cats. One of the most devastating complications of heart disease is development of blood clots called feline aortic thromboembolism (ATE), which cuts off the blood supply to one or more limbs. ATE is associated with a survival rate of less than 40% despite multiple efforts to try to improve outcomes. It is important to cats and their owners to be able to offer an intervention that improves survival with a good quality of life. Cats are recognized to have “reactive” blood vessels, and this response may worsen the outcome in ATE. The arteries in cats suffering from ATE will release various chemicals including one called endothelin. Endothelin causes an increased tendency to form more clots, and promotes severe inflammation and narrowing of collateral vessels supplying areas behind the site of the clot. Bosentan is a drug used successfully in people to treat various diseases such as coronary artery disease. This study looks to determine the effectiveness of bosentan in the treatment of cats with ATE.

More on cat health:
Winn Feline Foundation Library
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Each year, the Winn Feline Foundation receives proposals from veterinary researchers around the world who are interested in improving feline health. To date, Winn’s cumulative total in feline health research funding exceeds $4 million. Forty-four proposals were submitted by researchers seeking funding in this review cycle. This year, our team of veterinary consultants helped Winn select 10 projects for funding, for a total of $174,018. Here is one of those projects:

W12-037

The efficacy of bosentan, a mixed ETa ETb receptor antagonist, in cats with arterial thromboembolism

Investigators: Elizabeth Rozanski, Gareth Buckley; Tufts University

A Ricky Fund Project

Hypertrophic cardiomyopathy is a very common heart disease in cats. One of the most devastating complications of heart disease is development of blood clots called feline aortic thromboembolism (ATE), which cuts off the blood supply to one or more limbs. ATE is associated with a survival rate of less than 40% despite multiple efforts to try to improve outcomes. It is important to cats and their owners to be able to offer an intervention that improves survival with a good quality of life. Cats are recognized to have “reactive” blood vessels, and this response may worsen the outcome in ATE. The arteries in cats suffering from ATE will release various chemicals including one called endothelin. Endothelin causes an increased tendency to form more clots, and promotes severe inflammation and narrowing of collateral vessels supplying areas behind the site of the clot. Bosentan is a drug used successfully in people to treat various diseases such as coronary artery disease. This study looks to determine the effectiveness of bosentan in the treatment of cats with ATE.

More on cat health:
Winn Feline Foundation Library
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Read the Cat Health News Weekly
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Treatment of Blood Clots in Cats with Heart Disease

Welch KM, Rozanski EA, Freeman LM et al: Prospective evaluation of tissue plasminogen activator in 11 cats with arterial thromboembolism, J Feline Med Surg 12:122, 2010.

Feline arterial thromboembolism (ATE) is a serious and devastating event in cats often associated with acute ischemic necrosis of one or more limbs. It is seen in a small percentage of cats with hypertrophic cardiomyopathy. Acute aortic thromboembolism has been treated either by conservative methods such as supportive care and antithrombotics or by surgical thrombolectomy or administration of thrombolytic agents. This study’s objective was to evaluate the clinical response and side effects of a thrombolytic agent, tissue plasminogen activator (tPA), for the treatment of ATE. Eleven cats were prospectively enrolled into the study over a 6-month period. The study was terminated before enrollment of the planned 24 cats due to a high frequency of adverse outcomes. The results of this study demonstrate that tPA administration was associated with the return of pulses and improved limb scores in 6/9 cats within 12 hours of drug administration. However, adverse effects were seen in all cats following administration of tPA, including azotemia, neurological signs, cardiac arrhythmias, hyperkalemia, acidosis, and sudden death in one cat. The survival to discharge in this study was generally not higher than that reported in the literature with other therapies, including conservative therapy. [VT]

Related articles:
Stokol T, Brooks M, Rush JE et al: Hypercoagulability in cats with cardiomyopathy, J Vet Intern Med 22:546, 2008.

More on cat health: Winn Feline Foundation Library
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Welch KM, Rozanski EA, Freeman LM et al: Prospective evaluation of tissue plasminogen activator in 11 cats with arterial thromboembolism, J Feline Med Surg 12:122, 2010.

Feline arterial thromboembolism (ATE) is a serious and devastating event in cats often associated with acute ischemic necrosis of one or more limbs. It is seen in a small percentage of cats with hypertrophic cardiomyopathy. Acute aortic thromboembolism has been treated either by conservative methods such as supportive care and antithrombotics or by surgical thrombolectomy or administration of thrombolytic agents. This study’s objective was to evaluate the clinical response and side effects of a thrombolytic agent, tissue plasminogen activator (tPA), for the treatment of ATE. Eleven cats were prospectively enrolled into the study over a 6-month period. The study was terminated before enrollment of the planned 24 cats due to a high frequency of adverse outcomes. The results of this study demonstrate that tPA administration was associated with the return of pulses and improved limb scores in 6/9 cats within 12 hours of drug administration. However, adverse effects were seen in all cats following administration of tPA, including azotemia, neurological signs, cardiac arrhythmias, hyperkalemia, acidosis, and sudden death in one cat. The survival to discharge in this study was generally not higher than that reported in the literature with other therapies, including conservative therapy. [VT]

Related articles:
Stokol T, Brooks M, Rush JE et al: Hypercoagulability in cats with cardiomyopathy, J Vet Intern Med 22:546, 2008.

More on cat health: Winn Feline Foundation Library
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Follow us on Twitter
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Feline Cardiomyopathy and Thromboembolism

Winn funded research

Stokol, T., M. Brooks, et al. (2008). "Hypercoagulability in cats with cardiomyopathy." J Vet Intern Med 22(3): 546-552.

Arterial thromboembolism (ATE) is a serious and often fatal complication of cardiomyopathy in cats. Thromboemboli are believed to originate from clots in the left atrium or left atrial appendage. The factors causing clot formation are not fully understood. In this study, the researchers hypothesized that cats with cardiomyopathy develop ATE because they are in a systemic hypercoagulable state or have underlying endothelial (arterial or endocardial) injury. Healthy cats (n=30) and 3 groups of cats with cardiomyopathy were studied. Group 1 cats had left atrial enlargement (LAE) only. Group 2 cats had LAE with spontaneous echocardiographic contrast, atrial thrombi or both. Group 3 cats had acute ATE with LAE. Coagulation status was assessed in all three groups, including fibroginogen, Factor VIII, antithrombin, thrombin-antithrombin complex (TAT) and D-dimer concentrations. The 3 groups of cats with cardiac disease had higher median fibrinogen concentrations than did the healthy cats. Criteria of hypercoagulability were found exclusively in group 2 and group 3 cats. Hypercoagulability was not associated with left atrial size or congestive heart failure. Systemic hypercoagulability is evident in many cats with cardiomyopathy, often without concurrent congestive heart failure or overt ATE, and may represent a risk factor for ATE. The researchers concluded that the pathogenesis of ATE is multifactorial and therefore treatment and prevention of this syndrome might involve drug combinations modulating hemostasis and inflammatory pathways.

>> PubMed abstract

Related articles:

Bedard, C., A. Lanevschi-Pietersma, et al. (2007). "Evaluation of coagulation markers in the plasma of healthy cats and cats with asymptomatic hypertrophic cardiomyopathy." Vet Clin Pathol 36(2): 167-72.

>> PubMed abstract

Brazzell, J. L. and D. L. Borjesson (2007). "Evaluation of plasma antithrombin activity and D-dimer concentration in populations of healthy cats, clinically ill cats, and cats with cardiomyopathy." Vet Clin Pathol 36(1): 79-84.

>> PubMed abstract

More on cat health: Winn Feline Foundation Library

Winn funded research

Stokol, T., M. Brooks, et al. (2008). "Hypercoagulability in cats with cardiomyopathy." J Vet Intern Med 22(3): 546-552.

Arterial thromboembolism (ATE) is a serious and often fatal complication of cardiomyopathy in cats. Thromboemboli are believed to originate from clots in the left atrium or left atrial appendage. The factors causing clot formation are not fully understood. In this study, the researchers hypothesized that cats with cardiomyopathy develop ATE because they are in a systemic hypercoagulable state or have underlying endothelial (arterial or endocardial) injury. Healthy cats (n=30) and 3 groups of cats with cardiomyopathy were studied. Group 1 cats had left atrial enlargement (LAE) only. Group 2 cats had LAE with spontaneous echocardiographic contrast, atrial thrombi or both. Group 3 cats had acute ATE with LAE. Coagulation status was assessed in all three groups, including fibroginogen, Factor VIII, antithrombin, thrombin-antithrombin complex (TAT) and D-dimer concentrations. The 3 groups of cats with cardiac disease had higher median fibrinogen concentrations than did the healthy cats. Criteria of hypercoagulability were found exclusively in group 2 and group 3 cats. Hypercoagulability was not associated with left atrial size or congestive heart failure. Systemic hypercoagulability is evident in many cats with cardiomyopathy, often without concurrent congestive heart failure or overt ATE, and may represent a risk factor for ATE. The researchers concluded that the pathogenesis of ATE is multifactorial and therefore treatment and prevention of this syndrome might involve drug combinations modulating hemostasis and inflammatory pathways.

>> PubMed abstract

Related articles:

Bedard, C., A. Lanevschi-Pietersma, et al. (2007). "Evaluation of coagulation markers in the plasma of healthy cats and cats with asymptomatic hypertrophic cardiomyopathy." Vet Clin Pathol 36(2): 167-72.

>> PubMed abstract

Brazzell, J. L. and D. L. Borjesson (2007). "Evaluation of plasma antithrombin activity and D-dimer concentration in populations of healthy cats, clinically ill cats, and cats with cardiomyopathy." Vet Clin Pathol 36(1): 79-84.

>> PubMed abstract

More on cat health: Winn Feline Foundation Library

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