Title: Feline arterial thromboembolism

{{Short description|Domestic cat disease}}
[[File:Paraparesis-aortic thrombosis-cat.JPG|thumb|Bilateral hindlimb paralysis in a cat with arterial thromboembolism]]'''Feline arterial thromboembolism''' (FATE syndrome) (German: ''Feline arterielle Thromboembolie'') is a disease of the [[Cat|domestic cat]] in which blood clots ([[Thrombus|thrombi]]) block [[Artery|arteries]], causing severe [[circulatory problems]]. Relative to the total number of feline patients, the disease is rare, but relatively common in cats with heart disease: about one-sixth of cats with [[Cardiomyopathy|heart disease]] are affected. Heart disease is the most common underlying cause of arterial thromboembolism. It leads to the formation of blood clots in the heart, which leave it with the bloodstream and obstruct larger [[Blood vessel|blood vessels]], in cats mainly the [[aorta]] at the outlet of the two [[External iliac artery|external iliac arteries]]. Arterial thromboembolism occurs suddenly and is very painful. The blockage of the terminal portion of the aorta results in an undersupply of blood to the hind legs. The result is paralysis, cold hind extremities and later severe tissue damage. Rarely, other blood vessels are also affected; the symptoms of failure then depend on the supply area of the affected artery. Since drug [[thrombolysis]] in cats does not achieve satisfactory results, the focus today is on the self-dissolution of the clot by the body's own repair processes. Accompanying pain therapy and [[thrombosis prevention]] are performed and the underlying disease is treated. The mortality of arterial thromboembolism in cats is very high. Fifty to 60% of affected animals are [[Animal euthanasia|euthanized]] without attempted treatment, and only one-quarter to one-third of animals survive such an event. In about half of the recovered cats, thromboembolism recurs despite anticoagulation prophylaxis.

== Incidence, cause and origin of disease ==
Feline arterial thromboembolism is a rare disease, accounting for approximately 0.1-0.3% of the total number of feline patients.&lt;ref&gt;{{cite journal | doi=10.1016/j.jvc.2015.10.006 | title=Cardiogenic embolism in the cat | date=2015 | last1=Hogan | first1=Daniel F. | last2=Brainard | first2=Benjamin M. | journal=Journal of Veterinary Cardiology | volume=17 | pages=S202–S214 | pmid=26776579 }}&lt;/ref&gt;&lt;ref name=&quot;:0&quot;&gt;{{Cite journal |last=Borgeat |first=Kieran |date=Jan–Feb 2014 |title=Arterial thromboembolism in 250 cats in general practice: 2004-2012 |journal=Journal of Veterinary Internal Medicine |volume=28 |issue=1 |pages=102–108 |doi=10.1111/jvim.12249 |pmc=4895537 |pmid=24237457}}&lt;/ref&gt; The median age at onset of thromboembolism is 12 years (1 to 21 years).&lt;ref name=&quot;:0&quot; /&gt;
{| class=&quot;wikitable&quot;
|+Most common causes and their proportion in cats with arterial thromboembolism (after Smith et al. 2003).
!Underlying disease
!Frequency
|-
|hypertrophic cardiomyopathy
|52%
|-
|other cardiomyopathy
|17%
|-
|Hyperthyroidism
|9%
|-
|Tumor
|5%
|}

FATE syndrome develops in approximately 70% of cases as a result of heart disease, most commonly heart disease with cardiac wall thickening ([[Hypertrophic cardiomyopathy|Hypertrophic Cardiomyopathy]], HCM). Up to 17% of cats with HCM experience arterial thromboembolism, but cats with other cardiomyopathies are also at increased risk. Cats with abnormally increased [[hemostasis]], which can occur with [[Feline hyperthyroidism|hyperthyroidism]], [[Neoplasm|tumors]], extensive [[inflammation]], [[Sepsis|blood poisoning]] (sepsis), [[injury]], or [[disseminated intravascular coagulation]], represent another risk group.&lt;ref name=&quot;:1&quot;&gt;{{Cite journal |last1=Sänger |first1=Florian |last2=Dörfelt |first2=Rene |date=2020 |title=Feline arterielle Thromboembolie – Aktueller Stand der Diagnostik und Therapie. |journal=Kleintierpraxis |volume=65 |issue=4 |doi=10.2377/0023-2076-65-220}}&lt;/ref&gt; There is an increased genetic predisposition in male cats, which is related to the higher incidence of heart disease in male cats.&lt;ref&gt;{{Cite journal |last=Smith |first=Stephanie A. |year=2003 |title=Arterial thromboembolism in cats: acute crisis in 127 cases (1992–2001) and long-term management with low-dose aspirin in 24 cases. |journal=J Vet Intern Med |volume=17 |issue=1 |pages=73–83|doi=10.1111/j.1939-1676.2003.tb01326.x |pmid=12564730 }}&lt;/ref&gt;&lt;ref name=&quot;:0&quot; /&gt;
[[File:Reitender-Thrombus-numbered.jpg|thumb|Thrombus in the terminal branch of the aorta in a cat. 1 opened aorta with thrombus, 2 external iliac arteries, 3 common trunk of both internal iliac arteries, 4 circumflex ilium profunda, 5 mesenteric caudal artery, 6 descending colon. circumflexa ilium profunda, 5 A. mesenterica caudalis, 6 Colon descendens]]
Damage to the [[endocardium]] and slowing of blood flow in the enlarged left [[Atrium (heart)|atrium]] and [[Atrium (heart)|atrial auricle]] are primarily responsible for the formation of blood clots (thrombi). Tissue damage leads to the release of [[tissue factor]] and hemostasis.&lt;ref&gt;{{Cite journal |last1=Sänger |first1=Florian |last2=Dörfelt |first2=Rene |year=2020 |title=Feline arterielle Thromboembolie – Aktueller Stand der Diagnostik und Therapie. |journal=Kleintierpraxis |volume=65 |issue=4 |page=222 |doi=10.2377/0023-2076-65-220}}&lt;/ref&gt; The intact [[glycocalyx]] of the [[Endothelium|endothelial cells]] of the inner lining of the heart normally reduces contact with [[Blood cell|blood cells]] and [[Macromolecule|macromolecules]]. If endothelial cell injury occurs, [[reactive oxygen species]] (ROS), [[nitric oxide]] (NO), [[matrix metalloproteinase]], and proinflammatory [[Cytokine|cytokines]] are produced in increased amounts and [[Cell adhesion molecule|cell adhesion molecules]] are upregulated. Endothelial cell damage exposes the underlying [[extracellular matrix]], to which [[Platelet|platelets]] attach and form a clot.&lt;ref&gt;{{Cite journal |last1=Dehghani |first1=T. |last2=Panitch |first2=A. |year=2020 |title=Endothelial cells, neutrophils and platelets: getting to the bottom of an inflammatory triangle |journal=Open Biology |volume=10 |issue=10 |article-number=200161 |doi=10.1098/rsob.200161 |pmc=7653352 |pmid=33050789}}&lt;/ref&gt; The clot consists of platelets interconnected by the clotting protein [[fibrin]]. As the clot matures, the fibrin content increases and the clot may exhibit stratification.&lt;ref name=&quot;:2&quot;&gt;{{Cite journal |last=Loquet |first=Laurent |year=2018 |title=Feline arterial thromboembolism: prognostic factors and treatment |journal=Vlaams Tiergeneeskundig Tijdschrift |volume=87 |pages=164–175}}&lt;/ref&gt; Even in healthy animals, injuries to the endothelium occur spontaneously from time to time, but there is a balance between thrombus formation and breakdown. Substances such as [[Antithrombin|antithrombin III]], [[thrombomodulin]], [[tissue-type plasminogen activator]] and [[urokinase]] dissolve formed blood clots and [[prostacyclin]] and nitric oxide inhibit platelet aggregation.&lt;ref name=&quot;:1&quot; /&gt; Conservative treatment of arterial thromboembolism in cats is also based on this endogenous dissolution of the clot (see below).

In cats, the blood clots originate mainly in the left atrial auricle.&lt;ref name=&quot;:7&quot;&gt;{{Cite journal |last=Kochie |first=S. L. |date=January 2021 |title=Effects of pimobendan on left atrial transport function in cats |journal=Journal of Veterinary Internal Medicine |volume=35 |issue=1 |pages=10–21 |doi=10.1111/jvim.15976 |pmc=7848333 |pmid=33241877}}&lt;/ref&gt; They or parts of them are carried along with the blood flow, enter the [[aorta]] via the left ventricle, get stuck at vascular outlets and block them. This condition is called thrombo[[embolism]]. In cats, this occurs predominantly in the aorta in the area of its terminal branch, i.e., at the outlet of the two external iliac arteries (''[[External iliac artery|Aa. iliacae externae]]''). This is also called &quot;saddle thrombus&quot; or &quot;riding thrombus&quot;. This results in an [[ischemia]] to the rear extremities. In addition, platelets release [[thromboxane]] and [[serotonin]], which leads to [[vasoconstriction]] and thus to reduced blood flow even to blood vessels that are not directly affected. Serotonin also stimulates [[nociceptor]], which contributes to the high painfulness of the disease.&lt;ref name=&quot;:3&quot;&gt;{{Cite journal |last1=Sänger |first1=Florian |last2=Dörfelt |first2=Rene |year=2020 |title=Feline arterielle Thromboembolie – Aktueller Stand der Diagnostik und Therapie. |journal=Kleintierpraxis |volume=65 |issue=4 |doi=10.2377/0023-2076-65-220}}&lt;/ref&gt; Only in 10% of cases are other blood vessels affected, for example the [[brachial artery]], [[Pulmonary artery|pulmonary arteries]], [[cerebral circulation]], [[Superior mesenteric artery|intestinal vessels]] or [[coronary arteries]].&lt;ref name=&quot;:4&quot;&gt;{{Cite journal |last=Kirsch |first=Andreas |year=2008 |title=Aortenthrombose der Katze |journal=Veterinärspiegel |issue=2 |pages=84–90}}&lt;/ref&gt;&lt;ref name=&quot;:8&quot;&gt;{{Cite journal |last=AtkinsIn |first=Clarke |year=2007 |title=Systemic Arterial Embolism in Cats |url=https://www.vin.com/apputil/content/defaultadv1.aspx?id=3860863&amp;pid=11242&amp; |journal=World Small Animal Veterinary Association World Congress Proceedings }}&lt;/ref&gt;

In humans, heart disease (especially [[atrial fibrillation]]), increased blood clotting, and [[atherosclerosis]] are the most common underlying diseases for the development of [[Arterial embolism|arterial thromboembolism]]. Again, thrombi develop primarily in the left side of the heart. Most commonly, cerebral arteries ([[cerebral infarction]]) and arteries of the leg ([[limb infarction]], acute lower limb ischemia) are displaced. Less frequently, thromboembolism of the vessels of the arm, upper mesenteric artery or renal arteries ([[renal infarction]]) occurs.&lt;ref&gt;{{Cite journal |last=Lyaker |first=M. R. |date=January 2013 |title=Arterial embolism |journal=International Journal of Critical Illness and Injury Science |volume=3 |issue=1 |pages=77–87 |doi=10.4103/2229-5151.109429 |pmc=3665125 |pmid=23724391 |doi-access=free }}&lt;/ref&gt; In contrast, [[aortoiliac occlusive disease]] (aortic bifurcation syndrome), which corresponds to the most common localization in cats, is extremely rare in humans.&lt;ref&gt;{{Cite journal |last1=Chong |first1=B. K. |last2=Kim |first2=J. B. |date=April 2015 |title=Successful surgical treatment for thoracoabdominal aortic aneurysm with leriche syndrome |journal=The Korean Journal of Thoracic and Cardiovascular Surgery |volume=48 |issue=2 |pages=134–138 |doi=10.5090/kjtcs.2015.48.2.134 |pmc=4398158 |pmid=25883898}}&lt;/ref&gt; In domestic dogs, arterial thromboembolism occurs much less frequently than in cats; common underlying diseases in dogs are protein-losing [[Kidney disease|nephropathy]], diseases of the immune system, tumors, sepsis, heart disease, [[Protein losing enteropathy|protein-losing enteropathy]], and [[hypertension]].&lt;ref&gt;{{Cite journal |last=Gardiner |first=K. |year=2020 |title=Aortic thromboembolism in a basset hound-beagle crossbred dog with protein-losing nephropathy |journal=The Canadian Veterinary Journal |volume=61 |issue=3 |pages=309–311 |pmc=7020641 |pmid=32165756}}&lt;/ref&gt;&lt;ref&gt;{{Cite journal |last=Ruehl |first=M. |year=2020 |title=Outcome and treatment of dogs with aortic thrombosis: 100 cases (1997–2014) |journal=J. Vet. Intern. Med. |volume=34 |issue=5 |pages=1759–1767|doi=10.1111/jvim.15874 |pmid=33463770 |pmc=7517508 }}&lt;/ref&gt; Aortic thrombosis does occasionally occur in dogs, but here the thrombi arise directly at the aortic branch; as a thromboembolic event, as in cats, they are extremely rare.&lt;ref&gt;{{Cite journal |last=Winter |first=R. L. |year=2012 |title=Aortic thrombosis in dogs: presentation, therapy, and outcome in 26 cases |journal=Journal of Veterinary Cardiology |volume=14 |issue=2 |pages=333–342 |doi=10.1016/j.jvc.2012.02.008 |pmid=22591640}}&lt;/ref&gt; There are also isolated case reports of thromboembolism in the domestic horse,&lt;ref&gt;{{Cite journal |last=Ross |first=M. W. |year=1997 |title=First-pass radionuclide angiography in the diagnosis of aortoiliac thromboembolism in a horse |journal=Veterinary Radiology &amp; Ultrasound |volume=38 |issue=3 |pages=226–230 |doi=10.1111/j.1740-8261.1997.tb00845.x |pmid=9238795}}&lt;/ref&gt; whereas in other species they are of no practical significance. In laboratory animals used in human medical stroke research, thrombi are artificially generated.

== Symptoms, clinical diagnosis and laboratory findings ==
The disease occurs suddenly (peracute) and is accompanied by severe pain. Affected cats meow (&quot;vocalize&quot;) and often have [[hypothermia]]. The extent of further signs of the disease depends on the location of the clot and whether the vessel is completely or only partially blocked. Occlusion of the iliac arteries results in partial ([[paresis]]) or complete paralysis ([[Paralysis|plegia]]) of the hind extremities. In most cases, both hind legs are affected.&lt;ref&gt;{{Cite book |last=Jaggy |first=Andre |title=Atlas und Lehrbuch der Kleintierneurologie |publisher=Schlütersche |year=2005 |isbn=3-87706-739-5 |page=272}}&lt;/ref&gt; The muscles are hardened and painful after about 10 hours, especially the lower leg muscles.&lt;ref name=&quot;:4&quot; /&gt; The [[pulse]] at the [[femoral artery]] (''Arteria femoralis)'' is markedly decreased or absent in 78% of cases. The paws are cold and especially the area of the claws and pads often show bluish discoloration ([[cyanosis]]) or are strikingly pale. The [[Reflex|reflexes]] of the hindlimb ([[patellar reflex]], [[tibialis cranialis reflex]], and [[Withdrawal reflex|flexor reflex]]) are severely reduced or absent. Increased respiratory rate, dyspnea, and [[Syncope (medicine)|syncope]] are common. Loss of perception may also occur.&lt;ref&gt;{{Cite journal |last=Hassan |first=Marwa H. |year=2020 |title=Feline aortic thromboembolism: Presentation, diagnosis, and treatment outcomes of 15 cats |journal= Open Veterinary Journal|volume=10 |issue=3 |pages=340–346 |doi=10.4314/ovj.v10i3.13 |pmc=7703610 |pmid=33282706}}&lt;/ref&gt; The main symptoms can be summarized in the &quot;5-P rule&quot; - paresis (''Lähmung''), pallor (''Blässe''), pain (''Schmerz''), pulselessness (''Pulsverlust''), poikilothermia (''Untertemperatur''). The [[tail muscles]], [[Anal wink|anal reflex]], and  [[bladder]] function are mostly unaffected.&lt;ref name=&quot;:2&quot; /&gt;&lt;ref name=&quot;:3&quot; /&gt;

Other occlusions are much less common and the clinical presentation depends on the body part or organ affected. Occlusion of the brachial artery occurs predominantly on the right side and causes sudden paralysis of the forelimb.&lt;ref&gt;{{citation|author=Wendy A. Ware|date=2008|edition=4|editor=Richard W. Nelson und C. Guillermo Couto|isbn=978-0-323-06512-2|pages=194–200|periodical=Small Animal Internal Medicine|publisher=Elsevier Health Sciences|title=Systemic arterial thromboembolism in cats}}&lt;!-- auto-translated by Module:CS1 translator --&gt;&lt;/ref&gt; Thromboembolism of the [[pulmonary circulation]] is manifested by increased respiratory frequency and [[shortness of breath]].&lt;ref name=&quot;:5&quot;&gt;{{Cite journal |last=Hylands |first=R. |year=2006 |title=Pulmonary thromboembolism |journal=The Canadian Veterinary Journal |volume=47 |issue=4 |pages=385–388 |pmc=2828335 |pmid=16642881}}&lt;/ref&gt; The clinical picture of occlusion of cerebral circulation ([[cerebral infarction]]) depends strongly on the vessel affected and thus on the area of the brain damaged. In most cases, there are unilateral neurological deficits.&lt;ref name=&quot;:6&quot;&gt;{{Cite journal |last=Garosi |first=L. S. |year=2010 |title=Cerebrovascular disease in dogs and cats |journal=The Veterinary Clinics of North America. Small Animal Practice |volume=40 |issue=1 |pages=65–79 |doi=10.1016/j.cvsm.2009.09.001 |pmid=19942057}}&lt;/ref&gt; Occlusion of a coronary artery ([[myocardial infarction]]) leads to [[Arrhythmia|cardiac arrhythmias]], usually with a fatal outcome, and is therefore often no longer presented to a veterinarian at all, so that its frequency is possibly underestimated. Occlusion of renal or intestinal vessels causes severe abdominal pain ([[acute abdomen]]) and often also leads quickly to death.&lt;ref name=&quot;:9&quot;&gt;{{Cite journal |last=Galloway |first=Pru |year=2001 |title=Feline Aortic Thromboembolism |journal=Proc of the Companion Animal Society of the NZVA |volume=214}}&lt;/ref&gt; There are also [[Case report|case reports]] of simultaneous occlusion of several vessels with paralysis of all limbs&lt;ref&gt;{{Cite journal |last=Bowles |first=D. B. |year=2010 |title=Cardiogenic arterial thromboembolism causing non-ambulatory tetraparesis in a cat |journal=Journal of Feline Medicine and Surgery |volume=12 |issue=2 |pages=144–150 |doi=10.1016/j.jfms.2009.06.004 |pmid=19692276|s2cid=37119533 |pmc=10911432 }}&lt;/ref&gt; or of cerebellum and kidneys with severe balance disorders.&lt;ref&gt;{{Cite journal |last1=Cherubini |first1=G. B. |last2=Rusbridge |first2=C. |last3=Singh |first3=B. P. |last4=Schoeniger |first4=S. |last5=Mahoney |first5=P. |year=2007 |title=Rostral cerebellar arterial infarct in two cats |journal=Journal of Feline Medicine and Surgery |volume=9 |issue=3 |pages=246–253 |doi=10.1016/j.jfms.2006.12.003 |pmid=17317258|s2cid=25909472 |url=http://researchonline.rvc.ac.uk/id/eprint/994/ |pmc=10822625 }}&lt;/ref&gt;
[[File:LA thrombus cat.webm|thumb|Large thrombus in the left atrium of a cat, echocardiography]]
Listening to the heart ([[auscultation]]) usually reveals [[Heart murmur|heart murmurs]], an [[Arrhythmia|irregular heartbeat]], [[palpitations]], [[Premature heart beat|extrasystoles]] and a &quot;gallop rhythm&quot; - a sequence of heart sounds reminiscent of a galloping horse. Up to two-thirds of FATE patients are in [[Vasocongestion|congestive]] heart failure,&lt;ref name=&quot;:3&quot; /&gt; in which the heart no longer pumps enough blood to the body. Atrial fibrillation detectable by [[Electrocardiography|ECG]] is an additional risk factor. Aortic thrombus can often be visualized directly by [[Medical ultrasound|sonography]],&lt;ref&gt;{{citation|author=Alan Kovacevic|date=2017|editor=Nadja Siegrist|isbn=978-3-13-205281-9|location=Stuttgart|pages=231–255|periodical=Notfallmedizin für Hund und Katze|publisher=Enke|title=Kardiologische Notfälle}}&lt;!-- auto-translated by Module:CS1 translator --&gt;&lt;/ref&gt; and [[angiography]] or [[electromyography]] may also be performed if necessary. [[Echocardiography]] can be used to visualize thrombi and their precursors in the heart and to assess the functional status of the heart. Loss of pulse at the femoral artery can also be detected by [[Doppler ultrasonography|doppler sonography]], although the pulse is still detectable sonographically if the vessel is incompletely occluded.&lt;ref&gt;{{Cite journal |last1=Smith |first1=S. A. |last2=Tobias |first2=A. H. |year=2004 |title=Smith Feline arterial thromboembolism: an update |journal=The Veterinary Clinics of North America. Small Animal Practice |volume=34 |issue=5 |pages=1245–1271 |doi=10.1016/j.cvsm.2004.05.006 |pmid=15325481}}&lt;/ref&gt; [[Thermography|Infrared thermography]] can be used to objectify temperature differences between the forelimbs and hindlimbs. The [[Evaluation of binary classifiers|sensitivity]] of this method is between 80 and 90 %, the specificity is 100 %.&lt;ref&gt;{{Cite journal |last=Pouzot-Nevoret |first=C. |year=2018 |title=Infrared thermography: a rapid and accurate technique to detect feline aortic thromboembolism |journal=Journal of Feline Medicine and Surgery |volume=20 |issue=8 |pages=780–785 |doi=10.1177/1098612X17732485 |pmid=28948905|s2cid=9199383 |pmc=11104137 }}&lt;/ref&gt; A thromboembolism of the lung often remains undetected; in this case, a [[chest radiograph]] can provide initial indications, and a definite diagnosis can be made by means of [[CT scan]]&lt;ref name=&quot;:5&quot; /&gt; or [[scintigraphy]] of the lung.&lt;ref&gt;{{Cite journal |last=Pouchelon |first=J. L. |year=1997 |title=Diagnosis of pulmonary thromboembolism in a cat using echocardiography and pulmonary scintigraphy |journal=The Journal of Small Animal Practice |volume=38 |issue=7 |pages=306–310 |doi=10.1111/j.1748-5827.1997.tb03472.x |pmid=9239634}}&lt;/ref&gt; If a stroke is suspected, [[magnetic resonance imaging]] is indicated.&lt;ref name=&quot;:6&quot; /&gt;

The [[Catalyst activity|activities]] of the [[Enzyme|enzymes]] [[creatine kinase]] (CK) and [[Aspartate transaminase|aspartate aminotransferase]] (AST) are elevated due to the death of muscle cells in the blood.&lt;ref name=&quot;:3&quot; /&gt; If cardiac disease is present, which is often the case, [[Brain natriuretic peptide 32|brain natriuretic peptide]] is above the [[reference range]].&lt;ref&gt;{{Cite journal |last=Ward |first=J. L. |year=2018 |title=Evaluation of point-of-care thoracic ultrasound and NT-proBNP for the diagnosis of congestive heart failure in cats with respiratory distress |journal=Journal of Veterinary Internal Medicine |volume=32 |issue=5 |pages=1530–1540 |doi=10.1111/jvim.15246 |pmc=6189386 |pmid=30216579}}&lt;/ref&gt; The &quot;kidney values&quot; ([[creatinine]], [[urea]], [[Asymmetric dimethylarginine|SDMA]]) may also be elevated due to the [[Shock (circulatory)|shock-induced]] reduced renal function (prerenal [[azotemia]]). However, all laboratory values are not specific for arterial thromboembolism and play only a minor role in confirming the diagnosis. Determination of [[Blood sugar level|blood glucose]] or [[lactate concentration]] in the body compared with that in the paralyzed limb may be helpful.&lt;ref&gt;{{Cite journal |last1=Sänger |first1=Florian |last2=Dörfelt |first2=Rene |year=2020 |title=Feline arterielle Thromboembolie – Aktueller Stand der Diagnostik und Therapie |journal=Kleintierpraxis |volume=65 |issue=4 |doi=10.2377/0023-2076-65-220}}&lt;/ref&gt; Determination of [[Levothyroxine|thyroxine]] (T4) concentration in the blood is useful for detecting hyperthyroidism; hyperthyroidism was not previously known in 1.7% of cats with thromboembolism.&lt;ref name=&quot;:0&quot; /&gt;

== Diagnosis and differential diagnosis ==
In most cases, the diagnosis can already be made in the most common location (aortic thrombosis) based on the previous report and clinical signs (peracute posthand paralysis without [[Traumatic brain injury|trauma]]).&lt;ref name=&quot;:0&quot; /&gt;&lt;ref name=&quot;:10&quot;&gt;{{Cite journal |last=Luis Fuentes |first=Virginia |year=2012 |title=Arterial thromboembolism: risks, realities and a rational first-line approach |journal=Journal of Feline Medicine and Surgery |volume=14 |issue=7 |pages=459–470 |doi=10.1177/1098612X12451547|pmid=22736680 |pmc=8495465 }}&lt;/ref&gt; Existing cardiac disease provides further clues, but cardiac disease is already known in only about 15% of cats with thromboembolism.&lt;ref name=&quot;:11&quot;&gt;{{Cite journal |last=Hogan |first=Daniel F. |year=2015 |title=Secondary prevention of cardiogenic arterial thromboembolism in the cat: The double-blind, randomized, positive-controlled feline arterial thromboembolism; clopidogrel vs. aspirin trial (FAT CAT) |journal=J Vet Cardiol |volume=17 |pages=306–317 |doi=10.1016/j.jvc.2015.10.004 |pmid=26776588}}&lt;/ref&gt;

The other more common [[ischemic myopathy]], [[Syndrome of Kippfenster|syndrome of ''Kippfenster'']], can usually be ruled out by questioning the animal's owner. In addition, tilt window syndrome is not associated with severe pain. [[Differential diagnosis]] should continue to exclude primarily trauma to the spinal cord (traffic accident, window fall), which may be due to an event not observed by the owner. A [[Spinal disc herniation|herniated disc]] or a [[spinal cord infarction]] can also lead to sudden signs of paralysis. [[Neoplasm|Tumors]] in the spinal cord or [[spinal canal]] can also cause afterhand paralysis, but these usually develop slowly and signs of loss occur gradually.&lt;ref&gt;{{citation|date=2019|editor=Jan-Gerd Kresken |editor2=Ralph T. Wendt |editor3=Peter Modler|isbn=978-3-13-242994-9|location=Stuttgart|pages=389–392|periodical=Praxis der Kardiologie Hund und Katze|publisher=Thieme|title=Feline Arterielle Thromboembolie}}&lt;!-- auto-translated by Module:CS1 translator --&gt;&lt;/ref&gt;

The diagnosis of vascular occlusions of the internal organs is more difficult; here, special examinations ([[CT scan|CT]], [[Magnetic resonance imaging|MRI]]) are required to confirm the diagnosis, which are only available in larger facilities.

== Therapy ==
Treatment of arterial thromboembolism in cats consists of pain management, prevention of further clot formation, and treatment of [[heart failure]], if necessary. Intensive medical care is usually required for three days before treatment can be continued at home.&lt;ref&gt;{{Cite journal |last1=Sänger |first1=Florian |last2=Dörfelt |first2=Rene |title=Feline arterielle Thromboembolie – Aktueller Stand der Diagnostik und Therapie |journal=Kleintierpraxis |date=2020 |volume=65 |issue=4 |page=232 |doi=10.2377/0023-2076-65-220}}&lt;/ref&gt;

To reduce pain, administration of potent analgesics is indicated, with [[Opioid|opioid analgesics]] such as [[levomethadone]] or [[fentanyl]] being the most effective.&lt;ref name=&quot;:10&quot; /&gt; However, both agents are not approved for use in cats in the EU and must therefore be redirected in the sense of a [[therapeutic emergency]]. In addition, fentanyl is only effective for about 30 minutes, while levomethadone is effective for about 5 hours, based on data for dogs,&lt;ref&gt;{{citation|author=Wolfgang Löscher|date=2006|edition=7|editor=Wolfgang Löscher, Fritz Rupert Ungemach und Reinhard Kroker|isbn=978-3-8304-4160-1|location=Berlin|pages=95–96|periodical=Pharmakotherapie bei Haus- und Nutztieren|publisher=Paul Parey|title=Vollsynthetische Morphinabkömmlinge}}&lt;!-- auto-translated by Module:CS1 translator --&gt;&lt;/ref&gt; which limits further treatment at home. Continuous drip infusion with the combination of fentanyl and lidocaine has been described. Lidocaine, in addition to its analgesic effect, also protects to some extent against damage caused by reopening of the occluded vessel ([[reperfusion injury]]). However, the [[Therapeutic index|therapeutic range]] of lidocaine in cats is very narrow; as little as 6 mg/kg can be lethal.&lt;ref&gt;{{Cite journal |last1=O' Brien |first1=T.Q. |last2=Clark-Price |first2=S.C. |last3=Evans |first3=E.E. |last4=Di Fazio |first4=R. |last5=McMichael |first5=M.A |date=December 2010 |title=Infusion of a lipid emulsion to treat lidocaine intoxication in a cat |journal=Journal of the American Veterinary Medical Association |edition=4 |volume=237 |issue=12 |pages=1455–1458|doi=10.2460/javma.237.12.1455 |pmid=21155686 |doi-access=free }}&lt;/ref&gt; The only opioid analgesic approved for cats, [[buprenorphine]], does not have sufficient analgesic effect for initial treatment, at least not when there is total occlusion of both external iliac arteries. It can be used for continuing treatment at home, especially since it can be easily administered through the oral mucosa and has a duration of action of about 8 hours. [[Nonopiod analgesics|Non-opioid analgesics]] do not provide adequate pain relief and may increase circulatory disturbances in animals, causing renal or gastrointestinal damage. Only metamizole is suitable for subsequent further treatment.&lt;ref&gt;{{Cite journal |last1=Sänger |first1=Florian |last2=Dörfelt |first2=Rene |year=2020 |title=Feline arterielle Thromboembolie – Aktueller Stand der Diagnostik und Therapie |journal=Kleintierpraxis |volume=65 |issue=4 |page=228 |doi=10.2377/0023-2076-65-220}}&lt;/ref&gt;
[[File:S-Clopidogrel structure.svg|thumb|Structural formula of clopidogrel]]
Inhibiting the formation of further blood clots, [[Thrombosis prevention|thrombosis prophylaxis]], is the second important pillar of FATE treatment. It should be carried out as early as possible.&lt;ref name=&quot;:10&quot; /&gt; For this purpose, agents to inhibit [[hemostasis]] such as [[Low-molecular-weight heparin|low-molecular-weight heparins]] are used first, along with agents to prevent platelet aggregation ([[thrombocyte aggregation]]) such as [[aspirin]] and [[clopidogrel]].&lt;ref name=&quot;:12&quot;&gt;{{Cite journal |last=Fontara |first=Sonja |year=2016 |title=Hypertrophe Kardiomyopathie bei der Katze |journal=Kleintierpraxis |volume=61 |issue=10 |pages=560–578}}&lt;/ref&gt; For long-term prophylaxis, clopidogrel is preferably administered because it significantly prolongs survival compared with aspirin.&lt;ref name=&quot;:11&quot; /&gt;&lt;ref&gt;{{Cite journal |last=Kovacevic |first=Alan |year=2014 |title=Feline Aortenthrombose – Ist eine Prophylaxe sinnvoll? |journal=Kleintier Konkret |volume=17 |issue=3 |pages=22–26 |doi=10.1055/s-0033-1361537|s2cid=71609253 |doi-access=free }}&lt;/ref&gt; The use of the active ingredient [[rivaroxaban]] as another effective drug is also being discussed.&lt;ref&gt;{{cite web | url=https://vet.uga.edu/vet-med-offers-clinical-trial-for-cats-with-history-of-arterial-thromb/ | title=Vet Med Offers Clinical Trial for Cats with History of Arterial Thromboembolism | date=2 March 2016 }}&lt;/ref&gt; A 2021 study was able to show that the combination of clopidogrel and rivaroxaban is an effective recurrence prophylaxis.&lt;ref&gt;{{Cite journal |last=Lo |first=S. T. |year=2022 |title=Dual therapy with clopidogrel and rivaroxaban in cats with thromboembolic disease |journal=Journal of Feline Medicine and Surgery |volume=24 |issue=4 |pages=277–283 |doi=10.1177/1098612X211013736 |pmc=8830184 |pmid=33966532}}&lt;/ref&gt;

Cats in congestive heart failure are given [[Breathing apparatus|supplemental oxygen]] to compensate for the [[Hypoxia (medical)|hypoxia]]. High doses of [[furosemide]] are used to reduce [[Preload (cardiology)|preload]] and [[afterload]] and thus unload the heart.&lt;ref name=&quot;:10&quot; /&gt; In advanced heart disease with ventricular dilatation (DCM) or heart disease with cardiac wall thickening ([[Dilated cardiomyopathy|DCM]]), pumping efficiency can be improved with [[pimobendan]], possibly also with [[dobutamine]].&lt;ref name=&quot;:13&quot;&gt;{{Cite journal |last1=Sänger |first1=Florian |last2=Dörfelt |first2=Rene |year=2020 |title=Feline arterielle Thromboembolie – Aktueller Stand der Diagnostik und Therapie |journal=Kleintierpraxis |volume=65 |issue=4 |page=229 |doi=10.2377/0023-2076-65-220}}&lt;/ref&gt; Pimobendan also increases blood flow in the left atrium and heart ear to a small extent and additionally improves atrial function.&lt;ref name=&quot;:7&quot; /&gt; On the other hand, if there is no congestive heart failure but reduced [[Hemodynamics|blood flow]] (perfusion), then [[intravenous therapy]] are [[Infusion|infused]].&lt;ref name=&quot;:13&quot; /&gt; In the case of underlying hyperthyroidism, [[Antithyroid agent|thyrostatic]] drugs such as [[thiamazole]] or [[carbimazole]] are administered.&lt;ref&gt;{{Cite journal |last1=Peterson |first1=M. E. |last2=Aucoin |first2=D. P. |year=1993 |title=Comparison of disposition of carbimazole and methimazole in clinically normal cats |journal=Res. Vet. Sci. |volume=54 |issue=3 |pages=351–355 |doi=10.1016/0034-5288(93)90134-2 |pmid=8337482}}&lt;/ref&gt;

The benefit of external heat application in cats with hypothermia is controversial. Often the anterior part of the body has a normal temperature and the undertemperature only affects the posterior part and thus also the [[rectum]], where body temperature is normally measured in cats. Measurement in the axillary region or in the ear is unreliable.&lt;ref&gt;{{Cite journal |last=Smith |first=Victoria A. |year=2015 |title=Comparison of axillary, tympanic membrane and rectal temperature measurement in cats |journal=J Feline Med Surg |volume=17 |issue=12 |pages=1028–1034 |doi=10.1177/1098612X14567550 |pmid=25600082|s2cid=31867178 |doi-access=free |pmc=10816342 }}&lt;/ref&gt; However, comparison between axillary and rectal temperature at least provides clues to distinguish between local and general undertemperature. In the case of the latter, an application of heat is indicated.&lt;ref&gt;{{Cite journal |last1=Sänger |first1=Florian |last2=Dörfelt |first2=Rene |year=2020 |title=Feline arterielle Thromboembolie – Aktueller Stand der Diagnostik und Therapie |journal=Kleintierpraxis |volume=65 |issue=4 |page=230 |doi=10.2377/0023-2076-65-220}}&lt;/ref&gt;

The obvious treatment, reopening of the vessel by drug dissolution (thrombolysis) or [[surgery|invasive]] removal of the clot ([[thrombectomy]]), as long established in human medicine for occlusive diseases such as [[cerebral infarction]] or [[myocardial infarction]], provides unsatisfactory results in cats and is therefore no longer recommended.&lt;ref name=&quot;:10&quot; /&gt; Thrombolysis with [[streptokinase]], [[urokinase]] or [[tissue-type plasminogen activator]] has not improved [[treatment success]] in various studies. This usually results in frequently fatal [[reperfusion injury]], [[hyperkalemia]], [[metabolic acidosis]], [[kidney failure]], and [[bleeding]], so that the survival rate is often lower than with conservative treatment.&lt;ref name=&quot;:14&quot;&gt;{{Cite journal |last=Reimer |first=S. B. |year=2006 |title=Use of rheolytic thrombectomy in the treatment of feline distal aortic thromboembolism |journal=Journal of Veterinary Internal Medicine |volume=20 |issue=2 |pages=290–296 |doi=10.1111/j.1939-1676.2006.tb02859.x |pmid=16594585|doi-access=free }}&lt;/ref&gt;&lt;ref&gt;{{Cite journal |last=Guillaumin |first=J. |year=2019 |title=Thrombolysis with tissue plasminogen activator (TPA) in feline acute aortic thromboembolism: a retrospective study of 16 cases |journal=Journal of Feline Medicine and Surgery |volume=21 |issue=4 |pages=340–346 |doi=10.1177/1098612X18778157 |pmid=29807505|s2cid=44135779 |pmc=10814639 }}&lt;/ref&gt; In human medicine, such treatments are only performed in highly specialized facilities ([[Cardic center|cardiac centers]], [[stroke units]]) with a high level of personnel and equipment. Surgical removal of the thrombus is also rarely performed in veterinary medicine because of the associated risks, although it can be successful in individual cases.&lt;ref&gt;{{Cite journal |last=Vezzosi |first=T. |year=2020 |title=Surgical embolectomy in a cat with cardiogenic aortic thromboembolism |journal=Journal of Veterinary Cardiology |volume=28 |issue=4 |pages=48–54 |doi=10.1016/j.jvc.2020.03.002 |pmid=32339993|s2cid=216183298 }}&lt;/ref&gt; It is associated with the same complications as thrombolysis and is therefore no longer recommended. Therefore, the current focus is on endogenous dissolution of the clot and thus spontaneous [[revascularization]], which occurs quickly enough in just under 40% of cases.&lt;ref name=&quot;:14&quot; /&gt;

== Prognosis and prevention ==
[[File:Smoke-in-feline-atrium.webm|thumb|Spontaneous echocardiographic contrast ('smoke') - a precursor of thrombus formation - in the left atrium of a cat]]
The treatment outlook ([[prognosis]]) for aortic thromboembolism is uncertain to poor. According to a U.S. study, only about one-third of cats survive arterial thromboembolism, with half of those who die being euthanized without attempted treatment.&lt;ref&gt;{{Cite journal |last=Hogan |first=D. F. |year=2017 |title=Feline Cardiogenic Arterial Thromboembolism: Prevention and Therapy |journal=The Veterinary Clinics of North America. Small Animal Practice |volume=47 |issue=5 |pages=1065–1082 |doi=10.1016/j.cvsm.2017.05.001 |pmid=28662872}}&lt;/ref&gt; In a U.K. study, about 60% of patients were euthanized. Only 27% survived the first 24 hours. The median survival time was 94 days, and after one year only 2% of the animals were still alive.&lt;ref name=&quot;:0&quot; /&gt;

Prognosis depends largely on the extent and duration of damage, with bilateral complete occlusions of the iliac arteries having the lowest chance of survival. If only one limb is affected and there is residual motor function, there is a better chance that the cat will recover and continue to live with a good quality of life. If the internal body temperature is above 37.2 °C - the normal temperature in domestic cats is about 39 °C - the prospect of treatment is better than if the temperature is more severely below normal. Excess blood potassium ([[hyperkalemia]]) and elevated kidney enzymes ([[azotemia]]) are other negative prognostic factors. Even after spontaneous reopening of the blood vessel ([[Revascularization|revaskularization]]), [[Relapse|relapses]] often occur due to a new thromboembolism, which even thromboprophylaxis cannot reliably prevent.&lt;ref name=&quot;:0&quot; /&gt;&lt;ref name=&quot;:12&quot; /&gt;&lt;ref name=&quot;:14&quot; /&gt; In half of the patients, a new thromboembolism occurs despite treatment with clopidogrel.&lt;ref name=&quot;:2&quot; /&gt; In addition, the extent of the heart disease, in particular the extent of atrial enlargement and the pumping capacity of the left ventricle, determines the further survival of the patient.&lt;ref&gt;{{Cite journal |last=Payne |first=J. R. |year=2015 |title=Risk factors associated with sudden death vs. congestive heart failure or arterial thromboembolism in cats with hypertrophic cardiomyopathy |journal=Journal of Veterinary Cardiology |volume=17 |pages=318–328 |doi=10.1016/j.jvc.2015.09.008 |pmid=26776589|url=https://researchonline.rvc.ac.uk/id/eprint/10015/1/10015.pdf }}&lt;/ref&gt;

In contrast, the prognosis is favorable for occlusion of smaller cerebral arteries. There is often a reduction in the signs of failure within two to three weeks, as other areas of the brain take over the function of the infarcted area.&lt;ref&gt;{{Cite journal |last=Boudreau |first=C. E. |year=2018 |title=An Update on Cerebrovascular Disease in Dogs and Cats |journal=The Veterinary Clinics of North America. Small Animal Practice |volume=48 |issue=1 |pages=45–62 |doi=10.1016/j.cvsm.2017.08.009 |pmid=29056397}}&lt;/ref&gt; Occlusion of the brachial artery also has a good chance of recovery.&lt;ref name=&quot;:8&quot; /&gt; The prognosis and mortality of [[Pulmonary embolism|pulmonary thromboembolism]] is not known, as it is very rare.&lt;ref&gt;{{Cite journal |last=Goggs |first=Robert |year=2009 |title=Pulmonary thromboembolism |journal=Journal of Veterinary Emergency and Critical Care |volume=19 |issue=1 |pages=30–52 |doi=10.1111/j.1476-4431.2009.00388.x |pmid=19691584|url=https://researchonline.rvc.ac.uk/id/eprint/1789/1/1789.pdf }}&lt;/ref&gt; Anecdotal reports indicate that cats can survive such an event and lung function can return to normal with formation of [[Collateral circulation|collaterals]].&lt;ref name=&quot;:5&quot; /&gt; Other occlusions (intestinal, renal, and coronary arteries) are very often fatal.&lt;ref name=&quot;:8&quot; /&gt;&lt;ref name=&quot;:9&quot; /&gt;

Some [[small-animal]] [[Cardiology|cardiologists]] recommend coagulation prophylaxis already in the presence of certain cardiac changes, i.e., before the occurrence of thromboembolism. For example, one study showed that a flow velocity in the left heart ear of less than 0.2 m/s was associated with the occurrence of thrombi and spontaneous echocardiographic contrast (smoke). Spontaneous echocardiographic contrast is an aggregation of red blood cells and thus a thrombus precursor that resembles smoke on sonographic imaging.&lt;ref&gt;{{Cite journal |last1=Schober |first1=Karsten E. |last2=Maerz |first2=Imke |title=Assessment of left atrial appendage flow velocity and its relation to spontaneous echocardiographic contrast in 89 cats with myocardial disease |journal=J Vet Intern Med |date=2006 |volume=20 |issue=1 |pages=120–130 |doi=10.1892/0891-6640(2006)20[120:aolaaf]2.0.co;2 |pmid=16496931}}&lt;/ref&gt; However, [[Prospective cohort study|prospective studies]] demonstrating the efficacy of such treatment have yet to be performed.&lt;ref name=&quot;:2&quot; /&gt;

== References ==
&lt;references /&gt;

== Bibliography ==

* {{citation|author=Dominik Faissler|date=2005|editor=Andre Jaggy|isbn=3-87706-739-5|location=Hannover|pages=272–273|periodical=Atlas und Lehrbuch der Kleintierneurologie|publisher=Schlütersche|title=Ischämische Myopathie}}&lt;!-- auto-translated by Module:CS1 translator --&gt;
* Florian Sänger und Rene Dörfelt: ''Feline arterielle Thromboembolie – Aktueller Stand der Diagnostik und Therapie.'' In: [[:de:Kleintierpraxis_(Zeitschrift)|''Kleintierpraxis'']] Band 65, Nummer 4, April 2020, S. 220–235. [[doi:10.2377/0023-2076-65-220]]
* {{citation|author=Lisa Joy Miriam Keller|date=2019|editor=Markus Killich|isbn=978-3-13-219991-0|location=Stuttgart|pages=369–370|periodical=Kleintierkardiologie.|publisher=Georg Thieme|title=Hypertrophe Kardiomyopathie der Katze}}&lt;!-- auto-translated by Module:CS1 translator --&gt;
* {{citation|author=Alan Kovacevic|date=2017|editor=Nadja Siegrist|isbn=978-3-13-205281-9|location=Stuttgart|pages=231–255|periodical=Notfallmedizin für Hund und Katze|publisher=Enke|title=Kardiologische Notfälle}}&lt;!-- auto-translated by Module:CS1 translator --&gt;

[[Category:Cat diseases]]
[[Category:Diseases of arteries, arterioles and capillaries]]