Cardiovascular System III & IV - Veterinary Study Notes PDF

Diseases of the Cardiovascular System III: Cardiomyopathies and Valvular Disease Dr Paul Pollard MVB Cert AVP (VC) MSc VetEd SFHEA MRCVS [email protected] PollEv.com/paulpollard090 Learning Objectives » Discuss the phenotypic recognition of cardiomyopathies in small animals » Explore the re...

Diseases of the Cardiovascular System III: Cardiomyopathies and Valvular Disease Dr Paul Pollard MVB Cert AVP (VC) MSc VetEd SFHEA MRCVS [email protected] PollEv.com/paulpollard090 Learning Objectives » Discuss the phenotypic recognition of cardiomyopathies in small animals » Explore the relationship between phenotype, cause, and, where applicable, genotype in the case of small animal cardiomyopathies » Construct a differential diagnosis list based on clinical presentations associated with valvular diseases and choose appropriate diagnostics » Determine appropriate medical and surgical interventions in the management and treatment of valvular disease and determine appropriate prognosis #universityofsurrey 2 Cardiomyopathies » Cardiomyopathies = “Disease of the myocardium” » Distinguish from heart disease of a known cause such as: Hypertension Ischaemia (coronary heart disease) Viral myocarditis Septic myocarditis Hyperthyroidism Neoplastic infiltrative disease of the myocardium #universityofsurrey 3 Cardiomyopathies 1. Dilated Cardiomyopathy (DCM) Common in dogs Characterised by ventricular dilation and thin hypomotile ventricular wall 2. Hypertrophic Cardiomyopathy (HCM) Common in cats Characterised by hypertrophy of the ventricular wall and a restricted ventricular lumen 3. Restrictive Cardiomyopathy (RCM) Characterised by a stiff ventricular wall and marked dilation of the atrium feeding that ventricle 4. Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC) Boxers Fibrofatty infiltrate that preferentially affects the right ventricle 5. Unclassified Cardiomyopathy #universityofsurrey 4 Dilated Cardiomyopathy » Progressive cardiac enlargement, systolic dysfunction and eccentric hypertrophy of the left ventricle » High prevalence in some breeds, therefore a hereditary predisposition is suspected » True aetiology is likely to be multifactorial » Diseases that can mimic DCM include: Taurine deficiency (cats – now very rare; Golden Retrievers? https://doi.org/10.1371/journal.pone.0209112) Taurine and carnitine deficiency in American Cocker Spaniels L-carnitine deficiency in Boxers Toxic (doxorubicin, a chemotherapeutic agent) Grain free diets? – Ask this if you get DCM in an unusual breed eg Yorkie Lamb based diets / Vegan Diets #universityofsurrey 5 #universityofsurrey 6 #universityofsurrey 7 #universityofsurrey 8 #universityofsurrey 9 Grain Free Diets and DCM? » FDA website https://www.fda.gov/animal-veterinary/news-events/fda-investigation-potential-link-between-certain-diets-and-canine- dilated-cardiomyopathy » The FDA is continuing to investigate and gather more information in an effort to identify whether there is a specific dietary link to development of DCM and will provide updates to the public as information develops #universityofsurrey 10 #universityofsurrey 11 #universityofsurrey 12 Dilated Cardiomyopathy » Breed predisposition: Medium to large breed dogs – Doberman, Great Dane, Wolfhound, Weimeraner, GSD, Labrador, Springer Spaniel, Newfoundland, Dogue de Bordeaux, Boxers, Old English Sheepdog… Doberman Pinschers – appears to be autosomal dominant. Splice-site mutation in pyruvate dehydrogenase kinase 4 (PDK4) gene identified in North American Dobermans – incompletely penetrant Great Danes – appears to be familial. One study showed male dogs were over-represented suggesting X-linked inheritance in at least some families » Sex: No predisposition (except above case in Great Danes) » Clinical presentation: adult onset disease Asymptomatic/occult phase – usually progressive Symptomatic phase – coughing/dyspnoea/ascites due to CHF, syncope, exercise intolerance, sudden death #universityofsurrey 13 Dilated Cardiomyopathy » Physical Findings Occult Phase: Commonly seen clinical signs Overt clinical signs Soft systolic heart murmur Moderate intensity systolic heart murmur Irregular heart rhythm Irregular heart rhythm Pulse deficits Pulse deficits Tachypnoea Dyspnoea Increased bronchovesicular sounds and pulmonary Occult Phase: Occasional clinical signs crackles Diastolic gallop Weakness Weak pulse Jugular vein distension Less common clinical signs Decreased intensity of heart sounds Jugular vein distension Ascites Hepatomegaly Pale MM, hypothermia #universityofsurrey 14 Dilated Cardiomyopathy » Radiography #universityofsurrey 15 Dilated Cardiomyopathy » Echocardiography – the only reliable way to diagnose DCM Ettinger, 2017 #universityofsurrey 16 Dilated Cardiomyopathy » Early diagnosis is possible with echocardiography before clinical signs of heart failure occur » Annual two-dimensional and M-mode echocardiography is recommended for adult dogs of at risk breeds or if early signs (heart murmur, gallop, tachyarrhythmias) are detected » Also ECG for signs of LV and LA enlargement +/- arrhythmias (atrial fibrillation and/or ventricular tachyarrhythmias are most common) » Cardiac biomarkers NTproBNP - Troponin Beijerink, 2012 » Treatment – covered in later lectures #universityofsurrey 17 Hypertrophic Cardiomyopathy (HCM) » HCM is a primary myocardial disease that results in thickening (concentric hypertrophy) of the left ventricular walls (free wall and interventricular septum) » Prevalence of up to 20% in the general feline population » It is the most frequent cause of congestive heart failure in cats #universityofsurrey 18 Hypertrophic Cardiomyopathy Relationship between genotype and phenotype » Maine Coon A causative mutation A31P in the cardiac Myosin Binding Protein C sarcomeric gene (MyBPC3) for inherited HCM, with autosomal dominant inheritance, was identified in the Maine Coon in2005 Prevalence for this mutation is high: 42% Europe, 46% Australia Prevalence of HCM phenotype 7-10%, increases with age and is strongly dependent on genetic status Some Maine Coon cats with HCM do not have the mutation Affected to unaffected mating: HCM commonly apparent by 2 years – more severe disease in males Affected to affected mating: HCM apparent by 3 months – both sexes severe #universityofsurrey 19 Hypertrophic Cardiomyopathy Relationship between genotype and phenotype » Ragdoll Cat A second substitution mutation in MyBPC3 associated with HCM has been identified in the Ragdoll breed in 2007 Not all Ragdolls with HCM have this mutation » Most cases of HCM are diagnosed in domestic short hair cats – genetics are as yet unresolved #universityofsurrey 20 Clinical Signs » Often asymptomatic – murmur or gallop is picked up at a routine examination Heart murmurs can be absent in cats with HCM and heart failure Murmurs are best heard over the left apex or cranial sternum, often dynamic Gallop rhythm (up to 33%) and arrythmias (up to 10%) can be detected in HCM cats – uncommon in subclinical cats What do we do about asymptomatic cats with HCM? https://www.vin.com/apputil/content/defaultadv1.aspx?id=7259364&pid=14365 » Congestive heart failure Anorexia, lethargy, dyspnoea, syncope, pleural effusion/pulmonary oedema » Feline aortic thromboembolism (next lecture) » Most have elevated levels of cardiac biomarkers: NTproBNP (myocardial stretch) +/- troponin-I (myocardial damage) But these tests are neither very specific nor 100% sensitive Can monitor trends #universityofsurrey 21 Diagnosis » Evaluate and test for diseases that cause secondary hypertrophy Important to do so before making diagnosis to ensure correct treatment for the cat Hyperthyroidism – age (elderly), history, clinical signs, serum biochemistry and T4 Hypertension – clinical signs, blood pressure, biochemistry » ECG Insensitive for diagnosing May have left axis deviation or increased QRS height May have VPCs, VT, supraventricular premature complexes Beijerink, 2012 #universityofsurrey 22 Echocardiography » Gold standard for feline HCM » Phenotype Papillary muscle hypertrophy +/- increased LV wall thickness (≥ 6mm in diastole) Regional Global +/- systolic anterior motion (SAM) of the mitral valve +/- left atrial enlargement (severe if in failure) +/- spontaneous echo contrast – “smoke”/thrombus #universityofsurrey 23 Echocardiography » Spontaneous echo contrast – “smoke” sign #universityofsurrey 24 Echocardiography » HCM – LV wall thickness ≥ 6mm, normal systolic function, +/- LA dilation, diastolic impairment » HOCM – HCM with systolic anterior motion of mitral valve present creating a mild to severe LVOT obstruction and mitral regurgitation Ettinger, 2012 #universityofsurrey 25 Treatment » Treatment of congestive heart failure will be covered in further lectures » Treatment of FATE will be covered next lecture » Beta blockers or calcium channel antagonists - act as negative chronotropes and negative inotropes to improve diastolic filling Can be controversial if SAM present – sleep more effective than beta-blockade and diltiazem has questionable long term effect on survival #universityofsurrey 26 Restrictive Cardiomyopathy (RCM) » Second most common primary cardiomyopathy in the cat » Characterised by a diastolic dysfunction, with impaired ventricular filling due to increased myocardial stiffness (reduced ventricular compliance) » No causal mutations for either feline form (endomyocardial and myocardial) have been identified » Clinical signs: most cats will present in CHF Dyspnoea (89%), followed by non-specific signs (lethargy, weakness, hypothermia, anorexia), ascites (14%), and paresis/paralysis related to ATE (6%)) Heart murmur (81%) (left apical systolic in 77% of murmurs) and gallop rhythm (31%) of RCM cats » Thoracic radiographs Atrial dilation, pleural effusion, pulmonary oedema » Echocardiography Significant LA dilation (+/- biatrial enlargement), with normal or near normal LV wall thickness but impaired compliance, +/- thrombi, +/- broad bands of soft tissue #universityofsurrey 27 Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC) » AKA Box cardiomyopathy (but Boxers can also develop DCM!) » Inherited as an autosomal dominant trait, variable penetrance » Most commonly characterised by ventricular arrhythmias, syncope, and sudden death – but can also be asymptomatic » Clinical Signs and prognosis 1) asymptomatic dogs with ventricular tachyarrhythmia 2) dogs with normal heart size and LV function, but with syncope or weakness from paroxysmal or sustained ventricular tachycardia 3) Boxers with poor myocardial function and CHF, as well as ventricular arrhythmias. The prognosis is especially poor in the last category. #universityofsurrey 28 Arrhythmogenic Right Ventricular Cardiomyopathy » Histology: multifocal myocyte vacuolisation, myocyte loss, and significant fatty infiltration » Diagnosis: can have normal physical exam, or; tachyarrhythmia, pulse deficits, systolic murmur – may require 24-hour Holter monitor Note: many Boxers have a soft basilar systolic murmur due to SAS or may be physiological and NOT necessarily due to ARVC Likely to be multiple factors that may influence which dogs develop overt clinical signs of the disease » Treatment: Sotalol (β-blocker) 1.5-3.5 mg/kg PO q 12hr, or mexiletine (VG Na+ blocker) 5-6 mg/kg PO q 8hr +/- fish oils (780 mg EPA and 497 mg DHA PO per day) Ettinger, 2012 #universityofsurrey 29 Conclusions - Cardiomyopathies » Cardiomyopathies are a common group of disorders with common pathophysiological features, on echocardiography in particular » Recognition of a cardiomyopathy in a certain breed of animal might provide useful clues to cause, therapy, prognosis etc. » Usually systolic failure in the dog » Usually diastolic failure in the cat #universityofsurrey 30 Valvular Disease » Myxomatous Mitral Valve Disease (MMVD) #universityofsurrey 31 MMVD » Estimated 10% of dogs presented to GPs in the US have heart disease » MMVD accounts for 75% of these cases – most common heart disease in dogs » Sex: males > females » Breed predisposition: Prevalence higher in small breed dogs CHF #universityofsurrey 33 MMVD - Staging » Can we predict the rate of progression? Age Progressive heart enlargement (LA and LV) Increased blood flow velocities Increased cardiac biomarkers (NT-proBNP) Increase in resting heart rate #universityofsurrey 34 MMVD – History and Clinical Presentation Signalment, clinical signs, and physical examination findings are often of such character they strongly suggest MMVD » Murmur https://depts.washington.edu/physdx/audio/mr.mp3 Timing Duration PMI (point of maximal intensity) Grade » Clinical signs: Stage C » Differentials include: Dilated cardiomyopathy Bacterial endocarditis of mitral valve Previously undetected congenital heart disease (e.g. mitral valve dysplasia, or PDA) #universityofsurrey 35 MMVD - Diagnostics » Auscultation » Blood pressure » Thoracic radiography BSAVA manual of Thoracic Imaging, 2011 Ettinger 2016 #universityofsurrey 36  Ettinger 2016 MMVD - Diagnostics » Echocardiography Identify the cause of the murmur Chamber enlargement (LA:Ao >1.6) Comorbidities Keene et al 2019 #universityofsurrey 37 MMVD - Treatment » Medical Depends on stage Stage B2: Murmur intensity ≥ 3/6, remodelling of LA and LV, breed adjusted VHS > 10.5 If echo is not available then VHS > 11.7, serially increasing VHS, VLAS > 3 #universityofsurrey 38  Both left ventricular and left atrial diameter must be increased in order to say that dogs have significant MVD LA:Ao ratio ≥ 1.6 Normalised left ventricular internal diameter in diastole [LVIDd-N] ≥ 1.7 (normalized to body weight ) #universityofsurrey 39 Further Reading » Cardiovascular chapters of Ettinger’sTextbook of Veterinary Internal Medicine (8th Edition) » Small Animal Cardiovascular Medicine (Kittleson and Kienle) - only available on VIN online (free registration for students) » ACVIM Consensus Statement for MMVD #universityofsurrey 40 Disease of the Cardiovascular System IV: Diseases of the Peripheral Vasculature Dr Paul Pollard MVB Cert AVP (VC) MSc Vet Ed SFHEA MRCVS Director of clinical training [email protected] Learning Objectives » Construct a differential diagnosis list based on clinical presentations associated with diseases of the peripheral vasculature and choose appropriate diagnostics » Determine appropriate medical and surgical interventions in the management and treatment of diseases of the peripheral vasculature » Determine appropriate prognosis #universityofsurrey 42 Common Peripheral Vascular Diseases » Dirofilariasis – Heartworm » Aortic thromboembolism » Systemic hypertension #universityofsurrey 43  Dirofilariasis #universityofsurrey 44 Dirofilariasis » Infestation of the pulmonary arteries and occasionally right heart by a mosquito-borne nematode – Dirofilaria immitis » Domestic dogs and some wild canids are the normal definitive hosts and serve as the main reservoir for infection – cats can be occasionally infected » Large, whitish worm Females - ~30 cm long Males - ~23 cm long Adults reside in the pulmonary arterial system – cause damage to pulmonary vessels and lungs #universityofsurrey 45 Distribution of Heartworm » Worldwide distribution of D. immitis – though limited to regions with suitable mosquito intermediate hosts » Some regions have seasonal periods of susceptibility » Not currently in the UK – but beware of travelling dogs and future potential with climate change! » (European, Asian and African distribution of D. repens – a related worm that resides in subcutaneous nodules – usually asymptomatic) https://www.sciencedirect.com/science/article/pii/S2211320721000142 #universityofsurrey 46 Life Cycle of Dirofilaria immitis #universityofsurrey 47 Clinical Signs - Dogs » Most dogs with low heartworm burden have no clinical signs » Clinical signs seen in dogs if they have a severe allergic responses to the adult worms and/or microfilariae, or have high worm burdens » Signs may develop 3-6 months after infection as L5 larvae reach the lungs. Signs may occur acutely with worm death » Signs include: Coughing Exercise intolerance Syncope Weight loss Tachypnoea, dyspnoea, abnormal respiratory sounds Abnormal heart sounds Congestive heart failure (ascites, hepatomegaly, jugular distension) Pulmonary thromboembolism Multi-organ involvement Death #universityofsurrey 48 Clinical Signs - Cats » Hyper-acute Sudden death » Chronic Coughing Dyspnoea Asthma-like attacks Vomiting Inappetence/weight loss Lethargy Chylothorax #universityofsurrey 49 Diagnosis: Haematology » Eosinophilia » Neutrophilia » Basophilia » Lymphopaenia » Anaemia #universityofsurrey 50 Diagnosis: Radiography » Enlarged main pulmonary artery » Right ventricular enlargement » Enlarged tortuous caudal lobar pulmonary arteries Ettinger 2017 #universityofsurrey 51 Diagnosis: Radiography » Diffuse interstitial to alveolar pattern » Eosinophilic pneumonitis Ettinger 2017 #universityofsurrey 52 Diagnosis: Echocardiography » Mild disease – echocardiography is usually normal » Moderate disease – RV often dilated +/- RV free wall thickening » Severe disease – moderate to severe RV dilation » Doppler evidence of pulmonary hypertension can be estimated if tricuspid or pulmonic regurgitation is identified » Heartworms may be identified in the main pulmonary artery and branches, and in the right heart chambers and vena cavae in some cases #universityofsurrey 53 Diagnosis: Specific Tests » Heartworm antigen test Heartworms must mature before either antigen or microfilaria tests become positive (6-7 months after infection) Sensitivity is proportional to worm burden and specificity is nearly 100% Detect female worms only (detects an antigen most abundant in the uteri of gravid females and eggs) False negative results occur in cases of light infections, immature females, male-only infections, antigen-antibody complex-related interference, test malfunction, and by not following the manufacturer instructions! #universityofsurrey 54 Diagnosis: Specific Tests » Microfilaria Test - Fresh blood direct smear Modified Knott’s Test #universityofsurrey 55 Diagnosis: Specific Tests #universityofsurrey 56 Treatment » Can be complex due to the complicated parasite lifecycle » Goal – to improve the clinical condition of the animal and to eliminate all life stages of heartworm with minimal post-treatment complications » Adulticide – melarsomine dihydrochloride » SEE AHS recommendations!! #universityofsurrey 57 Treatment » Surgical Removal Caval Syndrome » Supportive Therapy Doxycycline (not only has effects on adult worms but also decreases numbers of microfilariae and prevents development of heartworm in subsequently.) infected dogs Corticosteroids / Antihistamines Macrocyclic lactones Exercise restriction #universityofsurrey 58 Prevention – the KEY! » Ivermectin E.g. Heartgard® (USA) 24 mg/kg PO Not licensed for use in dogs in the UK » Selamectin E.g. Stronghold® (Europe) 6-12 mg/kg topically » Milbemycin oxime E.g. Milbemax®, Program Plus® PO TRAVELLING ABROAD? » Moxidectin REMEMBER PREVENTATIVE THERAPY! E.g. Advocate®, Pro-heart® Less than 1 month: A single treatment when back in the UK Topical More than 1 month: 1st treatment within 30 days of arrival at destination. Then monthly until 30 days after return to UK #universityofsurrey 59 Learning Objectives Dirofilariasis – Heartworm » Construct a differential diagnosis list based on clinical presentations associated with diseases of the peripheral vasculature and choose appropriate diagnostics » Determine appropriate medical and surgical interventions in the management and treatment of diseases of the peripheral vasculature » Determine appropriate prognosis #universityofsurrey 60 Case: Flynn » A client rings your practice distressed because she has just found her 9yr old DSH, Flynn, hiding under the bed and isn’t able to use his back legs. He also appears to be open mouth breathing. You tell the client to bring him straight to the clinic… Flynn is an outdoor cat. » What are you thinking? Problems? Hind leg paralysis Dyspnoea Differentials? #universityofsurrey 61 Case: Flynn » Flynn arrives – this is what you see » Flynn is also intermittently open mouth breathing and vocalising » What do you want to do first? #universityofsurrey 62 Clinical Signs » As you are administering pain relief and oxygen you triage Flynn and take his vital signs. Pertinent clinical exam findings include: HR 220, gallop rhythm Temp 37.2 °C RR 66 Vocalising Posterior paresis or paralysis Pulselessness in the hind limbs Cyanosis of the hind limbs Cold hind limbs » Problem list? #universityofsurrey 63 Differentials? » Acute trauma (examine carefully, review Hx) » Acute intervertebral disc disease (careful neurological exam) » Neoplasia (e.g. spinal lymphoma) (but peracute) » Dry FIP (with spinal involvement) (but pain) » Fibrocartilaginous embolism (but pain) » Feline Aortic Thromboembolism! #universityofsurrey 64 Feline Aortic Thromboembolism (Saddle Thrombus) » A common, frequently per-acute, catastrophic condition » Usually caused by heart disease (>90%) HCM and severe left atrial enlargement Heart failure » Often the is no known history of heart disease » Occurs when thrombo-emboli (usually from LA) lodge in the distal aortic bifurcation (most common), or in brachial, visceral or cerebral arteries » ATE is rare in dogs #universityofsurrey 65 Pathophysiology » Virchow’s Triad Damage to vascular endothelium of LA Sluggish blood flow (typically due to LA enlargement with spontaneous echo contrast of blood in the LA Hypercoagulability (more difficult to identify but inflammation and altered platelet function play a role) » Clot forms in LA and washes down the arterial tree #universityofsurrey 66 Clinical Signs »The 5 Ps! » Posterior Paresis or Paralysis » Pain » Pulselessness (or very poor pulses) » Pallor (or cyanosis) or the pads/claw beds » Poikilothermia (cold limbs) L. Locquet, D. Paepe, S. Daminet, P. Smets; 2018 #universityofsurrey 67 Underlying Heart Disease » Check underlying heart disease and failure » Heart rate and rhythm Gallops, tachy- or bradycardia » Is there a murmur present » Hypothermia » ECG, Echocardiography, Radiography » NT-proBNP #universityofsurrey 68 Echocardiography » Point of care cardiac ultrasound. Check for an increased LA Ettinger 2017 L. Locquet, D. Paepe, S. Daminet, P. Smets; 2018 #universityofsurrey 69 Echocardiography » Point of care cardiac ultrasound. #universityofsurrey 70 Treatment » We need to discuss prognosis with owner » Supportive care Analgesia Oxygen Heart failure medications » Specific therapy Prevent continued thrombus formation Clopidogrel 18.75 mg/kg PO q24hr Improving flow to infarcted organ(s) Monitor for reperfusion injury But…while it can buy some time, ATEs can and do still occur and long-term survival is poor » Euthanasia #universityofsurrey 71 Prognosis » Poor to grave (25-30% can recover completely) Depends on presenting signs Single pelvic limb infarctions do much better compared to bilateral Non-survival has been associated with hypothermia, bradycardia and absence of motor function » Survival to discharge in cats presenting with ATE is low, and recurrence rates are high (approx. 50%) Important to discuss with clients at presentation Secondary prevention with clopidogrel (Plavix®) – FAT CAT study » Primary Prevention? Difficult to predict which cats will develop FATE Increased LA:Ao? Prophylactic antithrombotic therapy? #universityofsurrey 72 Learning Objectives Feline Aortic Thromboembolism » Construct a differential diagnosis list based on clinical presentations associated with diseases of the peripheral vasculature and choose appropriate diagnostics » Determine appropriate medical and surgical interventions in the management and treatment of diseases of the peripheral vasculature » Determine appropriate prognosis #universityofsurrey 73 Systemic Hypertension » A sustained elevation in systolic BP » There is a balance between sympathetic and parasympathetic tone. Ettinger 2017 » Influenced by the R-R interval, inotropism and peripheral resistance Ettinger 2017 #universityofsurrey 74 Systemic Hypertension » Arterial baroreflex is crucial in beat-to-beat control of the circulation: both heart rate and blood pressure » Every time the heart beats, BP rises (artery stretch) » There are arterial and cardiopulmonary baroreceptors, activation of which will cause inhibition of sympathetic output » The body is constantly measuring and readjusting heart rate » Blood volume is also constantly being measured https://www.cvphysiology.com/Blood%20Pressure/BP002 #universityofsurrey 75 Systemic Hypertension » Regulation of arteriolar diameter is regulated both intrinsically and extrinsically Dilate Intrinsic Regulation Normal Myogenic response Endothelially derived factors: Nitric oxide Extrinsic Regulation Endothelin Vasomotor nerves – esp. sympathetic Prostacyclin vasoconstrictors Paracrine factors e.g. histamine Vasoactive hormones: Local metabolites Angiotensin II Temperature Vasopressin Adrenaline Aldosterone Constrict Etc. #universityofsurrey 76 Systemic Hypertension » Two categories: Secondary hypertension – more common Cats > 160 mmHg Primary (idiopathic) hypertension Dogs > 150 mmHg » More common in older male dogs than females » Doppler (better for cats) or oscillometric techniques for measurement » Be aware of the “white coat” effect Take multiple readings Quiet room https://todaysveterinarypractice.com/systemic-hypertension-in-dogs-cats/ #universityofsurrey 77 Secondary Hypertension Conditions commonly associated with systemic hypertension: » Kidney disease – most common » Hyperadrenocorticism » Adrenal tumours » Hyperthyroidism » Diabetes mellitus » Cardiovascular disease #universityofsurrey 78 Clinical Manifestations » Target organ damage (TOD) 1. Ocular manifestations Choroidopathy/retinopathy – altered vessel diameter – partial or complete retinal detachment, haemorrhage, multifocal oedema Common in geriatric feline patients #universityofsurrey 79 Clinical Manifestations » Target organ damage (TOD) 2. Cardiac manifestations Left ventricular hypertrophy most common Normalise wall stress and preserve chamber function https://www2.vet.cornell.edu/departments-centers-and-institutes/cornell-feline- health-center/health-information/feline-health-topics/hypertrophic-cardiomyopathy #universityofsurrey 80 Clinical Manifestations » Target organ damage (TOD) 3. Renal manifestations Hypertensive nephrosclerosis Cause and effect? 4. Neurological manifestations Hypertensive encephalopathy 5. Epistaxis Bilateral https://irishvetjournal.biomedcentral.com/articles/10.1186/s13620-015-0033-6 #universityofsurrey 81 Treatment » Once identified – should be treated » Treatment of primary disease » Goal – amelioration of clinical signs if present » Prognosis Dependent on target organ damage Treatment usually life-long When well managed further complications are minimised Ettinger 2017 #universityofsurrey 82 Learning Objectives Systemic Hypertension » Construct a differential diagnosis list based on clinical presentations associated with diseases of the peripheral vasculature and choose appropriate diagnostics » Determine appropriate medical and surgical interventions in the management and treatment of diseases of the peripheral vasculature » Determine appropriate prognosis #universityofsurrey 83 Further Reading » Cardiovascular chapters of Ettinger’sTextbook of Veterinary Internal Medicine (8th Edition) » Small Animal Cardiovascular Medicine (Kittleson and Kienle) - only available on VIN online (free registration for students) » American Heartworm Society (https://www.heartwormsociety.org) #universityofsurrey 84  PollEv.com/paulpollard090 Questions? Please use the discussion forums on SurreyLearn [email protected] 85