Agnieszka Zoltowska BVSc MANZCVS (Medicine of Cats) ISFM AdvCertFB MRCVS

1. Hypertension in Cats - can we afford to ignore it in practice? Aetiology, diagnosis, management and practical tips on using your blood pressure machine Agnieszka Zoltowska BVSc MANZCVS (Medicine of Cats) ISFM AdvCertFB MRCVS RCVS Advanced Practitioner in Small Animal Medicine (Feline)

2. Systemic Arterial Hypertension = a persistent increase in systemic blood pressure Idiopathic (= primary) hypertension: no apparent underlying disease Secondary hypertension: due to an underlying disease or the use of medication ‘White Coat Hypertension = excitement- or anxiety-related sympathetic activation (on average increase of 15-20mmHg but it can be as much as 75mmHg!)

3. Idiopathic Hypertension Reported 13-20% of hypertensive cats Is it the same as ‘Essential Hypertension’ in humans? Environmental factors? Genetic predisposition?

4. Secondary Hypertension • Chronic Kidney disease: • Most common condition associated with feline hypertension • Azotaemia found in up to 74% of hypertensive cats • Between 19% and 65% of cats with CKD have been found to be hypertensive • Pathogenesis in cats uncertain (in humans related to: sodium retention, RAAS ans sympathetic nervous system activation, structural changes to arterioles, endothelial dysfunction, oxidative stress and genetics). Limited response to ACE inhibitors may suggest that systemic RAAS activation is unlikely to be a major factor.

5. Don’t forget that regular blood pressure monitoring is essential in your hyperthyroid patients! Secondary Hypertension • Hyperthyroidism : • Hypertension documented in 10-23% of cats at the time of the diagnosis (some of the cats with concurrent CKD) • 25% of cats that were normotensive at the time of diagnosis, develop hypertension • Poorly understood

6. Secondary Hypertension • Primary Hyperaldosteronism: • Excess of aldosterone • Hypertension reported in 40-60% of cats • Pheochromocytoma (rare tumour) • Circulating catecholamines • Sustained or paroxysmal bouts of hypertension • Hyperadrenocorticism: • limited data, one report to date • Diabetes Mellitus? • In humans: a risk factor; no evidence that it is the same in cats • Low prevalence and usually limited to cats with a concomitant condition e.g. CKD • However: BP in diabetic cats has been found to be higher than in age-matched, healthy controls. Link?

7. Target Organs Damage (= TOD) Hypertension is most likely cause the damage in organs with rich arteriolar supply or in cardiovascular system Clinical manifestation may be the reason for the owner to bring a cat to a vet Occasionally there may be no overt signs of hypertension that are easily observed www.vettimes.co.uk: Caney.S (2016) Diagnosis and treatment of systemic hypertension.

8. Target Organ Damage Why does it happen? EYE: failure of the retinal vessels to auto-regulate, chorioid vessels are not located in the tissues they supply therefore they cannot auto-regulate, structure of the blood-retina barrier. HEART: hypertrophy in response to hypertension BRAIN: hypertensive encephalopathy, hyperplastic arteriosclerosis, interstitial white matter oedema, parenchymal micro haemorrhages (nephrectomised cats) KIDNEY: important causal factor in human and canine kidney disease and factor contributing to the disease progression; in cats: more research needed (BUT: proteinuria and the association with blood pressure, degree of proteinuria and link to reduced survival…however managing hypertension had not yet been demonstrated to provide a survival benefit)

9. Target Organ Damage Clinical signs are related to the organ affected: - visual deficits and/or ocular abnormalities consistent with systemic hypertension (detachment of retina, oedema, bleeding) - unexplained proteinuria - heart murmur and/or gallop rhythm - left ventricular hypertrophy on echocardiography - behavioural or neurological signs (for example: dementia-like signs, night vocalisation, changes in behaviour)

10. Target Organ Damage - Eye https://www.cliniciansbrief.com/article/image-gallery-feline-fundus-diseases https://www.slideserve.com/pules/normal-fundus-and-variations-in-the-dog-cat-and-horse Normal Feline Fundus RED ARROWS = retinal vasculature (cilioretinal arteries) BLACK ARROW = optic nerve WHITE ARROW =non-tapetum area BLUE ARROWS = flash artefacts

11. Indirect ophthalmoscopy as a technique for identifying hypertensive ocular changes: https://www.youtube.com/watch?v=bFHOafsYd0Y Indirect Examination of the Fundus = indirect ophthalmoscopy 20 or 28 dioptre condensing lens Strong source of light Tropicamide (1%) eye drops to dilate the eye (?) Dark room

12. Indirect Ophthalmoscopy Indirect because we look at the fundus through a condensing lens The image is formed close to the principle focus of the lens, between the lens and the observer https://pdfs.semanticscholar.org/f602/a310b5cce45fc920d27219107849cd1e74a4.pdf

13. Indirect Ophthalmoscopy https://vetgirlontherun.com/veterinary-continuing-education-how-to-do-fundic-examination-vetgirl-blog/

14. Fundic Changes https://www.researchgate.net/figure/Photographs-of-the-fundus-a-e-g-l-of-cats-diagnosed-with-hypertensive-ocular_fig2_258058040 Normal Fundus Retinal detachment Single bulls retinal lesion Vitral haemorrhage

15. Fundic Changes https://www.vettimes.co.uk/app/uploads/wp-post-to-pdf-enhanced-cache/1/hypertension-and-importance-of-ocular-examination-in-cats.pdf

16. Palpation of the pulses Femoral pulse absent = severe hypotension Palpable femoral pulse = blood pressure of at least 60mmHg Palpable dorsal metatarsal pulse = blood pressure of at least 90mmHh

17. Palpation of the pulses Dorsal pedal artery

18. Monitoring Blood Pressure in Cats Recommendations based on ISFM Consensus Guidelines 2017 Healthy adult cats (3-6 years old) - consider every 12 months to establish ‘normal’ for the cat Healthy Senior Cats (7-10 years old) - at least every 12 months Healthy Geriatric Cat (>11 years old) - at least every 6-12 months Cats with recognised risk factors (underlying disease) CKD, Hyperthyroidism including treated cats, Primary Hyperaldosteronism, Hyperadrenocorticism, Pheochromocytoma) Drug therapy (e.g. erythropoietin) Evidence of Target Organ Damage

19. When to Treat? Indirect SBP measurement >150mmHg and clear evidence of ocular or neurological target organ damage Indirect SBP on at least 2 separate occasions of > 160mmHg and evidence of target organ damage (renal, neurological, cardiac or ocular) Indirect SBP >170 mmHg on at least 2 separate occasions AND no ‘white coat hypertension’ to be the cause Indirect SBP <150mmHg AND CLEAR target organ damage (careful monitoring) - investigate other causes! www.icatcare.org www.cliniciansbrief.com https://www.cliniciansbrief.com/article/image-gallery-feline-fundus-diseases

20. Investigation of other causes • Complete physical examination (including cardio-vascular, neurological and ophthalmic examination) • Laboratory evaluation (to identify any underlying disease): • - serum creatinine (and SDMA?) • - Urinalysis (specific gravity, proteinuria assessment) • - serum thyroxin level • - electrolytes (Na, K, Cl) • Additional Investigations (diagnostic imaging- cardiac and abdominal, serum aldosterone and renin, dynamic adrenal function testing etc.) https://www.cliniciansbrief.com/article/image-gallery-feline-fundus-diseases

21. AMLODIPIN BESYLATE: • Calcium channel blocker • Drug of choice for managed feline hypertension • Acts on smooth muscle (peripheral arterial dilatation), minimal cardiac effect • Monotherapy works in most of the cats with adjustments in some • Side-effects: hypotension (rare) ACE INHIBITORS, ARBs (angiotensin receptor inhibitors e.g. Telmisartan), BETA-BLOCKERS: -all have been used in treatment of feline hypertension -not as efficacious ( reduction of SBP by approx. 10-20mmHg) as a monotherapy - commonly used as an adjunct therapy depending on other conditions affecting the patient (e.g. CKD, hyperthyroidism) How to treat? Treat underlying disease Treatment goal: deceasing the risk of Target Organ Damage Target goal: <150 mmHg (IRIS Group: www.iris-kidney.com)

22. Mean blood pressure < 70mmHg (systolic <100mmHg) = inadequate perfusion of the vital organs (brain, kidneys, heart) Blood Pressure Measurement under General Anaesthetic • Causes of hypotension under general anaesthetic: • Drug-induced vasodilation may be the most common cause of hypotension in anaesthetised animals, • reducing the dose of vasodilating anaesthetic agents, particularly isoflurane/sevoflurane, will help • Hypothermia • Bradycardia • Anaesthetic-induced cardio-vascular depression

23. Non-Steroidal Anti-Inflammatory Drugs NSAIDS effect on kidney: decrease in prostaglandins level which leads to inability to vasodilate as a compensation to systemic vasoconstriction, drop in filtration rate

24. Indirect Blood Pressure Measurement

25. Indirect Blood Pressure Measurement • Equipment: • Make sure you have correct sizes • Make sure the cuffs work! Testing cuffs (maintaining the pressure and working velcro) • Batteries (good quality) or fully charged internal unit • Spare batteries! • Headphones

26. Indirect Blood Pressure Measurement Environment & Management of Stress Levels

27. Indirect Blood Pressure Measurement Environment & Management of Stress Levels

28. Environment & Management of Stress Levels Manage client’s expectations Cat Friendly Practice starts at the answering client’s phone call Explain what will happen and how it will be done Booking the appointment (amount of time needed, time of the day - other animals in the clinic and travel time e.g. rush hour) Waiting room - Be Cat Friendly! Can the patient go and settle in a separate room before the measurement? Quiet room, allowing the cat to acclimatise to the room, manage scents - dog smells, strong disinfectants, use pheromones, clean soft bedding If the cat is becoming more and more distressed, re-book the appointment (most important thing: make it a positive experience for the cat and allow the cat to be in control) BE PREPARED! All you need in the room to minimise the disruptions Clinic’s checklist ready! Sign on the door: DO NOT DISTURB! BLOOD PRESSURE MEASUREMENT! Patience, patience and patience… Be Kind, Be Gently, Be quiet Indirect Blood Pressure Measurement

29. SWITCH OFF MOBILE PHONES (yours and your client’s) Indirect Blood Pressure Measurement

30. Bedding, soft, free of strong smells, non-slippery surface Pheromones eg. Feliway Classic Very quiet, low vibration clippers (IF shaving the fur is necessary) Tape (e.g. microporous tape) Small (non-squirting container) with water or surgical spirit (cotton wool) Ultrasound gel Treats Spare batteries Sheet to record the details Pen or pencil Paper towels to wipe off the gel from the coat or hand. Comfortable place for both cat and people measuring the pressure Indirect Blood Pressure Measurement Personalised Check List:

31. Indirect Blood Pressure Measurement

32. Mastering ‘your doppler’ without a patient • Use your finger to practice • Think about the discomfort of measurement (arthritis in an older cat, not allowing the venous drainage) • Control the speed of inflation and deflation • Assess the pressure necessary to be able to detect the blood flow • Use it with and without headphones (though in a conscious patient ALWAYS use headphones!)

33. Indirect Blood Pressure Measurement Placing the cuff…WHERE and HOW? Can I use a tape to keep the cuff closed? If the velcro is not working anymore, we can use a small piece of tap to hold the cuff in place for this reading only! If the velcro is not working, replace the cuff!

34. Measure the cuff and position it gently, make sure it doesn’t slide off Feed the cats treats, gently restrain Allow breaks if unsettled Wet the coat over the vessel you are going to use to detect the blood flow (water or spirit) Cover the area with ultrasound gel Put the headphones on and turn the sound right down-sudden movement of the probe generates a noise that can be painful! Put the probe onto the vessel Gently increase the volume to detect the blood flow Gently fill the cuff to approximately 200mmHg above the point when the sounds disappear Slowly release the air (2mmHg/second) and listen for the reappearance of the signs Deflate the cuff completely, allow the venous drainage from the area! Indirect Blood Pressure Measurement Remember about patient comfort! Elderly patients can be painful when joints are moved (arthritis - tail as well as limbs) An average of 5-7 measurements that have less than 20% variability Record size of the cuff, site and patient’s attitude/any problems

35. https://www.youtube.com/watch?v=LU-aaPDMw6o Doppler vs Oscillometric Methode • DOPPLER TECHNIQUE: • Steep learning curve but can be mastered easily • Reliable and used by most of the feline medicine specialists (animals <5kg of BW, bradycardia, hypotensive, tachycardia, with arrhythmia) • Requires a person to perform measurement • Systolic blood pressure is the easiest to measure (the detection of diastolic blood pressure is possible) • OSCILLOMETRIC TECHNIQUE: • High definition oscillometry (increases reliability) • Very sensitive to movement of an animal therefore artefacts possible • Automatically measures systolic, diastolic and mean blood pressure • Ideally the machine is connected to a computer screen to identify movement artefacts • Requires little input from the person who is assessing the pressure

36. Blood pressure measurement TROUBLE SHOOTING Check the cuff size and placement (is it sliding down?) Use small amount of type if the velcro is damaged If in doubt, look for other clinical signs - does the clinical examination confirms your BP findings? Patient too distressed? Have a break Patient not relaxing? Try another time and teach the owner how to familiarise the cat with the procedure

37. Blood pressure measurement Tail vs. Leg Measurements at the tail were by mean 18.7 ± 37 mmHg higher therefore a percentage of cats was diagnosed as “mildly hypertensive” (coccygeal artery) vs “normotensive’ (radial artery)

38. Can we afford to ignore the blood pressure measurement in practice? • Animal’s Perspective: • Early detection of the disease • Prevention of the serious clinical signs (e.g. acute blindness) • Prevention of the complications/minimising complications (i.e. general anaesthetic) • Monitoring the depth of anaesthesia (indication of the anaesthetic depth) • Client’s Perspective: • Early detection of the disease in pet = prevention of the serious problems • Allows to provide the best advice and treatment, no sudden ‘surprises’ • Looking after beloved pet • Minimizing and managing risk (e.g. under general anaesthetic)

39. Can we afford to ignore the blood pressure measurement in practice? • Veterinary Team Perspective: • Better service offered, improved monitoring and detection • More satisfying job • Practicing medicine not just ‘doing things like a robot’ • Helping the patients • Practice’s Perspective: • Better service offered to the clients and the patients (wider scope of services) • Improved relationship with the clients • More staff satisfaction as being able to work to a higher standard • Increased revenue

40. Any questions?