Systemic Hypertension

Question 1

According to the Doppler study, what is the normal blood pressure for a cat?

Answer 1

120-160mmHg

Question 2

According to the Doppler study, what is the normal blood pressure for a dog and what is the exception to this rule?

Answer 2

140-150mmHg is normal
Sighthounds and Brachycephalic breeds have a slightly higher SBP (10-20mmHg higher)

Question 3

What SBP carries severe risk of target organ damage?

Answer 3

> 180 mmHg is severely hypertensive and has severe risk of organ damage

Question 4

What structures can target organ damage affect? (4)

Answer 4

Eye
CNS
Cardiovascular system
Kidney

Question 5

Target organ damage in the eye due to hypertension is identified in what percentage of cats?
And can this be reversed?

Answer 5

60-100% of cats
57.6% of cats regain vision with treatment

Question 6

What target organ damage may we expect to see in the heart due to hypertension? (3)

Answer 6

Left ventricular hypertrophy
Murmurs
Gallop heart sounds

Question 7

When would we expect to see CNS target organ damage?

Answer 7

in Acute SBP changes (less common in chronic hypertension)

Question 8

Would we expect to see kidney damage in cases of mild hypertension?
Why?

Answer 8

NO- kidney has the capacity for autoregulation which controls renal blood flow and pressure at the glomerulus- this works with SBP of up to 160mmHg

Question 9

What happens to the kidney when systolic blood pressure exceeds 160mmHg?

Answer 9

Autoregulation stops > increased pressures are transferred to the glomerular capillaries > this damages the glomerulus and causes proteinuria

Question 10

What are the three types of Hypertension seen in Veterinary Practice?

Answer 10

Idiopathic Hypertension
Situational Hypertension (aka white coat)
Secondary Hypertension

Question 11

What is white coat hypertension?

Answer 11

increase in blood pressure due to the physiological response to clinic

Question 12

What drugs can predispose an animal to secondary hypertension?
Give 3.

Answer 12

Glucocorticoids
Mineralcorticoids
Erythrocyte stimulating agents such as erythropoietin
Epinephrine
Toceranib

Question 13

What are the most common blood pressure monitoring devices used in clinic?

Answer 13

Doppler and High Definition Oscillometric Device

Question 14

When measuring blood pressure what position should the animal ideally be in?

Answer 14

Lateral Recumbency
(don’t force it though!)

Question 15

When measuring blood pressure, the cuff size should be…

Answer 15

30-40% of the animals limb circumference

Question 16

How many readings of SBP do we take?

Answer 16

5-7 readings during one session- discard the first reading and take an average of the rest to get a mean SBP

Question 17

When is a blood pressure measurement indicated? (5)

Answer 17

• Concern that patient presents with target organ damage
• Patient has been diagnosed with a condition that causes hypertension
• Patient is receiving a drug that can be associated with secondary hypertension
• Patient is of a certain criteria for screening e.g. cats over 9 years old
• Patients already diagnosed with hypertension

Question 18

When do we diagnose and treat hypertension?

Answer 18

When SBP is above 160mmHg AND there is evidence of target organ damage OR evidence of concurrent disease

Question 19

What two drugs are licensed to treat hypertension in cats?

Answer 19

Amlodipine (first line) & Telmisartan

Question 20

How does Amlodopine work?

Answer 20

Calcium channel blocker- causes AFFERENT arterial dilation to decrease glomerular capillary pressures

Question 21

How does Telmisartan work?

Answer 21

Angiotensin receptor blocker- inhibits the vasoconstrictory actions of Angiotensin II on the EFFERENT arteriole to decrease GFR

Question 22

What is the maximum dose of Amlodipine you can give to a cat in the treatment of Hypertension?

Answer 22

Maximum 1.25mg/cat (this is off license!) and rare to need this dose

Question 23

What do we do if treating a cat with Amlodipine doesn’t work?

Answer 23

Use a combination of Amlodipine and an Angiotensin receptor blocker such as Telmisartan
[just ensure you don’t overcompensate and cause hypo tension]

Question 24

What products are licensed to treat Hypertension in dogs?

Answer 24

NONE!- need to prescribe Telmisartan or a Calcium channel blocker through the cascade