Hypertension

Question 1

Systemic blood pressure is a product of which of the following?
A. cardiac output and heart rate
B. cardiac output and systemic vascular resistance
C. systemic vascular resistance and stroke volume
D. stroke volume and cardiac output

Answer 1

B. cardiac output and systemic vascular resistance

Question 2

Systemic blood pressure is regulated by what 2 systems?

Answer 2

1. sympathetic nervous system (ex. stress –> increased release of catecholamines –> vasoconstriction –> inc BP)
2. Renin-angiotensin-aldosterone system

Question 3

Where is renin produced and what is its function?

Answer 3

Renin is produced by the kidneys in response to low blood pressure.

It functions to convert angiotensinogen into angiotensin I

Question 4

What is produced by the liver than gets converted by renin into angiotensin II?

Answer 4

Angiotensinogen

Question 5

What organ produced angiotensin-converting enzyme (the enzyme needed to convert angiotensin I to angiotensin II)?

Answer 5

The lungs

Question 6

What are the 2 main results of angiotensin II?

Answer 6

1. acts on the adrenal gland to stimulate the release of ALDOSTERONE
2. Acts on smooth muscle of the blood vessels and causes VASOCONSTRICTION

Question 7

When angiotensin II acts on the adrenal glands to produce aldosterone, what effect does aldosterone then have on the kidneys and blood pressure?

Answer 7

Aldosterone stimulates reabsorption of sodium and water (which is increases blood volume and thus blood pressure).

Question 8

What BP value defines systemic hypertension?

Answer 8

A persistent elevation of BP:
systolic > 160 mmHg
diastolic > 120 mmHg

Question 9

T/F: the most common cause of systemic hypertension in companion animals is idiopathic.

Answer 9

false – it is most commonly secondary and is causes by conditions that increase cardiac output or increase systemic vascular resistance.

Question 10

What physical exam finding in cats is highly supportive of systemic hypertension?

Answer 10

retinal hemorrhage and retinal vessel tortuosity

Question 11

What blood pressure measurement method is described below?

Preferred method for SMALL cats and dogs. Measures only systolic

Answer 11

Indirect – Doppler

Question 12

What blood pressure measurement method is described below?

Preferred method for medium to large dogs. Measures systolic, diastolic, and mean.

Answer 12

Indirect – Oscillometric

Question 13

What is considered the gold standard method to measure blood pressure?

Answer 13

direct – arterial catheterization

it is the most accurate, but it is not always feasible.

Question 14

Blood pressure cuff width should be _____% (range) the circumference of the chosen site.

Why?

Answer 14

30-40

too big –> false low BP
too small –> false high BP

Question 15

what 2 areas can you use for blood pressure measurement with doppler or cuffs?

Answer 15

limbs
tail

note: restrain in ventral or lateral recumbency to limit vertical distance from the heart base to the cuff

Question 16

T/F: anxiety induced situational hypertension will be fairly obvious to distinguish from true hypertension because values will not be markedly elevated.

Answer 16

false – anxiety induced situational hypertension can be very marked.

Question 17

When measuring blood pressure, describe the technique to ensure you are getting the MOST accurate results.

Answer 17

Always discard your 1st measurement
Average the values of 5-7 measurements
Always note pt demeanor, cuff size, and measurement site to be consistent during follow-up measurements.

Question 18

What are the 4 possible areas of target organ damage?

Answer 18

1. eyes
2. kidneys
3. brain
4. heart and vasculature

Question 19

The risk for target organ damage becomes moderate to high when systemic blood pressures rise above what value?

Answer 19

> 160-180

<159 have low-minimal risk

Question 20

Primary hypertension is less common in cats than secondary. What are the 4 MOST common causes of secondary hypertension in CATS?

Answer 20

1. chronic kidney disease*
2. hyperthyroidism*
3. adrenal disorders (conn’s, pheochromocytoma, cushing’s)
4. medications (steroids, proin, erythropoietin)

Question 21

Primary hypertension is more uncommon in dogs than secondary. What are the 5 MOST common secondary causes of hypertension in DOGS?

Answer 21

1. Kidney disease*
2. hyperadrenocorticism*
3. Diabetes mellitus
4. Pheochromocytoma
5. Hyperaldosteronism

Question 22

Which of the following factors is NOT a known factor to commonly affect blood pressure?
A. age
B. breed
C. blood type
D. obesity
E. anxiety/stress
F. drugs

Answer 22

C. blood type

Question 23

When should hypertension be treated?
(3 criteria)

Answer 23

1. severe hypertension (>180)
2. evidence of TOD with mod-sev hypertension
3. persistent BP>160 with disease associated with hypertension (CKD, cushings, etc.)

Question 24

When patients fall into the “gray zone” of needing treatment for hypertension (moderately elevated BP (160-180) with no TOD), what should your plan be?

Answer 24

Evaluate patient for TOD and recheck BP in 1-2 weeks.

Question 25

When is hypertensive treatment NOT recommended?

Answer 25

Patients with PREhypertension (140-159) with NO clinical signs

In these patients, its best to monitor BP during future visits.

Question 26

The aim/goals of treatment for hypertension are?

Answer 26

1. address the underlying disease
2. reduce CO, SVR, or both
3. weight loss in obese patients
4. avoid high-sodium treats and diets.

Question 27

Which drug is FIRST line treatment for hypertension in CATS?

*give MOA too *

Answer 27

Amlodipine

MOA = Ca channel blocker –> vasodilation –> decrease BP

Note: it can also be used in dogs with severe hypertension

Question 28

Amlodipine reduces blood pressure by _____ mmHg.

Answer 28

30-50
It does take 7-10 days to take full effect.

Note: this is why a lower dose is used first to see the effects, then BP is rechecked in 7-10d to see is dose adjustments are needed

Question 29

Why is amlodipine commonly combined with an ACE-inhibitor in dogs?

Answer 29

amlodipine may activate RAAS leading to increased proteinuria if the blood pressure is not significantly reduced.
ACE-inhibitors reduce proteinuria.

Question 30

What is the mechanism of action of ACE-inhibitors (benazipril and enalapril)?

Answer 30

ACE-inhibitors inhibit the angiotension converting enzyme (ACE), which leads to decreased production of angiotensin II.
This results in vasodilation and decreased aldosterone production. Additionally, ACE inhibitors preferentially vasodilates the efferent arteriole of the glomerulus, which reduces proteinuria.
The downside to this is it may cause azotemia.

Question 31

After you start a patient on an ACE-inhibitor, what should follow-up look like?

Answer 31

First, ensure that they are well-hydrated before starting.

You should evaluate their renal values and electrolytes 7-10 days after starting treatment or after increasing the dose.

Question 32

T/F: ACE-inhibitors have minimal control of hypertension in cats, reducing BP by only ~10 mmHg.

Answer 32

true

they are the first line treatment in dogs, except dogs with SEVERE hypertension (>180)

Question 33

What is the MOA of angiotensin II receptor blockers such as telmisartan?

Answer 33

They inhibit RAAS by blocking the action of angiotensin II.
They serve as an alternative to ACE-inhibitors because they also reduce proteinuria.

Question 34

What is the use for telmisartan?

Answer 34

moderate hypertension in cats (<200)
and dogs too.

Question 35

What are 2 “emergency” drugs that are rarely needed but used for severe life-threatening hypertension?

Answer 35

1. hydralazine
2. sodium nitroprusside

they carry a risk for causing hypotension

Question 36

What 2 drugs are used in cases of hypertension caused by pheochromocytomas?

Answer 36

1. phenoxybenzamine
2. prazosin

Question 37

What is the MOA of spironolactone in the treatment of hypertension?

Answer 37

spironolactone is a diuretic that acts as an aldosterone antagonist which reduces sodium and water reabsorption, thus decreasing BP.
This drug is useful in cases of hyperaldosteronism.

Question 38

T/F: when patients have hypertension, we want to start treatment as soon as possible in order to reduce their systemic blood pressure acutely to avoid TOD.

Answer 38

false – yes, its important that the blood pressure is decreased in a timely fashion to avoid TOD, but a gradual decrease in BP rather than acute is the goal.
The goal is to reach 110-140 mmHg. Any BP <120 with signs of weakness, syncope, or tachycardia is indicative of hypotension and the dose needs to be decreased.