Hypertension Flashcards
What is systemic blood pressure?
Cardiac output x systemic vascular resistance (SVR)
-Regulated by the sympathetic nervous system (baroreceptors in heart sense a decrease in BP, catecholamines released and increase CO)
-Renin-angiotensin aldosterone system
What is the RASS System and what does it do?
Renin-angiotensin-aldosterone system - regulates blood volume and vascular resistance
Liver makes angiotensin, when kidneys are not well perfused the release renin that converts angiotensinogen to angiotensin , then ACE from the lungs concerts 1 to 2 which then causes vasoconstriction, increaseing resistance with contraction smooth muscle and release of aldosterone from adrenals to stimulate reabsorption of sodium and water to increase blood volume and output
What values consist of systemic hypertension?
Systolic >160mm Hg, diastolic >120mm HG
What causes systemic hypertension?
Primary idiopathic
Secondary -most common cat and dog (conditions that increase co or SVR)
What does severe hypertension lead to in cats?
Blindness
What methods are used to measure blood pressure?
Indirect
-Most practical
-Doppler
-Oscillometric
Direct
-Gold
-Arterial catheterization
What cuff size should be used?
30-40% circumference of chosen site
-Too big = false low
-Too small = false high
Where should you place a BP cuff?
On limb or tail
Should be in lateral
What are the keys to getting a good blood pressure measurement?
Minimize stress
-quiet
-prior to other procedure
-acclimation period of 5-10min
-owner present
-minimal restraint
Which measurement should you trust?
Discard the 1st
Average 5-7 consecutive measurements
Note - demeanor, cuff size, measurement site
What are the target organs of damage with high BP?
Eye, kidney, brain, heart and vasculature
What blood pressure = what risk TOD?
Normotensive <140 mmHG (minimal)
Prehypertensive 140-159 (low)
Hypertensive 160-179 (Moderate)
Severe >180mm HG (high)
What are some underlying causes of hypertension in cats?
CKD
Hyperthyroidism
Adrenal disorders
Medications
What medications can cause hypertension?
Glucocorticoids
Mineralocorticoids
Phenypropanolamine
Erythropoietin
What are some underlying causes of hypertension in dogs?
Kidney disease
hyperadrenocortism
DM
Pheochromocytoma
Hyperalsodterism
What are some other factors that affect BP?
Age, breed, obesity, anxiety, pharmacologic agents
When should hypertension be treated?
Severe
TOD
Persistent blood pressure with disease associated with hypertension
When is treatment of hypertension not recommended?
Systolic BP 140-159 with no signs
Monitor in future
How do you treat hypertension?
Address underlying cause
Antihypertensive
Diet - weight loss, avoid high sodium treat or food
What is amlodipine?
Calcium channel blocker (Relax vascular smooth muscle leading to vasodilation and decreased resistance)
-1st line in cat
reduce BP by 30-50 mm Hg
Concern in dogs - activate RASS and increase proteinuria
What is an ACE inhibitor?
Enazepril and enalapril
- Inhibit ace and decreased production angiotensin 2
-vasodilate efferent arteriole of glomerulus
*Patient needs to be well hydrated
*Check renal values and electrolyte 7-10 days
*Minimal control hypertension in cat
*1st line treatment dogs except severe hypertesion (180-200) - amplodine 1st
What are angiotensin 2 receptor blockers?
Inhibit RAAS
Telmisaratan
Moderate in cat
Alternative to Ace - decrease proteinuria
What is an alpha adrenergic antagonist?
Pheochromocytoma
Phenoxybenzamine
Prazosin
What is a sprionolactone?
Diuretic act as aldosterone antagonist - reduce sodium and water resorption
-Hyperaldosteronism
What are the goals of treating hypertension?
Decreased damage to TO
Gradually decrease BP 110-140
mm Hg
(Decrease dose if less than 120)
How do you monitor hypertension?
TOD - recheck BP 3 days
TOD not present - recheck BP 7-10d
BP stable recheck e 3 month
