Diastolic Dysfunction - Hypertension Flashcards
What are primary causes of diastolic dysfunction?
- Hypertrophic cardiomyopathy
- Restrictive cardiomyopathy
- Hypertrophic obstructive cardiomyopathy
Secondary causes of diastolic dysfunction
- Pressure overload diseases
- Pericardial diseases
What are the categories of pressure overload diseases?
Hypertension and stenosis
What are categories of diseases causing hypertension?
- Pulmonic vs systemic
What are categories of diseases causing stenosis?
- usually congenital
- Either pulmonic stenosis or aortic stenosis
What type of hypertrophy occurs with diastolic dysfunction or pressure overload?
- Concentric hypertrophy
What happens if BP is too low?
- Not enough vascular tone to perfuse brain and kidneys
- Badness
What happens if blood pressure is too high
- Impact on capillary beds
- Capillary beds are very thin walled
- If they are high pressure, they will rupture
- Heart is also unhappy with this
Definition of systemic hypertension?
- Systolic BP > 160 mmHg
- persistent elevation
- Can be elevated with stress, but even so shouldn’t be higher than 180 mmHg
Diagnosing systemic hypertension
- Measure BP
- Doppler ideally over oscillometric
Where to measure blood pressure?
- Front limb, hind limb, or tail
- You just need to be consistent
What can happen is cuff size is too big?
- Decrease your blood pressure
What can happen if cuff size is too small?
- Artificially increase your blood pressure
Causes of primary systemic hypertension
- never been reported
Causes of secondary systemic hypertension
- Renal disease
- Hyperadrenocorticism (Cushing’s)
- Hypothyroidism or hyperthyroidism
- Diabetes mellitus
- Medications
- Acromegaly
- Pheochromocytoma
- Hyperaldosteronism
Who gets systemic hypertension: age?
- Older animals
What diseases do only cats generally get that can lead to systemic hypertension?
- Hyperthyroidism
What diseases do only dogs generally get that can lead to systemic hypertension?
- Hypothyroidism
- Hyperadrenocorticism
- Pheochromocytoma
What diseases can either dogs or cats generally get that can lead to systemic hypertension?
- Renal disease
- Diabetes mellitus
- Hyperaldosteronism
- Acromegaly
- medications
Which diseases can directly lead to concentric hypertrophy based on direct effect on the heart?
- Hyperthyroidism
- Hyperaldosteronism
- Pheochromocytoma
- Acromegaly
What target organs must you worry about with systemic hypertension?
- Kidneys
- Brain
- Eye
- Heart
What can happen to the brain with systemic hypertension?
- Hypertensive encephalopathy
- Hemorrhage into the brain
- Seizures
- Ataxia
- Stupor
- Blindness
What can happen to the eyes with systemic hypertension?
- Hypertensive retinopathy or hypertensive choroidopathy or hypertensive optic neuropathy
- More often with cats
Hypertensive retinopathy findings on fundic exam
- Vascular distension and tortuosity
- Retinal hemorrhage
Hypertensive choroidopathy findings on fundic exam?
- Focal necrosis and hypopigmentation
- Retinal detachment
- Fat retinal arteries due to dilation
Hypertensive optic neuropathy findings on fundic exam
- Optic nerve ischemia (no retinal vessels)
- Edema
- Atrophy
What should you do if an animal suddenly becomes blind?
- Check a blood pressure
What can happen with concentric hypertrophy of the LV?
- Blood supply to the heart changes
- Epicardial surfaces are supplied with coronary artery, but as the heart thickens inward, your blood supply does not change
- HIGH RISK FOR ISCHEMIC INJURY
What does systemic hypertension do to the heart?
- Causes concentric hypertrophy of the left ventricle
- Morphologically will look like an HCM like heart
What leads to the other: heart disease and systemic hypertension?
- Systemic hypertension leads to secondary cardiac remodeling***
- Do not diagnose as HCM
- Heart disease would generally lead to hypotension as it gets worse
Appearance of concentric hypertrophy on echocardiogram
- Very thick wall and small lumen
Kidney disease and systemic hypertension
- Increased glomerular pressure
- Proteinuria, glomerular ischemia
- Dysregulation of autoregulatory mechanisms
- Interstitial inflammation and fibrosis
- Kidney disease worsens!!
- One of IRIS substages is with systemic hypertension
Geriatric screening should include what?
- CBC/Chem/UA/T4
- BLOOD PRESSURE!
Treatment for systemic hypertension
- Treat underlying disease
- Give drugs to decrease Blood Pressure
Drugs for decreasing SVR?
- ACE inhibitors to block Ang II
- Phenoxybenazamine to block alpha 2
- Amlodipine to block calcium channels
- SEE CHART
Drugs to decrease heart rate
- Beta blockers
- Decrease contractility too
Drugs to decrease preload to decrease blood pressure
- Diuretics to decrease vascular volume
Amlodipine MOA
- Calcium channel blocker
- Blocks L-type Calcium channel
- Targets vessels directly
Who gets amlodipine?
- Cats with renal disease
- Decreases blood pressure
ACE inhibitors MOA
- Block ACE which converts Ang I to Ang II
- Ang II causes peripheral vasoconstriction and efferent arteriolar vasoconstriction
When to give ACE inhibitors?
- Kidney and glomerular disease
- Especially if proteinuria is present
Who gets beta-blockers?
- Hyperthyroid cats
- Not sotalol or amiodarone
Hyperthyroid effects on the heart
- Increased T3 –> increased beta-receptors on the heart
- This leads to tachycardia and concentric hypertrophy
Phenoxybenzamine MOA
- Alpha antagonist
Who gets phenoxybenzamine?
- Secretes norepinephrine, which binds to alpha 1
- Alpha 1 leads to peripheral vasoconstriction and high blood pressures
PPA
- Urethral sphincter constricts
-
Diuretics for treatment of systemic hypertension
- Diuretics are not a first line drugs, especially with kidney disease
Goals of treatment for systemic hypertension
- Target BP: 100-160 mmHg
- Ameliorate clinical signs (might be PU/PD)
- Prevent progression to end-organ damage
Prognosis for systemic hypertension
- Underlying disease
- Severity of hypertension
- Severity of clinical signs
