hypertension

• Pulmonary arterial hypertension - high bp in right atrium and pulmonary artery
• Dogs and cats with liver disease- pressure in the portal system goes up - portal venous hypertension
• Dogs and cats in HF do not have an abnormal BP but they do have venous hypertension.
• Patients with RCHF have systemic venous hypertension
• Patients with LCHF will have a pulmonary venous hypertension
• When we talk about hypertension we often mean arterial systemic hypertension (high BP in the systemic arteries which are supplied by the left ventricle)
• Hypertension can occur due to an array of circumstances and this can cause false positives when measuring blood pressure…..

  • Fear or excitement (white coat effect)
  • Drugs (Fluid therapy, steroids, cyclosporin A, phenylpropanolamine)
  • Age
  • Breed (sighthounds have 10 –20 mmHg Higher BP)
  • Obesity (small increase)
• When it comes to blood pressure, there is no cut-off value which states what is hypertension but there are guidelines.

  • Systolic greater than 160 mmHg warrants further investigation
  • Diastolic greater than 100 mmHg warrants further investigation
• Common signs of hypertension are retinal haemorrhage and sudden blindness, in these cases, you would measure BP. The other time you measure BP is in an animal with renal failure (commonly associated with hypertension.
• Causes of hypertension fit into three groups:

  • Artefact (Stress induced / white coat effect)
  • Primary (idiopathic)
  • No underlying disease was detected. This is more common in humans (Diet and lifestyle related) and is rare in veterinary patients.
  • Secondary (underlying disease detected)
  • Renal disease
  • Hyperadrenocorticism (dog)
  • Hyperthyroidism (cat)
  • Diabetes mellitus (dog and cat)
  • Phaeochromocytoma (rare)
  • Hyperaldosteronism (rare)
  • Drug therapy (steroids, NSAID, cyclosporin A, phenylpropanolamine)
• Blood pressure cannot remain persistently elevated without abnormal sodium handling (chronic renal

  failure/insufficiency). Kidney disease of any type result in areas of ischaemia that lead to activation of the RAAS. Hence, kidney disease leads to dilation of the afferent arteriole and constriction of the efferent arteriole resulting in dramatic raises in glomerular pressures which leads to renal damage and proteinuria.
• There are no clinical signs at the initial phases, the patient may be more depressed, have headaches, feel unease etc but won't present until there is end organ damage

  • Greater than 180 mmHg or if 30 mmHg rise within 48 hours

  End organ damage can present in 4 areas of the body…

  • Ocular (hypertensive retinopathy)
  • Acute blindness, retinal detachment and intraocular haemorrhage
  • CNS (hypertensive encephalopathy)
  • Disorientation, ataxia, stupor, seizures and strokes
  • Renal (proteinuria)
  • Pu/Pd
  • Cardiac (left ventricular hypertrophy)
  • Murmur, Arrhythmias and CHF
• The cuff width size should measure 40% of the cuff site circumference and be placed on a limb (cats) or tail (dogs)

  • Too large of a cuff will cause an under-estimate
  • Too small of a cuff will cause an over-estimate
• The patient should remain calm and motionless during the measurement. Be sure to maintain the cuff at the same level as the heart.

  • First measurement should be discarded and an average of 3 to 7 (?10) consecutive measurements should be obtained.
• Beta blockers are barely used but can be used in hyperthyroid cats (due to their increased sensitivity to catecholamines) commonly ca channel blockers are used. ACEI likely works better in increases renin levels e.g. DM and Cushing's.
• fill in the blanks

  A) moderate

  B) severe

  
• treatment...

  • Beta blockers
  • These are used to reduce heart rate and contractility and are the treatment of choice in hyperthyroid cats (poor results as a single agent in other conditions)
  • ACE inhibitors block the RAAS
  • Ca channel blockers inhibit calcium influx to the cell causing vasodilation
  • Angiotensin II receptor blocker reduced proteinuria associated with chronic kidney disease in cats