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Cats under pressure

Feline hypertension can cause target organ damage if it isn’t managed early, but is the condition going undiagnosed?

22 June 2018, at 9:39pm

The clinical importance of feline systemic hypertension has been recognised for many years and most veterinary surgeons in the UK are aware of the disease and its implications. Despite this, it has been revealed that many cats with elevated blood pressure are not being diagnosed or treated until late on in the disease process. 

Known as the “silent killer” because there are no early warning signs, feline hypertension is common, with one in eight cats over nine years of age suffering from idiopathic hypertension. The risk increases as cats age or if cats have other conditions such as chronic kidney disease (CKD) (where one in three cats suffer with hypertension) or hyperthyroidism (where an estimated one in four cats suffer with hypertension). 

The lack of early diagnosis is concerning because feline systemic hypertension can cause target organ damage (TOD) if not managed early. TOD can be sudden and acute, such as blindness caused by retinal detachment, or subtle, such as accelerated renal deterioration. Once feline hypertension has been identified, long-term management of the patient is needed to avoid these changes. 

Veterinary attitudes to blood pressure screening

A recent survey conducted of 100 veterinary surgeons practising in the UK revealed some interesting data. The vets questioned conducted 143 feline consultations per month on average, yet under half of these vets diagnosed feline hypertension routinely and a diagnosis was made less than once per month. Most vets (88 percent) stated that senior cats would benefit clinically if blood pressure was monitored routinely (the ISFM recommends the annual measurement of blood pressure from the age of seven), yet 82 percent of vets did not monitor the blood pressure of healthy senior cats. 

Despite this, over 90 percent of the vets questioned agreed that treating feline hypertension in its own right was beneficial to the patient – so what are the barriers? Why aren’t more cats being tested before clinical signs appear? 

It would appear that the main barrier to the measurement of feline hypertension is time – short consultation times and

Measuring blood pressure in cats can become routine
Measuring blood pressure in cats can become routine

busy surgeries mean vets do not have the capacity to add the measurement of blood pressure into routine visits. The perception of the average time required for each cat was 10 minutes. 

Interestingly, a 2016 study conducted in France showed that 87 percent of the 139 cats enrolled had their blood pressure measured by experienced investigators in less than five minutes. 

Other barriers stated include a perception of additional cost, hassle for owners and the concern that a stressed cat will not deliver an accurate reading in the consultation room. 

In 93 percent of cases it is the vet that makes the decision about whether to take a blood pressure measurement, yet all vets agreed that they would be happy for an RVN to take the measurement. In fact, 90 percent of the time, measuring blood pressure in cats is considered a two-person job and vet nurse support is critical.

Change in approach 

Feline hypertension can lead to devastating and life-changing problems. The potential for significant TOD to the ocular, renal, nervous and cardiovascular systems cannot be ignored. Veterinary health care teams need to find ways to remove some of the barriers to monitoring, ensuring hypertension in cats is picked up early. The good news is that a simple daily treatment, Amodip (amlodipine), is available to reduce blood pressure once a diagnosis has been made – so what can we do differently? 

It is important to assess certain groups of cats regularly: 

  • Those over seven years old 
  • Those presenting with TOD 
  • Those presenting with commonly associated conditions, such as CKD and hyperthyroidism, as secondary hypertension occurs in 80 percent of cats with hypertension 

Getting an accurate blood pressure measurement 

To save time during the consultation, it may be useful to invite owners to attend the clinic 15 minutes before their appointment to allow the nursing team to reassure patients and take a blood pressure reading before seeing the vet (lowering the risk of situational or “white coat” hypertension). It is useful to take enough readings to obtain a reliable average that can be entered into the patient’s records. 

Ideally, a cat’s blood pressure should be below 140mmHg but readings of up to 160mmHg can be expected in stressed individuals. In these healthy cats, no treatment is needed and typically, annual monitoring of cats over seven is recommended. 

Cats with primary (idiopathic) hypertension

If a cat’s blood pressure is over 160mmHg and the patient is not showing signs of any concurrent disease associated with hypertension or TOD, it is worth repeating the measurement in one to two weeks to assess for primary hypertension. A second reading above 160mmHg, even if no other clinical signs are present, requires immediate treatment to prevent future TOD. Following a diagnosis, cats need to be monitored every three to four months unless there is a change in clinical status.