Hypertension Flashcards
For adults aged ≥18 yrs hypertension is:
diastolic pressure (DP) >90 mmHg and/or
systolic pressure (SP) >140 mmHg
Risk factors
Male
Increasing age
Lifestyle factors – smoking, obesity, alcohol intake, recreational drug use
Fhx of CKD, HTN, DM, dyslipidaemia, stroke or early onset heart disease (men aged
Dyslipidaemia
DM or prediabetes
Depression, social isolation, and psychosocial factors affecting management of chronic disease
Definition and classification of blood pressure in adults aged >18 years, measured as sitting blood pressure (mmHg)
Category Systolic Diastolic Follow-up
Optimal <120 <80 2 yrs
Normal 120–129 80–84
High normal 130–139 85–90 1yr or earlier
Grade 1 HTN (mild) 140–159 90–99 2 m
Grade 2 HTN (moderate) 160–179 100–109 witihin 1 m
Grade 3 HTN (severe) ≥180 ≥110 1–7 days
Isolated systolic HTN ≥140 <90 1 m
When a pt’s systolic and diastolic BPs fall into different categories, the higher category should apply.
Recommended BP measurement
All people aged 18+ yrs
Every 2 yrs
For every 2 mmHg increase in systolic blood pressure the risk of death from ischaemic heart disease and stroke rises by
7% and 10% respectively
The WHO-ISH recommendation is that
decisions about management of pts with hypertension should not be based on BP alone,
- but also on the presence or absence of other risk factors,
including important factors such as:
- age
- diabetes
- smoking
Cardiovascular risk should be stratified according to the BP level and the presence of:
absolute cardiovascular risk factors
associated clinical conditions
target organ damage
Perform a cardiovascular risk assessment
Should be undertaken for any pt with HTN
Risk assessment forms the basis for:
- discussions about prognosis and Rx options with pt
- provides information about other factors affecting CVD management, e.g. diabetes medicines
- primary and secondary prevention of MI and stroke.
When all risk factors are taken into account, an individual’s CVR may be higher than individual risk-factors may suggest.
Balancing total cardiovascular risk (CVR) against modifiable risk factors
The advantage of basing Rx decisions on total cardiovascular risk is that the majority of people with HTN have other CVR, which are often additive and lead to a risk “that is greater than the sum of its parts”.
HTN in high-risk people is often resistant to Rx and requires multiple interventions, e.g. lipid modifying treatment.
However, the disadvantage of relying solely on 5 yr cardiovascular risk is that Rx may be withheld from some people because their CVR is assessed as being too low to require treatment.
For ex, a 35 year old Māori male who is obese, with a total cholesterol:HDL ratio of 7.8, and a BP of 165/98 mmHg has an absolute cardiovascular risk of 9% (calculated with a decision support tool) and therefore management by lifestyle interventions alone is recommended until the pt reaches the age of 46 years.
When considering antihypertensive Rx in younger pts with a cardiovascular risk of less than 15%, the long-term burden of disease needs to be taken into account.
It is currently being debated internationally if a 5yr period is long enough to meaningfully convey CVR in younger patients.
A practical approach is to stratify total cardiovascular risk in the terms
- low
- moderate (medium)
- high
- very high
added risk which are calibrated to indicate an absolute 10-yr risk of CVD of :
- <15%
- 15–20%
- 20–30% and
- >30% respectively
(based on Framingham criteria).
For example:
- low risk indicates starting Rx and monitoring
- high risk indicates treat immediately
Risk estimates can be determined by referring to
various cardiovascular risk tables on the website.
A commonly used tool is:
- the modified NZ Cardiovascular Risk Calculator (http://www.nzgg.org.nz or www.heartfoundation.com.au).
It is important to collaborate with pts in decision making and thus discussing:
- the cardiovascular risk assessment, and BP level
- the risks and benefits of treatment.
