Blood Pressure and CVD Risk

Blood Pressure and Absolute Cardiovascular Disease Risk

In Australia the risk of an adverse cardiovascular disease (CVD) event in the coming 5 years is assessed using the FRE (Framingham Risk Equation; Anderson and colleagues 1991). This is a predictive equation borne out of the Framingham Heart Study, which started in 1948. You can read about the Framingham Heart Study by clicking here.

The National Vascular Disease Prevention Alliance recommend completing a Framingham risk assessment for anyone aged 45 to 74 years of age (or from the age 35 if your patient is of Aboriginal or Torres Strait Islander background).

Blood Pressure is just a small part of CVD risk but my plan is to focus on one aspect at a time. Remember that in real life patients develop clusters of risk factors which may be additive. Moderate reduction in a range of modifiable risk factors (see below) may be more effective than just focussing on BP for example. 

But First--Back To Basics!

Blood pressure is the force of circulating blood against the arterial walls. The components to a heart beat include--systole when the heart contracts--and diastole when it relaxes and fills with blood. During systole the blood pressure is at its highest (the systolic reading) and during diastole it is at its lowest (the diastolic blood pressure). When we attach a cuff to a patient's arm we are recording the pressure in mm of Hg that their blood exerts against the brachial artery walls.

For elderly or diabetic patients BP must be recorded in both the sitting and standing position to detect autonomic dysfunction/ orthostatic hypotension.

Individual cardiovascular risk for each patient determines management--not just the blood pressure reading.

Classification and follow up of BP levels in adults:

normal <120/ <80 (recheck in 2 years)

...from here on the grades jump by 20 mm Hg systolic and by 10 mm Hg diastolic...so if you remember the first one, you can recall the others in an exam...

• high normal       120-139 / 80 - 89             (recheck in 1 year)
• Grade 1             140- 159/ 90 - 99             (recheck in 2 months)
• Grade 2             160- 179/ 100-109           (recheck in 1 month)
• Grade 3            ≥180 / ≥ 110                      (reassess or refer in 1 to 7 days)

and isolated systolic hypertension  >140 / < 90
and isolated systolic with widened pulse > 160 / < 70

When your patient's systolic and diastolic fall into two different categories, use the HIGHER of the two to determine your treatment.

Always consider the ubiquitous SNAP (smoking, nutrition, alcohol, physical activity)

Only start anti-hypertensive treatment straight away if the patient is at high risk of CVD.
Below is a poem to help you remember what factors put your patient in the “high risk” group (and the blue table below contains the actual details):

Start with SNAP at the beginning
And you’re already winning

BUT

Diabetics who are aged

with ACR above the range
need antihypertensives
as a main counteroffensive.
If GFR be 45
with proteinuria too high
treatment will be a breeze
with  ACE or ARB to slow disease.
Total fat over 7.5 ought to be treated to survive
and if high lipids are a mystery
don’t forget the family history!

increased cardiovascular risk

 
*Taken from page 7 "Guidelines for the Management of Absolute Cardiovascular Disease Risk." National Vascular Disease Prevention Alliance 2012)

The presence of any of these factors, or having BP persistently over 180 systolic or 110 diastolic, means you don’t do the Framingham calculation, but go straight ahead and consider modifiable risk factors and while initiating pharmacotherapy.

Summary of blood pressure recommendations

Ø  Consider treating any BP over 160/100 regardless of risk

Ø  Treat ant BP in a person with moderate risk if they have

o   A positive family history of premature CVD

o   “at risk” ethnic background (ie Sth Asian, Middle Eastern, Pacific or SE Islander, or ATSI)

Ø  Treat any BP in a person at high risk (see the blue table above*)

The Framingham Risk Equation underestimates risk in:

Ø  Aboriginal and Torres Strait Islanders

Ø  Adults with diabetes (under age 60)

Ø  Adults over age 74

The usefulness of the FRE in obese adults is uncertain

BP targets for specific populations

Ø  Diabetics ≤ 130/80

Ø  Albuminuria (urine ACR > 2.5 male or 3.5 female)  ≤130/80

Ø  Chronic kidney disease (CKD) < 140/90 (Note that this target as recommended by the Stroke Foundation and Kidney Health Australia is higher than that recommended by the Heart Foundation who suggest that a target of < 130/80 should be achieved in patients with CKD)

Here is a very basic way to remember these targets...

The 13 of 130/80 is hidden in the word diabetes and albuminuria:

The 140 of 140/90 is hidden in the initials CKD: 

 

Modifiable risk factors:

(Important part of assessment of CVD risk)

Remember “SNAP BBL”

Smoking, Nutrition, Alcohol, Physical activity, BMI & waist circumference (the two always go together), Blood Pressure and serum Lipids.

Non-modifiable risk factors

Remember "NAFS"

Non modifiable factors=Age & sex, Family Hx of premature CVD and Social history including ethnicity and socioeconomic status.

To calculate CVD riak use the online calculator www.cvdcheck.org.au or from www.heartfoundation.org.au

The following blogs will address evaluation of patients with confirmed hypertension, followed by management, and aspects of anti-hypertensives, including case studies and questions.

NHMRC Health Priority Areas

NHMRC Health Priority Areas

(In my mind, this means areas to know inside-out)

see http://www.nhmrc.gov.au/grants/research-funding-statistics-and-data/nhpas

These areas will be addressed in detail over the coming months:

Arthritis and Osteoporosis

Osteoarthritis, rheumatoid arthritis and gout - account for more than 95 per cent of arthritis in Australia.

see "Think Osteoporosis!" GP guide to Osteoporosis

Asthma

Asthma is Australia's most widespread chronic health problem. It affects 1 in 7 primary school-aged children, 1 in 8 teenagers and 1 in 9 adults.

See National Asthma Council Australia. Asthma Management Handbook 2006. Melbourne, 2006
An excellent  (essential) resource if you can get a copy.
Download one from the Asthma council: http://www.nationalasthma.org.au/handbook

Cancer

It is estimated that more than 43,000 people will die of cancer in 2010

The most commonly diagnosed cancer (excluding non-melanoma skin cancer) is prostate cancer, followed by colon cancer, then breast cancer, melanoma and lung cancer. There are more than 100 different types of cancer, but these five most common types account for 60% of all cases. While lung cancer is the fifth most common type of cancer overall, it is the leading cause of cancer death in Australians.

Under this heading comes "cancer screening" which will be addressed in detail.

Cardiovascular Disease

Cardiovascular disease (CVD) is (macro and microvascular) is the leading cause of death in Australia, accounting for 34% of all deaths in Australia in 2006. Cardiovascular disease kills one Australian nearly every 10 minutes.
For resources on lipid management, hypertension and absolute risk see http://www.heartfoundation.org.au/information-for-professionals/Clinical-Information/Pages/default.aspx

Diabetes

Diabetes is Australia’s fastest growing chronic disease and is the sixth leading cause of death in Australia. For every person diagnosed, it is estimated that there is another who is not yet diagnosed. Indigenous Australians are four time more likely to develop diabetes than non-indigenous Australians.
Norman Swan has an excellent series on diabetes, the audiofiles of which can be freely downloaded from the Rural Health Education Foundation. See http://www.rhef.com.au/programs/
The booklet "Diabetes Management in General Practice 2011/12" is crucial reading. An electronic version of these guidelines is available at www.racgp.org.au or www.diabetesaustralia.com.au. For a hard copy of the 2011-12 publication, contact your State or Territory diabetes office on 1300 136 588.
Of note there are charts in both Murtagh  (John Murtagh's General Practice 5th edition) and the diabetes guidelines which are identical and which also appear in RACGP learning modules....so it would be helpful to learn these.

Obesity

Results from the 2007-08 National Health Survey, the first since 1995, reveal that in 2007-08, 61.4%of the Australian population were either overweight or obese.

42.1% of adult males and 30.9% of adult females were classified as overweight (Body Mass Index between 25.0 and 30.0 kg/m2). 25.6% of males and 24% of females were classified as obese (Body Mass Index > 30.0 kg/m2). For children and adolescents, results indicate that 24.9% of children aged 5 – 17 years are overweight or obese - 25.8% of boys and 24.0% girls.

Injury Related Issues

Injuries were responsible for 7% of the total burden of disease and injury in Australia in 2003, with suicide, self-inflicted injuries, road traffic injuries and falls accounting for nearly two thirds of this burden.

Mental Health
The National Survey of Mental Health and Wellbeing 2007 found that one in five (20%) Australian adults experience some form of mental illness in any year. One in four of these people may experience more than one mental disorder. Based on these prevalence rates, over 3.2 million Australians had a mental disorder in the previous 12 months. This means that:

• one in seven (14.4%) Australians had an anxiety disorder;
• one in 16 (6.2%) had an depressive disorder; and
• one in 20 (5.1%) had a substance use disorder.

Almost half of the Australian population (45.5%) will experience mental illness at some point in their lifetime.

The RANZP have some very helpful clinical practice guidelines which can be accessed at: http://www.ranzcp.org/Publications/Clinical-Practice-Guidelines-2.aspx  including

• Clinical guidance on the use of antidepressants medications in children and adolescents
• Guidance on the use of SSRIs and SNRI in late pregnancy

I had trouble locating the clinical practice guidelines for depression on their website but here is a link from another Australian site to the RANZCP Clinical Practice Guidelines for Treatment of Depression 2004 http://smileyaustralia.org/images/downloads/CPG_Clinician_Full_Depression.pdf



NB although not specifically mentioned as a health priority area, Chronic Kidney Disease is a cause of major morbidity and mortality and is closely tied to hypertension, cardiovascular risk and diabetes. This will also be an area I will cover in detail in the coming months. "Timely identification and treatment of CKD can reduce the risks of cardiovascular disease and CKD progression by up to 50%"--See www.kidney.org.au for a copy of Chronic Kidney Disease Management in General Practice in 2012. Ive found this booklet exceptionally clear and a great resource in day-to-day medical practice.

Other areas that connect with the above health priority areas include smoking cessation, preventative health and lifestyle modification (see Smoking Cessation pharmacotherapy: an update for health professionals; available from www.racgp.org.au.)