Cvd Risk Past, Present & Future

CVD RISK PREDICTION:  PAST, PRESENT & FUTURE Ramesh Singh Veriah Cardiology Unit University Malaya Medical Centre (UMMC)

AIMS • History • What is risk? • How does risk relate to the management of  cardiovascular disease (CVD)? • Calculating CVD risk. • How can we communicate risk to patients?

Introduction • CVD initially thought of as a natural  consequence of aging. • With time life‐style factors and biochemical as  well as genetic factors were identified. 

Seven Countries Study • 1958 – 1970, men ages 40‐59 from 7 countries • Clearly demonstrated that CVD rates varied  around the world and is influenced by  environmental factors. • Migration factors appeared to have a strong  influence.

Framingham Heart Study 1961 • Earliest landmark study. • Showed that hypertension, high cholesterol  and smoking increased CV risk. • Development of CVD involves a number of risk  factors.

Cardiovascular Disease is a Common Complex Disease Elevated Blood Pressure

Adverse Lipid Profile

Diabetes

Family History Cardiovascular Disease

Sedentary Lifestyle

Obesity

Smoking

Nutrition

"At least hundreds of genes are involved in cardiovascular disease” - Lusis AJ, 2000

“You can only predict things after  they have happened”

Eugéne Ionesco 1912‐1994

What is risk? Risk is the likelihood of being harmed in some way How we define and understand risk depends on  – – – – –

emotional factors rather than hard facts our instinctive bias if we understand the difference between risks and hazards based on evidence common sense

Harm is not often due to a single cause so it becomes  harder to define what a risk is When we try to avoid a risk, we can change some part  of the situation that potentially results in exposure to  a different risk

Risk Factor Assessment • Rarely occur in isolation. • Rather CVD is a convergence of a number of risk  factors thus global assessment is needed. • Combine risk factors with disease markers can  prove to be beneficial • Important to identify the modifiable risk factors  as it is a potential target for intervention. • Which risk factor is an important predictor,   assess it at minimal cost and easiest way.

CV Risk Prediction: Application • Population ‐ planning for public health messages/forums • Individual ‐ target more intensive programs that are also  personalized to maximize the prevention of  disease

A ‘Perfect’ Risk Factor • • • •

Prevalent in the population Can be easily and safely measured Good predictive value Inexpensive to measure

Risk Scoring • Many risk factors are correlated with one another. • When conducting an initial screen only a handful of  easily measured risk factors are needed to measure  the individuals overall cardiac risk. • Low risk or high risk (clearly scored) individuals will not  need any further evaluation of additional risk factors as  this will only add to cost and not yield further  information. • It is the intermediate risk individuals that will warrant  further stratification.  • Allows cost‐effective targeting of interventions.

CRUDE ASSESSMENT Risk of a Second Vascular Event Increased risk vs general population (%) Original event

Myocardial infarction

Stroke

Myocardial infarction

5–7 x greater risk1

3–4 x greater risk2

(includes death)

(includes TIA)

2–3 x greater risk2

9 x greater risk3

Stroke

(includes angina and sudden death*) Peripheral arterial disease 4 x greater risk4 (includes only fatal MI and other CHD death†)

2–3 x greater risk3 (includes TIA)

*Sudden death defined as death documented within 1 hour and attributed to coronary heart disease (CHD) † Includes only fatal MI and other CHD death; does not include non-fatal MI 1. Adult Treatment Panel II. Circulation 1994; 89:1333–63. 2. Kannel WB. J Cardiovasc Risk 1994; 1: 333–9. 3. Wilterdink JI, Easton JD. Arch Neurol1992; 49: 857–63. 4. Criqui MH et al. N Engl J Med 1992; 326: 381–6.

High Risk Group • Diabetics • Chronic renal failure • These groups warrant aggressive preventive  interventions.

Risk Prediction Scores • • • • • •

Simple and reliable way. Low cost. Framingham Risk Scoring HeartScore (ESC) PROCAM Algorithm New Zealand Risk Scoring

Improving Risk Scoring • • • • •

Calcium scoring Multi‐slice CT Echocardiography Cardiac catheterization C‐reactive protein (CRP)

Women’s Health Study • Addition of family history, HBA1c if diabetic  and CRP can further reclassify women at  intermediate risk to either low or high risk.

LOWERING RISK • 3 complementary approaches ‐ therapeutic interventions for secondary  prevention in patients with known CVD ‐ identification and targeting of high‐risk  individuals for primary prevention through  mass screening or case finding ‐ general recommendations disseminated  throughout the population 

Framingham Data Individuals who can reduce and  minimize risk factor burden before  age of 50 will substantially lower  their life‐time risk of developing CVD

Communicating risk to patients • It is difficult to communicate risk and uncertainty • When  discussing  cardiovascular  disease  (CVD)  risk  with people,  show  them  the  risk  prediction  charts  (and  calculator)  to  help  them  understand  their  estimated  risk  of  experiencing  a  cardiovascular  event within the next 10 years  • It  is  usually  more  helpful  to  discuss  total  CVD  risk  rather than individual risks for CHD, stroke or other  events • Individuals  may  have  differing  thresholds of  risk  before considering drug treatment to lower risk and  this may be associated with social class

Communicating risk to patients • If  people  want  to  know  the  benefits  and  risks  of  investigations  and  treatments  then  we  have  to  be  able to communicate them effectively • The  way  in  which  health  professionals  communicate  risk  affects  patients’ perception  of  that risk • Patients  should  be  provided  with  a  balanced  and  fair assessment of the pros and cons of the various  options, based on well‐founded data • Use  of  simple  visual  aids  and  everyday  analogies  can help to increase understanding and ensure that  consent is properly informed