Pathlab Cardiovascular Profile, Comprehensive, Blood TEST

Overview

Cardiovascular Disease refers to all diseases and conditions involving the heart and blood vessels. There can be many forms and causes of this diverse group of diseases, however, in Australia the main underlying problem is atherosclerosis.

Cardiovascular disease (CVD) is Australia's greatest health problem. In 2004-05, an estimated 3.5 million Australians, or 18% of the population, had cardiovascular conditions. It kills more people than any other disease, accounting for 47,637 deaths in 2004. It contributes to significant illness, disability, poor quality of life and premature death, and is the most expensive disease group in Australia in terms of health expenditure.

Standards for laboratories in relation to measurement of lipids and lipoproteins have been clearly set in many international studies of primary and secondary prevention of cardiovascular disease and there are many references in the literature supporting these tests and outcomes. There is strong evidence that lipid modifying treatment reduces CVD progression, morbidity and mortality in people at high risk of cardiovascular events, but these therapies are significantly underutilized.

Other markers of significance include inflammatory markers such as C-reactive protein (CRP), fibrinogen; infectious markers such as Helicobacter pylori and cytomegalovirus; oxidative stress factors include insulin levels; and the association of homocysteine with CVD is well documented.

Our Comprehensive Cardiovascular Profile includes: Cholesterol, Triglycerides, HDL, LDL, ratios, Apolipoprotein A1, Apolipoprotein B, Lipoprotein (a), CRP, Homocysteine, Fibrinogen.

Cholesterol and Low Density Lipoprotein cholesterol (LDL)

Most cholesterol is transported as a component of LDL, hence the evidence linking total cholesterol to LDL is essentially the same. As cholesterol is reduced, the risk of CVD decreases progressively. From the results of intervention trails, a 1.0mmol/L reduction in total cholesterol translates into an approximate 20% reduction in the risk of future coronary events and these benefits are apparent for a wide range of people both with and without CVD. While there is a continuous relationship between cholesterol concentration and death rates from CVD, it is also evident that most patients who develop CVD do not have markedly elevated cholesterol or LDL levels

Triglyceride and High Density Lipoprotein cholesterol (HDL)

There is an inverse relationship between the concentrations of triglycerides and HDL and each is probably independently related to CVD. Both are important tests to include in an assessment of CVD risk. Elevated triglyceride levels reflect chylomicron and VLDL (very low density lipoprotein) remnants, both of which are risk in triglycerides and cholesterol, and are at least as atherogenic as LDL. An elevated triglyceride level will predict CVD when either LDL is elevated or HDL is reduced, with risk being greatest with triglyceride levels between 2.0mmol/L – 6.0mmol/L. HDL exerts a direct protective effect against atherosclerosis by a mechanism of cholesterol removal from cells. The major proteins of HDL also have antioxidant properties and thus inhibit the oxidative action of LDL and reduce the atherogenicity of these lipoproteins. HDL should ideally be 1.0mmo/L or greater.

Apolipoprotein A1 (Apo A) and Apolipoprotein B (Apo B)

Apo A1 is the major protein constituent of HDL which activates the lecithin cholesterol acyltransferase enzyme (LCAT) thus esterifying cholesterol and increasing the lipid carrying capacity of the lipoproteins. Apo B is the major protein constituent of LDL. Determination of both apolipoproteins enables calculation of the ApoA/ApoB ratio, which is an indicator of the risk of developing atherosclerosis.

Lipoprotein (a)

Lipoprotein (a) is an LDL-like particle which is synthesized in the liver and is not influenced by age or diet but can act as an atherogenic agent. It has been associated with premature development of CVD and when concentrations exceed 300mg/L coronary risk is approximately doubled with a combined risk when LDL is elevated of approximately six-fold.

C-Reactive Protein (CRP)

CRP is a major acute phase reactant, which activates the complement pathway. It has a short half-life of a few hours and changes are apparent in 6-8 hours. Chronic inflammation plays an important role in atherosclerosis and CRP has a high predictive value for future coronary events in apparently healthy people especially when used in combination with lipid values.

Homocysteine

Homocysteine is an amino acid produced from methionine which circulates in the blood bound to plasma proteins. Elevated levels have been associated with an increased risk of CVD. The risk associated with a 5mmol/L increase in total homocysteine is the same as that associated with a 0.5mml/L in cholesterol.

Fibrinogen

Fibrinogen is the soluble precursor of fibrin, the end stage product of coagulation. It is also an inflammatory marker involved in atherosclerosis. Elevated fibrinogen levels are a risk factor in the development of CVD.

CLINICAL INDICATIONS

All the above components of the Cardiovascular Profile will enable an assessment to be made of an individual’s risk of developing CVD and lead to early and appropriate interventional treatment.

Lipid levels alone make only a relatively small difference to the risk of early CVD but when combined with other risk factors, make an important difference. There is strong evidence that lipid modifying treatment reduces CVD progression, morbidity and mortality for those at high risk of CVD events. This includes people with known CVD, other signs of atherosclerosis, Diabetes, Chronic Renal Failure, Aboriginals and Torres Strait Islanders, those with familial hypercholesteremia and hyperlipidemia, significant family history, hypertension, obesity, smoking, glucose intolerance and renal impairment.

Lipid modifying treatment should go hand-in-hand with lifestyle interventions such as eating a healthy diet consisting of reduced fat, increased fruit and vegetables, increased fish and fish oils, cease smoking, weight reduction, limiting alcohol and salt intake, and engaging in physical activity daily.

Pathlab Cardiovascular Profile: $175

MediCare rebate available if ordered by a medical practitioner.