Molecular Diagnosis of Cardiovascular Disorders - Applications of Biotechnology in Cardiovascular Therapeutics - page 139

Early Detection of Congestive Heart Failure
Early detection of CHF is an important factor in reducing mortality and morbidity
associated with the condition. However, diagnosis of CHF is a complex and often
expensive process. The symptoms of CHF are nonspecific and are sometimes con-
fused with those of other conditions such as chronic obstructive pulmonary disease.
Echocardiography, the gold standard for diagnosis of left ventricular dysfunction,
is expensive and not always easily accessible. Other items on the cardiovascular
panel are CK-MB, myoglobin, troponin I, and homocysteine. These are expanded
by the BNP (B-type natriuretic peptide) assay. The BNP molecule is physiologi-
cally active and measures the direct biologic response to cardiovascular stress
providing a direct reflection of the patient's current status. This allows more timely
treatment and patient management. Recent research has shown that elevated levels
of BNP indicate the presence of CHF, thus providing physicians with an important
diagnostic tool in the early detection and treatment.
Triage BNP Test (Biosite Inc), based on protein chip technology, is a quantita-
tive test for measurement of BNP in CHF. ADVIA Centaur ® BNP assay (Bayer
Diagnostics) is a fully automated test that provides results in minutes, requiring less
hands on labor while reducing human error associated with manual testing. The
assay is currently available only outside the USA. Roche Diagnostics's Elecsys ®
proBNP is an automated immunoassay for diagnosis of CHF by detecting the level
of the NT-proBNP peptide. It was approved by the FDA in 2003 for risk stratifica-
tion in CHF and acute coronary syndrome.
Genetic Testing in Hypertension
The angiotensinogen (AGT) gene has been implicated as a candidate gene of high
blood pressure. AGT gene and some of its variants represent the best examples of
genetic influences that are involved in the determination of essential hypertension
and associated cardiovascular diseases. However, because the variants of the AGT
gene are point mutations, it is difficult to detect them in large-scale population
studies.
CardiaRisk (Myriad Genetic Laboratories) is a genetic analysis of the AGT
gene, which helps identify individuals with a particular form of hypertension and
to individualize therapy by analyzing genetic factors that influence each patient's
physiology and responsiveness to various interventions. It identifies those patients
who may benefit most from a low-salt diet and who also may have a greater risk of
cardiovascular diseases, such as coronary heart disease and myocardial infarction.
The test may also be useful in the T235 variant of the AGT gene that has been
associated with an increased risk of coronary heart disease and certain forms of
hypertension.