A New Diagnostic Test to Detect Coronary Artery Disease
As this year and the first decade of the new millennium end, one wonders what is in the future for medicine. Not long ago we had the genome worked out and there was the promise for all sorts of genetic testing to tell us who would get what disease and maybe even when. Well, that is still a hope, but the diagnostic tests to tell us if we are susceptible or likely to have an important disease like cancer, coronary artery disease, stroke or Alzheimer’s are not yet available, although there are some tests in cancer and Alzheimer’s that suggest susceptibility, especially in high risk patients.
Thus it is with optimism that I report that a paper just came out in the Journal of Hypertension that shows promising results with regard to identifying the presence of coronary artery disease (angina or heart attack patients.) The best part of this test is that it is done with a simple urine sample, meaning no blood needs to be drawn and no genetic sampling is required. The basis of the test is actually proteomics, which is the study of proteins made in the body by the various genes. Some have thought all along that proteomics would be a more effective way than genetics to detect disease since the proteins identified in diseased patients are a marker for that disease. The trick has been to know what proteins to look for and where to find them, since it is impractical to take a sample of heart tissue if one is interested in heart disease, for example.
Physician scientists at the University of Glasgow have found that there are 238 coronary artery disease specific polypeptides (proteins) in patients with known coronary artery disease. These peptides appear in urine and can be detected with relatively simple laboratory instruments. In the investigation, the protein pattern was sought in 71 patients with disease compared with 67 normal individuals. The test was able to identify those with the disease in 87% sensitivity, meaning that it is a very good predictor of coronary artery disease. Obviously, many more patients must be screened and others need to validate this promising work, but it just may be that in a couple of years, we will be able to determine if we have coronary artery disease with a urine test instead of all the methods used today including cardiac catheterization. If this early finding proves correct in larger population screens, then we will be able to see if “that indigestion or tightness in the chest with exercise” is really coronary artery disease for which there are many treatments.
MUSC researchers also are conducting studies with the goal of developing blood tests that will predict cardiovascular disease.
"The important implications of these kind of studies is that they allow us to start to develop strategies to prevent cardiac events in high risk patients." said Michael R. Gold, M.D., Ph.D., MUSC's director of cardiology. "This is a study looking at proteomics rather than at biomarkers. Other studies have shown that there are genetic markers of patients predisposed to coronary artery disease or arrhythmic events. Proteomics looks at the proteins in blood or urine. It is simpler than genetic testing."
The reason that a urine test is so welcome is that it is inexpensive and some people put off other tests because of expense, time or trouble and their family only finds out they had coronary artery disease when they die suddenly from a heart attack. This is what we want to prevent, and this test might just do that. It is also good to see that the genomics and proteomics for which we had such high hopes are beginning to prove useful.
Read about coronary artery disease in our Health Information Library