Checking for clogged arteries could one day be as simple as a blood test. Researchers report that a relatively quick and inexpensive analysis of chemicals in the blood can reliably detect the disease and indicate its severity.
Coronary artery disease, the leading cause of death in the United States, results when fats clog the arteries that supply blood to the heart. Currently, doctors screen patients for disease by checking off a laundry list of risk factors, including high cholesterol, cigarette smoking, and obesity. But they can't be sure until they thread a catheter through the coronary arteries and take x-ray movies that reveal their condition. This procedure, called angiography, is invasive, time-consuming, and costly. Biochemist David Grainger of Addenbrooke's Hospital in Cambridge, U.K., and his team say they've found an effective alternative in a powerful technique borrowed from analytical chemistry.
The technique, called proton nuclear magnetic resonance (1H-NMR), records light reflected off a sample placed in a magnetic field and zapped with radio waves. Every chemical has a emission spectrum as unique as a fingerprint. Grainger's team sampled serum (blood with the clotting cells removed) from 36 people with coronary disease diagnosed by angiography and 30 healthy people. After analyzing the spectra with a statistics program, the team was able to diagnosis the samples with a 92% accuracy. Differences in the amount of lipoproteins--a type of fat--were the most significant indicators of disease, they found.
The team also demonstrated that 1H-NMR can indicate disease severity: They accurately assigned another 76 patients to one of three categories--mild condition (one artery affected), moderate (two arteries in trouble), and major (all three coronary arteries clogged). These findings, along with the ease with which the technique can be done, make ¹H-NMR well-suited for clinical use, the team argues in the 25 November issue of Nature Medicine.
“This study is a beautiful integration of analytical chemistry, clinical medicine, and biostatistics,” says chemist and toxicologist Mark Viant of the University of California, Davis. The technique captures tremendous amounts of data that can be mined for new insights into how diseases progress, adds toxicologist Marion Miller, also at UC Davis.