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WEDNESDAY, August 20, 2003 (HealthDayNews) -- Exercise heart scans may offer a clearer picture of the effectiveness of cholesterol-lowering statin drugs in people with coronary artery disease, says a study in the Aug. 20 issue of the Journal of the American College of Cardiology.
The pilot study found that using heart scans to monitor stress-induced coronary artery blood flow abnormalities may provide a better way to evaluate treatment response to statin therapy than measuring changes in blood cholesterol.
Over a period of six months, researchers compared changes in the blood flow to the heart muscle and the blood cholesterol profile in people with coronary artery disease who took the drug pravastatin, a cholesterol-lowering drug that's been shown to reduce heart attack and cardiac death.
Six weeks into treatment with pravastatin, the patients' cholesterol levels began to decline. But improvements in blood flow to the heart muscle detected by heart scans became statistically significant only after six months of drug therapy.
The timing of the scan responses matches trends of reduced heart attack and cardiac death within six months seen in previous large clinical studies of pravastatin.
The study found that some of the patients showed improvement in their heart scans along with expected substantial reductions in cholesterol. But in others, the improvement of scans wasn't associated with major decreases in blood cholesterol levels.
And some patients in the study had improved cholesterol levels during the early period of statin treatment with no change or worsening of their heart scans.
So which test--heart scan or cholesterol level--is the better predictor of a patient's response to statins?
"The incremental value of the stress test with nuclear imaging, or SPECT MPI (single photon emission computed tomography, myocardial perfusion imaging) for predicting coronary events compared to other clinical data such as coronary risk factors and exercise electrocardiogram testing is very well established," researcher Dr. Ronald G. Schwartz of the University of Rochester Medical Center says in a news release.
"It seems likely the heart scans ... track the expected prognostic benefit of statin therapy better than do cholesterol levels. However, further study in larger ongoing trials which is now taking place is required to evaluate this question," Schwartz says.
For more on cholesterol, visit the American Heart Association.