FRIDAY, May 9, 2003 (HealthDayNews) -- Drugs known as calcium channel blockers reduce the risk of heart attack and other problems when given to patients during cardiac bypass surgery, says a new report that refutes previous research.
The drugs also cut the risk of an abnormally fast heart rhythm, called supraventricular tachyarrhythmia, and the risk of ischemia, decreased blood flow due to obstructed or occluded vessels, for heart surgery patients, says Dr. W. Scott Beattie, co-author of the report appearing in the May 7 issue of the Journal of the American College of Cardiology.
Among commonly prescribed calcium channel blockers (also called calcium antagonists), which are also used to treat high blood pressure, are Norvasc, Cardizem, Procardia and Tiazac. They work by interrupting the movement of calcium into the heart and blood vessel cells, relaxing the vessels and making it easier for the heart to pump blood.
The study was a meta-analysis, in which the authors combined the findings of 41 studies involving more than 3,300 patients and looked at the overall results. But they believe it's the first systematic review of all the medical literature to examine the use of the calcium channel blockers during cardiac bypass surgery.
While heart bypass surgery reduces deaths from heart disease, the surgery itself has complications associated with it, including heart attack and death.
Beattie, a physician at the University of Toronto and Toronto General Hospital, says the research team began the project after a graduate student, Dr. Duminda N. Wijeysundera, suggested another look at the drugs even though some studies had found no benefits with them.
The study shows the drugs reduced the risk of heart attack by 42 percent, of ischemia by 47 percent and also lowered the incidence of abnormal heart rhythms after surgery, Beattie says.
Another expert says he's not surprised by the findings. "This really does not come as a great surprise, because these drugs have actually been used in this regard," says Dr. Matthew R. Weir, a professor of medicine and head of nephrology at the University of Maryland in Baltimore.
While the evidence that the calcium channel blockers are helpful for patients having cardiac surgery is useful, he says what was not done was a "head-to-head" comparison with other drugs used for the same purposes.
Based on the meta-analysis, Weir says, "one cannot say that one [drug] is better than anything else. All I would say is, they are certainly very safe and certainly very helpful."
Beattie agrees with some of Weir's criticisms. "This study has many flaws," he says, including the fact that some of the original studies were poor to medium quality. "We think what is needed is further study." He and his colleagues are in the process of obtaining the funding, he adds.
Until more is known, Beattie says, patients should discuss their treatment options with their doctor.
More information
Learn about calcium channel blockers and other blood pressure lowering drugs from the American Heart Association, which also has a rundown on bypass surgery.
