NEW YORK, Jul 01 (Reuters Health) -- Too many heart attack patients in the US may be undergoing cardiac catheterization procedures, in contrast to Canada, where it appears that the procedure may be performed in too few patients, results of a study suggest.
During cardiac catheterization, a doctor guides a thin plastic tube or catheter through a large vessel in the groin and guides it into the coronary (heart) arteries. Then, the doctor injects a liquid dye through the catheter in order to make the vessels visible on x-ray. X-rays map the dye's flow, enabling the doctor to locate blockages. Once the mapping is done, the doctor can see how many arteries are affected and decide on the best treatment course, which may include immediate use of revascularization techniques during the procedure to reopen blockages.
Writing in the July issue of the Journal of the American College of Cardiology, researchers, led by Dr. Wayne B. Batchelor of Duke University in Durham, North Carolina, found that 71% of US heart attack patients who were enrolled in a specific study underwent cardiac catheterization during their initial hospital stay, compared with only 27% of Canadian heart attack patients who were enrolled in the same trial.
In both countries, however, just 17% of the catheterized patients were found to have severe heart disease.
Based on these results, researchers report that US heart doctors detect 12 cases of severe heart disease per 100 heart attack patients, compared with 4.6 cases of severe heart disease detected per 100 heart attack patients in Canada.
They estimate that these differences may result in a survival advantage of five additional lives saved per 1,000 heart attacks among US patients.
"In the United States, most patients end up getting a cardiac catheterization after a heart attack," Batchelor notes in a statement issued by the American College of Cardiology. "Perhaps fewer procedures could be done by avoiding the procedure in very low-risk patients who are unlikely to benefit," he adds.
In Canada, where far fewer patients get catheterized, the opposite is the case, he points out. "Our results suggest that Canadian physicians could make more efficient use of restricted resources by selecting more high-risk patients for catheterization."
High-risk patients may include those who are likely to have severe heart disease and therefore require bypass surgery or another type of procedure to clear blocked arteries.
In an editorial accompanying the study, Drs. David A. Alter and C. David Naylor of the Sunnybrook and Women's College Health Science Centre in Toronto, Ontario, point out that neither country's system is ideal.
"Most of us have long since recognized that there's probably a happy medium," said Naylor. "Canada and much of the world are less aggressive than they should be. Conversely, we know that there are some parts of America where the rush to revascularize is fairly difficult to justify."
In a second accompanying editorial, Drs. John Ayanian and Eugene Braunwald of the Brigham and Women's Hospital in Boston, Massachusetts, suggest that heart doctors be more selective in their use of this procedure by stratifying patients according to their risk of having severe heart disease.
SOURCE: Journal of the American College of Cardiology 1999;34:12-23.
