Sticking with guidelines for acute coronary syndromes benefits even very elderly patients

Apr 24 2007

Some say age 90 is the new age 70. If so, there's never been a better time for elderly patients to discuss with family and physicians just how aggressive medical care should be in case of a threatened or definite heart attack.

According to a study published in the May 1, 2007 issue of the Journal of the American College of Cardiology (JACC), patients age 90 and older who came to the emergency room with acute coronary syndromes were less likely than younger patients to receive recommended treatments, but for those who did, survival was much better.

"Having an acute coronary syndrome, even over the age of 90, is not as dire as it once was," said David J. Cohen, M.D., M.Sc., F.A.C.C., director of cardiovascular research at Saint Luke's Mid America Heart Institute, Kansas City, MO. "With optimal medical therapy and invasive care, the outcomes were nearly as good as in a somewhat younger group of patients."

Acute coronary syndrome is an umbrella diagnosis that encompasses both a type of heart attack known as non ST-segment elevation myocardial infarction (NSTEMI) and unstable angina, or chest pain. It is usually caused by a blood clot that temporarily or partially blocks the coronary artery.

Therapies recommended by American College of Cardiology/American Heart Association guidelines include: aspirin, which prevents blood clotting by interfering with platelets; heparin, a "blood thinner" that interferes at a different point in the blood clotting cascade; and beta blockers, which slow the heart rate, reduce the force of the heart's contraction and prevent rhythm abnormalities.

In addition, the guidelines recommend that, within 48 hours, high-risk patients have cardiac catheterization, a procedure that allows cardiologists to see inside the coronary arteries using x-rays, catheters and high-contrast dye, and helps to determine the need for angioplasty, stenting or surgery. These patients should also be treated with glycoprotein IIb/IIIa inhibitors, which interfere with blood platelets and, therefore, prevent clotting inside the artery during or after the invasive procedure.

Each of these therapies has been shown to improve clinical outcomes in patients with acute coronary syndromes, but the studies proving their value have generally been conducted in younger patients. Their effectiveness in the extreme elderly, one of the most rapidly growing segments of the U.S. population, has not been tested.

"The elderly have different responses to medications and treatments than younger patients," said Dr. Cohen. "One of the major goals of our study was to find out whether proven therapies for acute coronary syndromes would work in the extreme elderly."

To do that, Dr. Cohen and his colleagues analyzed data from the CRUSADE National Quality Improvement Initiative, which recruited nearly 52,000 patients age 75 and older with acute coronary syndromes. Of these, more than 5,500 were at least 90 years old, and 112 were at least 100 years old. On January 1, 2007, the CRUSADE registry was replaced by the American College of Cardiology's NCDR-ACTION Registry, (Acute Coronary Treatment & Intervention Outcomes Network). The ACC's NCDR- Registry, now collects myocardial infarction data from hundreds of hospitals across the country into one unified platform with standardized clinical data elements to facilitate benchmark outcomes, and analyze treatment regimens.

Researchers found that extremely elderly patients were often considered unsuitable for recommended therapies. For example, doctors noted that cardiac catheterization was inadvisable in nearly 60 percent of patients age 90 and above, as compared to 27 percent of patients age 75 to 89. The reason most often cited was age itself. Even when there was no apparent reason to consider therapy inadvisable, extreme elderly patients were significantly less likely to receive recommended treatments.

Doctors may have acted out of caution, rather than age bias. CRUSADE researchers found that anticlotting medications and cardiac catheterization were more likely to cause bleeding complications in extremely elderly patients. In fact, as the number of therapies increased from one to five, the risk of major bleeding complications climbed from 3.5 percent to 17.3 percent. Nonetheless, survival was also better with increasing adherence to recommended therapies, particularly aspirin, beta blockers and cardiac catheterization.

"The data are telling us that that the balance favors survival, and we have to be willing to tolerate some increased bleeding," Dr. Cohen said. "We shouldn't simply, on the basis of age, say a person is too high-risk. We should discuss these therapies with patients and their families."

Robert J. Applegate, M.D., F.A.C.C., a professor of cardiology at Wake Forest University School of Medicine, Winston-Salem, NC, said the results of the CRUSADE analysis were encouraging but not definitive. "These results indicate that use of treatments recommended for younger patients with threatened or definite heart attacks was also effective in older patients, but at a cost of more bleeding. Although these findings are encouraging, it is not clear whether the better outcomes simply reflected treatment of healthier patients," he said. "Treatment of threatened or definite heart attacks in very elderly patients should still be made on a case-by-case basis until further studies confirm these results."

In the meantime, bleeding risk may be minimized by adjusting the dosage of anticlotting medications, based on a more careful assessment of kidney function, Dr. Cohen noted. In extremely elderly patients, a normal blood creatinine may give false assurance that kidney function is normal. Calculating creatinine clearance, which takes into account age, gender, and body size, often paints a more accurate picture.

"One of the things we've learned over the last several years from the CRUSADE registry is the importance of checking kidney function and adjusting medication dosage," Dr. Cohen said. "Neglecting to do that really does seem to be associated with worse outcomes."

Dr. Cohen reports receiving research grants from Bristol-Myers Squibb, Sanofi-Aventis, and Eli Lilly, all companies that manufacture anticlotting medications.