THURSDAY, Nov. 6, 2003 (HealthDayNews) -- Testing key biochemical markers for heart disease right after vascular surgery could alert patients to future heart attack risk, says a new Israeli study.
Testing for above-normal levels of two proteins -- troponins and creatine kinase, MB fraction (CK-MB) -- associated with heart disease is standard for cardiac patients. Researchers at the Hadassah Medical Center in Jerusalem found, however, that doing the same tests on patients who have had vascular surgery outside the heart was a significant predictor for future heart attacks and mortality in these patients.
"There was a correlation between postoperative troponin elevation and long-term survival, and even low-level troponin elevation was significantly predictive of increased long-term mortality in these patients," says study author Dr. Giora Landesberg, a cardiologist at the Jerusalem medical center. The report appears in the Nov. 5 issue of the Journal of the American College of Cardiology.
CK-MB levels also predict survival, Landesberg adds. Troponin and CK-MB are proteins inside heart cells that leak into the blood when those cells die. They are easily detectable in blood tests.
Also important, Landesberg says, is that the patients who had the elevated biochemical markers of either troponins or CK-MB showed no other obvious signs of heart trouble.
In their work, researchers studied 447 patients, average age 68, who had approximately 500 major vascular procedures, including reconstruction of the abdominal aorta, low-extremity bypass surgery or carotid endarterectomy, which is the removal of plaque from one of the arteries that supplies blood to the brain. During the first three days following surgery, the patients had daily electrocardiograms as well as tests of their troponin and CK-MB levels.
During a follow-up period that averaged nearly three years, elevated troponin and CK-MB levels were associated with higher death rates, even when the levels were only slightly elevated.
"While our study does not prove that troponin should be routinely tested after every major vascular surgery -- the cost effectiveness and the clinical efficacy of such routine testing has yet to be proven -- it is the first step, showing the prognostic importance of this test," Landesberg says.
People who have vascular surgery have atherosclerosis, which is when the arteries are clogged, and it is known that those who have the condition are more likely to also have problems with the arteries of the heart, says Dr. David L. Pearle, a Georgetown University Medical Center cardiologist. In fact, heart attacks are the most dangerous complication of vascular surgery, affecting about 5 percent of patients, so these people are carefully monitored before and after surgery for possible cardiac problems.
"What's new here is that very small releases of these substances are a predictor of long-term problems," he says. "If you can identify those high-risk groups, it helps motivate patients and makes both doctors and patients more conscientious in care, like diet and exercise."
Pearle says that at Georgetown, a thorough work-up of patients facing vascular surgery includes testing for troponins and CK-MB levels before and after surgery, but that such tests are less common in many medical settings.