Santé Magazine
Salute Magazine
Новости Здоровья
Although blood pressure lowering drugs, called beta-blockers, may help prevent heart attacks during surgery, they may increase the risk of major stroke and death. Out of the approximately 100 million adults who have major, non-heart related surgery annually, over 1 million will suffer a major heart complication including heart attack and death. Surgery increases the stress hormones in patients, which increase the heart's need for oxygen. Since beta-blockers reduce the effects of increased stress hormones, some physicians believed they could prevent serious heart complications when given around the time of surgery.
POISE, the world's largest randomized trial addressing perioperative cardiac complications, evaluated the effects of a beta-blocker versus placebo given to patients around the time of surgery. The results of the study were recently published in the medical journal, The Lancet. POISE Investigator, Dr. P.J. Devereaux, said "POISE demonstrates that a beta-blocker given around the time of surgery decreases a patient's risk of a heart attack but increases their risk of a major stroke and death."
Dr. Salim Yusuf, POISE steering committee chair, stated, "A major accomplishment of POISE was that anesthesiologists, cardiologists, internists, and surgeons at 190 centers in 23 countries came together and randomized 8,351 patients—more than 4 times as many patients than all the previous perioperative beta-blocker trials combined. Such efforts are rare, but essential in order to make progress in the management of these patients." The trial randomized 4,174 patients to receive extended-release metoprolol succinate and 4,177 patients to receive placebo beginning two to four hours before surgery and continuing for 30 days after surgery.
There were 176 patients in the metoprolol group who suffered a heart attack, which were fewer than the 239 in the placebo group who suffered a heart attack. This suggested that patients who received metoprolol were 27 percent less likely to suffer a heart attack, yet, 129 metoprolol patients in comparison to 97 placebo patients died. This indicates that patients who received metoprolol were 33 percent more likely to die. In addition, 41 metoprolol patients suffered a stroke compared with only 19 placebo patients, suggesting that patients who received metoprolol had more than double the risk of a stroke. Less than a third of heart attack patients also had complications from their heart attacks such as heart failure, whereas over half of the those who suffered a stroke were incapacitated or in need of help with everyday activities.
The analysis of the POISE data suggests that metoprolol increased the risk of death or stroke by increasing the risks for low blood pressures requiring treatment. According to Devereaux, "The most likely explanation for the increase in deaths and stroke among those taking beta-blockers was that these patients could go into shock if their blood pressure were too low, a not uncommon complication of surgery. If they were on the beta blockers they were in big trouble, and increased their likelihood of dying or suffering a stroke."
Devereaux said that using a beta-blocker to prevent heart attacks is not the right strategy and he doesn't think reducing the risk of heart attack is worth increasing the risk of stroke or death. "I don't think most patients would be willing to accept the excess death and excess stroke for preventing a heart attack," he said. "If we are causing so much harm to prevent heart attacks, we need to find another solution which will prevent these events, but not have the same risk."
In a comment accompanying the study, Lee A. Fleisher, MD, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, and Don Poldermans, MD, Erasmus Medical Center, Rotterdam, Netherlands, agree that the POISE study shows the use a of higher-dose beta-blockers in the perioperative period has greater risk than benefit. However, they also discussed how other protocols using a low-dose beta-blocker regimen have established a beneficial effect on postoperative outcome without an increased incidence of stroke. They recommended using beta-blockers carefully in the perioperative period, in a low dose, to be supervised by clinicians who are experienced in blood circulation care during surgery.
