Metoprolol May Increase Postsurgical Risk of Stroke or Death
During the 12 months after undergoing noncardiac surgery, patients with heart disease or at risk for heart disease who are treated with the beta blocker metoprolol for 30 days are less likely than patients who receive a placebo to have a heart attack, but more likely to die or have a stroke, said researchers.
These follow-up findings confirm that an increased risk for death or stroke persists at one year post surgery in patients treated with metoprolol, said P. J. Devereaux, MD, PhD, Director of Cardiology at McMaster University in Hamilton, Ontario. Previously reported results from the same study at 30 days post surgery showed a similar pattern, with a reduction in heart attacks, but increases in deaths and strokes.
“Our results suggest at one year, for every 1,000 patients having noncardiac surgery, treatment with metoprolol would prevent heart attacks in 12 patients, but would result in an excess of 13 deaths and six strokes,” said Dr. Devereaux.
“While there is little doubt that some patients benefit from receiving beta blockers during the period immediately before and after noncardiac surgery, these data show that at least as many patients are seriously harmed,” he said. “These data tell us that we need to exercise caution when using beta blockers in this setting until we figure out how to mitigate the substantial risks and enable all patients to obtain the potential benefits of this intervention.”
Beta blockers work by slowing the heart rate and relaxing the blood vessels, which, in turn, reduces blood pressure. The problem is that during the period immediately after major noncardiac surgery (such as a hip or knee replacement, bowel resection, or abdominal aortic aneurysm repair), patients are usually treated with opioid medications to relieve pain, said Dr. Devereaux. The effects of those medications may mask drops in blood pressure or heart rate to dangerously low levels. “Hypotension is common in this setting and is a main contributor to the adverse effects resulting from perioperative beta blockers,” he said.
Patients who become hypotensive for whatever reason after surgery (eg, sepsis, bleeding, or heart failure) find their problem exacerbated when they are receiving a beta blocker, which further lowers blood pressure and makes treating hypotension more challenging.
The PeriOperative Ischemic Evaluation (POISE) trial enrolled 8,351 patients in 23 countries. Eligible patients were age 45 or older and had a history of heart disease, blood-vessel disease, stroke, congestive heart failure, or other health problems such as diabetes or impaired kidney function. Patients’ median age was 69, and 63% were men.
Patients were randomly assigned to receive metoprolol or a placebo, beginning a few hours before surgery and for 30 days afterward. Patients, health care providers, and research staff, except those analyzing data, were blinded to which group received metoprolol and which received a placebo. The study’s primary end point was a composite of the combined rate of death from heart disease, nonfatal heart attack, and nonfatal cardiac arrest after 30 days.
At one-year follow-up, fewer patients in the metoprolol group than in the placebo group had heart attacks (5% vs 6.2%), but more patients in the metoprolol group had died (9.8% vs 8.5%) or had a stroke (2% vs 1.4%).
These results followed the same pattern that had previously been seen at the 30-day follow-up: statistically fewer heart attacks in the metoprolol group (4.2% vs 5.7% in the placebo group), but statistically more deaths (3.1% vs 2.3% in the placebo group) and strokes (1% vs 0.5% in the placebo group).
Observers have suggested that the metoprolol dose in the POISE trial (200 mg/day) was too high and that a lower dose would have produced fewer adverse effects. But a lower dose might also have decreased the drug’s effectiveness in reducing heart attacks, said Dr. Devereaux, noting that the metoprolol dose in POISE only resulted in a 7-bpm lower heart rate, compared with placebo. More continuous monitoring “I believe the answer is more continuous patient monitoring during the immediate postsurgical period so that dangerous drops in heart rate or blood pressure are promptly identified and treated.”
Managing Blood Pressure in Barbershops Yields Improvements
African American men who received medical intervention aimed at controlling their high blood pressure while at the barber saw a marked drop in blood pressure in six months, according to researchers. Specifically, men who received frequent monitoring and medication management from a specially trained pharmacist who met them monthly in their barbershop lowered their systolic blood pressure by 21 mm Hg more, on average, compared with men who were encouraged by their barber to follow up with a doctor and to make healthy lifestyle choices.