Can Beta-Blockers Be Stopped Post-AMI With Preserved LVEF? Insights from FAST-MI

Shelley Wood

August 31, 2014

BARCELONA, SPAIN — Continuing beta-blocker therapy long term in post-AMI patients with preserved ejection fraction may not be warranted, according to a new analysis from the FAST-MI registry.

Dr Etienne Puymirat (European Hospital of Georges Pompidou, Paris, France) floated this controversial concept here in a hot-line registry session on day 2 of the European Society of Cardiology (ESC) 2014 Congress .

Most randomized controlled trials of beta-blockers in AMI were led before the era of reperfusion therapy and modern secondary prevention, Puymirat explained. As such, their usefulness in patients following AMI who have preserved LV function is controversial. The most recent ACC/AHA guidelines for STEMI and for secondary prevention give extended beta-blocker therapy post-AMI in patients without HF or hypertension a class I recommendation (for at least three years), but recent ESC guidance in STEMI downgraded their recommendation from I to IIa, he notes.

As previously reported by heartwire , FAST-MI is a nationwide French registry that tracked STEMI and NSTEMI patients over a five-year period, 2005 to 2010, at 223 hospitals and clinics representing 60% of French AMI centers.

For the current analysis, Puymirat and colleagues looked only at AMI survivors with no history of heart failure and an LVEF at discharge of 40% or greater. The cohort was further whittled down according to whether beta-blocker prescription status was known at one year, leaving 184 patients out of an original 3670 who were no longer taking beta-blockers at one year and another 1446 who were still taking beta-blockers. For the analysis, patients were matched according to their baseline clinical features and management, Puymirat said, leaving 142 patients no longer taking beta-blockers and 280 patients who were still on the drugs at 12 months.

After one year, survival was 95.3% among patients still taking their beta-blockers and 87.8% among those who had discontinued (HR 0.76, 95% CI 0.53–1.10). While the survival advantage did not meet statistical significance, Puymirat concluded, "Beta-blockers might be useful during the first year" in these post-AMI, preserved-LV-function patients.

After five years, however this pattern was reversed, with continued beta-blocker use associated with a trend toward increased mortality, although here again the numbers did not meet statistical significance (HR 1.18, 95% CI 0.67–2.08).

"Stopping beta-blockers during the first year after discharge was not associated with increased mortality at five years, [supporting] the changes adopted in the most recent ESC guidelines," Puymirat said.

Prospective Trials Needed

In discussion following the presentation, Dr Anselm Gitt (Herzzentrum Ludwigshafen, Germany) pointed out that Puymirat had not presented any data on how long patients had taken beta-blockers beyond the one-year mark or whether patients in the registry had been restarted on a beta-blocker for another reason.

"At least in Germany, despite the fact that the hypertension guidelines don't recommend this, many patients do receive a beta-blocker for hypertension, and some of them receive a beta-blocker for A-fib, rate control, or angina. So it's very difficult to interpret this [study]. This gives us a good glance at what's ongoing, but it's very difficult for us to draw conclusions from this subset of patients."

In response, Puymirat acknowledged the limitations but noted that he and his coinvestigators had followed up on beta-blocker continuation at the three-year mark and found that just 10% had stopped taking their medication. "Even when we exclude these patients, the results are consistent with the overall analysis," he said.

Also commenting on the study, Dr Christopher Granger (Duke University, Durham, NC) called the study "confounded." Pointing to one of the earlier slides in Puymirat's presentation, Granger noted that patients who stopped taking beta-blockers were also significantly less likely to be taking other secondary-prevention medications, including statins, clopidogrel, and ACE inhibitors.

"We know from clinical trials that people who stop placebo have much worse outcomes than people who continue placebo: there's a healthy-user bias and all kinds of confounding with unmeasured variables that can never be fully adjusted, and those are important caveats."

Puymirat agreed, stressing that "these are observational data. . . . Other studies and especially randomized controlled trials are necessary to confirm these data," he said.

And therein lies the problem, said session comoderator Dr Udo Sechtem (Robert-Bosch-Krankenhaus, Stuttgart, Germany). "It just [goes to] show that with established medications like beta-blockers, where industry has no interest in running randomized controlled trials any more, it is the government, the health authorities, who need to step in and . . . address really important questions. This may be one of those important questions: should beta-blockers be given to post-MI patients who have no HF? This needs to be addressed by a randomized controlled trial, sponsored by the EU or the [National Heart, Lung, and Blood Institute] NHLBI, but I'm afraid the governments are not aware of this yet."

Puymirat disclosed fees for lectures and/or consulting from AstraZeneca, Bayer, MSD, Eli-Lilly, and Servier.

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