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ARBs Do Not Cause Post-op Atrial Fibrillation

Reuters Health • The Doctor's Channel Daily Newscast

NEW YORK (Reuters Health) – The use of angiotensin blocking therapy before cardiac surgery is not associated with postoperative atrial fibrillation (AF), researchers report in the August American Heart Journal.

“[These drugs] seem to be safe, if held prior to surgery,” Dr. Florian Rader from Case Western Reserve University, Cleveland, Ohio told Reuters Health in an email. “I suspect that studies which have reported an increased event rate of AF in patients on angiotensin blocking therapy have not adjusted for confounding to the extent that we did.”

Dr. Rader and colleagues examined the association of preoperative use of angiotensin blocking drug therapy with postoperative atrial fibrillation in 10,552 patients (4795 with angiotensin blocking therapy, 5757 without) who underwent coronary artery bypass graft surgery with or without valve surgery. Any preoperative angiotensin blocking drug was withdrawn before surgery.

Atrial fibrillation after cardiac surgery affects about 35% of patients, the investigators say.

Angiotensin blocking drug therapy was associated with a 13% increased risk of postoperative AF in univariate analysis, but there was no such association when a subset of 6744 propensity score matched patients was analyzed.

Moreover, multivariable logistic regression analysis adjusted by propensity score confirmed the absence of an association between angiotensin blocking drug therapy and postoperative AF.

There were no procedural subgroups that benefited from preoperative use of angiotensin blocking therapy, and results were similar after patients with prior episodes of AF were excluded from the analysis.

Although unadjusted analysis suggested an association between preoperative angiotensin blocking drug therapy and postoperative ventricular tachycardia, ventricular fibrillation, and cardiac arrest, propensity matched analyses eliminated these associations.

“From a physiologic point of view, an increased risk of AF in these patients does not make a whole lot of sense,” Dr. Rader said. “Withdrawal could be an explanation, but evidence to support this theory is lacking.”

“For prevention of postoperative AF, we may want to focus on different drug classes than ACE-inhibitors and ARBs,” Dr. Rader concluded.

To address the appropriate preoperative use of angiotensin blocking drug therapy, Dr. Rader added, “We really need a randomized trial; at the moment such a trial is not planned.”

Reference:

Preoperative angiotensin-blocking drug therapy is not associated with atrial fibrillation after cardiac surgery