Pre-op oral amiodarone shortens LOS - study
Well-tolerated, drug reduces post-op atrial fib
A study late last year assessed the benefits of preoperative amiodarone as prophylaxis against atrial fibrillation (AF) following open-heart operations.1 Post-op AF is one of the most frequent complications after cardiovascular surgery - it occurs in 40% of patients. The condition usually doesn't have long-term sequelae, but can result in thromboembolic events, hemodynamic deterioration, and increased costs and lengths of stay (LOS) due to attempts at cardioversion and prolonged monitoring. It usually occurs 24 to 60 hours after surgery with a peak incidence on the second post-op day. (See related article on discharging AF patients, p. 129.)
For the study, more than 100 patients scheduled for elective cardiac surgery were given either oral amiodarone - 600 mg/day for seven days, then 22 mg/day until discharge - or placebo for a minimum of seven days before their operations. Post-op AF occurred in a quarter of the patients receiving amiodarone and in half of the placebo group. Complications occurred in a slightly higher percentage of the amiodarone-treated patients than the others. Patients in the amiodarone group were hospitalized for significantly fewer days than were patients in the placebo group, and their total hospitalization costs were significantly lower: $18,375+/-$13,863 vs. $26,491+/-$23,837.
For another amiodarone trial, the ARCH (Amiodarone Reduces CABG Hospitalization) study, reported at the American College of Cardiology meeting in Atlanta, in late March, investigators evaluated 300 patients undergoing common open-heart operations such as CABG or valve surgery at one center and randomized them to IV amiodarone for two days or placebo. Patients with prior AF or antiarrhythmia therapy, digoxin or calcium blocker use, or hemodynamic compromise - shock, balloon pump - were excluded, but beta-blocker therapy was continued. The incidence of postoperative AF was reduced in the amiodarone group 35% vs. 42%. Hospital stays were not significantly different in the two groups - 7.5 vs. 8.2 days - but were shorter in those developing AF who were on amiodarone - 7.1 vs. 9.1 days. The investigators conclude that two days of IV amiodarone prophylaxis post common cardiac surgery procedures in stable patients reduces the incidence of AF and shortens hospital stays in those who develop the condition.
"Although significant, the reduction in atrial fibrillation and hospital stays for those in fibrillation is not impressive enough to recommend this approach routinely," says Michael H. Crawford, MD, chief of cardiology at the University of New Mexico in Albuquerque. "It may be worth considering in those at high risk of developing atrial fibrillation, such as those with a prior history or large left atrium or those in whom atrial fibrillation would be dangerous, such as patients with left ventricular hypertrophy."
Rhonda Liberto, PharmD, clinical pharmacist in cardiac and vascular training at Sentara Norfolk (VA) General Hospital, says, "There is an increase in the risk of pulmonary toxicity with high concentrations of oxygen, so therefore if somebody's going to be intubated and on a ventilator with high percents of oxygen use, you may see an increased risk in pulmonary adverse effects."
Reference
1. Daoud EG, Strickberger SA, Man KC, et al. Preoperative amiodarone as prophylaxis against atrial fibrillation after heart surgery. N Engl J Med 1997;337: 1785-1791.
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