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TalkingNutrition

Providing perspectives on recent research into vitamins and nutritionals

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Surgery, Atrial Fibrillation, Anticoagulant Drugs and Omega-3 Fatty Acids

By Michael McBurney

Undoubtedly nutrition is important to our health. Too little of an essential vitamin or mineral can lead to deficiency. Too much may be hazardous although there is a very wide range of safety. Researchers often rely upon meta-analyses of multiple randomized controlled trials (RCTs) with their larger number of participants to guide standards of care. These large studies often make headlines. Dietary supplement are often compared to drugs. Today’s question: Why do people accept drugs and reject the benefits of omega-3 fatty acid supplementation?

Omega-3 fatty acids are known to support cardiovascular health. There are many aspects to heart health: heart attacks (myocardial infarction), heart arrhythmias, atrial fibrillations, stroke volume, etc. Omega-3 fatty acid supplementation reduces platelet aggregation (McKewen et al, 2013). This supports healthy blood flow and may affect the risk of thrombotic events.  Let’s focus on the occurrence of atrial fibrillation (AF) in patients who are going to have heart surgery.

In 2005, Calo and colleagues studied the effect of omega-3 supplementation (2g/d) on AF incidence during first 5 days postoperatively. They reported a 54% reduced incidence in AF.  Since then the literature on omega-3 fatty acids and AF has been mixed.   Costanzo and colleagues conducted a meta-analysis and reported a 16% reduction in postoperative AF by preoperative omega-3 supplementation. In their recent meta-analysis, Mozaffarian and colleagues did not find convincing evidence that short-term fish oil use appreciably reduced AF but they report considerable variability in trials. Subgroup analyses showed a potential benefits of omega-3 fatty acids in reducing risk of major bleeding (Odds Ratio, OR = 0.76).  Now let’s look at today’s main citation.

Dabigatran and warfarin are oral anticoagulants often prescribed during AF ablation to prevent thrombotic events. The efficacy studies for anticoagulant drug use in AF is typically compared between interventions, i.e. dabigatran or apixaban  vs warfarin. There isn’t a control group. In their meta-analysis of 5,513 patients undergoing surgery, Sardar and colleagues compared outcomes in those treated with dabigatran vs warfarin. In terms of risk of thromboembolic complications, they report an OR of 3.94 for dabigatran compared to warfarin.

With aging, there is increased risk of stroke associated with atrial fibrillation. It is prudent to take steps to decrease platelet aggregation and reduce the risk of thrombotic events. For this reason, doctors often prescribe anticoagulant drug, especially pre-operatively. With respect to omega-3 supplementation in patients with AF, surgeons should consider the words of Mozafarian et al (2013) “Overall, the findings indicate that perioperative fish oil use was well tolerated and safe, suggesting little need for its discontinuation in patients who are taking fish oil before cardiac surgery.

Main Citation

Sardar P, Nairooz R, Chatterjee S, Wettersley J, Ghosh J, Arrow WS. Meta-analysis of risk of stroke or transient ischemic attack with dabigatran for atrial fibrillation ablation. 2014 Am J Cardiol doi: 10.1016/j.amjcarrd.2013.12.027

Citations

Calo L, Bianconi L, Colivicchi F, Lamberti F, Loriccio ML, de Ruvo E, Meo A, Pandozi C, Staibano M, Santini M. N-3 fatty acids for the prevention of atrial fibrillation after coronary artery bypass surgery. 2005 J Am Coll Cardiol doi:10.1016/j.jacc.2005.02.079

McEwen BJ, Morel-Kopp M-C, Chen W, Tofler GH, Ward CM. Effects of omega-3 polyunsaturated fatty acids on platelet function in healthy subjects and subjects with cardiovascular disease. 2013 Semin Thromb Hemost doi: 10.0155/s-0032-133309

Costanzo S, di Niro V, Castelnuovo A, Gianfagna F, Donati MB, De Gaetano G, Lacoviello L. Prevention of postoperative atrial fibrillation in open heart surgery by preoperative supplementation of n-3 polyunsaturated fatty acids: An updated meta-analysis. 2013 J Thorac Cardiov Surg doi: 10.1016/j.jtcvs.2013.03.015


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