Atherosclerosis 184 (2006) 237–246 Review Effects of omega-3 fatty acids on coronary restenosis, intima–media thickness, and exercise tolerance: A systematic review Ethan M. Balk a,∗ , Alice H. Lichtenstein b , Mei Chung a , Bruce Kupelnick a , Priscilla Chew a , Joseph Lau a a Tufts-New England Medical Center Evidence-based Practice Center, Institute for Clinical Research and Health Policy Studies, 750 Washington Street, NEMC #63, Boston, MA 02111, USA b Cardiovascular Nutrition Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging, Tufts University, 711 Washington Street, Boston, MA 02111, USA Received 11 November 2004; received in revised form 31 May 2005; accepted 7 June 2005 Available online 9 August 2005 Abstract Greater omega-3 fatty acid consumption is associated with reduced cardiovascular disease risk. Though the mechanisms of their effect are unclear, they may involve lesion formation and heart function. We conducted a systematic review of the clinical literature on the effect of omega-3 fatty acids on measures of vascular structure and function. We included studies that assessed fish and plant sources of omega-3 fatty acids on coronary artery restenosis after angioplasty, carotid IMT, and exercise capacity. Compared to placebo, the summary risk ratio of coronary artery restenosis with fish oil is 0.87 (95% CI 0.73, 1.05) across 12 randomized controlled trials. Two prospective studies reported increased carotid IMT, whereas two cross-sectional studies reported a reduction of IMT, with fish, fish oil or ALA consumption. Three randomized trials and three uncontrolled studies reported small non-significant improvements in exercise capacity with fish oil. Overall, little or no effect of fish oil was found for a variety of markers of cardiovascular disease risk. There are insufficient studies to draw conclusions about the effect of ALA. The dearth of long term data on fish consumption or omega-3 fatty acid supplementation on measures of cardiovascular disease risk severely limits our ability to draw definitive conclusions at this time. © 2005 Published by Elsevier Ireland Ltd. Keywords: Systematic review; Omega-3 fatty acids; Fish; Eicosapentaenoic acid; Docosahexaenoic acid; Alpha linolenic acid; Restenosis; Intima–media thickness; Exercise tolerance testing Contents 1. Background ......................................................................................................... 238 2. Methods ............................................................................................................. 238 2.1. Literature search ............................................................................................... 238 2.2. Definitions of omega-3 fatty acids ............................................................................... 238 2.3. Eligibility criteria .............................................................................................. 238 2.4. Quantitative analysis ........................................................................................... 239 2.5. Quality and applicability assessment ............................................................................. 239 3. Results .............................................................................................................. 239 3.1. Restenosis after coronary angioplasty (by angiography) ............................................................ 239 Abbreviations: ALA, alpha linolenic acid (18:3 n - 3); CI, confidence interval; DHA, docosahexaenoic acid (22:6 n - 3); EPA, eicosapentaenoic acid (20:5 n - 3); IMT, intima–media thickness; PTCA, percutaneous transluminal coronary angioplasty; RR, relative risk ∗ Corresponding author. Tel.: +1 617 636 3282; fax: +1 617 636 8628. E-mail address: ebalk@tufts-nemc.org (E.M. Balk). 0021-9150/$ – see front matter © 2005 Published by Elsevier Ireland Ltd. doi:10.1016/j.atherosclerosis.2005.06.042