***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
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    Input: Study Design Retrospective case-control study . Objective The purpose of this study was to assess whether preoperative use of fish oil supplements increases intraoperative blood loss and postoperative bleeding complications during lumbar decompression surgery . Summary of Background Data Omega-3 fatty acids ( n-3FA ) are widely used as over-the-counter supplements because of well-established cardioprotective and antiplatelet effects . Concern over bleeding associated with changes in platelet function have led to prohibiting these supplements before surgery although there are no clinical data available in the spinal surgery literature to guide such recommendations . Methods Ninety-five consecutive patients who underwent posterior-only lumbar decompression by a single surgeon were included . Patients who had taken n-3FA  within 14 days of surgery were compared with a control group with respect to demographics , preoperative use of other anticoagulants , surgical time , estimated intraoperative blood loss , and postoperative complications including reoperation for epidural hematoma and wound infection . Power analysis suggested 11 patients taking n-3FA were necessary to reach statistical significance based on pilot data . Results Sixteen patients took n-3FA supplements , stopping an average of 2.3 days before surgery . These were no significant between-group differences in demographic parameters , use of other anticoagulants , and surgical time . Estimated blood loss was higher in the control group but the difference was not significant ( 154 vs. 138 mL , P=0.53 ) . There were 2 complications related to bleeding in the control group and none in the n-3FA group . Conclusions We found no increase in intraoperative blood loss or postoperative bleeding complications associated with preoperative use of n-3FA supplements up to an average of 2.3 days before surgery . Although further studies are necessary before this finding can be generalized to other types of spinal surgery , our study corroborates findings from investigations in other surgical specialties that suggest preoperative n-3FA is not associated with increased risk of intraoperative and postoperative bleeding To examine the potential role of fish oil supplementation in the prevention of  restenosis after coronary angioplasty ( PTCA ) , a r and omised double-blind trial was conducted in 204 patients . The treatment group received 6 g/day of n-3 fatty acids , beginning 5.4 ( SD 3.2 ) days before PTCA , and continuing for 6 months ; the control group received olive oil placebo .  Compliance was assessed by pill count and plasma levels of eicosapentaenoic acid ( EPA ) . Restenosis was identified by symptoms and exercise testing and confirmed by angiography . PTCA was successful in 186 patients ( 93 % ) . The incidence of angiographic restenosis was 34 % in the fish oil group and 23 % in the control group ( relative risk 1.7 , 95 % CI 0.9 - 3.4 ) . The lack of benefit of fish oil was not influenced by length of pretreatment , compliance with study medication , or the concentrations of plasma EPA achieved Platelet/vessel wall interactions following injury play an important role not only in hemostasis , but also in acute thrombosis and subsequent atherogenesis1 . In cardiac surgery , particularly coronary artery bypass grafting ( CABG ) , these platelet/vessel wall interactions are thought to contribute to acute thrombus formation and chronic vessel wall hyperplasia and subsequent vessel wall restenosis . To date , the most common approach to attenuate these responses is the short-term administration of high dose heparin during cardiac surgery ( to inhibit thrombin activity ) and the long-term administration of low dose aspirin to inhibit platelet thromboxane A2 ( TxA2 ) generation ( which is thought to promote platelet aggregation and vasoconstriction 2 . Despite these approaches , acute thrombosis and chronic restenosis remain significant problems in 5 – 40 % of these patients within 6–12 months post surgery BACKGROUND Epidemiological and clinical evidence suggests that an increased intake of long-chain n-3 fatty acids protects against mortality from coronary artery disease . We aim ed to test the hypothesis that long-term use of eicosapentaenoic acid ( EPA ) is effective for prevention of major coronary events in hypercholesterolaemic patients in Japan who consume a large amount of fish . METHODS 18 645 patients with a total cholesterol of 6.5 mmol/L or greater were recruited from local physicians throughout Japan between 1996 and 1999 . Patients were r and omly assigned to receive either 1800 mg of EPA daily with statin ( EPA group ; n=9326 ) or statin only ( controls ; n=9319 ) with a 5-year follow-up . The primary endpoint was any major coronary event , including sudden cardiac death , fatal and non-fatal myocardial infa rct ion , and other non-fatal events including unstable angina pectoris , angioplasty , stenting , or coronary artery bypass grafting . Analysis was by intention-to-treat . The study was registered at Clinical Trials.gov , number NCT00231738 . FINDINGS At mean follow-up of 4.6 years , we detected the primary endpoint in 262 ( 2.8 % ) patients in the EPA group and 324 ( 3.5 % ) in controls-a 19 % relative reduction in major coronary events ( p=0.011 ) . Post-treatment LDL cholesterol concentrations decreased 25 % , from 4.7 mmol/L in both groups . Serum LDL cholesterol was not a significant factor in a reduction of risk for major coronary events . Unstable angina and non-fatal coronary events were also significantly reduced in the EPA group . Sudden cardiac death and coronary death did not differ between groups . In patients with a history of coronary artery disease who were given EPA treatment , major coronary events were reduced by 19 % ( secondary prevention subgroup : 158 [ 8.7 % ] in the EPA group vs 197 [ 10.7 % ] in the control group ; p=0.048 ) . In patients with no history of coronary artery disease , EPA treatment reduced major coronary events by 18 % , but this finding was not significant ( 104 [ 1.4 % ] in the EPA group vs 127 [ 1.7 % ] in the control group ; p=0.132 ) . INTERPRETATION EPA is a promising treatment for prevention of major coronary events , and especially non-fatal coronary events , in Japanese hypercholesterolaemic patients Objective The effects of ω-3 fatty acids on endothelial function , fibrinolysis and platelet function are uncertain . We investigated the effects of ω-3 fatty acid supplementation on endothelial vasomotor function , endogenous fibrinolysis , and platelet and monocyte activation in healthy cigarette smokers ; a group at increased risk of myocardial infa rct ion . Design , setting , participants Twenty cigarette smokers were recruited into a r and omised , double-blind , placebo-controlled , crossover trial of ω-3 fatty acid supplementation . Intervention ω-3 fatty acid supplements ( 2 g/day ) or placebo for a 6-week period . Main outcome measures Peripheral blood was taken for analysis of platelet and monocyte activation , and forearm blood flow ( FBF ) was assessed in a subset of 12 smokers during intrabrachial infusions of acetylcholine , substance P and sodium nitroprusside . Stimulated plasma tissue plasminogen activator ( t-PA ) concentrations were measured during substance P infusion . Results All vasodilators caused dose-dependent increases in FBF ( p<0.0001 ) . Compared with placebo , ω-3 fatty acid supplementation led to greater endothelium-dependent vasodilatation with acetylcholine and substance P ( p=0.0032 and p=0.056 ) . Substance P caused a dose-dependent increase in plasma t-PA concentrations ( p<0.0001 ) that was greater after ω-3 fatty acid supplementation compared with placebo ( 8.8±2.3 IU ml−1 vs 3.6±1.1 IU ml−1 ; p=0.029 ) . ω-3 fatty acids did not affect platelet-monocyte aggregation , platelet P-selectin or CD40L , or monocyte CD40 . Conclusions We have demonstrated for the first time that ω-3 fatty acids augment acute endothelial t-PA release and improve endothelial vasomotor function in cigarette smokers . Improved endogenous fibrinolysis and endothelial function may represent important mechanisms through which ω-3 fatty acids confer potential cardiovascular benefits Free radical damage has long been believed to be a risk factor for the degenerative processes which accompany aging ( 1 ) . Reactive oxygen species initiate a wide variety of oxidative reactions , including peroxidation of lipids , and contribute to the process of aging , as well as age-related pathology such as cardiovascular diseases . Moreover , platelet activation is believed to play a role in the development of such diseases , and an increased reactivity to most aggregating agents of platelets was reported in elderly people . An exacerbated arachidonic acid metabolism was also found , as well as a significant lowered vitamin E and glutathione peroxidase activity ( 2 ) . On the other h and , epidemiologic studies suggest that consumption of n-3 polyunsaturated fatty acids ( PUFA ) may protect against thromboembolic diseases ( 3 ) . Especially , eicosapentaenoic ( EPA ) and docosahexaenoic ( DHA ) acids could be responsible for such beneficial effects . However , an increase of n-3 PUFA in membrane phospholipids may enhance membrane susceptibility to lipid peroxidation and thus counteract these beneficial effects . In this context , the purpose of the present study was to investigate the effects of low intake of n-3 PUFA on platelets from elderly people . In a r and omized double-blind study , 20 healthy subjects ( 70 - 83 yr ) were carefully selected . Ten subjects ingested one capsule of 600 mg ( corresponding to 150 mg DHA and 30 mg EPA ) of RO-PUFA triglyceride ( Roche ) per day and 10 others ingested one capsule of 600 mg sunflower oil as placebo during 42 d. RO-PUFA and placebo capsules contained 1900 and 600 ppm of o~-tocopherol , respectively , representing at most 5 % of the recommended daily allowance . Blood anticoagulated with ACD ( acid/citrate/dextrose ) was drawn before ( day 0 ) and after oil supplementation ( day 42 ) . Platelets were isolated and several biochemical parameters were measured . The low intake of n-3 PUFA modestly affected platelet aggregation . Indeed , a tendency to decrease the percentage of thrombin-induced aggregation in RO-PUFA group was observed . Although no modification in the composition of platelet total phospholipids appeared after the oil intake , a slight but A study was performed to explore the effects of supplemental intake of various marine oils known to be part of the Eskimo diet . Healthy men and women ( 134 ) were r and omly selected to consume 15 mL/d of oil from blubber of seal , cod liver , seal/cod liver , blubber of Minke whale , or no oil for ten weeks . Total cholesterol was unchanged in the oil groups , whereas high density lipoprotein cholesterol increased 7 % in the seal/cod liver oil ( CLO ) group ( P<0.05 ) and 11 % in the whale oil group ( P<0.005 ) . Triacylglycerol was significantly reduced in the CLO group only . The concentration of prothrombin fragment 1 + 2 was reduced 25 % ( P<0.05 ) after whale oil supplementation . No change in fibrinogen or factor VIIc was detected . Tumor necrosis factor generation in lipopolysaccharide (LPS)-stimulated blood was 30 % reduced after whale oil ( P<0.05 ) , but was unaffected by intake of seal or CLO . The LPS-induced tissue factor activity in monocytes was reduced to a significant degree only in the seal/CLO group ( 34 % ) and whale oil group ( 35 % ) ( P<0.05 ) . The most dramatic change in thromboxane B2 in LPS-stimulated blood was seen after whale oil intake with 44 % reduction ( P<0.01 ) . Supplementation of a regular diet with a combination of seal oil and CLO and especially with whale oil seems to have beneficial effects on several products thought to be associated with cardiovascular and thrombotic diseases Fish are a rich source of eicosapentaenoic acid ( EPA ) and docosahexaenoic acid ( DHA ) , two long-chain polyunsaturated n-3 fatty acids ( LC n-3 PUFA ) with cardiovascular benefits . A related but less-investigated LC n-3 PUFA , docosapentaenoic acid ( DPA ) , is more common in seal oil and pasture-fed red meats . This study compared indicators of platelet function and plasma lipids in healthy volunteers given supplements containing these different fatty acids ( FA ) for 14 days . Subjects , r and omised into three groups of ten , consumed capsules of tuna oil ( 210 mg EPA , 30 mg DPA , 810 mg DHA ) , seal oil ( 340 mg EPA , 
    Output:
    
Overall , fish oil supplements reduced platelet aggregation in healthy subjects .
Fish oil exposure in surgical patients did not increase bleeding or blood transfusions either during or after surgery .
Fish oil supplements reduced platelet aggregation in healthy subjects .
This biochemical effect was not reflected in increased bleeding risk during or after surgery evaluated in r and omised controlled trials .
Consequently , this systematic review does not support the need for discontinuation of fish oil supplements prior to surgery or other invasive procedures